JP2003023800A - Motor controller and method of motor control - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a high speed and high response position-sensorless controller utilizing an arithmetic unit, such as a microcomputer. SOLUTION: This motor controller comprises an AC motor 1, a PWM inverter for applying voltage to the AC motor 1 and a controller 4 for controlling the PWM inverter with the PWM signal. Moreover, the controller 4 comprises a first arithmetic unit 5, including a current controlling means for controlling the current of the AC motor 1 and a second arithmetic unit 6 which includes a magnetic pole detecting means for detecting rotor magnetic pole position of the AC motor, which becomes the reference position of the current control means.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a motor control device and a motor control method for controlling an AC motor with high performance, and more particularly to a magnetic pole position sensorless system control device and control method for a synchronous motor.

[0002]

2. Description of the Related Art In order to control the speed and torque of a synchronous motor with high response, the motor current is coordinate-converted into a magnetic flux direction (d axis) and a direction (q axis) orthogonal thereto based on the magnetic pole position of the motor rotor. However, it is necessary to perform vector control. Therefore, conventionally, a position sensor such as a resolver is attached to the rotary shaft of the motor 1 to detect the magnetic pole position. However, when using the position sensor, there are problems such as cost, wiring, and reliability. Therefore, in recent years, various "position sensorless control methods" have been proposed in which the synchronous motor is controlled without detecting the magnetic pole position by the position sensor. Synchronous motors are generally classified into cylindrical type and salient pole type (including reverse salient pole type). Among them, the magnetic pole position estimation method of salient pole type synchronous motor is based on the method of using the induced voltage generated by the motor or the voltage equation of the motor. Several methods have been proposed so far, including a method based on the above and a method using the inductance characteristic of the motor. For example, such a position sensorless control system has been proposed in JP-A-7-107776, JP-A-9-56199, JP-A-2001-8486 and the like. Each of these methods is a theoretical method based on the characteristics of the motor and the voltage equation, and is a method capable of highly accurately estimating the magnetic pole position by inputting the motor current and further the motor voltage.

For example, the salient pole ratio of the inductance (Ld ≠ L
An example of the method using q) is as follows.
First, an example of the inductance current characteristic of the permanent magnet synchronous motor having saliency is shown in FIG. Ld is the inductance in the d-axis direction, and Lq is the inductance in the q-axis direction. As shown in FIG. 4, Ld and Lq have different values (having saliency). Therefore, as shown in FIG. 2, by applying the position detection signal 14 to the motor and detecting the amount of change in current generated by the application of this voltage signal, the d-axis direction, that is, the magnetic pole position θ direction can be detected. . The position detection signal 14 is, for example, a pulse having a frequency sufficiently higher than the motor frequency in order to distinguish it from the current control voltage.

[0004]

However, the following problems are conceivable in the above prior art. First, in order to realize such a position sensorless system with a controller such as a microcomputer, it is necessary to perform arithmetic processing with a certain number of steps. Furthermore, motors tend to have higher frequencies with cost reduction and miniaturization,
Need to control faster. In order to maintain high responsiveness even when the motor is operated at high speed and high frequency,
The sampling period of the controller should be as short as possible. On the other hand, in an arithmetic unit such as a microcomputer, it is necessary to perform processing such as protection function and communication function in addition to motor control processing. From the viewpoint of software load factor, one microcomputer is a highly reliable position sensorless system. It may be difficult to realize the above.

Considering the above-mentioned matters, when a high-speed and high-response position sensorless control is performed using a controller such as a conventionally used microcomputer, the calculation may not be completed in a desired sampling cycle. Comes out.

Therefore, an object of the present invention is to provide a highly reliable motor control device and control method, which is equipped with a high-speed and high-response position sensorless control device, is suitable for low cost and downsizing.

[0007]

According to the present invention, in a motor control device comprising an AC motor, an inverter for applying a voltage to the AC motor, and a controller for controlling the inverter, the controller is a torque command. And a first arithmetic unit having current control means for controlling the electric current of the AC motor based on the detected current value of the AC motor, and a second arithmetic unit for monitoring an abnormal state of the first arithmetic unit.
And a communication means for transmitting and receiving data between the first arithmetic device and the second arithmetic device,
The second arithmetic device includes magnetic pole position detection means for detecting the rotor magnetic pole position of the AC motor,
The above object is achieved.

