JP2011109750A - Current controller for electric load - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a current controller which improves the accuracy of current control by coping with solid dispersions and variations of parts and changes in environmental temperature. <P>SOLUTION: An electric load 107 is supplied with electricity via a switching element 121 and a current detecting resistor 126 from a driving power source 101, and a voltage across the current detecting resistor 126 is amplified by an amplifying circuit 150, and a monitoring voltage Ef roughly proportional to the load current is generated and fed back negatively into a comparative difference integrating circuit 140. A microprocessor 111A computes an estimated monitoring voltage Es corresponding to the target load current Is and inputs it into a comparative deviation integrating circuit 140 as a target set voltage, thus the duty of the switching element 121 is controlled according to the output signal of the comparative deviation integrating circuit 140. The current proportion coefficient and the error component of the monitoring voltage Ef are calibrated using an ammeter for calibration according to the environmental temperature and the target load current, and the calibrating operation is executed by the microprocessor 111A. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a current control device for an inductive electric load used, for example, in an in-vehicle electronic control device, and more particularly to a current control device for an electric load that is negatively feedback controlled so that a target set current and a detected load current coincide with each other. is there.

  There are various electric load current control devices that control the switching energization rate of the switching element connected between the drive power supply and the electric load so that the energization target current and the detection current by the current detection resistor coincide with each other. For example, there are applications such as current control of a linear solenoid that requires a wide range of variable constant current and current control of a solenoid valve for fuel injection that keeps the valve open at a constant low current after rapid opening. is there.

In these current control devices, the microprocessor generates a target current command and also uses an internal feedback control method in which the microprocessor generates a switching drive command that responds to a deviation from the detected current, and the microprocessor simply outputs the target current command. There is an external feedback control type that generates an open / close drive command in response to a deviation between a target current and a detected current by a deviation integrating circuit provided outside the microprocessor.
For example, those described in Patent Document 1 and Patent Document 3 described later are internal feedback control systems, those described in Patent Document 2 are external feedback control systems, and those in the external feedback control system reduce the control burden on the microprocessor. However, the hardware configuration is complicated.

According to Patent Document 1 or Patent Document 2, the monitoring voltage obtained by amplifying the voltage across the current detection resistor connected in series to the electric load includes a current proportional component and an error component, and the error component is a voltage proportional component. It is divided into offset components, and the current proportionality factor of the current proportional component, the voltage proportionality factor of the voltage proportional component and the offset component are calculated with good procedures using a calibration ammeter and voltmeter, and these calibration constants are used. A means for performing highly accurate current control is disclosed.
According to Patent Document 3, the temperature detection means for detecting the ambient temperature (environment temperature) in the current control device, and the drive current (load current) detected by the current detection means based on the detected ambient temperature. A linear solenoid control device having a temperature correction means for correction is disclosed.

JP 2006-238668 (Summary column, FIG. 1) JP 2006-100509 A (summary column, FIG. 1) JP 10-225179 A (summary column, FIG. 1)

  Since the current control device according to Patent Document 1 or Patent Document 2 is calibrated for each factor of current detection error, it is possible to perform current control with high accuracy against variations in individual parts and power supply voltage. It is possible. However, there are a problem that the control error corresponding to the environmental temperature change is not corrected and the linearity error is not corrected for the target current.

  On the other hand, the current control device according to Patent Document 3 is not calibrated with an actual load current using a high-precision ammeter, the resistance value of the current detection resistor is constant, and there is no variation in solids. This control method is established on the assumption that the resistance value is as accurate as the design value. Therefore, even if correction is performed based on the ambient temperature, the ambient temperature measures the environmental temperature inside the current control device, and does not detect the temperature of the current detection resistor itself. The resistance value of the current detection resistor fluctuates due to power consumption proportional to the square of the current, and there is a problem that accurate current control cannot be performed.

  A first object of the present invention is to provide a current control device for an external feedback type or an internal feedback type electric load capable of performing highly accurate current control in response to individual variation of parts and various environmental changes. It is to be.

  A second object of the present invention is to reduce the occurrence of an error in the linearity of the actual load current corresponding to the target load current based on the resistance value variation due to self-heating of the current detection resistor. It is to provide a current control device of a feedback type or an internal feedback type electric load.

  According to a first aspect of the present invention, there is provided a current control device for an electric load, which is fed from a driving power source, a power feeding circuit unit in which a switching element, a current detection resistor, and an electric load are connected in series, and a target load for the electric load. A control circuit unit that controls an ON / OFF ratio of the switching element so that a current and a detected load current by the current detection resistor coincide with each other, wherein the control circuit unit includes: Further, a nonvolatile program memory including a control program serving as a control constant calibration unit and a conversion setting unit, a microprocessor having a nonvolatile data memory, and amplifies the voltage across the current detection resistor connected in series to the electrical load And a monitoring voltage generated mainly including a current proportional component proportional to the load current for the electric load and including an error component An amplification circuit unit that inputs to the processor, a temperature detection circuit that generates a measurement voltage corresponding to the internal environment temperature of the current control device, and inputs the measurement voltage to the microprocessor, and an estimated monitoring voltage that corresponds to the target load current And a feedback control circuit that controls the energization of the switching element using the monitoring voltage as a feedback value, and the control constant calibration means has an internal environment temperature of one or both of a normal temperature environment and a high temperature environment. In the actual use internal environment detected by the temperature detection circuit by separately calculating a current proportionality factor and an error component related to a current proportional component of the monitoring voltage based on an actual load current from an external calibration ammeter A calculation formula or data table for interpolating the temperature, the current proportionality coefficient corresponding to the variable target load current, and the error component, or a data table is stored in the nonvolatile data memory. The conversion setting means, when assuming that the same current as the target load current determined by the microprocessor flows to the electric load, the current proportional coefficient corresponding to the actual use internal environmental temperature and The estimated monitoring voltage is calculated based on the error component.

  According to a second aspect of the present invention, there is provided a current control device for an electric load, wherein a power supply is supplied from a driving power source, and a power supply circuit unit in which an opening / closing element, a current detection resistor, and an electric load are connected in series, A control circuit unit that controls an ON / OFF ratio of the switching element so that a current and a detected load current by the current detection resistor coincide with each other, wherein the control circuit unit includes: Further, a nonvolatile program memory including a control program serving as a control constant calibration unit, a conversion estimation unit, and a feedback control unit, a microprocessor including a nonvolatile data memory, and a current detection resistor connected in series to the electrical load A monitoring voltage generated by amplifying the voltage at both ends, and mainly including a current proportional component proportional to the load current for the electric load, including an error component An amplification circuit unit that inputs to the microprocessor; and a temperature detection circuit that generates a measurement voltage corresponding to an internal environment temperature of the current control device and inputs the measurement voltage to the microprocessor, and the control constant calibration The means includes a current proportionality factor and an error component relating to the current proportional component of the monitoring voltage based on an actual load current by an externally installed ammeter for calibration at one or both of the normal temperature environment and the high temperature environment. A calculation formula or data table for performing interpolation calculation of the actual use internal environment temperature detected by the temperature detection circuit, the current proportionality coefficient corresponding to the variable target load current, and the error component is calculated as the non-volatile data. The conversion estimating means stores an estimated negative voltage based on a current proportional coefficient corresponding to the monitored voltage and the actual internal environment temperature. When it is assumed that the same current as the target load current determined by the microprocessor is flowing in the electric load, an estimated monitoring voltage corresponding to the actual use internal environment temperature is calculated, and the feedback The control means controls the energization duty of the switching element using the target load current as a control target value and the estimated load current as a feedback value, or uses the estimated monitoring voltage as a control target value and the monitoring voltage as a feedback value. It controls the energization duty of the switching element.

  According to a first aspect of the present invention, there is provided a current control device for an electric load comprising a comparison deviation integrating circuit for negative feedback control and a current detection resistor outside a microprocessor for outputting a setting signal proportional to a target load current. A calibration operation is performed to correct the variation in the solid state of the current control characteristics and the temperature variation using an external calibration ammeter at the product shipment stage, and the calibration operation is performed in a normal temperature environment and a high temperature environment. Implemented in at least one of them, a calibration constant is obtained based on the error factor due to fluctuations in the solid variation of the control element, characteristic fluctuations due to temperature, and fluctuations in the resistance value of the current detection resistor due to self-heating.

  Therefore, calibration of detection error is performed for each cause of detection error, and it is calibrated taking temperature fluctuation factors into account, so the calibration constants can be used appropriately during operation of the current control device in various operating environments. Thus, highly accurate current control can be performed, and calibration operation can be easily performed with a simple external calibration facility.

  According to a second aspect of the present invention, an electric load current control device sets a target load current, receives a detection signal proportional to the load current, and generates a pulse output having a duty corresponding to the deviation signal voltage. A calibration operation that includes a microprocessor and corrects for variations in current control characteristics and fluctuations in temperature using an external calibration ammeter at the product shipment stage. Performed in at least one of a normal temperature environment and a high temperature environment to obtain calibration constants based on error factors due to fluctuations in solids of control elements, characteristic fluctuations due to temperature, and fluctuations in resistance of current detection resistors due to self-heating. ing.

  Therefore, calibration of detection error is performed for each cause of detection error, and it is calibrated taking temperature fluctuation factors into account, so the calibration constants can be used appropriately during operation of the current control device in various operating environments. Thus, highly accurate current control can be performed, and calibration operation can be easily performed with a simple external calibration facility.

1 is an overall circuit diagram showing a first embodiment of the present invention. It is an operation | movement flowchart for the calibration driving | operation by 1st Embodiment of this invention. 3 is an operation flowchart for calibration operation according to the first embodiment of the present invention. It is an operation | movement flowchart for the calibration driving | operation by 1st Embodiment of this invention. 3 is an operation flowchart for calibration operation according to the first embodiment of the present invention. 3 is an operation flowchart for calibration operation according to the first embodiment of the present invention. 3 is an operation flowchart for calibration operation according to the first embodiment of the present invention. It is the figure which showed the framework of the data table of the calibration constant by 1st Embodiment of this invention. It is operation | movement explanatory drawing of the normal control routine by 1st Embodiment of this invention. It is operation | movement explanatory drawing of the interruption control routine by 1st Embodiment of this invention. It is a whole circuit diagram which shows 2nd Embodiment of this invention. It is an operation | movement flowchart for the calibration driving | operation by 2nd Embodiment of this invention. It is an operation | movement flowchart for the calibration driving | operation by 2nd Embodiment of this invention. It is an operation | movement flowchart for the calibration driving | operation by 2nd Embodiment of this invention. It is an operation | movement flowchart for the calibration driving | operation by 2nd Embodiment of this invention. It is an operation | movement flowchart for the calibration driving | operation by 2nd Embodiment of this invention. It is an operation | movement flowchart for the calibration driving | operation by 2nd Embodiment of this invention. FIG. 10 is a calibration constant data table and current detection characteristic diagram according to the second embodiment of the present invention. It is operation | movement explanatory drawing of the normal control routine by 2nd Embodiment of this invention.

  Preferred embodiments of a current control device for an electric load according to the present invention will be described below with reference to the accompanying drawings. Note that the present invention is not limited to these embodiments.

Embodiment 1 FIG.
FIG. 1 is an overall circuit diagram showing an electric load current control apparatus according to a first embodiment of the present invention. In FIG. 1, a current control device 100 </ b> A is centered on a microprocessor 111 </ b> A fed from a control power supply unit 110, and a switching circuit unit 120, a target current setting circuit 130, a comparison deviation integration circuit 140 constituting a feedback control circuit, and an amplification circuit Part 150, smoothing circuit 160, temperature detection circuit 170, and the like, and is housed in a sealed housing (not shown).

  First, as an external device connected to the current control device 100A, a drive power supply circuit including a drive power supply 101, a fuse 102, and a power switch 103 is connected between a power supply terminal 104P and a ground terminal 104N. An analog input group 105a, which is various analog sensors, is connected to an analog input port AIN of a microprocessor 111A described later via a connector and an interface circuit (not shown). A switch input group 105d such as a sensor switch or an operation switch is connected to a digital input port DIN of the microprocessor 111A via a connector and an interface circuit (not shown).

  An electrical load group 106 such as an actuator or a display device is connected to an output port OUT of the microprocessor 111A via a connector and an interface circuit (not shown). An electric load 107 that requires current control, such as a linear solenoid, which is one of the electric load groups 106, is supplied with power from an output terminal 108. An alarm / display 109, which is one of the electrical load groups 106 and is an abnormality notification means, is driven from an abnormality notification output DSP of the microprocessor 111A.

  In the calibration operation before product shipment, the external tool 900 is connected to the microprocessor 111A via the serial interface circuit 116, the output signal of the calibration digital ammeter 901d connected in series to the electric load 107, and the power supply terminal The output signal of the calibration digital voltmeter 902d for measuring the drive power supply voltage Vb of the drive power supply 101 applied to 104P and the calibration digital thermometer 903d for estimating the internal temperature of the current control device 100A are connected to the external tool 900. And supplied to the microprocessor 111A via the RAM memory 112, which will be described later.

  The temperature sensor connected to the calibration digital thermometer 903d is ideally installed in the vicinity of the temperature detection circuit 170 provided inside the current control device 100A. However, when a temperature sensor connected to the calibration digital thermometer 903d is installed near the outside of the current control device 100A, the external environment temperature vs. internal environment temperature characteristics are measured in advance based on a large number of experimental data. Based on the experimental measurement data, the internal environment temperature can be estimated from the actually measured external environment temperature, and the estimated internal environment temperature can be converted and written to the RAM memory 112. Further, when the temperature detection circuit 170 is calibrated in advance at the component level, it is not necessary to connect the calibration digital thermometer 903d, and the ambient temperature inside the current control device 100A based on a predetermined measured voltage vs. temperature characteristic. Can know.

  As an internal configuration of the current control device 100A, the control power supply unit 110 generates a stabilized control power supply voltage Vcc of, for example, DC 5V from a drive power supply voltage Vb of, for example, DC 10 to 16V, and supplies power to each part in the current control device 100A. It is supposed to be.

  The microprocessor 111A includes a RAM memory 112 for arithmetic processing, a program memory 113A such as a non-volatile flash memory that can be erased electrically and written / read, and a non-volatile memory that can be electrically written / read in units of 1 byte. A data memory 114A such as an EEPROM memory, a multi-channel AD converter 115, and a serial communication interface circuit 116 are configured to cooperate with each other.

  The switch circuit unit 120 includes, for example, a switch circuit 121 that is a PNP junction transistor, a series circuit of a drive resistor 122 connected to the base circuit of the switch element 121 and an NPN transistor 123, and a base / emitter of the switch element 121. The switch is composed of a first stable resistor 124 connected between the terminals and a second stable resistor 125 connected between the base and emitter terminals of the transistor 123. One end of the switching element 121 is connected to the power supply terminal 104P. The other end is connected to the output terminal 108 via a current detection resistor 126 having a resistance value R1, and supplies power to the electric load 107.

