JP5099579B2 - Electric vehicle control device - Google Patents

Description

  The present invention relates to a control device for an electric vehicle equipped with a system in which a voltage of a DC power source is converted by a conversion means to generate a system voltage and an AC motor is driven by the system voltage via an inverter.

  In an electric vehicle equipped with an AC motor as a power source for a vehicle, for example, as described in Patent Document 1 (Japanese Patent Application Laid-Open No. 2004-274945), an AC motor for driving a drive wheel of a vehicle and an internal combustion engine are disclosed. An AC motor driven by an engine to generate electric power, and a DC voltage obtained by boosting a voltage of a DC power source (secondary battery) by a boost converter is generated in the power line, and each power line is connected to each of the power lines via an inverter. An AC motor is connected and the DC voltage boosted by the boost converter is converted to AC voltage by an inverter to drive the AC motor, or the AC voltage generated by the AC motor is converted to DC voltage by the inverter and this DC voltage is converted. Some are stepped down by a step-up converter and collected by a battery.

In such a system, in order to stabilize the voltage of the power supply line, the voltage of the power supply line is controlled to the target voltage by the boost converter, and the voltage of the power supply line is smoothed by the smoothing capacitor connected to the power supply line. There is something that was made.
JP 2004-274945 A

  However, when the relationship between the driving power of one AC motor and the generated power of the other AC motor (power balance of the two AC motors) changes greatly due to changes in the driving state of the vehicle, etc., the voltage of the power line generated by the change The fluctuation may not be absorbed by the boost converter or the smoothing capacitor, the voltage of the power supply line becomes excessive, and the overvoltage may be applied to the electronic device connected to the power supply line. As a countermeasure, there is a method to increase the voltage stabilization effect of the power supply line by increasing the performance of the boost converter and increasing the capacity of the smoothing capacitor. However, this method increases the size and cost of the boost converter and smoothing capacitor. As a result, there is a problem that it is impossible to satisfy the demands for downsizing and cost reduction of the system.

  In Patent Document 1, when the DC power supply fails, the inverter is set so that the total energy (power balance) of the two AC motors is set to “0” when the DC power supply and the boost converter are interrupted by a relay. Although a control technique is disclosed, this technique is a countermeasure against a failure of a DC power supply, and cannot increase the voltage stabilization effect of the power supply line when the DC power supply is normal. Further, even if it is attempted to control the inverter so that the sum of the energy of the two AC motors is set to “0” during normal operation, one AC motor is connected to the drive shaft of the vehicle and the other AC motor is connected to the internal combustion engine. When connected to the output shaft (that is, when two AC motors are connected to elements with different behaviors), or when the vehicle driving state changes, the influence of the inverter control calculation delay increases. In this case, it is extremely difficult to control the sum of the energy of the two AC motors to be “0”. Furthermore, the AC motor connected to the internal combustion engine cannot avoid the power fluctuation caused by the torque fluctuation of the internal combustion engine, which makes it more difficult to control the sum of the energy of the two AC motors to “0”.

  The present invention has been made in consideration of these circumstances. Therefore, the object of the present invention is to enhance the voltage stabilization effect of the power supply line while satisfying the demands for system miniaturization and cost reduction. It is to provide a control device for an electric vehicle.

In order to achieve the above object, the invention according to claim 1 converts the voltage of a DC power supply to generate a system voltage in the power supply line, the inverter connected to the power supply line, and the inverter driven by the inverter In a control device for an electric vehicle including at least one motor drive unit (hereinafter referred to as “MG unit”) composed of an AC motor, the power required for generating torque of the AC motor of the MG unit by the system voltage control means The system voltage stabilization control is performed to control the fluctuation of the system voltage by operating different input powers. The rotation speed of the AC motor detected by the rotation speed detecting means during the system voltage stabilization control and der those configured for changing the direction of operating a current or voltage to energize the AC motor in accordance with / or torque Specifically, during the system voltage stabilization control, the AC motor is energized when the rotational speed of the AC motor detected by the rotational speed detecting means is not more than a predetermined value and the generated torque of the AC motor is not more than a predetermined value. The current or voltage is selected and operated, and the AC motor is energized when the rotational speed of the AC motor detected by the rotational speed detection means is higher than a predetermined value or the generated torque of the AC motor is higher than a predetermined value. The current or voltage to be operated is selected and operated on the delay side.