Further, the first arithmetic unit is the second arithmetic unit.
The current control calculation is performed on the basis of the rotor magnetic pole position of the AC motor detected by the arithmetic unit, and the command value of the voltage applied to the AC motor is output.

Further, the second arithmetic unit calculates the rotor magnetic pole position by an arithmetic process using at least the detected current value of the AC motor as an input, and the calculated value is used as the detected value of the rotor magnetic pole position. 1 is output to the arithmetic unit.

Further, in order to make the above-mentioned structure work,
It is necessary to transfer data between the first arithmetic device and the second arithmetic device, and serial communication means or dual port RAM is used for this data transmission.

Further, it is necessary to synchronize the PWM carrier generated in the first arithmetic unit with the arithmetic task started in the second arithmetic unit. For this reason, the first arithmetic unit has a P carrier synchronized with the PWM carrier generated in the device.
The WM carrier synchronization signal is output to the second arithmetic device, and the second arithmetic device generates an interrupt by the PWM carrier synchronization signal to activate the arithmetic task synchronized with the PWM carrier in the previous period.

According to the present invention, since the magnetic pole position of the AC motor is detected by the second arithmetic unit that monitors the abnormal state of the first arithmetic unit, high speed and high speed using a controller such as a microcomputer. It is possible to provide a motor control device and a control method which are responsive and have high reliability, low cost and small size.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of the present invention will be described below with reference to FIG. FIG. 1 is a diagram showing a configuration of a motor control device having a first arithmetic device and a second arithmetic device according to an embodiment of the present invention. The first arithmetic unit 5 and the second arithmetic unit 6 in the figure can be realized by, for example, a microcomputer. In FIG. 1, the DC voltage of the battery 2 is converted into a 3-phase AC voltage by the PWM inverter 3 and applied to the synchronous motor 1.

The command V * (Vu *, Vv *, Vw *) of the applied voltage is calculated by the first arithmetic unit 5 in the controller 4 as follows. (The block diagram of FIG. 2 shows the contents of the calculation performed by the first calculation device 5.) First, in the current command generator 7, the d-axis current command value is changed with respect to the torque command value Tr * that should be generated by the motor. id * and q-axis current command value iq * are determined. Here, the d-axis indicates the magnetic pole position (magnetic flux) direction of the rotor of the motor 1 (the direction of θ with respect to the α-axis), the q-axis indicates the direction electrically orthogonal to the d-axis, and the dq-axis indicates It constitutes a rotating coordinate system that rotates at a motor angular velocity ω.

FIG. 3 shows the relationship between the rotating coordinate system (dq axes) and the stationary coordinate system (α-β axes). The controller 4 of this embodiment constitutes a current control system on the dq axes. The feedback value to the current control unit 8 receives the signals from the current sensors 9u, 9v, 9w as input, and the current detection unit 1
D obtained by coordinate conversion of the u-phase current iu ^, v-phase current iv ^, and w-phase current iw ^ detected at 0 in the dq conversion unit 11.
They are the axis current detection value id ^ and the q axis current detection value iq ^. Further, the voltage commands Vd *, Vq * calculated by the current control unit 8 are coordinate-converted by the three-phase conversion unit 12 to obtain three-phase AC voltage commands Vur, Vvr, Vwr. Then, the three-phase AC voltage commands Vur, Vvr, Vwr are converted into PWM signals Vu *, Vv *, Vw * in the PWM signal generator 13,
It is output to the gate circuit of the inverter 3.

The above is the applied voltage command V * (Vu *, Vv *, Vw *)
Is a calculation procedure of. At this time, the magnetic pole position θ of the rotor is required for coordinate conversion performed by the dq converter 11 and the three-phase converter 12, and a position sensorless system is adopted.