  The commutation diode 127 is connected in parallel to the series circuit of the current detection resistor 126 and the electric load 107 which is an inductive load, and the polarity at which the attenuation current of the electric load 107 circulates when the switching element 121 is opened. It is connected to the.

  The target current setting circuit 130 includes a smoothing resistor 131 and a smoothing capacitor 132, and is a smoothing circuit that smoothes the output signal of the pulse width modulation control output PMW generated by the microprocessor 111A to obtain the target voltage Es = αVcc. ing. However, the pulse duty α is a ratio between a period during which the pulse width modulation control output PWM is at the logic level “H” and the control power supply voltage Vcc is generated as an output voltage and the pulse cycle. The target current setting circuit 130 is used as analog conversion means in place of the DA converter, and is configured such that the target voltage Es as an analog value can be obtained by one pulse train output of the microprocessor 111A. Therefore, the pulse duty α and the pulse duty γ, which is the ON / OFF control ratio of the switching element 121, do not coincide directly.

  The comparison deviation integrating circuit 140 includes a comparator 141, a first input resistor 142, a second input resistor 143, an integrating capacitor 144, and a hysteresis circuit 145. The target voltage Es is a first input resistor. 142 is connected to the non-inverting input of the comparator 141, a monitoring voltage Ef described later is connected to the inverting input of the comparator 141 via the second input resistor 143, and the integrating capacitor 144 is connected to the comparator 141. Connected between the output terminal and the inverting input terminal, an integrated voltage output with respect to the deviation value between the target voltage Es and the monitoring voltage Ef is obtained.

  The hysteresis circuit 145 drives the transistor 123 to be energized when the output voltage of the comparator 141 exceeds 3 V, for example, and the transistor 123 is energized, and the output voltage of the comparator 141 decreases to, for example, 2.5 V or less. In this case, the output logic level is returned to “L” and the transistor 123 is made non-conductive, so that the switching element 121 is reliably turned ON / OFF to constitute a positive feedback comparison circuit. Instead of the hysteresis circuit 145, the output voltage of the sawtooth wave signal generation circuit synchronized with the pulse period of the control output signal PWM of the microprocessor 111A is compared with the output voltage of the comparator 141, and the transistor 123 is determined according to the comparison result. In this case, the open / close cycle of the open / close element 121 coincides with the pulse cycle of the control output signal PWM of the microprocessor 111.

  The amplification circuit unit 150 includes a differential amplifier 151 that operates using the drive power supply voltage Vb as a power supply voltage, a third input resistor 152 having a resistance value R2, a resistance value R3, and a design theoretical value R2 = A fourth input resistor 153 which is R3, a voltage dividing resistor 154 whose resistance value is R4, a negative feedback resistor 155 whose resistance value is R5 and whose design theoretical value is R4 = R5, and whose resistance value is R6 , A second bias resistor 157 whose resistance value is R7 and whose design theoretical value is R6 = R7, and a bias power source 158 constituting a bias correction circuit.

  The third input resistor 152 is connected between the positive terminal of the current detection resistor 126 whose ground potential is V1 and the non-inverting input terminal of the differential amplifier 151 whose ground potential is E1, and the fourth input resistor 153 is Are connected between the negative terminal of the current detection resistor 126 whose ground potential is V2 and the inverting input terminal of the differential amplifier 151 whose ground potential is E2. The voltage dividing resistor 154 is connected between the non-inverting input terminal and the ground terminal of the differential amplifier 151, and the negative feedback resistor 155 is connected between the output terminal and the inverting input terminal of the differential amplifier 151 whose ground potential is E0. ing. The first bias resistor 156 is connected between the non-inverting input terminal of the differential amplifier 151 and the bias power supply 158, and the second bias resistor 157 is connected to the inverting input terminal of the differential amplifier 151 and the bias power supply 158. The bias power supply 158 is configured by a reference voltage generation circuit that operates by the input voltage of the power supply terminal 104P, and generates a bias voltage of the ground potential V0.

  The smoothing circuit 160 includes a series resistor 161, a capacitor 162, a parallel resistor 163, and a voltage limiting diode 164. The series resistor 161 is connected between the output terminal of the differential amplifier 151 and the voltage monitoring input terminal Ef of the microprocessor 111A, and the capacitor 162 is connected between the voltage monitoring input terminal Ef and the ground terminal. The parallel resistor 163 is connected in parallel to the capacitor 162, and the voltage limiting diode 164 is connected to the voltage monitoring input terminal Ef and the power supply line of the control power supply voltage Vcc by the control power supply unit 110.

  The current detection circuit 170 supplies power to the series circuit including the temperature detection element 171 and the series resistance 172 from the control power supply voltage Vcc, and inputs the divided voltage generated by the temperature detection element 171 and the series resistance 172 as the measurement voltage Vt to the microprocessor 111A. It has become.

  The output voltage E0 of the differential amplifier 151 is the voltage at the front stage of the monitoring voltage Ef input to the microprocessor 111A, and the voltage obtained by dividing the front stage voltage E0 by the series resistor 161 and the parallel resistor 163 is The monitoring voltage Ef is set. As will be described later, the pre-stage voltage E0 usually varies between E0 = 0 and Vcc (= 5V) depending on the magnitude of the load current flowing through the electric load 107. However, when an abnormality such as a short circuit accident occurs, E0 = Vb ( = 10 to 16V), and a voltage limiting diode 164 is connected to limit the voltage applied to the input terminal of the microprocessor 111A to the control power supply voltage Vcc or lower when such an abnormality occurs.

  The voltage dividing resistors 191a and 192a constituting the average voltage measuring circuit are connected in series to each other and connected in parallel to the electric load 107, and the voltage across the voltage dividing resistor 192a is passed through the series resistor 193 as the monitored average voltage Va. To the microprocessor 111A. A smoothing capacitor 194 is connected to the input terminal of the microprocessor 111A. As shown by the dotted line in the figure, voltage dividing resistors 191b and 192b constituting the power supply voltage measuring circuit are connected in series with each other to divide the drive power supply voltage Vb applied to the power supply terminal 104p to monitor the power supply. The voltage Vf can be input to the microprocessor 111A so that it can be used as reference information in the microprocessor 111A.

In the current control device for an electrical load according to the first embodiment configured as described above, assuming that the ON time of the switching element 121 is τon, the OFF time is τoff, and the switching period is τ, the energization duty γ is expressed by the following equation.
γ = τon / τ, (τ = τon + τoff) (1)

On the other hand, the standard reference resistance Rc = Rmin to Rmax is determined between the minimum resistance Rmin and the maximum resistance Rmax corresponding to the temperature change of the electric load 107, and the fluctuation range of the drive power supply voltage Vb is set to the minimum value Vmin and the maximum value Vmax. Sometimes, the standard reference current Ir is defined by Ir = Vmin / Rc, and fixed constants such as Rmin, Rc, Rmax, Vmin, and Vmax are stored and stored in advance in the nonvolatile program memory 113A or the nonvolatile data memory 114A. It is like that. In this case, if the target load current of the electric load 107 is Is and the resistance of the electric load 107 matches the standard reference resistance Rc, the energization duty γ0 when the drive power supply voltage is Vb is given by Indicated. However, the resistance value R1 of the current detection resistor 126 is R1 << Rmin, which is a negligible value.
γ0 = (Is / Ir) × (Vmin / Vb), Ir = Vmin / Rc (2)
At this time, the average voltage Vaa applied to the electric load 107 is calculated by the following equation.
Vaa = γ0 × Vb = Vmin × (Is / Ir) = Is × Rc, Rc
= Rmin to Rmax (3)

Next, when the characteristics related to the differential amplifier 151 are clarified, the following equation is established because the sum of currents flowing into the non-inverting input is substantially zero.
(V1-E1) / R2 + (0-E1) / R4 + (V0-E1) / R6 = 0
∴V1 / R2 + V0 / R6 = E1 / R246 (4)
However, R246 = 1 / (1 / R2 + 1 / R4 + 1 / R6)

Similarly, the following equation is established because the sum of the currents to flow into the inverting input of the differential amplifier 151 becomes substantially zero.
(V2-E2) / R3 + (E0-E2) / R5 + (V0-E2) / R7 = 0
∴V2 / R3 + E0 / R5 + V0 / R7 = E2 / R357 (5)
However, R357 = 1 / (1 / R3 + 1 / R5 + 1 / R7)

Since the non-inverting input potential E1 and the inverting input potential E2 of the differential amplifier 151 are substantially equal, the output potential E0 is calculated as follows using the equations (4) and (5).
R246 × (V1 / R2 + V0 / R6) = R357 × (V2 / R3 + E0 / R5 + V0 / R7)
∴ (R246 / R2) × V1− (R357 / R3) × V2 + [(R246 / R6) − (R357 / R7)] × V0 = (R357 / R5) × E0 (6)

Here, when the load current flowing through the current detection resistor 126 is Im, the following equation is established.
V2 = V1-Im × R1 (7)
Therefore, the output voltage E0 is calculated by the following equation using the equations (6) and (7).
E0 = Kd × V1 + Ki × Im + K0 (8)
However, Kd = (R246 / R2-R357 / R3) × (R5 / R357)
= (R246 / R357) x (R5 / R2)-(R5 / R3)
Ki = R1 × (R357 / R3) × (R5 / R357) = R1 × (R5 / R3)
K0 = [(R246 / R6) − (R357 / R7)] × (R5 / R357) × V0
= [(R246 / R357) x (R5 / R6)-(R5 / R7)] x V0
Since R2≈R3, R4≈R5, and R6≈R7, R246≈R357, and originally Kd≈0 and K0≈0.

  However, some resistors are intentionally designed to be inconsistent so that the output voltage of the differential amplifier 151 does not become a negative value in a minute load current state. When an intentional unbalanced circuit is configured in this way, for example, a minute resistor corresponding to the error ratio may be connected in series to the voltage dividing resistor 154.

Next, when the average value Ef of the monitoring voltage divided by the resistance value R163 of the parallel resistor 163 and the resistance value R161 of the series resistor 161 is calculated, V1 = Vb in the period τon and V1 = −Vd in the period τoff. Therefore, it is calculated by the following formula.
Ef = [∫E0dt / τ] × [R163 / (R163 + R161)]
= [(Kd × Vb + Ki × Im + K0) × τon / τ + (− Kd × Vd + Ki × I
m + K0) × τoff / τ] × [R163 / (R163 + R161)]
∴Ef = A × (Vb + Vd) × γ + B × Im + C (9)
However, A = Kd × [R163 / (R163 + R161)]
B = Ki × [R163 / (R163 + R161)]
C = K0 × [R163 / (R163 + R161)]
The error component in this case is ΔEf = A × (Vb + Vd) × γ + C.

Further, when the monitored average voltage Va is calculated using the resistance values of the voltage dividing resistors 191a and 192a as R191 and R192, V2≈Vb in the period τon and V2≈−Vd in the period τoff.
Va = [Vb × τon / τ−Vd × τoff / τ] × G
= [(Vb + Vd) × γ−Vd] × G
≒ (Vb + Vd) x γ x G (10)
However, G = R192 / (R191 + R192)
From the equations (9) and (10), the monitoring voltage Ef can also be expressed by the following equation.
Ef = D × Va + B × Im + C (11)
However, D = A / G = Kd × [R163 / (R163 + R161)] × (R191 + R192) / R192

  The calibration constants A and D in the equations (9) and (11) are the voltage proportionality factors in the error component of the monitoring voltage Ef, the calibration constant B is the current proportionality factor, and the calibration constant C is the error offset component. It has become. The error component in this case is ΔEf = D × Va + C.

Next, the operation of the electric load current control apparatus according to the first embodiment will be described.
FIG. 2 is an operation flowchart for the calibration operation in the electric load current control apparatus according to the first embodiment. The details of the process block 210a and the process block 210b in FIG. 2 are shown in FIG. 3, the details of the process block 220a and the process block 220b are shown in FIG. 4, and the details of the process block 230a and the process block 230b in FIG. It is shown. Details of the process block 240a and the process block 240b are shown in FIG. 6, and details of the process block 250a and the process block 250b are shown in FIG.

  In FIG. 2, a process 200 is a calibration operation start process of the microprocessor 111A, and a subsequent process 201 determines whether or not a calibration operation command is received from the external tool 900. If a calibration command is received, a determination of YES is made. If the calibration command is not received, the process proceeds to 202, where NO is determined, and the operation is terminated. In the operation end step 209, another control operation is performed, and the start step 200 is activated again within a predetermined time.

  When a calibration command is received in a cycle while circulating through step 200, step 201, and step 209, the process proceeds to step 202. In step 202, when the received calibration command is a calibration operation command in a high temperature environment, a determination of YES is made. The process proceeds to the process block 210a, and when it is a calibration operation command in a room temperature environment, NO is determined and the process proceeds to the process block 210b.

  In FIG. 3 showing the details of the process block 210a and the process block 210b, the subroutine start process 210 is activated when the execution of the process block 210a and the process block 210b is started, and the process of FIG. 2 follows the subroutine return process 219 described later. The process proceeds to block 220a and process block 220b.

  Step 212 is performed subsequent to step 210 to determine whether the first calibration command transmitted by the external tool 900 has been received. When the determination result is YES and it is received, the process proceeds to step 213, and when it is not received, the process returns to step 212 and waits until the first calibration command is received. In order to generate the first calibration command, a predetermined drive power supply 101 is connected to the current control device 100A in advance in step 211, and a calibration ammeter 901d, a calibration voltmeter 902d, and a calibration thermometer 903d are connected. It is supposed to be connected.

  In step 213, the measured voltage Vt of the temperature detection circuit 170 is read and stored via the multi-channel AD converter 115, and in the subsequent step 214, the external environmental temperature input from the calibration thermometer 903d via the external tool 900 is read and stored. To do.

  In the following step 215, the pulse duty α of the pulse width modulation control output PWM is set to 0, and in the subsequent step 216, the error voltage Ef0 which is the value of the monitoring voltage Ef at this time is converted into data, for example, a memory at a predetermined address in the RAM memory 112. After transferring to the register D10, the process proceeds to the return step 219.

  In FIG. 4 showing the details of the subsequent process block 220a and process block 220b, the subroutine start process 220 is activated with the start of execution of the process block 220a and process block 220b, and the subroutine return process 229 described below is followed by the subroutine return process 229 of FIG. The process block 230a and the process block 230b are shifted to.

  Step 222 is performed subsequent to step 220 and determines whether a second calibration command transmitted by the external tool 900 has been received. When the determination result is YES and it is received, the process proceeds to step 223, and when it is not received, the process returns to step 222 and waits until the second calibration command is received. In generating the second calibration command, the connection circuit to the electric load 107 is opened in a state where the predetermined drive power supply 101 is connected to the current control device 100A in advance in step 221, and the calibration voltmeter 902d, A calibration thermometer 903d is connected.