  In this configuration, it is possible to control the fluctuation of the system voltage by operating the input power of the MG unit by the system voltage stabilization control, so that the power balance of the AC motor has changed greatly due to the change of the driving state of the vehicle, etc. Even in this case, the system voltage (power supply line voltage) can be stabilized effectively. In addition, the voltage stabilizing effect of the power supply line can be enhanced without increasing the performance of the conversion means and increasing the capacity of the smoothing means, and the requirements for downsizing and cost reduction of the system can be satisfied. Further, since the system voltage is controlled by manipulating input power (that is, reactive power) that is different from the power required for generating torque of the AC motor, the AC motor is maintained with a constant torque (for example, torque command value). The system voltage can be controlled by manipulating the input power of the system, and fluctuations in the system voltage can be suppressed without adversely affecting the driving state of the vehicle.

  By the way, as shown in FIG. 5, the current limit value when controlling the AC motor can be represented by a current limit circle, and the voltage limit value can be represented by a voltage limit ellipse. The range inside the current limit circle and inside the voltage limit ellipse is the current vector and voltage vector operation range. The higher the AC motor speed, the smaller the voltage limit ellipse and the current vector and voltage vector operations. There is a characteristic that the possible range is narrowed in the negative direction of the d-axis (the direction in which the d-axis current decreases).

  For this reason, during the system voltage stabilization control, the current vector or voltage vector is advanced when the rotational speed of the AC motor increases and the current vector or voltage vector operation range is narrowed in the negative direction of the d-axis. If you try to operate the input power by operating to the side (d-axis positive direction), there is a possibility that the input power manipulated variable necessary for system voltage stabilization cannot be realized within the current vector or voltage vector operation range . Also, when the generated torque of the AC motor increases and the current vector and voltage vector become longer, if you try to operate the input power by operating the current vector or voltage vector in the forward direction (positive direction of d-axis) There is a possibility that the input power manipulated variable necessary for stabilizing the system voltage cannot be realized within the current vector or voltage vector operable range.

As a countermeasure against this, the present invention selects either the advance side or the delay side of the current or voltage to be supplied to the AC motor according to the rotational speed and / or generated torque of the AC motor during the system voltage stabilization control. To operate. Specifically, as in claim 1 , when the rotational speed of the AC motor is equal to or lower than a predetermined value and the generated torque of the AC motor is equal to or lower than the predetermined value, the current or voltage to be supplied to the AC motor is selected as the advance side. When the rotational speed of the AC motor is higher than a predetermined value or the generated torque of the AC motor is higher than a predetermined value, the current or voltage supplied to the AC motor may be selected and operated on the lag side. .

  In this way, when the rotational speed of the AC motor is higher than the predetermined value and the operable range of the current vector or voltage vector is narrowed in the negative direction of the d-axis, or the generated torque of the AC motor is lower than the predetermined value. When the current vector or voltage vector becomes longer and the current vector or voltage vector becomes longer, the input power can be manipulated by operating the current vector or voltage vector to the lag side (minus direction of the d-axis). The amount of operation of input power necessary for system voltage stabilization can be realized within the operable range of the vector, and the system voltage stabilization function can be sufficiently exhibited.

  Further, when operating the input power of the AC motor while keeping the torque of the AC motor constant, that is, when operating the current vector or voltage vector along the constant torque curve (see FIG. 3), the current vector or voltage vector Since there is a tendency for torque fluctuation to be smaller when operating on the forward side than operating on the delay side, the current vector when the rotational speed of the AC motor is less than the predetermined value and the generated torque of the AC motor is less than the predetermined value Alternatively, the torque fluctuation can be reduced in the low rotation / low torque region of the AC motor in which the influence of the torque fluctuation becomes large by manipulating the voltage vector to the advance side and manipulating the input power.

The specific control method of the system voltage stabilization control is, as in claim 2 , setting the target value of the system voltage by the target voltage setting means and detecting the system voltage by the voltage detection means, Based on the value and the detected system voltage, the operation amount of the input power of the MG unit is calculated by the operation amount calculating means, and the system voltage is controlled by operating the input power of the MG unit based on the operation amount. Also good. In this way, the input power of the MG unit can be manipulated so as to reduce the deviation between the target value of the system voltage and the detected value of the system voltage, and fluctuations in the system voltage can be reliably suppressed.

In this case, as in claim 3 , a first low-pass means for passing a component having a predetermined frequency or less in the system voltage detected by the voltage detection means is provided, and the first low-pass means is passed. The manipulated variable of the input power of the MG unit may be calculated using the system voltage below the predetermined frequency. In this way, when calculating the operation amount of the input power of the MG unit, the system voltage obtained by removing the noise component (high frequency component) included in the detected value of the system voltage by the first low-pass means is used. The calculation accuracy of the manipulated variable of the input power of the MG unit can be improved.