Further, the controller 4 has a second arithmetic unit 6 as shown in FIG. Second arithmetic unit 6
FIG. 5 shows the processing contents of the above. The second arithmetic unit 6 basically detects the abnormality of the first arithmetic unit 5 by the abnormality monitoring means 30. There are various possible methods for detecting this abnormality. For example, there is a method of comparing the detected values of the dq axis currents. The first arithmetic unit 5 detects the dq axis currents id ^, iq ^ for current control. Therefore, similarly, in the second arithmetic unit 6 as well, the motor current is input by the current detector 32, and dq
The conversion unit 41 detects the dq axis currents id2 ^, iq2 ^.
Subsequently, the communication means 25 shown in FIG. 1 receives the output data id ^, iq ^ from the first computing means 5 at the communication input / output unit 31, and the abnormality monitoring means 30 receives id ^, iq ^ and id2 ^, i
If q2 ^ is compared and the difference is equal to or greater than a predetermined value, it is considered that an abnormality has occurred in the arithmetic unit. When an abnormality is detected by the abnormality monitoring means 30, the first arithmetic unit 5 is transmitted via the communication means 25.
The detection result is transmitted to the abnormality monitoring means 33. The abnormality monitoring means 33 stops the output of the PWM signal in response to the abnormality detection. Here, the abnormality monitoring means 30 of the second arithmetic unit 6
In the above, the abnormality determination is made, but the abnormality monitoring means 33 of the first arithmetic unit 5 may make the abnormality determination. in this case,
Data necessary for abnormality monitoring is transmitted from the second arithmetic unit 6 to the first arithmetic unit 5 via the communication means 25. Also,
This abnormality detection processing does not have to be performed every minimum sampling of the controller, and the abnormality monitoring function can be realized if it is performed every several msec.

In this embodiment, the motor current is
Although three phases of U phase, V phase, and W phase are used, the present invention can be implemented by using two phase currents. Further, in the present embodiment, the controller is described as constituting a torque control system, but the present invention can be applied without any problem even when a speed control system is added above the torque control system. is there.

An object of the present invention is to provide a high-speed, high-response position sensorless control device using a controller such as a microcomputer as described above.

In order to solve such a problem, in the present invention, the magnetic pole position detecting means 40 is newly added to the second arithmetic unit 6.
To be installed. The second arithmetic device is originally provided to monitor the abnormality of the first arithmetic device, and the soft load factor is lower than that of the first arithmetic device. Therefore, by providing the magnetic pole position detection means 40 in the second arithmetic device,
It is possible to configure a low-cost and highly reliable position sensorless control system without increasing the soft load factor of the arithmetic unit.

Here, the configuration of the second arithmetic unit 6 will be described. Similarly to the first arithmetic unit 5, the second arithmetic unit 6 is also realized by a microcomputer or the like. Second
The processing contents of the arithmetic unit 6 are shown in the block diagram of FIG.
In the second arithmetic unit 6, the three-phase motor currents iu, iv, iw are input to the current detector 32, and the current change generated by the position detection signal 14 applied to the motor 1 by the first arithmetic unit 5 is changed. The current change amount detector 15 detects Δiα and Δiβ. Further, the phase detection unit 16 calculates the magnetic pole position detection value θ ^ based on the current changes Δiα and Δiβ. Although the algorithm to be executed differs depending on the type of the position detection signal 14, the phase detection unit 16 executes an operation to obtain the phase of the current change vector, an operation to obtain the magnitude of the current change amount, and the like.

Further, in the first arithmetic unit 5, the motor speed ωm is required in addition to the magnetic pole position θ in order to control the motor. The position where the motor speed is required is the current command generator 7, and when the speed control system is configured, it is used for feedback to the speed control system. The motor speed ωm can be obtained by calculating the time change of the magnetic pole position detection value θ ^ in the speed detecting unit 17 of the second arithmetic device 6.

The above is the main processing contents of the magnetic pole position detecting means 40 constituted by the second arithmetic unit 6, and the second arithmetic unit 6 monitors the abnormality of the first arithmetic unit as described above. It mainly operates the processing and the magnetic pole position detection processing.