  In step 223, the pulse duty α of the pulse width modulation control output PWM is set to 100%, and in the subsequent step 224, the error voltage Ef1, which is the value of the monitoring voltage Ef at this time, is stored in, for example, data in a memory at a predetermined address in the RAM memory 112 In step 225, the value of the monitored average voltage Va at this time is transferred to the data register D21. In the subsequent step 226, the value of the drive power supply voltage Vb input from the calibration digital voltmeter 902d via the external tool 900 is transferred to the data register D22, and then the process proceeds to the return step 229.

  In FIG. 5 showing the details of the subsequent process block 230a and process block 230b, the subroutine start process 230 is activated with the start of execution of the process block 230a and process block 230b, and the subroutine return process 239 described later is followed by the process shown in FIG. The process block 240a and the process block 240b are shifted to.

  Step 232 is executed following step 230 to determine whether a third calibration command transmitted by the external tool 900 has been received. When the determination result is YES and it is received, the process proceeds to step 233, and when it is not received, the process returns to step 232 and waits until the third calibration command is received. In generating the third calibration command, the electric load 107 is connected in a state where the predetermined drive power source 101 is connected to the current control device 100A in advance in step 231, and the calibration ammeter 901d, the calibration voltmeter is connected. 902d and a calibration thermometer 903d are connected.

  In step 233, the pulse duty α of the pulse width modulation control output PWM is set to 100%, and in the subsequent step 234, the measured voltage Ef2, which is the value of the monitoring voltage Ef at this time, is stored in, for example, data in a memory at a predetermined address in the RAM memory 112. In step 235, the value of the actual load current Imm input from the calibration digital ammeter 901d through the external tool 900 is transferred to the data register D33, and then the process proceeds to the return step 239.

  In FIG. 6 showing the details of the subsequent process block 240a and process block 240b, the subroutine start process 240 is activated with the start of execution of the process block 240a and process block 240b, and the subroutine return process 249 described later follows FIG. The process block 250a and the process block 250b are shifted to.

  Step 242 is executed subsequent to step 240 to determine whether a fourth calibration command transmitted by the external tool 900 has been received. When the determination result is YES and it is received, the process proceeds to step 243. When it is not received, the process returns to step 242 and waits until the fourth calibration command is received. In generating the fourth calibration command, it is confirmed in step 241 whether or not the generation of calibration commands 1 to 3 has been completed.

In step 243, the average voltage calibration coefficient Ka is calculated by the following equation based on the value of the data register transferred and stored in step 225 and step 226, and this is transferred and written to the data register D41.
Ka = Vb / Va = D22 / D21 → D41

  In subsequent step 244, the value of error voltage Ef0 transferred and stored in step 216 is transferred and written to data register D42 as offset component C.

In the following step 245, the voltage proportional coefficient D of the error component of the monitoring voltage Ef is calculated by the following equation based on the value of the data register transferred and stored in step 224, step 216, and step 225, and this is transferred and written to the data register D43.
D = (Ef1-Ef0) / Va = (D20-D10) / D21 → D43

In the following step 246, the current proportionality coefficient B of the monitoring voltage Ef is calculated by the following equation based on the value of the data register transferred and stored in the step 234, step 224, and step 235, and this is transferred to the data register D44 and written back. 249.
B = (Ef2−Ef1) / Imm = (D30−D20) / D33 → D44

  Step 243 is an average voltage calibrating unit, step 245 is a voltage proportionality factor calculating unit, step 246 is a current proportionality factor calculating unit, and step block 240a and step block 240b mainly including step 243 to step 246 are calibrated. The coefficient calculation means 240A is configured.

  In FIG. 7 showing the details of the subsequent process block 250a and process block 250b, the subroutine start process 250 is activated with the start of execution of the process block 250a and process block 250b, and the subroutine return process 259 described later is followed by FIG. The process proceeds to Step 203a and Step 203b.

  Step 252 is executed following step 250 to determine whether a fifth calibration command transmitted by the external tool 900 has been received. When the determination result is YES and it is received, the process proceeds to step 253. When it is not received, the process returns to step 252 and waits until a fifth calibration command is received. In generating the fifth calibration command, the electric load 107 is connected in a state where the predetermined drive power source 101 is connected to the current control device 100A in advance in step 251, and the calibration ammeter 901d, the calibration voltmeter is connected. 902d and a calibration thermometer 903d are connected. In steps 253 to 258, which will be described later, a plurality of measurement currents Isi (i = 0, 1, 2,... N) equally distributed from the maximum value to the minimum value of the target load current Is are set. The current proportionality factor Bi corresponding to each measurement current Isi is calculated. In addition, the process block 257 comprised by the process 253-the process 256 becomes a linearity calibration means.

  In step 253, for example, an initial value i = 0 is set as the measurement number i, and in a subsequent step 254, a predetermined target current Isi is set. In the subsequent step 255, the actual load current Immi is read by the calibration ammeter 901d, and in the subsequent step 256, Bi = B × Isi / Immi is calculated and stored as the correction value Bi of the current proportionality coefficient. The current proportionality coefficient B applied here is a value calculated in the process block 240a and the process block 240b.

  In the following step 258, it is determined whether or not the measurement is completed. If it is not completed, NO is determined and the process proceeds to step 253 to increase the measurement number i to i + 1. If the measurement is completed, YES is determined. Then, the process proceeds to the return step 259.

  Process 203a and process 203b are executed following process block 250a and process 250b, and each calibration constant calculated in process block 250a and process block 250b is transferred and stored in nonvolatile data memory 114A from process block 210a and process block 210b. After performing transfer confirmation collation (not shown), the process proceeds to step 204a and step 204b. The process block 203A constituted by the processes 203a and 203b serves as a transfer storage unit.

  In step 204a, the high temperature calibration completion flag is set and then the process proceeds to step 205. In step 204b, the normal temperature calibration completion flag is set and then the process proceeds to step 205. In step 205, by monitoring the flag states in steps 204a and 204b, if calibration at normal temperature and high temperature is completed, a determination of YES is made and the process proceeds to step 207, and both calibrations must be completed. If NO, the process proceeds to step 206.

  In step 206, an incomplete message command for the external tool 900 is generated, and the operation shifts to the operation end step 209.

  In step 207, the internal environment temperature is estimated with reference to the external environment temperature measured in step 214 in the process block 210a and the process block 210b, and the characteristic of the measured voltage Vt of the temperature detection circuit 170 versus the internal environment temperature T is calibrated and stored. To do. The nonvolatile program memory 113A of the microprocessor 111A stores conversion data obtained by experimentally measuring in advance the relationship of the internal environment temperature T corresponding to the external environment temperature measured by the calibration thermometer 903d. The internal environment temperature in this case is measured by a highly accurate temperature sensor and thermometer for calibration. Therefore, the internal environmental temperature T is estimated from the external environmental temperature measured in step 214 of FIG. 3 and the conversion data stored in the program memory 113A, and the measured voltage Vt of the temperature detection circuit 170 measured in step 213 and the internal A correspondence with the environmental temperature T is detected.

The process 207 serving as the detection temperature calibration means of the temperature detection circuit 170 differs in specific processing depending on whether the temperature calibration is performed only in the normal temperature environment or in the normal temperature environment and the high temperature environment.
When temperature calibration is performed only in a room temperature environment, predetermined temperature-to-measurement voltage characteristic data in the applied temperature detection circuit 170, for example, standard temperature-to-measurement voltage characteristic data is used as an approximate expression or data table. The calibration constant is calculated by the ratio between the measured voltage Vt1 of the actual calibration and the measured voltage Vt2 calculated from the standard characteristic data, which is stored in advance in the nonvolatile program memory 113A and is calibrated at the normal ambient temperature. become.
When the calibration operation is performed in both a normal temperature environment and a high temperature environment, the digital conversion value of the measurement voltage Vt of the temperature detection circuit 170 and a known internal environment temperature, or an externally installed calibration thermometer 903d. In comparison with the estimated internal environment temperature, the interpolation calculation formula for calculating the actual use environment temperature T from the actual measurement voltage Vt, or the data table is calculated.

  The step 208 serving as the control constant calibration means includes a current proportional coefficient B, a voltage proportional coefficient D of an error component, and an offset component C as a result of the calibration operation from the process block 210a and the process block 210b to the process block 250a and the process block 250b. Then, after creating a data table as will be described later with reference to FIG.

Next, FIG. 8A to FIG. 8C showing the framework of the calibration constant data table will be described.
FIG. 8A is a data table for obtaining internal environment temperatures Ta to Te corresponding to the output voltages Vta to Vte of the temperature detection circuit 170. This data table is a highly accurate temperature detection circuit 170 that has been calibrated at the component level. When the temperature detection circuit 170 having a relatively low accuracy is used as it is, the value of the actual measurement voltage Vtb actually measured at the internal environment temperature Tb in a normal temperature environment, Based on the standard temperature-to-measurement voltage characteristics of the applied temperature detection circuit 170, the measurement voltages Vta, Vtc, Vtd, and Vte at other internal environmental temperatures Ta, Tc, Td, and Te are proportionally calculated. Yes. More preferably, the measured voltages Vta, Vtc, and Vte at the internal environmental temperatures Ta, Tc, and Te are statistically calculated based on the measured voltages Vtb and Vtd that are actually measured at two internal environmental temperatures in the normal temperature environment Tb and the high temperature environment Td. This is to estimate and calculate by interpolation and extension.

  FIG. 8B shows the framework of the data table related to the offset component C of the error component, and different data is applied to the offset components Ca to Ce for each of the divided practical environment temperature bands Ta to Te. It has become. The offset components Cb and Cd at the internal environment temperatures Tb and Td are values calculated in the process block 240a and the process block 240b based on values actually measured in the process block 210a and the process block 210b. Offset components Ca, Cc, and Ce at temperatures Ta, Tc, and Te are estimated and calculated by statistically interpolating and extending from actually measured offset components Cb and Cd.

  FIG. 8C shows the framework of the data table related to the voltage proportional coefficient D of the error component, and the voltage proportional coefficients Da to De are applied with different data for each of the divided practical environment temperature bands Ta to Te. It is like that. The voltage proportional coefficients Db and Dd at the internal environmental temperatures Tb and Td are values calculated in the process block 240a and the process block 240b based on the values actually measured in the process block 220a and the process block 220b. The voltage proportional coefficients Da, Dc, De at the environmental temperatures Ta, Tc, Te are estimated and calculated by statistically interpolating and extending from the actually measured voltage proportional coefficients Db, Dd.

  FIG. 8D shows a data table framework for the current proportionality factor B. The current proportionality factor B corresponds to the divided practical environment temperature bands Ta to Te and the set current bands Is0 to Is5. Different data is applied. The current proportional coefficients Bbi and Bdi at the internal environmental temperatures Tb and Td are calculated in the process block 240a and the process block 240b based on the values actually measured in the process block 230a and the process block 230b, and further in the process block 250a and the process block. The values measured by 250b are added, and the current proportional components Bai, Bci, Bei at other internal environment temperatures Ta, Tc, Te are statistically interpolated and extended from the measured current proportional coefficients Bbi, Bdi. Thus, it is estimated and calculated.

  Note that the temperature-to-measurement voltage characteristic related to the high-accuracy temperature detection circuit 170 or the standard temperature-to-measurement voltage characteristic related to the low-accuracy temperature detection circuit 170 is stored in advance in the nonvolatile program memory 113A. Various calibration data calculated by the calibration operation as the control device 100A is stored in the nonvolatile program memory 113A or the nonvolatile data memory 114A.

Next, the operation of the normal control routine in the electric load current control apparatus according to the first embodiment will be described with reference to the flowchart of FIG.
In FIG. 9, a process 300 is one of many control flows executed by the microprocessor 111A, and is an operation start process related to pulse width modulation control for outputting a set value of a target load current. This is a step of reading the value of the target load current Is determined in another control flow that is not performed. The subsequent step 302 is a step of determining whether or not the following control flow is the first operation after the start of operation based on the operation state of a flag (not shown). If the step 302 is a determination of the first operation, the process proceeds to step 303. If it is determined that the operation is not the first operation, the process proceeds to step 310.

  In step 303, the value of the target load current Is read and set in step 301 and the standard reference resistance Rc = Rmin to Rmax as a fixed constant stored in advance in the nonvolatile program memory 113A or the nonvolatile data memory 114A are used. In this step, the average voltage Vaa = Is × Rc is calculated by the above-described equation (3).

The subsequent step 304 is a step of calculating the estimated monitoring voltage Es corresponding to the target load current Is. In this step, the target load current Is set in step 301 flows instead of the load current Im in the above-described equation (11). Assuming that the value of the monitoring voltage Ef is calculated as the estimated monitoring voltage Es, the constants D, B, and C are read and used as data stored in the nonvolatile data memory 114A as calibration constants. As the average voltage Va, the value of the average voltage Vaa calculated in step 303 is used.
Es = D × Vaa + B × Is + C

  In the subsequent step 305, α = Es / Vcc is set as a pulse duty α which is a ratio between a period in which the output voltage of the pulse width modulation control output PWM is the logic level “H” and the control power supply voltage Vcc and the pulse period. In the calculation step, the estimated monitoring voltage Es used here is the one calculated in step 304. The value of the control power supply voltage Vcc is a fixed constant stored in advance in the nonvolatile program memory 113A or the nonvolatile data memory 114A. It is designed to be used for reading.

  In the subsequent step 306, the value of the pulse duty α calculated in step 305 is multiplied by a predetermined magnification N, and the integer value is stored in the data register D1, which is a specific address memory in the RAM memory 112, and the value of N−D1. Is stored in the data register D2. As the predetermined magnification N, for example, N = 1000.

  The process block 307 is an initial setting means constituted by the processes 303 to 306, and the process 304 is a provisional conversion estimating means.

Step 310 is executed when the determination in step 302 is not the initial operation or subsequent to step 306, reads the measured voltage Vt of the temperature detection circuit 170, and calculates the internal environment temperature T from the data table of FIG. calculate. In the subsequent step 311, the offset component C and the voltage proportional coefficient D corresponding to the current environmental temperature are read from the data tables in FIGS. 8B and 8C,
In subsequent step 312, a current proportionality coefficient B corresponding to the current environmental temperature and the target load current Is set in step 301 is calculated from the data table of FIG. Note that the calibration constant determining means is configured by the process block 314 configured by the process 310, the process 311 and the process 312.

  A subsequent step 315 is a step of reading the value of the monitored average voltage Va input to the microprocessor 111A.

The subsequent step 316 is a step of calculating the estimated monitoring voltage Es corresponding to the target load current Is. In this step, the target load current Is set in step 301 flows instead of the load current Im in the above-described equation (11). Assuming that the value of the monitoring voltage Ef is assumed, the estimated monitoring voltage Es is calculated by the following equation. As the constants D, B, and C, the values calculated in the process block 314 are used, and the actual average voltage Va read in the process 315 is used as the average voltage Va.
Es = D × Va + B × Is + C

  Subsequent Step 317 and Step 318 are steps of calculating the pulse duty α and writing to the data registers D1 and D2 as in Steps 305 and 306. The value of the estimated monitoring voltage Es used here changes according to the value of the average voltage Va read in step 315.