  By the way, when system voltage stabilization control is performed to suppress fluctuations in system voltage by manipulating the input power of the MG unit, the control of the system voltage by the input power operation of the MG unit and the control of the system voltage by the conversion means are mutually performed. There is a possibility of interference.

As a countermeasure, the conversion power control means may control the input power or output power (hereinafter referred to as “conversion power”) of the conversion means as in claim 4 . Specifically, as in claim 5 , the conversion power command value is calculated by the conversion power command value calculation means, the conversion power is detected by the conversion power detection means, and the conversion power detected as the conversion power command value is detected. The control amount of the conversion power may be calculated by the conversion power control amount calculation means based on the power, and the conversion power may be controlled based on the control amount. In this way, even if the conversion power (input power or output power of the conversion means) fluctuates due to the influence of the system voltage stabilization control (system voltage control by the input power operation of the MG unit), the command value of the conversion power By controlling the conversion power so as to reduce the deviation between the detected conversion power and the detected conversion power, it is possible to prevent interference between the system voltage control by the input power operation of the MG unit and the system voltage control by the conversion means.

Further, the command value of the conversion power, as in claim 6, all connected to a power supply line MG unit input power total value laden power (eg commercial 100V to the total value of the input power of the MG unit The converted power command value may be calculated on the basis of the power obtained by adding a power load other than the MG unit such as a DCAC converter that drives the electric device. When the input power of the MG unit is manipulated, the total value of the input power of all MG units changes, so if the converted power command value is calculated based on the power including the total value of the input power of all MG units. The command value of the converted power that accurately reflects the influence of the input power operation of the MG unit can be calculated.

In this case, the second low-pass means for passing a component having a frequency equal to or lower than a predetermined frequency out of the power including the total value of the input power of all the MG units connected to the power supply line as in claim 7. It is also possible to calculate the command value of the converted power based on the power having a predetermined frequency or less that has passed through the second low-pass means. In this way, the command value of the converted power is accurately obtained based on the power obtained by removing the noise component (high frequency component) included in the power including the total value of the input power of the MG unit by the second low-pass means. In addition to being able to perform calculations, it is possible to prevent interference with control of the system voltage due to operation of the input power of the MG unit by limiting the band.

The detection of the conversion power, as in claim 8, the target value or the detected system voltage of the system voltage may be computed the conversion power based on the output current of the detected converter. In this way, the conversion power can be calculated with high accuracy.

In this case, as in claim 9 , there is provided third low-pass means for passing a component having a frequency equal to or lower than a predetermined frequency in the output current of the converting means detected by the current detecting means, and this third low-pass means is provided. You may make it calculate conversion electric power using the output current below the predetermined frequency which passed the means. In this way, when calculating the conversion power, the output current after the noise component (high frequency component) included in the detected value of the output current of the conversion means is removed by the third low-pass means is used. It is possible to improve the calculation accuracy of the conversion power.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
First, a schematic configuration of an electric vehicle drive system will be described with reference to FIG. An engine 12 that is an internal combustion engine, a first AC motor 13, and a second AC motor 14 are mounted, and the engine 12 and the second AC motor 14 serve as a power source for driving the wheels 11. The power of the crankshaft 15 of the engine 12 is divided into two systems by the planetary gear mechanism 16. The planetary gear mechanism 16 includes a sun gear 17 that rotates at the center, a planetary gear 18 that revolves while rotating on the outer periphery of the sun gear 17, and a ring gear 19 that rotates on the outer periphery of the planetary gear 18. The crankshaft 15 of the engine 12 is connected through a carrier that is not connected, the rotary shaft of the second AC motor 14 is connected to the ring gear 19, and the first AC motor 13 mainly used as a generator is connected to the sun gear 17. Are connected.

  A step-up converter 21 (conversion means) is connected to the DC power source 20 composed of a secondary battery or the like. The step-up converter 21 boosts the DC voltage of the DC power source 20 so as to connect a DC between the power line 22 and the earth line 23. The system voltage is generated or the system voltage is stepped down to return power to the DC power supply 20. A smoothing capacitor 24 for smoothing the system voltage and a voltage sensor 25 (voltage detection means) for detecting the system voltage are connected between the power supply line 22 and the earth line 23, and the current sensor 26 (current detection means) is used. A current flowing through the power supply line 22 is detected.

  Further, a voltage-controlled three-phase first inverter 27 and a second inverter 28 are connected between the power supply line 22 and the ground line 23, and the first inverter 27 is connected to the first AC motor 13. While being driven, the second inverter 28 drives the second AC motor 14. The first inverter 27 and the first AC motor 13 constitute a first motor drive unit (hereinafter referred to as “first MG unit”) 29, and the second inverter 28 and the second AC motor 14 A second motor drive unit (hereinafter referred to as “second MG unit”) 30 is configured.