Next, a communication method between the first arithmetic unit 5 and the second arithmetic unit 6 will be described. In the controller of the present embodiment, the communication unit 25 transmits and receives the data necessary for abnormality detection, the magnetic pole position detection value θ ^ and the motor speed detection value ωm ^ calculated by the second arithmetic unit 6.
FIG. 6 shows a configuration example of the communication means 25. Among the data to be communicated, the magnetic pole position detection value θ ^ needs to be transferred at higher speed as the motor frequency becomes higher. One of data communication methods between the first arithmetic unit 5 and the second arithmetic unit 6 is a method using serial communication which is a peripheral device of a microcomputer.

FIG. 6 shows a connection example when serial communication is used.
Shown in. In the connection example of FIG. 6, the communication clock is shared, and the data transmission terminal of the second arithmetic device 6 and the data reception terminal of the first arithmetic device 5 are connected. In the case of FIG. 6, only data transmission from the second arithmetic unit 6 to the first arithmetic unit 5 is shown, but the opposite is naturally possible. In that case, the data transmission terminal of the first arithmetic unit 5 and the data reception terminal of the second arithmetic unit 6 are connected. Normally, serial communication means transmits data bit by bit. For example, a 16-bit width magnetic pole position detection value and 1
In order to transmit the motor speed detection value of 6-bit width, 32 bits in total, if the communication speed is 10 Mbps, it is possible to complete one data transmission in a communication time of about 3.2 μsec. With a communication speed of this level, it is possible to sufficiently cope with high-speed motor control.

Further, as shown in FIG. 6, another data transmission / reception method between the first arithmetic unit 5 and the second arithmetic unit 6 is such that the data is transmitted between the first arithmetic unit 5 and the second arithmetic unit 6. To DPRA
This is a method of providing an M (Dual Port RAM) 20. DPRAM2
When 0 is used, data writing and reading are performed with an arbitrary data width (for example, 8 bits). It is sufficient that the data transfer rate used for abnormality monitoring is about several msec. Here, the magnetic pole position detection value θ for motor control
When passing ^, the DPRAM 20 is required to have a capability of reading and writing at a speed of about 10 μsec.

The above is the description of the data transmission / reception method between the first arithmetic unit 5 and the second arithmetic unit 6. In this embodiment, the magnetic pole position detection value and the motor speed detection value are transferred, but if the soft load of the first arithmetic unit 5 has some margin, only the magnetic pole position detection value may be used. In this case, the motor speed is calculated by the first calculation device 5, so that the time required for data transfer can be shortened.

Next, a method of synchronizing the PWM carrier generated by the first arithmetic unit 5 and the arithmetic task started by the second arithmetic unit 6 will be described. The magnetic pole position detection method used in the present invention is a method in which a position detection signal 14 is applied to the motor 1 and a change in current generated thereby is detected. In this case, the first arithmetic unit 5 outputs the position detection signal 14
Is applied, and the change in current generated thereby is detected by the second arithmetic unit 6. Therefore, the application timing of the position detection signal 14 in the first arithmetic unit 5 and the second
It becomes necessary to synchronize with the detection timing of the motor current in the arithmetic unit 6.

There are the following methods for this synchronization method. First, FIG. 7 shows a configuration of a method for synchronizing two arithmetic devices. In FIG. 7, the PWM carrier synchronization signal 21 from the first arithmetic unit 5 applying the position detection signal 14 is applied.
Is output to the second arithmetic unit 6. The second arithmetic unit 6 receives the PWM carrier synchronization signal 21 at the external interrupt terminal 22 and generates an external interrupt to detect the motor current. Normally, the voltage command output to the inverter (update of the voltage command) is performed in synchronization with the PWM carrier. Therefore, by activating the task in synchronization with the PWM carrier as described above, the application timing of the position detection signal 14 and It is possible to synchronize with the detection timing of the motor current in the second arithmetic unit 6.