  The process block 319 is a conversion setting means constituted by the process 316, the process 317, and the process 318. The estimated value Es of the monitoring voltage Ef corresponding to the target load current Is is set as the target voltage and corresponds to the target voltage Es. The pulse width modulation control output PWM having the pulse duty α is generated.

  The subsequent step 320 is a step of calculating the minimum load current value Imin = Ka × Va / Rmax. The average voltage calibration coefficient Ka and the maximum resistance Rmax of the electric load 107 are stored in the nonvolatile data memory 114A or the nonvolatile program memory 113A. The average voltage Va is the current value of the average voltage Va read in step 315, and the value of Ka × Va corresponds to the average voltage itself applied to the electric load 107. Yes.

  The subsequent step 321 is a step of calculating the minimum value Imax = Ka × Va / Rmin of the load current, and the average voltage calibration coefficient Ka and the minimum resistance Rmin of the electric load 107 are stored in the nonvolatile data memory 114A or the nonvolatile program memory 113A. The average voltage Va is the current value of the average voltage Va read in step 315, and the value of Ka × Va corresponds to the average voltage itself applied to the electric load 107. Yes.

  A subsequent step 322 is a step of calculating the load current Im from the current monitoring voltage Ef based on the above-described equation (11).

  Subsequent step 323 is a step serving as an overcurrent state detection means. In this step 323, when the load current Im calculated in step 322 is larger than the maximum current Imax calculated in step 321, a determination of YES is made and an excessive current state is detected. If the load current Im calculated in step 322 is not larger than the maximum current Imax calculated in step 321, NO is determined to determine that the current is not an excessive current state. It has come to move to.

  Step 324 is a step for detecting an undercurrent state. In this step, when the load current Im calculated in step 322 is smaller than the minimum current Imin calculated in step 320, a YES determination is made and an undercurrent state is assumed. If the load current Im calculated in step 322 is not smaller than the minimum current Imin calculated in step 320, NO is determined to determine that the current is not an undercurrent state, and the operation end step 330 is performed. It has come to move to.

  Step 325 is executed when step 323 determines an overcurrent state, or when step 324 determines an undercurrent state, sets the value of the data register D1 for determining the pulse duty α to 0, and the microprocessor The pulse width modulation control output PWM of 111A is stopped and an abnormality notification output DSP is generated to activate the alarm / display 109.

  When the determination in step 324 is not an under-current state, or the operation end step 330 that transitions to step 325 is a standby step, the operation is performed again after the microprocessor 111A executes another control flow. The start process 300 is activated, and the control flow from the process 300 to the process 330 is repeatedly executed.

An overview of the control flow configured as described above will be described.
First, the target voltage Es set by the conversion setting means 319 is a value corresponding to the monitoring voltage Ef when the target current Is actually flows, and originally the target current Is and the load current Im that actually flows. The negative feedback control by the comparison deviation integration circuit 140 is executed outside the microprocessor 111A so as to match. However, the monitoring voltage Ef includes an error component proportional to the average voltage Va applied to the electric load 107 in addition to the main component proportional to the load current Im.

  Since the resistance value of the electric load 107 changes depending on the environmental temperature and the temperature rise of the load itself, the average voltage Va for obtaining the predetermined load current Im also changes, and therefore the error component of the monitoring voltage Ef also changes.

  The conversion setting means 319 feeds back the value of the average voltage Va that changes with the resistance fluctuation of the electric load 107 and reflects it in the target voltage Es. If the control is primary feedback control, the conversion setting means 319 is secondary feedback control.

  The initial setting means 307 estimates the average voltage Vaa by comparing the standard reference current Ir and the target load current Is at the start of operation when the average voltage Va has not yet been measured, and sets the temporary target voltage Es. It has become a means to do.

  Next, when the overcurrent state detection means 323 determines the overcurrent state, the load is short-circuited between the positive and negative output wires of the electric load 107, the interlayer short-circuit between the windings, and the output terminal 108. Cause a ground fault connected to the positive phase wiring and the ground terminal 104N or the vehicle body, the ground, etc. The output voltage E0 of the differential amplifier 151 is normally in the range of 0 to Vcc (for example, 5V), but suddenly increases to the drive power supply voltage Vb (for example, 10 to 16V). However, since the monitoring voltage Ef is limited by the voltage limiting diode 164 so as not to become a value equal to or higher than the control power supply voltage Vcc, it cannot be detected that the load current Im is excessive.

  However, since the average voltage Va decreases due to the load short circuit, the value of the maximum current Imax in the step 321 decreases rapidly, and the overcurrent state is determined in the step 323.

  On the other hand, when the undercurrent state detection means 324 determines the undercurrent state, there are a case where the electrical load 107 and the wiring are disconnected and a case where the normal phase wiring is in a power fault. In particular, when the output terminal 108 and the power supply terminal 104P are completely short-circuited due to a power fault of the positive phase wiring, the current flowing through the current detection resistor 126 becomes zero, so there is a discrepancy between the target current and the actual current. Occurrence and abnormality detection can be easily performed.

  Similarly, when a disconnection accident occurs, the current flowing through the current detection resistor 126 becomes zero, so that a divergence occurs between the target current and the actual current, so that the abnormality detection can be easily performed. However, if a power fault occurs between the remote position of the positive phase wiring from the output terminal 108 to the electric load 107 and the remote position of the power supply wiring from the power supply terminal 104P to the drive power supply 101, the wiring resistance R0 A parallel circuit with the resistance value R1 of the current detection resistor 126 is configured, and the current flowing through the current detection resistor 126 decreases at a ratio of R0 / (R0 + R1).

  In such a case, an abnormal state cannot be detected simply by comparing the target current and the actual current. For example, if the current shunted to the current detection resistor 126 when the switching element 121 is completely turned on in a state where a power fault has occurred due to the resistor R0 is Ix, the target current is a value equal to or less than Ix. Feedback control is possible so that the target value matches the actual measurement value, and no divergence occurs between the target value and the actual measurement value. Therefore, abnormality detection cannot be performed.

  However, the comparison reference in step 323 and step 324 is to monitor the current average voltage Va applied to the electric load 107 and estimate the maximum current, the minimum current calculated from the minimum resistance, and the maximum current. Since it is determined whether or not this is flowing through the current detection resistor 126, a highly accurate abnormality determination can be performed. In steps 323 and 324, the load current Im is compared with the maximum load current Imax and the minimum load current Imin. However, the maximum load current Imax and the minimum load current Imin calculated in the steps 321 and 320 are used as a differential amplifier circuit. The maximum monitoring voltage Emax and the minimum monitoring voltage Emin converted into the output voltage of the unit 150 may be converted to compare the monitoring voltage Ef with the maximum monitoring voltage Emax and the minimum monitoring voltage Emin. In short, it is only necessary to determine that the relative relationship between the monitoring voltage Ef and the monitoring average voltage Va does not deviate abnormally.

Next, the operation of the interrupt control routine in the electric load current control apparatus according to the first embodiment will be described with reference to the flowchart of FIG.
In FIG. 10, step 400 is an interrupt operation start step of the microprocessor 111A, and this start step is activated at substantially constant time intervals.

  Step 401 is executed following the start step 400, and it is monitored whether or not an abnormality notification output in step 325 of FIG. 9 has occurred. If no abnormality has occurred, NO is determined and the process proceeds to step 402. If an abnormality has occurred, a determination of YES is made and the process proceeds to step 406.

  In step 402, it is determined whether or not the operation is an initial operation after the start of the operation of the microprocessor 111A. If the operation is an initial operation, the process proceeds to step 403. If not, the process proceeds to step 407. In step 403, the logic level of the pulse width modulation control output PWM is set to “L”. In the subsequent step 404, the content of the current value register D0 of the interruption count counting subtraction counter is set to 1, and in the subsequent step 405, the output flag F0 is turned ON. Then, the process proceeds to step 407.

  In step 406 serving as output stop / notification means, the logic of the pulse width modulation control output PWM is set to “L”, the output flag F0 is reset, the abnormality notification output DSP is generated, the alarm / display 109 is activated, In step 408, the process returns to the original control process at the time when the interruption was started.

  In Step 407, it is determined whether or not the output flag F0 is set in Step 405 or Step 423 described later. If it is set, the process proceeds to Step 410, and if it is not set, the process proceeds to Step 420. Yes.

  Step 410 is a step of subtracting one count from the current value of the subtraction counter that counts the number of interruptions. In the following step 411, it is determined whether or not the value of the current value register D0 still exceeds zero. When the current value is zero, the process proceeds to step 408, and when the current value becomes zero, the process proceeds to step 412.

  In step 412, the value of the data register D 2 set in step 306 or 318 in FIG. 9 is transferred to the current value register D 0, and in the subsequent step 413, the output flag F 0 set in step 405 or step 423 described later. In step 414, the logic level of the pulse width modulation control output PWM is set to “L”, and the process proceeds to step 408.

  Step 420 is a step of subtracting one count from the current value of the subtraction counter that counts the number of interruptions. In the following step 421, it is determined whether or not the value of the current value register D0 still exceeds zero. If the current value is zero, the process proceeds to step 422.

  In step 422, the value of the data register D1 set in step 306 or 318 of FIG. 9 is transferred to the current value register D0, and in the subsequent step 423, the output flag F0 that has been reset in step 413 is set. At 424, the logic level of the pulse width modulation control output PWM is set to “H”, and the process proceeds to step 408.

  The process block 415 constituted by the process 410 to the process 414 is an operation process from the output flag F0 being set by the process 423 to being reset by the process 413, and the period is the data register set in the process 422. It depends on the value of D1, which corresponds to a period during which the logic level of the control output PWM is “H”.

  In addition, the process block 425 configured by the process 420 to the process 424 is an operation process from when the output flag F0 is reset by the process 413 until it is set by the process 423. The period depends on the value of the data register D2 set in Step 412. This corresponds to a period in which the logic level of the control output PWM is “L”.

  As described in detail above, the current control device for an electrical load according to the first embodiment is fed from the drive power supply 101 and includes a power supply circuit unit in which the switching element 121, the current detection resistor 126, and the electrical load 107 are connected in series. In the electric load current control device 100A, the control circuit unit controls the ON / OFF ratio of the switching element 121 so that the target load current Is for the electric load 107 and the detection load current Im detected by the current detection resistor 126 coincide with each other. The control circuit unit further includes a microprocessor 111A including a non-volatile program memory 113A, a non-volatile data memory 114A, an arithmetic processing RAM memory 112, and a multi-channel AD converter 115, an amplifier circuit unit 150, and a temperature detection unit. Circuit 170 and comparison deviation integration circuit 140, and nonvolatile program memory 113A is further updated. A control constant calibration unit 208, which includes a control program to be converted setting means 319.

  The amplification circuit unit 150 amplifies the voltage across the current detection resistor 126 connected in series to the electric load 107, and mainly includes a current proportional component proportional to the load current Im for the electric load 107, and includes a monitoring voltage including an error component ΔEf. Ef is generated and input to the microprocessor 111A as calibration monitoring information. The temperature detection circuit 170 generates a measurement voltage Vt (= Vta to Vte) corresponding to the internal environment temperature T (= Ta to Te) of the current control device 100A, and the measurement voltage Vt is a multi-channel AD converter. The data is input to the microprocessor 111A via 115.

  The control constant calibration unit 208 is configured to monitor the monitoring voltage Ef based on the actual load current Imm from the calibration ammeter 901d installed externally in one or both of the internal environmental humidity T (= Tb, Td). A current proportional coefficient B (= Bb, Bd) and an error component ΔEf (= ΔEfb, ΔEfd) are calculated for the current proportional component of the actual use internal environment temperature T (= Ta to Te) detected by the temperature detection circuit 170. ) And a current proportionality factor Bi (= Bai to Bei) corresponding to the variable target load current Isi (i = 0, 1,... N) and an error component ΔEf (= ΔEfa to ΔEfe). Alternatively, the data table is stored in the nonvolatile data memory 114A.

  The conversion setting means 319 is based on the current proportional coefficient and the error component corresponding to the actual use internal environment temperature T, assuming that the same current as the target load current Is determined by the microprocessor 111A flows to the electric load 107. Thus, the estimated monitoring voltage Es is calculated.

  The comparison deviation integration circuit 140 controls the energization of the switching element 121 using the estimated monitoring voltage Es corresponding to the target load current Is as a control target value and the monitoring voltage Ef as a feedback value.

  As described above, the electric load current control device according to the first embodiment has a negative feedback control comparison deviation integration circuit 140 and a current detection resistor outside the microprocessor 111A that outputs a setting signal proportional to the target load current. 126, and a calibration operation is performed to correct fluctuations in solids of current control characteristics and temperature fluctuations using a calibration ammeter installed externally at the product shipment stage, and the calibration operation is performed at room temperature. It is implemented in at least one of an environment and a high temperature environment to obtain a calibration constant based on error factors due to fluctuations in the solids of control elements, characteristic fluctuations due to temperature, and fluctuations in the resistance value of the current detection resistor 126 due to self-heating. Therefore, calibration of detection error is performed for each cause of detection error, and it is calibrated taking into account the factor of temperature fluctuation, so the calibration constant can be used properly during operation of the current control device in various operating environments. In addition to being able to perform high-precision current control, it is characterized by easy calibration operation with a simple external calibration facility.

  Further, the nonvolatile program memory 113A of the electric load current control device according to the first embodiment further includes a control program which becomes the detected temperature calibration means 207. The detected temperature calibration means 207 is a digital conversion value of the measured voltage Vt (= Vtb or Vtd) of the temperature detection circuit 170, a known internal environment temperature, or an external installation in at least one of a normal temperature environment and a high temperature environment. The estimated internal environment temperature T (= Tb or Td) by the calibration thermometer 903d is compared, and the actual measured voltage Vt (based on the standard temperature versus measured voltage characteristic of the applied temperature detection circuit 170 is compared. = A calculation formula for estimating the actual use internal environmental temperature T (= Ta to Te) from the Vta to Vte), or a data table is stored in the nonvolatile data memory 114A.

  As described above, the current control device for an electric load according to the first embodiment is a standard based on the applied temperature detection circuit 170 in which the measurement voltage at least at a specific temperature is accurately captured among the solid variation of the temperature detection circuit 170. The ambient temperature corresponding to the actual measurement voltage can be estimated by correcting the measured voltage vs. temperature characteristic. Therefore, among the solid variation fluctuations of the temperature detection circuit 170, at least the measurement voltage at a specific temperature is accurately supplemented, and the temperature detection accuracy as a whole is improved.

  Further, the nonvolatile program memory 113A of the electric load current control device according to the first embodiment further includes a control program which becomes the detected temperature calibration means 207. The detected temperature calibration means 207 is a digitally converted value of the measurement voltage Vt (= Vtb, Vtd) of the temperature detection circuit 170 and a known internal environment temperature or an externally installed in both a normal temperature environment and a high temperature environment. Interpolation for estimating the actual use internal environment temperature T (= Ta to Te) from the actual measurement voltage Vt (= Vta to Vte) by comparing the estimated internal environment temperature T (= Tb, Td) by the calibration thermometer 903d. An arithmetic expression or a data table is stored in the nonvolatile data memory 114A.

  As described above, the electric load current control device according to the first embodiment accurately captures the variation in solids in the temperature detection circuit 170 at room temperature and high temperature, and accurately estimates the environmental temperature corresponding to the actual measurement voltage. can do. Therefore, the variation in the solid state of the temperature detection circuit 170 is corrected, and the temperature detection accuracy is improved in a wide temperature range.

  In addition, the control circuit unit of the electric load current control apparatus according to the first embodiment further includes a serial communication interface circuit 116 for connecting the external tool 900 for calibration operation and the microprocessor 111A, and a control constant calibration unit 208. Alternatively, the calibration command in the detected temperature calibration means 207 and the measurement value of the calibration ammeter 901d or thermometer 903d installed externally are input from the external tool 900 and transferred and written to the RAM memory 112. .

  As described above, the electric load current control apparatus according to the first embodiment includes the external tool 900 for calibration operation, and the external tool 900 is used to transfer the measurement signal to the microprocessor 111A. Therefore, there is a feature that a measurement value obtained by a high-precision calibration measuring instrument can be directly transferred to the RAM memory 112 in the current control device as digital data. Further, since the calibration calculation is performed by the microprocessor 111A on the current control device side, the calibration equipment installed outside is simple, and it is characterized in that it can be applied as standard to current control devices of various specifications.

  In addition, the amplification circuit unit 150 of the electric load current control device according to the first embodiment uses the differential amplifier 151 to convert the differential voltage between the both ends of the current detection resistor 126 connected between the switching element 121 and the electric load 107. In addition to amplification, the power supply circuit unit includes a commutation diode 127, and the amplifier circuit unit 150 includes a bias correction circuit 158.

  The commutation diode 127 is connected in parallel to the series circuit of the electric load 107 and the current detection resistor 126 connected between the electric load 107 and the switching element 121, or does not include the current detection resistor 126. The diode is directly connected in parallel to the electric load 107, and is connected to a polarity at which the continuous decay current due to the inductance of the electric load 107 flows back when the switching element 121 is opened.

  The bias correction circuit 158 applies a substantially equal positive bias voltage to the first input E1 and the second input E2 of the differential amplifier 151, and the commutation diode when the switching element 121 is open. The negative voltage applied by the voltage drop of 127 is canceled out so that the negative voltage input is not applied to the differential amplifier 151.

  The control constant calibration means 208 further includes an error component in addition to the current proportionality coefficient B (= Bb, Bd) of the monitoring voltage Ef at least two types of internal environment temperatures T (= Tb, Td) of the normal temperature environment and the high temperature environment. At least one of the voltage proportionality coefficient D (= Db, Dd) and the offset component C (= Cb, Cd) of ΔEf is calculated, and the voltage proportionality coefficient D (= Da˜) at the actual use internal environment temperature T (= Ta˜Te). Dd) or an arithmetic expression for interpolation calculation of the offset component C (= Ca to Cd) or a data table is stored in the nonvolatile data memory 114A.

  As described above, in the electric load current control device according to the first embodiment, the power supply circuit unit includes the commutation diode 127, and the amplifier circuit unit 150 includes the bias correction circuit 158. Therefore, the negative voltage input generated due to the fact that the current detection resistor 126 is not provided on the ground side is canceled so that the differential amplifier 151 and the multi-channel AD converter 115 do not need to handle positive and negative voltages. There are features that can be done.

  In addition, the control circuit unit of the electric load current control device according to the first embodiment further includes an average voltage measurement circuit including voltage dividing resistors 191a and 192a, and the nonvolatile program memory 113A further transfers to the calibration coefficient calculation means 240A. A control program serving as the storage unit 203A is included.

  The average voltage measurement circuit divides the voltage across the electric load 107 and inputs it to the microprocessor 111A to obtain the monitored average voltage Va.

  The calibration coefficient calculation unit 240A assumes that the relationship between the average value Ef of the monitoring voltage by the amplifier circuit unit 150, the monitoring average voltage Va, and the load current Im is Ef = D × Va + B × Im + C, and becomes an error component in this formula. The offset component C, the voltage proportional coefficient D, and the current proportional coefficient B are calculated from measurement data obtained by calibration operation.

  The transfer storage means 203A transfers and stores the values of the voltage proportionality coefficient D, current proportionality coefficient B, and offset component C, which are the calculation results of the calibration coefficient calculation means 240A, as calibration constants in the nonvolatile data memory 114A. And at least two kinds of environmental temperatures of the high temperature environment, two kinds of internal environment temperatures T (= Tb, Td), a voltage proportional coefficient D (= Db, Dd), and a current proportional coefficient B (= Bb, Bd), The offset component C (= Cb, Cd) is transferred and stored.

  As described above, the electric load current control device according to the first embodiment includes the average voltage measurement circuit including the voltage dividing resistors 191a and 192a, the calibration coefficient calculation unit 240A, and the transfer storage unit 203A. Accordingly, the calibration constants for each factor can be calculated and stored efficiently in a step-by-step manner, and the calibration operation can be performed by adding a simple automated facility in the production line for mass-produced products.

  The calibration coefficient calculation means 240A of the electric load current control apparatus according to the first embodiment further includes an average voltage calibration means 243.

  In the calibration operation, the average voltage calibration means 243 inputs the driving power supply voltage Vb measured by the externally installed calibration voltmeter 902d, writes and stores it in the RAM memory 112, and the switching element 121 is completely conducted. The average voltage calibration coefficient Ka = Vb / Va between the monitored average voltage Va and the drive power supply voltage Vb is calculated and stored in the nonvolatile data memory 114A, or the voltage dividing ratio with respect to the voltage across the electric load 107 A fixed constant determined in advance is applied as the reciprocal of.

  As described above, the electric load current control apparatus according to the first embodiment includes the average voltage calibration means 243. Therefore, there is a feature that the drive power supply voltage Vb can be accurately calculated from the value of the monitored average voltage Va and the calculated voltage can be used for other purposes in a state where the open / close element 121 is completely conductive.

  Further, the nonvolatile program memory 113 </ b> A of the electric load current control device according to the first embodiment further includes a control program serving as the linearity calibration means 257.

  The linearity calibration unit 257 determines the monitoring voltage Ef based on the actual load current Immi measured by an externally installed calibration ammeter 901d in a calibration operation using a plurality of target load currents Isi (i = 0 to n). The current proportionality coefficient Bi = B × (Isi / Immi) of the current proportional component is calculated and stored in the nonvolatile data memory as an approximate expression or a data table. The calculation of the current proportionality coefficient by the linearity calibration means 257 is executed at the internal environment temperature T (= Tb, Td) in one or both of the normal temperature environment and the high temperature environment, and the current in the practical internal environment T (= Ta to Te). The values of the proportional coefficients Bai to Bei are stored in the nonvolatile data memory 114A as an approximate expression or a data table.

  As described above, the electric load current control device according to the first embodiment includes the linearity calibration unit 257 and corrects the current proportionality count so that a load current proportional to the target current can be obtained. . Therefore, the temperature detection circuit 170 merely measures the environmental temperature inside the current control device and does not directly detect the temperature of the current detection resistor 126 itself, whereas the temperature of the current detection resistor 126 There is a feature that it is possible to prevent a non-linear error in current control from occurring due to a change in proportion to the square of the load current and a change in the resistance value of the current detection resistor 126 accordingly.

  The electric load current control device 100A according to the first embodiment is a current control device for a plurality of linear solenoids in an automatic transmission for an automobile, and is housed in a hermetically sealed housing, and the temperature detection circuit 170 includes a microprocessor 111A. By measuring the vicinity temperature or the vicinity temperature of the constant voltage power supply circuit 110 that supplies power to the microprocessor 111A and the multi-channel AD converter 115, the average environmental temperature in the sealed casing is estimated.

  The calibration operation in the normal temperature environment is performed in the assembly inspection process of the current control device 100A, and the calibration operation in the high temperature environment is performed in the high temperature test process following the assembly inspection process. ing.

  As described above, in the current control device for an electric load according to the first embodiment, the calibration operation of the current control device 100A is performed in the assembly inspection process and the high-temperature shipment inspection process of the current control device 100A. Therefore, the calibration constant is calculated by combining the measurement data in the normal temperature environment in the assembly inspection process temporarily stored in the nonvolatile data memory 114A and the measurement data in the high temperature environment in the high temperature test process, and the calibration constant is calculated as the nonvolatile data. By storing and storing in the memory 114A, there is a feature that does not require a dedicated work process for the calibration operation.

Embodiment 2. FIG.
Next explained is a current control apparatus for electric loads according to a second embodiment of the invention. FIG. 11 is an overall circuit diagram showing a current control device for an electric load according to the second embodiment. The second embodiment will be described with a focus on differences from the first embodiment shown in FIG. In each figure, the same reference numerals indicate the same or corresponding parts. In the first embodiment shown in FIG. 1, an external negative circuit having a comparison deviation integrating circuit 140 that constitutes a feedback control circuit outside the microprocessor 111A. In contrast to the feedback control system, the second embodiment shown in FIG. 11 uses an internal negative feedback system in which the microprocessor 111B generates a pulse width modulation signal in response to the comparison deviation integral output. Yes.

  In FIG. 11, the current control device 100 </ b> B is composed of circuit units such as an open / close circuit unit 120, an amplification circuit unit 150, a smoothing circuit 160, and a temperature detection circuit 170, with a microprocessor 111 </ b> B fed from the control power supply unit 110 as a center. These are housed in a sealed housing (not shown).

  The external device connected to the current control device 100B is the same as that of the first embodiment, and the drive power supply circuit configured by the drive power supply 101, the fuse 102, and the power switch 103 is connected between the power supply terminal 104P and the ground terminal 104N. Has been. Similarly, an analog input group 105a, a switch input group 105d, an electric load group 106, an electric load 107 such as a linear solenoid that requires current control, and an alarm / display 109 are also connected.

  In the calibration operation before product shipment, the external tool 990 is connected to the microprocessor 111B via the serial interface circuit 116, the output signal of the calibration digital ammeter 991d connected in series to the electric load 107, and the power supply terminal An output signal of a calibration digital voltmeter 992d for measuring the drive power supply voltage Vb of the drive power supply 101 applied to 104P and a calibration digital thermometer 993d for estimating the internal temperature of the current control device 100B are supplied via the external tool 990. Are supplied to the microprocessor 111B and transferred to a RAM memory 112 described later.

  As an internal configuration of the current control device 100B, the control power supply unit 110 generates a stabilized control power supply voltage Vcc of, for example, DC 5V from a drive power supply voltage Vb of, for example, DC 10 to 16V, and supplies power to each part in the current control device 100B. It is supposed to be.

  The microprocessor 111B includes a RAM memory 112 for arithmetic processing, a program memory 113B such as a non-volatile flash memory that can be erased electrically and written / read, and a non-volatile memory that can be electrically written / read in units of 1 byte. A data memory 114B such as an EEPROM memory, a multi-channel AD converter 115, and a serial communication interface circuit 116 are configured to cooperate with each other.

  The switch circuit unit 120 includes, for example, a switch circuit 121 that is a PNP junction transistor, a series circuit of a drive resistor 122 connected to the base circuit of the switch element 121 and an NPN transistor 123, and a base / emitter of the switch element 121. The switch is composed of a first stable resistor 124 connected between the terminals and a second stable resistor 125 connected between the base and emitter terminals of the transistor 123. One end of the switching element 121 is connected to the power supply terminal 104P. The other end is connected to the output terminal 108 via a current detection resistor 126 having a resistance value R1, and supplies power to the electric load 107.

  The commutation diode 127 is connected in parallel to the series circuit of the current detection resistor 126 and the electric load 107 which is an inductive load, and the polarity at which the attenuation current of the electric load 107 circulates when the switching element 121 is opened. It is connected to the.

  The transistor 123 is driven from the feedback control output PWM of the microprocessor 111B via the drive resistor 128, and the transistor 123 and the switching element 121 are made conductive when the feedback control output PWM is at the logic level “H”. .

  The amplifier circuit unit 150 is mainly configured by a differential amplifier 151 that operates using the drive power supply voltage Vb as a power supply voltage, and is configured in the same manner as in the first embodiment. It is constituted similarly.

  The voltage dividing resistors 191b and 192b constituting the power supply voltage measuring circuit are connected in series to each other and connected to the input terminal of the switching element 121. The voltage across the voltage dividing resistor 192b is input to the microprocessor 111B as the power supply monitoring voltage Vf. ing. In addition, the voltage dividing resistors 191a and 192a constituting the average voltage measuring circuit indicated by the dotted line in the figure are connected in series to each other and connected in parallel to the electric load 107, and the voltage across the voltage dividing resistor 192a is The monitoring average voltage Va is input to the microprocessor 111B via the series resistor 193. A smoothing capacitor 194 is connected to the input terminal of the microprocessor 111B.

  In the second embodiment configured as described above, the value of the monitoring voltage Ef measured based on the amplifier circuit unit 150 is as shown in the equations (9) and (11) described in the first embodiment. Become. Further, the expressions (1) to (11) described in the first embodiment are similarly established in the case of the second embodiment.

Next, the operation of the electric load current control apparatus according to the second embodiment will be described.
FIG. 12 is an operation flowchart for the calibration operation in the electric load current control apparatus according to the second embodiment. The configuration of FIG. 12 is the same as that of the first embodiment shown in FIG. 2, and the process code of the 200th series is changed to the 1200th series. However, the contents of FIGS. 13 to 16 showing the details of the process blocks 1210a and 1210b, the process blocks 1220a and 1220b, the process blocks 1230a and 1230b, and the process blocks 1240a and 1240b are partially changed.

  The main point of the change is that the calibration operation based on the above-described equation (11) is performed in the case of the first embodiment shown in FIG. 2, whereas the above-mentioned (9) in the case of the second embodiment shown in FIG. This is because the calibration operation based on the formula) is performed.

  In FIG. 13 showing the details of the process block 1210a and the process block 1210b, the subroutine start process 1210 is activated with the start of the execution of the process block 1210a and the process block 1210b, and the process of FIG. 12 follows the subroutine return process 1219 described later. The process proceeds to block 1220a and process block 1220b.