FIG. 8 shows an outline of the PWM carrier synchronization signal. First, in the first arithmetic unit 5, the PWM as shown in FIG.
The carrier is generated and used as the standard for PWM signal conversion.
Normally, the voltage command is output (updated) at the timing of "peak" or "valley" of this PWM carrier wave. Further, the microcomputer may have a function capable of outputting a pulse synchronized with the PWM carrier as shown in FIG. In such a case, this pulse is output to the second arithmetic unit 6 as the PWM carrier synchronization signal 21.
In the second arithmetic unit 6, this PWM carrier synchronization signal 21 is input as an external interrupt signal to generate an interrupt.
By activating the A / D converter by this interrupt, it becomes possible to detect the current according to the position detection signal 14. In Figure 8, PWM carrier synchronization signal 2
The case where an interrupt occurs at the falling edge of 1 is shown.

By the above method, the voltage output timing of the first arithmetic unit 5 and the task activation timing of the second arithmetic unit 6 can be synchronized. When the microcomputer cannot generate a pulse signal synchronized with the PWM carrier, the first arithmetic unit 5 generates an interrupt at the “peak” or “valley” of the PWM carrier, and outputs the signal to the outside at that timing. Generate. In this way, the PWM carrier synchronization signal is output.

Although the embodiment has been described for a synchronous motor, the present invention can also be applied to a speed sensorless system for an induction motor. Further, the present invention is applicable to any application as long as it is a position (speed) sensorless motor control device.

Of these, the present invention is suitable for electric vehicles and hybrid vehicles. This is because the position sensorless system is effective for cost reduction, the driving motor tends to increase in speed, and it is necessary to detect the magnetic pole position in a short cycle.

The controller of an electric vehicle or a hybrid vehicle is often equipped with an arithmetic unit for detecting an abnormality, and this system can be applied relatively easily.

An electric vehicle to which the present invention is applied has a drive motor for driving the vehicle, a battery which is a power source of the drive motor and which recovers energy during regenerative braking, and operation of an accelerator and a brake. A motor control device for controlling the drive motor according to an operation command given through the motor control device is provided, and the motor control device is provided with an arithmetic unit for detecting an abnormality. The present invention can also be applied to a hybrid vehicle in which an engine and a drive motor are combined as a vehicle drive source, and the motor control device includes an arithmetic unit for detecting an abnormality.

[0036]

According to the present invention, there is provided a first arithmetic unit having current control means for controlling the current of an AC motor, and a second arithmetic unit for monitoring an abnormal state of the first arithmetic unit.
A controller such as a microcomputer is used by including a communication means for transmitting and receiving data between the first and second arithmetic devices, and detecting the magnetic pole position of the AC motor in the second arithmetic device. It is possible to provide a small-sized motor control device and control method with high speed, high response, high reliability, low cost.

[Brief description of drawings]

FIG. 1 is a diagram showing a configuration of a motor control device having a first arithmetic device and a second arithmetic device in an embodiment of the present invention.

FIG. 2 is a block diagram showing the contents of processing performed by the first arithmetic unit of FIG.

[Fig. 3] Rotating coordinate system (dq axes) and stationary coordinate system (α-β
It is a figure which shows the relationship with (axis).

FIG. 4 is a diagram showing an example of an inductance current characteristic of a permanent magnet synchronous motor having saliency.

5 is a block diagram showing the processing contents of the second arithmetic unit of FIG. 1. FIG.

FIG. 6 is a diagram showing a configuration example of a communication unit in the embodiment of the present invention.

FIG. 7 is a diagram showing a synchronization method between two arithmetic devices according to the embodiment of the present invention.

FIG. 8 is a diagram showing an outline of a PWM carrier synchronization signal in the synchronization method of FIG.

[Explanation of symbols]

1-AC motor, 2-battery, 3-PWM inverter,
4-controller, 5-first arithmetic unit, 6-second arithmetic unit, 7-current command generator, 8-current controller, 9u, 9
v, 9w-current sensor, 10,32-current detector, 11,4
1-dq converter, 12-3 phase converter, 13-PWM signal generator, 14-position detection signal, 15-current change amount detector,
16-phase detector, 17-speed detector, 20-DPRAM,
21-PWM carrier synchronization signal, 22-external interrupt input terminal, 25-communication means, 30, 33-abnormality monitoring means, 40
-Magnetic pole position detection means.

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Headquarters Mitsuyuki             Hitachinaka City, Ibaraki Prefecture 2520 Takaba             Ceremony Company Hitachi Ltd. Automotive equipment group (72) Inventor Hiroshi Katayama             Hitachinaka City, Ibaraki Prefecture 2520 Takaba             Ceremony Company Hitachi Ltd. Automotive equipment group (72) Inventor Kenfumi Sawada             Hitachinaka City, Ibaraki Prefecture 2520 Takaba             Ceremony Company Hitachi Ltd. Automotive equipment group F term (reference) 5H115 PG04 PI16 PU10 PU11 PU21                       PV09 QN02 QN03 QN09 RB22                       SE01 TO16                 5H560 AA08 BB04 BB12 DA14 DB14                       EB01 EC01 GG04 RR06 SS02                       TT11 TT15 TT16 UA01 XA02                       XA13 XB10                 5H576 AA15 BB09 CC02 DD07 EE01                       EE14 FF02 FF03 FF04 GG01                       GG02 GG04 HA01 HB02 JJ03                       LL14 LL22 LL41 LL55 MM10

Claims (10)

[Claims] 1. A motor control device comprising an inverter for applying a voltage to an AC motor and a controller for controlling the inverter, wherein the controller controls the AC motor based on a torque command and a detected current value of the AC motor. A first arithmetic unit having a current control means for controlling an electric current; a second arithmetic unit monitoring an abnormal state of the first arithmetic unit;
And a communication means for transmitting and receiving data between the second arithmetic device and the second arithmetic device, wherein the second arithmetic device comprises:
A motor control device comprising magnetic pole position detection means for detecting a rotor magnetic pole position of the AC motor. 2. The first arithmetic device according to claim 1, wherein the first arithmetic device performs a current control arithmetic operation based on the rotor magnetic pole position of the AC motor detected by the second arithmetic device, and applies the current control arithmetic operation to the AC motor. A motor control device that outputs a command value of a voltage to be applied. 3. The rotor according to claim 1, wherein the second arithmetic unit calculates the rotor magnetic pole position by an arithmetic process using at least the detected current value of the AC motor as an input, and calculates the calculated value. A motor control device which outputs the detected value of the position to the first arithmetic unit. 4. The communication means according to claim 1, wherein the communication means includes at least serial communication means for transferring data from the second arithmetic device to the first arithmetic device. Motor control device. 5. The communication means according to claim 1, further comprising a dual port RAM for transferring data from at least the second arithmetic device to the first arithmetic device. Motor control device. 6. The PWM inverter for applying a voltage to the AC motor according to claim 1,
The PWM inverter is controlled by the controller, and the first arithmetic unit is generated in the motor controller.
The PWM carrier synchronization signal synchronized with the PWM carrier is the second
To the arithmetic unit, and the second arithmetic unit causes an interrupt in response to the PWM carrier synchronization signal to activate a task synchronized with the PWM carrier. 7. The motor control device according to claim 6, wherein the task started by the second arithmetic device performs at least arithmetic processing of the motor current. 8. A drive device for an electric vehicle, comprising a drive motor for driving a vehicle to travel, comprising:
A drive device for an electric vehicle, comprising the motor control device according to any one of 1. 9. A drive system for a hybrid vehicle including an engine for driving the vehicle to drive and a drive motor, comprising the motor control device according to claim 1. Description: A drive unit for a hybrid vehicle. 10. A method of controlling a motor for controlling the AC motor, comprising: an inverter for applying a voltage to the AC motor; and a controller for controlling the inverter, wherein the controller comprises a first arithmetic unit and a second arithmetic unit. An arithmetic unit and a communication unit for transmitting and receiving data between the first arithmetic unit and the second arithmetic unit are provided, and the torque instruction and the detected current value of the AC motor are provided by the first arithmetic unit. A control signal is generated based on the control signal to control the current of the AC motor, the second arithmetic device monitors an abnormal state of the first arithmetic device, and the detected current value of the AC motor is used. A method of controlling a motor, characterized by calculating a rotor magnetic pole position of the AC motor by performing arithmetic processing.