  Step 1212 is executed subsequent to step 1210 to determine whether the first calibration command transmitted by the external tool 990 has been received. When the determination result is YES and it is received, the process proceeds to step 1213. When it is not received, the process returns to step 1212 and waits until the first calibration command is received. In order to generate the first calibration command, a predetermined drive power source 101 is connected to the current control device 100B in advance in step 1211, and the calibration ammeter 991d, the calibration voltmeter 992d, and the calibration thermometer 993d are connected. It is supposed to be connected.

  In step 1213, the measured voltage Vt of the temperature detection circuit 170 is read and stored via the AD converter 115, and in the subsequent step 1214, the external environment temperature input from the calibration thermometer 993d via the external tool 990 is read and stored.

  In the subsequent step 1215, the energization duty γ = 0 of the feedback control output PWM is set, and in the subsequent step 1216, the error voltage Ef0 which is the value of the monitoring voltage Ef at this time is converted into a data register D10 which is a memory of a predetermined address in the RAM memory 112, for example. Then, the process proceeds to the return step 1219.

  In FIG. 14 showing the details of the process block 1220a and the process block 1220b, the subroutine start process 1220 is activated when the execution of the process block 1220a and the process block 1220b is started, and the process of FIG. 12 follows the subroutine return process 1229 described later. The process proceeds to block 1230a and process block 1230b.

  Step 1222 is executed following step 1220 to determine whether the second calibration command transmitted by the external tool 990 has been received. When the determination result is YES and it is received, the process proceeds to step 1223, and when it is not received, the process returns to step 1222 and waits until the second calibration command is received. In generating the second calibration command, the connection circuit to the electric load 107 is opened with the predetermined drive power supply 101 connected to the current control device 100B in advance in step 1221, and the calibration voltmeter 992d, A calibration thermometer 993d is connected.

  In step 1223, the energization duty γ of the feedback control output PWM is set to 100%, and in the subsequent step 1224, the error voltage Ef1, which is the value of the monitoring voltage Ef at this time, is converted into a data register D20 which is a memory of a predetermined address in the RAM memory 112, for example. In the subsequent step 1225, the value of the power supply monitoring voltage Vf at this time is transferred to the data register D21. In the subsequent step 1226, the value of the drive power supply voltage Vb input from the calibration digital voltmeter 992d via the external tool 990 is transferred to the data register D22, and then the process proceeds to the return step 1229.

  In FIG. 15 showing the details of the process block 1230a and the process block 1230b, the subroutine start process 1230 is activated with the start of execution of the process block 1230a and process block 1230b, and the process of FIG. 12 follows the subroutine return process 1239 described later. The process proceeds to block 1240a and process block 1240b.

  Step 1232 is executed following step 1230 to determine whether a third calibration command transmitted by the external tool 990 has been received. Then, when the determination result is YES and it is received, the process proceeds to Step 1233, and when it is not received, the process returns to Step 1232 and waits until the third calibration command is received. In generating the third calibration command, the electric load 107 is connected in a state where the predetermined drive power source 101 is connected to the current control device 100B in advance in step 1231, and the calibration ammeter 991d, the calibration voltmeter is connected. 992d and a calibration thermometer 993d are connected.

  In step 1233, the energization duty γ of the feedback control output PWM is set to 100%, and in the subsequent step 1234, the measured voltage Ef2 which is the value of the monitoring voltage Ef at this time is used as a data register D30 which is a memory of a predetermined address in the RAM memory 112, for example. In the subsequent step 1235, the value of the actual load current Imm input from the calibration digital ammeter 991d via the external tool 990 is transferred to the data register D33, and then the process proceeds to the return step 1239.

  In FIG. 16 showing the details of the process block 1240a and process block 1240b, the subroutine start process 1240 is activated with the start of execution of the process block 1240a and process block 1240b, and the process of FIG. 12 follows the subroutine return process 1249 described later. The process proceeds to block 1250a and process block 1250b.

  Step 1242 is executed following step 1240 to determine whether the fourth calibration command transmitted by the external tool 990 has been received. Then, when the determination result is YES and it is received, the process proceeds to Step 1243, and when it is not received, the process returns to Step 1242 and waits until the fourth calibration command is received. When the fourth calibration command is generated, it is confirmed in step 1241 whether or not the generation of the calibration commands 1 to 3 is completed.

In step 1243, the power supply voltage calibration coefficient Kv is calculated from the value of the data register transferred and stored in steps 1225 and 1226 by the following equation, and this is transferred and written to the data register D41.
Kv = Vb / Vf = D22 / D21 → D41
Note that the value of the power supply voltage calibration coefficient Kv corresponds to the inverse voltage division ratio obtained by dividing the total value of the voltage dividing resistor 191b and the voltage dividing resistor 192b by the value of the voltage dividing resistor 192b. The design theoretical value is used. However, the effect on accuracy is not significant.

  In subsequent step 1244, the value of error voltage Ef0 transferred and stored in step 1216 is transferred and written to data register D42 as offset component C.

In the following step 1245, the voltage proportional coefficient A of the error component of the monitoring voltage Ef is calculated by the following equation based on the value of the data register transferred and stored in step 1224, step 1216, and step 1226, and this is transferred and written to the data register D43. .
A = (Ef1-Ef0) / (Vb + Vd) = (D20−D10) / (D22 + 1) → D43

In the following step 1246, the current proportionality coefficient B of the monitoring voltage Ef is calculated by the following equation based on the value of the data register transferred and stored in step 1234, step 1224, and step 1235, transferred to the data register D44, and then returned. Control goes to step 1249.
B = (Ef2−Ef1) / Imm = (D30−D20) / D33 → D44

  Step 1243 is a power supply voltage calibration means, step 1245 is a voltage proportionality coefficient calculation means, and step 1246 is a current proportionality coefficient calculation means. Process blocks 1240a and 1240b mainly including steps 1243 to 1246 are calibrated. The coefficient calculation means 1240B is configured.

  In FIG. 17 showing the details of the process block 1250a and process block 1250b, the subroutine start process 1250 is activated along with the start of execution of the process block 1250a and process block 1250b, and the process of FIG. 12 follows the subroutine return process 1259 described later. The process proceeds to 1203a and step 1203b.

  Step 1252 is executed following step 1250 to determine whether the fifth calibration command transmitted by the external tool 990 has been received. Then, when the determination result is YES and it is received, the process proceeds to Step 1253, and when it is not received, the process returns to Step 1252 and waits until the fifth calibration command is received. In generating the fifth calibration command, the electric load 107 is connected in a state where the predetermined drive power source 101 is connected to the current control device 100B in advance in step 1251, and the calibration ammeter 991d, the calibration voltmeter is connected. 992d and a calibration thermometer 993d are connected.

  Steps 1253 to 1258 described later set a plurality of measurement currents Isi (i = 0, 1, 2,... N) equally distributed from the maximum value to the minimum value of the target load current Is. Then, the current proportionality factor Bi corresponding to each measurement current Isi is calculated, and the process block 1257 constituted by the processes 1253 to 1256 is a linearity calibration means. The operation of the process block 1250a and the process block 1250b is the same as the process block 250a and the process block 250b in the case of the first embodiment shown in FIG.

  Next, the calibration constant data table and current detection characteristic diagram shown in FIG. 18 will be described. 18A is a data table for obtaining internal environment temperatures Ta to Te corresponding to the output voltages Vta to Vte of the temperature detection circuit 170, similar to the case of FIG. 8A described in the first embodiment. Is shown. FIG. 18B shows a data table framework related to the offset component C of the error component, similar to the case of FIG. 8B described in the first embodiment, and the offset components Ca to Ce are divided into a plurality of parts. Different data is applied to each of the practical environmental temperature bands Ta to Te.

  FIG. 18C shows a data table framework for the voltage proportionality coefficient A, as in the case of the voltage proportionality coefficient D of FIG. 8C described in the first embodiment. ... Ae is applied with different data for each of the divided practical environmental temperature bands Ta to Te. FIG. 18D shows a data table framework for the current proportionality factor B measured at step 1235 in FIG. 15 and calculated in step 1246 in FIG. 16. The current proportionality factor B is divided into a plurality of parts. Different data are applied corresponding to the practical environment temperature bands Ta to Te.

  The current proportionality coefficients Bb and Bd at the internal environment temperatures Tb and Td are values calculated at the process block 1240a and the process block 1240b based on the values actually measured at the process block 1230a and the process block 1230b. The current proportional components Ba, Bc, and Be in Ta, Tc, and Te are estimated and calculated by statistically interpolating and extending from the actually measured current proportional coefficients Bb and Bd.

  FIG. 18E is a characteristic diagram when the horizontal axis represents the load current Im and the vertical axis represents the monitoring voltage Ef. The ideal characteristic 80 is that the temperature coefficient of the current detection resistor 126 is zero and the load current Im Even if the heat generation of the current detection resistor 126 increases with the increase of the resistance, the linear characteristic is obtained when the resistance value does not change. However, even when the load current Im = 0, ΔEf = A × (Vb + Vd) × γ + C calculated from the above equation (9) is included as an error component.

  Curves 81 to 85 in FIG. 18E show monitoring voltage characteristics when the current detection resistor 126 having a positive temperature coefficient is used and the internal environment temperature is Ta to Te. Note that the internal environmental temperature measured by the temperature detection circuit 170 is a temperature in the vicinity of the microprocessor 111B or the control power supply unit 110, and not in the vicinity of the current detection resistor 126.

The current detection resistor 126 is at a temperature higher than the internal environment temperature due to self-heating that is proportional to the square of the load current Im, and the resistance value increases as the load current Im increases. Therefore, when the target load current is Isi, the following approximate expression (12) is applied to the current proportional coefficients Bai to Bei corresponding to the internal environment temperatures Ta to Te.
Bai to Bei = (Ba to Be) / [K1 + K2 × T + K3 × Isi2]
(12)
The constants K1, K2, and K3 in this approximate expression are statistically calculated from the set current versus actual load current data measured by the process block 1250a and the process block 1250b, and stored in the nonvolatile program memory 113B or the nonvolatile data memory 114B. It has come to be.

Next, the operation of the normal control routine in the electric load current control apparatus according to the second embodiment will be described with reference to the flowchart of FIG.
In FIG. 9, a process 1300 is an operation start process related to pulse width modulation control for generating a feedback control output as one of many control flows executed by the microprocessor 111B, and the subsequent process 1301 is not shown. This is a step of reading and setting the value of the target load current Is determined in another control flow. The subsequent step 1302 is a step of reading the current value of the power supply monitoring voltage Vf.

  Subsequent step 1303 is a step of determining whether or not the following control flow is the first operation after the start of operation based on the operation state of a flag (not shown). If step 1303 is the determination of the first operation, the process proceeds to step 1304. When the determination is not the first operation, the process proceeds to step 1310.

In the subsequent step 1304, the value of the target load current Is read and set in step 1301 and the standard reference resistance Rc = Rmin to Rmax as a fixed constant stored in advance in the nonvolatile program memory 113B or the nonvolatile data memory 114B. Is a step of calculating the estimated energization duty γ0 by the equation (2) described in the first embodiment. However, the value of the drive power supply voltage Vb in the equation (2) is calculated by Vb = Kv × Vf based on the value of the power supply monitoring voltage Vf read in step 1302 and the value of the power supply voltage calibration coefficient Kv which is a calibration constant. As a result, the estimated energization duty γ0 is calculated by the following equation.
γ0 = (Is / Ir) × (Vmin / Vb) = Is × Rc / (Kv × Vf)
However, Ir = Vmin / Rc, Rc = Rmin to Rmax,
Vb = Kv × Vf = Vmin to Vmax

  In the step 1305 following the step 1304, the value of the energization duty γ0 calculated in the step 1304 is multiplied by a predetermined magnification N and the integer value is stored in the data register D1 which is a memory of a specific address in the RAM memory 112, and N In the step of storing the value of −D1 in the data register D2, the predetermined magnification N is, for example, N = 1000. The process block 1306 constituted by the processes 1304 and 1305 is an initial setting means, and the process 1304 is an estimated energization duty calculation means.

  Step 1310 is executed when the determination in step 1303 is not the first operation or following step 1305. Then, it is a step of reading the measurement voltage Vt of the temperature detection circuit 170 and reading the internal environment temperature T from the data table of FIG. In subsequent step 1311, the offset component C and the voltage proportional coefficient A corresponding to the current environmental temperature are read from the data tables of FIGS. 18B and 18C. Then, in the following step 1312, the current proportionality coefficient B corresponding to the current environmental temperature and the target load current Is set in step 1301 is calculated from the data table of FIG. 8D and the above-mentioned approximate equation (12). To do. It should be noted that the calibration constant determining means is configured by the process block 1314 configured by the processes 1310, 1311, and 1312.

A subsequent step 1315 is a step of reading the value of the monitoring voltage Ef input to the microprocessor 111B, and a subsequent step 1316 is to convert the value of the monitoring voltage Ef read in step 1315 into the above-described equation (9). By substituting, the load current Im is converted and estimated by the following equation.
Im = [Ef−A × (Vb + Vd) × γ−C] / B, Vb = Kv × Vf
Note that the energization duty γ0 calculated in step 1304 is used in the initial operation for the value of the energization duty γ in the above equation. However, since the energization duty γ is corrected in step 1324 described later, it is used in step 1316. As the energization duty γ, the latest value at that time is used. Further, the values stored in the nonvolatile data memory 114B are read and used as the values of the calibration constants A, B, C, and Kv, and the value read at step 1302 is used as the value of the power supply monitoring voltage Vf.

Step 1317 executed after step 1316 serves as an average voltage estimating means. In step 1317, the average voltage Va applied to the electric load 107 is calculated by the following equation.
Va = ∫V2 dt / τ = Vb × τon / τ−Vd × τoff / τ
= (Vb + Vd) × γ−Vd (Vd≈1V)
≒ Kv × Vf × γ
In the above equation, energization cycle τ = ON period τon + OFF period τoff. Further, the value of the drive power supply voltage Vb and the value of the energization duty γ are the same as those used in step 1311. However, when the monitored average voltage Va is input to the microprocessor 111B as indicated by the dotted line in FIG. 11, this input signal voltage may be read.

  In subsequent steps 1318 and 1319, the average voltage Va calculated in step 1317 and the minimum resistance Rmin and the maximum resistance Rmax of the electric load 107 stored in the nonvolatile program memory 113B or the nonvolatile data memory 114B as fixed constants. The maximum current Imax and the minimum current Imin are calculated. Here, the maximum resistance and the minimum resistance are the upper and lower limit values of the electric resistance in consideration of the variation of the solid variation, the change of the environmental temperature, and the temperature rise of the electric load itself with respect to one electric load.

  Subsequent step 1320 is a step serving as an overcurrent state detection means. In this step 1320, when the load current Im calculated in step 1316 is larger than the maximum current Imax calculated in step 1318, a determination of YES is made to determine an overcurrent state. If the load current Im calculated in step 1316 is not larger than the maximum current Imax calculated in step 1318, NO is determined to determine that the current is not an excessive current state. The process shifts to 1321.

  Step 1321 is a step for detecting an undercurrent state. In this step 1321, when the load current Im calculated in step 1316 is smaller than the minimum current Imin calculated in step 1319, a determination of YES is made to indicate an undercurrent state. When the load current Im calculated in step 1316 is not smaller than the minimum current Imin calculated in step 1319, NO is determined to determine that the current is not an undercurrent state, and the flow proceeds to step 1323. It is supposed to migrate.

  Step 1322 is performed when step 1320 determines an overcurrent condition or when step 1321 determines an undercurrent condition. Then, the value of the data register D1 for determining the energization duty γ is set to zero, the pulse width modulation control output PWM which is the feedback control output of the microprocessor 111B is stopped, and the abnormality notification output DSP is generated to The display 109 is activated.

  In step 1323, which is executed when the determination in step 1321 is not an undercurrent state, the target current Is set in step 1301 is compared with the load current Im calculated in step 1316, and the comparison error is predetermined. If it is equal to or greater than the value, the process proceeds to step 1324, and if the comparison error is small, the process proceeds to operation end step 1330.

  In step 1324, the correction value Δγ is increased or decreased with respect to the current energization duty γ in accordance with the magnitude or positive / negative of the comparison deviation in step 1323, the correction result is multiplied by a predetermined magnification N, and the integer value is stored in the RAM memory. In the step of storing in the data register D1, which is a memory having a specific address 112, and storing the value of N−D1 in the data register D2, the predetermined magnification N is, for example, N = 1000.

  When the judgment of the step 1323 is a small comparison deviation, or the operation end step 1330 which shifts to the step 1322 and the step 1324 is a standby step, and after the microprocessor 111B executes another control flow The operation start process 1300 is activated again, and the control flow from the process 1300 to the process 1330 is repeatedly executed. The process block 1325 by the processes 1323 and 1324 serves as an opening / closing control output generating means, and serves as a feedback control means for generating a feedback control output by pulse width modulation control.

An overview of the control flow configured as described above will be described.
First, the initial setting means 1306 compares the reference load current Ir and the target load current Is at a stage where an appropriate energization duty γ by feedback control has not yet been determined, and estimates the energization duty γ0 at the current drive power supply voltage Vb. Is to decide.

  In the conversion estimation means 1316, the load current Im is calculated based on the measured value of the monitoring voltage Ef and the calibration constant, and an accurate load current that eliminates the solid variation of the current detection resistor 126 and the current detection error of the amplifier circuit unit 150 is obtained. Im can be obtained. As a result, if there is a deviation between the target current Is and the load current Im by the feedback control means 1325, the energization rate γ is corrected to increase / decrease and control is performed so that they match. Note that the pulse width modulation control by the microprocessor 111B is executed in the same manner as in FIG. 10 described in the first embodiment, the ON width of the PWM output signal is determined by the contents of the data register D1, and is turned off by the contents of the data register D2. The width is determined.

  Next, when the overcurrent state detecting means 1320 determines the overcurrent state, it is connected to the load short circuit, which is a short circuit between the positive and negative output wires of the electric load 107, the interlayer short circuit between the windings, and the output terminal 108. This may be caused by a ground fault connected to the normal phase wiring and the grounding wire connected to the grounding terminal 104N or the vehicle body or the ground.

  On the other hand, when the undercurrent state detection means 1321 determines the undercurrent state, there are a case where the electric load 107 and the wiring are disconnected and a case where the normal phase wiring is in a power fault. In particular, when the output terminal 108 and the power supply terminal 104P are completely short-circuited due to a power fault of the positive phase wiring, the current flowing through the current detection resistor 126 becomes zero, so there is a discrepancy between the target current and the actual current. Occurrence and abnormality detection can be easily performed. Similarly, when a disconnection accident occurs, the current flowing through the current detection resistor 126 becomes zero, so that a divergence occurs between the target current and the actual current, so that the abnormality detection can be easily performed.

  However, if a power fault occurs between the remote position of the positive phase wiring from the output terminal 108 to the electric load 107 and the remote position of the power supply wiring from the power supply terminal 104P to the drive power supply 101, the wiring resistance R0 And a resistance value R1 of the current detection resistor 126 are configured, and the current flowing through the current detection resistor 126 decreases at a ratio of R0 / (R0 + R1). In such a case, an abnormal state cannot be detected simply by comparing the target current and the actual current.

  For example, if the current shunted to the current detection resistor 126 when the switching element 121 is completely turned on in a state where a power fault has occurred due to the resistor R0 is Ix, the target current is a value equal to or less than Ix. Feedback control is possible so that the target value matches the actual measurement value, and no divergence occurs between the target value and the actual measurement value. Therefore, abnormality detection cannot be performed. However, the comparison criteria in step 1320 and step 1321 are to estimate the current average voltage Va applied to the electric load 107 and calculate the minimum resistance and the maximum current calculated from the maximum resistance and the minimum resistance of the electric load 107. Since it is determined whether or not this is flowing through the current detection resistor 126, a highly accurate abnormality determination can be performed.

  In step 1320 and step 1321, the load current Im is compared with the maximum load current Imax and the minimum load current Imin. However, the maximum load current Imax and the minimum load current Imin calculated in the steps 1318 and 1319 are compared with each other in the amplification circuit unit. The maximum monitoring voltage Emax and the minimum monitoring voltage Emin converted to an output voltage of 150 may be converted into the monitoring voltage Ef, and the maximum monitoring voltage Emax and the minimum monitoring voltage Emin may be compared. In short, it is only necessary to determine that the relative relationship between the monitoring voltage Ef and the estimated average voltage Va does not deviate abnormally.

  In the above description, the case where the current detection resistor 126 is connected to the upstream side of the electric load 107 is taken up. However, the current detection resistor 126 is a circuit type in which the current detection resistor 126 is connected to the downstream position of the electric load. In this case, the error component of the amplifier circuit unit 150 does not include the voltage proportional component, but only the offset component.

  Further, in FIG. 1 showing the first embodiment and FIG. 11 showing the second embodiment, the commutation diode 127 is connected in parallel to the series circuit of the current detection resistor 126 and the electric load 107. 126 may be connected to the outside of the commutation diode 127. In this case, when the open / close element 121 is open, the negative voltage input to the amplifier circuit unit 150 is reduced. However, since the pulsation fluctuation of the detection current increases, the smoothing time constant of the smoothing circuit 160 is increased. It is necessary to keep it.

  Further, in FIG. 1 showing the first embodiment and FIG. 11 showing the second embodiment, the ammeter, voltmeter and thermometer for calibration generate digital outputs, and the microprocessor 111A is connected via the external tools 900 and 990. 111B, however, when an analog meter is used, it is also possible to input to the microprocessors 111A and 111B from the analog input port AIN as part of the analog input group 105a.

  The nonvolatile data memories 114A and 114B can also use partial areas of the nonvolatile program memories 113A and 113B. In this case, the above-described “reading / writing of data with respect to the nonvolatile data memories 114A and 114B” Needs to be read as “read / write data to / from the data memory area of the non-volatile program memory 113A, 113B”.

  The above description is effective when the target load current Is is a variable and constant value, does not change frequently, and the thermal time constant of the current detection resistor 126 is, for example, about several seconds. When the energization current to the load 107 is a high-speed driving overexcitation current that changes frequently and a low constant current for maintaining operation, the current current is calculated using the mean square value of large and small currents that change frequently. The temperature rise of the detection resistor 126 may be estimated. In any case, in the current control device for an electric load having a plurality of electric loads, a plurality of current detection resistors connected in series with each electric load, and one temperature detection element for measuring the internal environment temperature, By estimating the temperature of the current detection resistor, it is possible to prevent a decrease in current control accuracy and the occurrence of a linearity error due to the resistance value of the current detection resistor changing depending on the temperature.

  Further, in the data tables shown in FIGS. 8B, 8C, 8D, and 18B, 18C, 18D, the internal environment temperature T (= Tb, Td) in the normal temperature environment and the high temperature environment. A calibration operation is performed at, and other internal environmental temperatures T (= Ta, Tc, Te) are calculated by interpolation / extension by a statistical method. However, based on a large number of experimental samples, the temperature fluctuation characteristics relating to the current proportionality coefficient B, the error voltage proportionality coefficient (A or D), and the offset component C are measured, and the standard temperature fluctuation characteristics are captured in advance. In some cases, the calibration operation for the actual product should be performed in either a normal temperature environment or a high temperature environment, and in other temperature environments, each calibration constant should be estimated by referring to the standard temperature fluctuation characteristics described above. Is possible.

  As described in detail above, the current control device for an electric load according to the second embodiment is fed from the drive power supply 101, and a power feeding circuit unit in which the switching element 121, the current detection resistor 126, and the electric load 107 are connected in series, In the electric load current control device 100B, the control circuit unit controls the ON / OFF ratio of the switching element 121 so that the target load current Is for the electric load 107 and the detected load current Im by the current detection resistor 126 coincide with each other. The control circuit unit further includes a microprocessor 111B including a nonvolatile program memory 113B, a nonvolatile data memory 114B, an arithmetic processing RAM memory 112, and a multi-channel AD converter 115, a current detection amplifying circuit unit 150, Temperature detection circuit 170, and nonvolatile program memory 113B further includes control constant calibration. A stage 1208, a conversion estimating means 1316, encompasses a control program of the feedback control means 1325.

  The amplifying circuit unit 150 amplifies the voltage across the current detection resistor 126 connected in series to the electric load 107, and mainly includes a current proportional component proportional to the load current Im with respect to the electric load 107, and includes a monitoring voltage including an error component ΔEf. Ef is generated and input to the microprocessor 111B as negative feedback control information and calibration information. Further, the temperature detection circuit 170 generates a measurement voltage Vt (= Vta to Vte) corresponding to the internal environment temperature T (= Ta to Te) of the current control device 100B, and the measurement voltage Vt is a multi-channel AD converter. 115 to the microprocessor 111B.

  The control constant calibration means 1208 is configured to monitor the voltage Ef based on the actual load current Imm from the calibration ammeter 991d installed externally in one or both of the ambient environment temperature T and the ambient temperature T (= Tb, Td). A current proportional coefficient B (= Bb, Bd) and an error component ΔEf (= ΔEfb, ΔEfd) are calculated for the current proportional component of the actual use internal environment temperature T (= Ta to Te) detected by the temperature detection circuit 170. ), A current proportionality factor Bi (= Bai to Bei) corresponding to a variable target load current Isi (i = 0, 1,... N) and an error calculation ΔEf (= ΔEfa to ΔEfe). Alternatively, the data table is stored in the nonvolatile data memory 114B.

  The conversion estimating means 1316 calculates the estimated load current Im based on the current proportionality coefficient corresponding to the monitoring voltage Ef and the actual use internal environment temperature T, or the same current as the target load current Is determined by the microprocessor 111B. When it is assumed that the electric load 107 has flowed, an estimated monitoring voltage Es corresponding to the actual use internal environment temperature T is calculated.

  The feedback control means 1325 uses the target load current Is as a control target value and the estimated load current Im as a feedback value to control the energization duty γ that is the closing period / opening / closing cycle of the switching element 121 or to control the estimated monitoring voltage Es. The energization duty γ which is the closing period / opening / closing cycle of the switching element 121 is controlled using the monitoring voltage Ef as a feedback value as the target value.

  As described above, the current control device for an electric load according to the second embodiment sets a target current, receives a detection signal proportional to the load current, and generates a pulse output with a duty corresponding to the deviation signal voltage. A calibration operation that includes a processor 111B and that corrects fluctuations in solids of current control characteristics and temperature fluctuations using a calibration ammeter that is installed externally at the product shipment stage. It is implemented in at least one of a normal temperature environment and a high temperature environment so as to obtain a calibration constant based on an error factor due to a variation in solids of a control element, a characteristic variation due to temperature, and a variation in resistance value of the current detection resistor 126 due to self-heating. It has become. Therefore, calibration of detection error is performed for each cause of detection error, and it is calibrated taking into account the factor of temperature fluctuation, so the calibration constant can be used properly during operation of the current control device in various operating environments. In addition to being able to perform high-precision current control, it is characterized by easy calibration operation with a simple external calibration facility.

  In addition, the control circuit unit of the current control device for an electric load according to the second embodiment further includes a power supply voltage measurement circuit including voltage dividing resistors 191b and 192b, and the nonvolatile program memory 113B further includes a calibration coefficient calculation unit 1240B. A control program serving as the transfer storage unit 1203B is included.

The power supply voltage measurement circuit is a circuit for obtaining a power supply monitoring voltage Vf by inputting the drive power supply voltage Vb of the drive power supply 101 to the microprocessor 111B through a voltage dividing circuit. Further, the calibration coefficient calculating means 1240B sets the average value Ef of the monitoring voltage by the current detecting amplifier circuit 150 when the energization duty of the switching element 121 is γ and the voltage drop of the commutation diode 127 is Vd≈1V. The relationship between the drive power supply voltage Vb and the load current Im is
Ef = A × (Vb + Vd) × γ + B × Im + C
And the offset component C, the voltage proportionality factor A, and the current proportionality factor B, which are error components in this equation, are calculated from the measurement data from the calibration operation.

  The transfer storage unit 1203B transfers and stores the values of the voltage proportionality factor A, the current proportionality factor B, and the offset component C, which are the calculation results of the calibration coefficient calculation unit 1240B, as calibration constants in the nonvolatile data memory 114B. The calibration constant is calculated at at least two kinds of ambient temperatures, a normal temperature environment and a high temperature environment, and two kinds of internal environment temperatures T (= Tb, Td), a voltage proportional coefficient A (= Ab, Ad), and a current proportional coefficient. B (= Bb, Bd) and offset component C (= Cb, Cd) are transferred and stored.

  As described above, the electric load current control apparatus according to the second embodiment includes the power supply voltage measurement circuit including the voltage dividing resistors 191b and 192b, the calibration coefficient calculation unit 1240B, and the transfer storage unit 1203B. . Accordingly, the calibration constants for each factor can be calculated and stored efficiently in a step-by-step manner, and the calibration operation can be performed by adding a simple automated facility in the production line for mass-produced products.

  The calibration coefficient calculation means 1240B of the electric load current control apparatus according to the second embodiment further includes a power supply voltage calibration means 1243.

  In the calibration operation, the power supply voltage calibration unit 1243 writes and stores the power supply monitoring voltage Vf in the RAM memory 112 and compares the drive power supply voltage Vb measured by the externally installed calibration voltmeter 992d with the power supply voltage calibration. The coefficient Kv = Vb / Vf is calculated and stored in the nonvolatile data memory 114B, or a fixed constant determined in advance as the reciprocal of the voltage division ratio with respect to the drive power supply voltage Vb is applied.

  As described above, the electric load current control apparatus according to the second embodiment includes the power supply voltage calibration means 1243. Therefore, the driving power supply voltage Vb can be accurately calculated and the calculated voltage can be used for other purposes.

  Further, the nonvolatile program memory 113B of the electric load current control apparatus according to the second embodiment further includes a control program serving as the linearity calibration means 1257.

  The linearity calibration unit 1257 calculates the monitoring voltage Ef based on the actual load current Immi measured by an externally installed calibration ammeter 991d in a calibration operation using a plurality of target load currents Isi (i = 0 to n). The current proportionality coefficient Bi = B × (Isi / Immi) of the current proportional component is calculated. The calculation of the current proportionality factor Bi by the linearity calibration means 1257 is executed at one or both internal temperature T (= Tb, Td) in the normal temperature environment and the high temperature environment, and in the practical internal environment T (= Ta to Te). The values of the current proportional coefficients Bai to Bei are stored in the nonvolatile data memory 114B as approximate formulas or data tables.

  As described above, the current control device for an electric load according to the second embodiment includes the linearity calibration unit 1257, and corrects the current proportionality factor Bi so that a load current proportional to the target current can be obtained. Yes. Therefore, the temperature detection circuit 170 merely measures the environmental temperature inside the current control device and does not directly detect the temperature of the current detection resistor 126 itself, whereas the temperature of the current detection resistor 126 There is a feature that it is possible to prevent a non-linear error in current control from occurring due to a change in proportion to the square of the load current and a change in the resistance value of the current detection resistor 126 accordingly.

The current proportionality factor Bi calculated by the linearity calibration means 1257 of the electric load current control device according to the second embodiment is approximated when the temperature detected by the temperature detection circuit 170 is T and the target load current is Isi. As a formula, a formula of Bi = B / [K1 + K2 × T + K3 × Isi ² ] is applied. The linearity calibration means 1257 calculates current proportionality coefficients Bi corresponding to a plurality of target load currents Isi in at least one of a normal temperature environment and a high temperature environment, and calculates formula constants B, K1, K2, and K3 by the above formula, The formula constant is written and stored in the nonvolatile data memory 114B.

  As described above, the current control device for an electric load according to the second embodiment includes the linearity calibration unit 1257 for calculating the current proportionality factor Bi, and the current proportionality factor Bi is corrected in inverse proportion to the square of the target current. It has become. Therefore, the current proportionality factor Bi can be corrected by a simple approximation formula.

100A, 100B Current control device 101 Drive power supply 107 Electric load 111A, 111B Microprocessor 112 RAM memory 113A, 113B Program memory 114A, 114B Data memory 115 AD converter 116 Serial interface
121 switching element 126 current detection resistor 127 commutation diode 130 target current setting circuit 140 comparative deviation integrating circuit (feedback control circuit)
150 Amplifier circuit section 151 Differential amplifier 170 Temperature detection circuit 900, 990 External tool 901d, 991d Calibration ammeter 902d, 992d Calibration voltmeter 903d, 993d Calibration thermometer 203A, 1203B Transfer storage means 240A, 1240B Calibration coefficient calculation Means 207, 1207 Detection temperature calibration means 208, 1208 Control constant calibration means 243 Average voltage calibration means 1243 Power supply voltage calibration means 257, 1257 Linearity calibration means 319 Conversion setting means 1316 Conversion estimation means 1325 Feedback control means (open / close control output generation means) )
Ef Monitoring voltage Es Target voltage (estimated monitoring voltage)
PWM control output Vb Drive power supply voltage Vcc Control power supply voltage Va Monitor average voltage Vf Power supply monitor voltage Vt Measurement voltage
Is Target load current Im Load current (estimated load current, detected load current)
Imm Actual load current

Claims (13)

A power supply circuit unit in which power is supplied from the drive power source and the switching element, the current detection resistor, and the electric load are connected in series, and the target load current for the electric load and the detection load current by the current detection resistor coincide with each other. A control circuit unit for controlling the open / close element;
A current control device for an electric load comprising:
The control circuit unit further includes
A non-volatile program memory including a control program serving as a control constant calibration unit and a conversion setting unit; and a microprocessor including a non-volatile data memory;
An amplification circuit unit that amplifies the voltage across the current detection resistor, inputs a monitoring voltage generated mainly including a current proportional component proportional to a load current to the electric load, and includes an error component, to the microprocessor;
A temperature detection circuit that generates a measurement voltage corresponding to the internal environmental temperature of the current control device, and inputs the measurement voltage to the microprocessor;
A feedback control circuit for controlling the energization of the switching element using the estimated monitoring voltage corresponding to the target load current as a control target value, and using the monitoring voltage as a feedback value;
The control constant calibration means includes a current proportionality factor relating to a current proportional component of the monitoring voltage based on an actual load current from an externally installed calibration ammeter at one or both of a normal temperature environment and a high temperature environment. A calculation formula or data table for calculating and interpolating an error component and an actual use internal environment temperature detected by the temperature detection circuit, a current proportional coefficient corresponding to a variable target load current, and an error component by separately calculating an error component Save to non-volatile data memory,
The conversion setting means is based on the current proportional coefficient and the error component corresponding to the actual use internal environment temperature, assuming that the same current as the target load current determined by the microprocessor flows to the electric load. A current control device for an electric load, wherein the estimated monitoring voltage is calculated. A power supply circuit unit in which power is supplied from the drive power source and the switching element, the current detection resistor, and the electric load are connected in series, and the target load current for the electric load and the detection load current by the current detection resistor coincide with each other. A control circuit unit for controlling the open / close element;
A current control device for an electric load comprising:
The control circuit unit further includes
A microprocessor including a non-volatile program memory including a control program that serves as a control constant calibration unit, a conversion estimation unit, and a feedback control unit; and a non-volatile data memory;
An amplification circuit unit that amplifies the voltage across the current detection resistor, inputs a monitoring voltage generated mainly including a current proportional component proportional to a load current to the electric load, and includes an error component, to the microprocessor;
A temperature detection circuit that generates a measurement voltage corresponding to the internal environmental temperature of the current control device, and inputs the measurement voltage to the microprocessor;
With
The control constant calibration means includes a current proportionality factor relating to a current proportional component of the monitoring voltage based on an actual load current from an externally installed calibration ammeter at one or both of a normal temperature environment and a high temperature environment. A calculation formula or data table for calculating and interpolating an error component and an actual use internal environment temperature detected by the temperature detection circuit, a current proportional coefficient corresponding to a variable target load current, and an error component by separately calculating an error component Save to non-volatile data memory,
The conversion estimating means calculates an estimated load current based on a current proportionality factor corresponding to the monitoring voltage and the actual use internal environment temperature, or the same current as a target load current determined by the microprocessor is the electric current. Assuming that it has flowed to the load, calculate the estimated monitoring voltage corresponding to the actual internal environment temperature,
The feedback control means controls the energization duty of the switching element using the target load current as a control target value and the estimated load current as a feedback value, or feeds back the monitoring voltage using the estimated monitoring voltage as a control target value. A current control device for an electric load, wherein the duty ratio of the switching element is controlled as a value.   The nonvolatile program memory further includes a control program serving as a detection temperature calibration unit, and the detection temperature calibration unit is a digital conversion value of a measurement voltage of the temperature detection circuit in at least one of a normal temperature environment and a high temperature environment. Is compared with the known internal environment temperature or the estimated internal environment temperature by an externally installed calibration thermometer, and the actual temperature is measured based on the predetermined temperature vs. measured voltage characteristics in the applied temperature detection circuit. The current control device for an electric load according to claim 1 or 2, wherein an arithmetic expression for calculating a use internal environmental temperature or a data table is stored in the nonvolatile data memory.   The nonvolatile program memory further includes a control program serving as a detection temperature calibration unit, and the detection temperature calibration unit includes a digital conversion value of a measurement voltage of the temperature detection circuit in both a normal temperature environment and a high temperature environment. Comparing the known internal environment temperature or the estimated internal environment temperature with a calibration thermometer installed externally, the interpolation calculation formula to calculate the actual use environment temperature from the actual measurement voltage, or the data table in the nonvolatile data memory The electrical load current control device according to claim 1 or 2, wherein the current control device is stored. The control circuit unit further includes a serial communication interface circuit for connecting between an external tool and the microprocessor.
The calibration command in the control constant calibration means or the detected temperature calibration means and the calibration ammeter or thermometer measurement value externally installed are input from the external tool and transferred to the RAM memory of the microprocessor. The current control device for an electric load according to claim 3 or 4, wherein the current control device is written. The power supply circuit unit is connected in parallel to a series circuit of the current detection resistor and the electric load, or directly connected in parallel to the electric load, and when the switching element is opened Comprising a commutation diode connected to the polarity where the sustained decay current due to the inductance of the electrical load circulates;
The amplifying circuit unit applies a substantially equal positive bias voltage to a differential amplifier for amplifying a differential voltage between voltages across the current detection resistor, and an input of the differential amplifier, so that the switching element is opened. A bias correction circuit for canceling a negative voltage applied by a voltage drop of the commutation diode when the current is applied and preventing a negative voltage input from being applied to the differential amplifier;
The control constant calibration means further calculates at least one of a voltage proportional coefficient and an offset component of an error component in addition to the current proportional coefficient of the monitoring voltage at at least two types of internal environmental temperatures of the normal temperature environment and the high temperature environment. The current control of the electric load according to claim 1 or 2, wherein a calculation formula for interpolating a voltage proportionality coefficient or an offset component at an actual use internal environmental temperature or a data table is stored in the nonvolatile data memory. apparatus. The control circuit unit further includes an average voltage measurement circuit that obtains a monitored average voltage by inputting a voltage across the electric load to the microprocessor via a voltage dividing circuit, and the nonvolatile program memory further includes a calibration coefficient. Including a control program serving as a calculation means and a transfer storage means,
The calibration coefficient calculation means includes Ef as the average value of the monitoring voltage by the amplifier circuit unit, Va as the monitoring average voltage, Im as the load current, C as the offset component as an error component, D as the voltage proportional coefficient, and current proportionality When the coefficient is B, a relational expression among the average value Ef of the monitoring voltage, the monitoring average voltage Va, and the load current Im is an expression represented by Ef = D × Va + B × Im + C, and the offset component C and the voltage The proportionality coefficient D and the current proportionality coefficient B are calculated from the measurement data by the calibration operation,
The transfer storage means transfers and stores the voltage proportional coefficient, the current proportional coefficient, and the offset component values, which are the calculation results of the calibration coefficient calculation means, as calibration constants in the nonvolatile data memory, and the transfer stored calibration 2. The current control device for an electric load according to claim 1, wherein the constant is calculated at at least two kinds of environmental temperatures of a normal temperature environment and a high temperature environment. The calibration coefficient calculation means further includes an average voltage calibration means,
In the calibration operation, the average voltage calibration means inputs the voltage of the driving power source measured by an externally installed calibration voltmeter, writes and stores it in the RAM memory of the microprocessor, and makes the switching element conductive. When the average monitoring voltage is Va, the voltage of the driving power source is Vb, and the average voltage calibration coefficient between the monitoring average voltage Va and the voltage Vb of the driving power source is Ka, Ka = Vb / Va 8 is calculated and stored in the non-volatile data memory, or a predetermined fixed constant is applied as a reciprocal of a voltage dividing ratio with respect to a voltage across the electric load. Current control device. The power supply circuit unit is connected in parallel to a series circuit of the current detection resistor and the electric load, or directly connected in parallel to the electric load, and when the switching element is opened Comprising a commutation diode connected to the polarity to which a sustained decay current due to the inductance of the electrical load circulates;
The control circuit unit further includes a power supply voltage measurement circuit that inputs a voltage of the drive power supply to the microprocessor via a voltage dividing circuit to obtain a power supply monitoring voltage, and the nonvolatile program memory further includes a calibration coefficient calculation unit. And a control program that serves as a transfer storage means,
The calibration coefficient calculation means is configured such that the energization duty of the switching element is γ, the voltage drop of the commutation diode is Vd≈1V, the average value of the monitoring voltage by the amplifier circuit unit is Ef, the voltage of the drive power supply is Vb, When the load current is Im, the offset component as an error component is C, the voltage proportionality factor is A, and the current proportionality factor is B, the average value Ef of the monitoring voltage, the voltage Vb of the drive power supply, and the load current The relational expression with Im is assumed to be Ef = A × (Vb + Vd) × γ + B × Im + C, and the offset component C, the voltage proportional coefficient A, and the current proportional coefficient B in the above formula are calculated from the measurement data obtained by the calibration operation,
The transfer storage means transfers and stores the voltage proportionality coefficient, the current proportionality coefficient, and the offset component values, which are calculation results by the calibration coefficient calculation means, as calibration constants in the nonvolatile data memory, and the transfer storage is performed. 3. The electric load current control device according to claim 2, wherein the calibration constant is calculated at at least two kinds of environmental temperatures of a normal temperature environment and a high temperature environment. The calibration coefficient calculation means further includes a power supply voltage calibration means,
In the calibration operation, the power supply voltage calibration means writes and stores the power supply monitoring voltage in the RAM memory of the microprocessor, and compares it with the voltage of the drive power supply measured by an externally installed calibration voltmeter. The power supply voltage calibration coefficient is calculated and stored in the non-volatile data memory, or a predetermined fixed constant is applied as the reciprocal of the voltage division ratio with respect to the voltage of the drive power supply. Electric load current control device. The nonvolatile program memory further includes a control program serving as linearity calibration means,
The linearity calibration means calculates a current proportional coefficient of a current proportional component in the monitoring voltage based on an actual load current measured by an external calibration ammeter in a calibration operation with a plurality of target load currents. The calculation is executed at the internal environment temperature of one or both of the normal temperature environment and the high temperature environment, and the value of the current proportional coefficient in the practical internal environment is stored in the nonvolatile data memory as an approximate expression or a data table. The current control device for an electric load according to claim 1, wherein the current control device is an electric load. For the current proportionality factor Bi, the following formula is applied as an approximate formula when the temperature detected by the temperature detection circuit is T, the target load current is Isi, and the formula constants are B, K1, K2, and K3.
Bi = B / [K1 + K2 × T + K3 × Isi ² ]
The linearity calibration means calculates a current proportional coefficient corresponding to a plurality of target load currents in at least one of a normal temperature environment and a high temperature environment, calculates the formula constant, and writes and stores the formula constant in the nonvolatile data memory. The current control device for an electric load according to claim 11. The current control device is a current control device for a plurality of linear solenoids in an automatic transmission for an automobile, and is housed in a sealed housing.
The temperature detection circuit estimates an average ambient temperature in the sealed casing by measuring a temperature in the vicinity of the microprocessor, or a temperature in the vicinity of a constant voltage power supply circuit that supplies power to the microprocessor and the multi-channel AD converter,
The calibration operation in the normal temperature environment is performed in an assembly inspection process of the current control device, and the calibration operation in the high temperature environment is performed in a high temperature test process following the assembly inspection process. The electric load current control device according to claim 2.

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