  The main control device 31 is a computer that comprehensively controls the entire vehicle, and includes an accelerator sensor 32 that detects an accelerator operation amount (an accelerator pedal operation amount), a forward drive or reverse drive of a vehicle, a shift such as parking or neutral. Various sensors such as a shift switch 33 that detects an operation, a brake switch 34 that detects a brake operation, a vehicle speed sensor 35 that detects a vehicle speed, and the output signals of the switches are read to detect the driving state of the vehicle. The main control device 31 sends control signals and data signals between an engine control device 36 that controls the operation of the engine 12 and a motor control device 37 that controls the operation of the first and second AC motors 13 and 14. The control devices 36 and 37 control the operation of the engine 12 and the first and second AC motors 13 and 14 according to the driving state of the vehicle.

  Next, control of the first and second AC motors 13 and 14 will be described with reference to FIG. The first and second AC motors 13 and 14 are three-phase permanent magnet type synchronous motors, each having a built-in permanent magnet, and equipped with rotor rotational position sensors 39 and 40 for detecting the rotational position of the rotor. Has been. The voltage-controlled three-phase first inverter 27 is connected to the DC voltage (by the boost converter 21) of the power line 22 based on the three-phase voltage command signals UU1, UV1, UW1 output from the motor control device 37. The boosted system voltage is converted into three-phase AC voltages U1, V1, and W1, and the first AC motor 13 is driven. The U-phase current iU1 and the W-phase current iW1 of the first AC motor 13 are detected by current sensors 41 and 42, respectively.

  On the other hand, the voltage-controlled three-phase second inverter 28 converts the DC voltage of the power supply line 22 into the three-phase AC based on the three-phase voltage command signals UU2, UV2, UW2 output from the motor control device 37. The second AC motor 14 is driven by converting to voltages U2, V2, and W2. The U-phase current iU2 and the W-phase current iW2 of the second AC motor 14 are detected by current sensors 43 and 44, respectively.

  The first and second AC motors 13 and 14 function as generators when driven by inverters 27 and 28 with negative torque. For example, when the vehicle decelerates, AC power generated by the second AC motor 14 by the deceleration energy is converted into DC power by the inverter 28 and charged to the DC power source 20. Usually, a part of the power of the engine 12 is transmitted to the first AC motor 13 via the planetary gear 18 and is generated by the first AC motor 13 to extract the power of the engine 12, and the generated power is the second power. The second AC motor 14 functions as an electric motor. Further, in a state where the power of the engine 12 is divided by the planetary gear mechanism 16 and the torque transmitted to the ring gear 19 is larger than the torque required for vehicle travel, the first AC motor 13 functions as an electric motor. In this case, the second AC motor 14 functions as a generator, and the generated power is supplied to the first AC motor 13.

  When the torque of the first AC motor 13 is controlled by the motor control device 37, the torque command value T1 * output from the main control device 31, the U-phase current iU1 and the W-phase current of the first AC motor 13. Based on iW1 (output signals of current sensors 41 and 42) and rotor rotational position θ1 of first AC motor 13 (output signal of rotor rotational position sensor 39), three-phase voltage command signal UU1, UV1 and UW1 are generated as follows.

  First, the rotor rotational position θ1 of the first AC motor 13 (the output signal of the rotor rotational position sensor 39) is input to the first rotational speed calculator 45 to calculate the rotational speed N1 of the first AC motor 13. Thereafter, in the dq coordinate system set as the rotation coordinates of the rotor of the first AC motor 13, the first torque control current is used to independently control the d axis current id1 and the q axis current iq1. Calculation unit 46 maps torque control current vector it1 * (d-axis torque control current idt1 *, q-axis torque control current iqt1 *) according to torque command value T1 * of first AC motor 13 and rotational speed N1. Or it calculates by numerical formula etc.

  Thereafter, in the first current vector control unit 47, the U-phase and W-phase currents iU1 and iW1 (output signals of the current sensors 41 and 42) of the first AC motor 13 and the rotor rotation of the first AC motor 13 are rotated. Based on the position θ1 (output signal of the rotor rotational position sensor 39), an actual current vector i1 (d-axis current id1, q-axis current iq1) is calculated, and the d-axis torque control current idt1 * and the actual d-axis current id1 are calculated. The d-axis command voltage Vd1 * is calculated by PI control so that the deviation Δid1 of the q-axis becomes small, and the q-axis by PI control so that the deviation Δiq1 between the q-axis torque control current iqt1 * and the actual q-axis current iq1 becomes small Command voltage Vq1 * is calculated. The d-axis command voltage Vd1 * and the q-axis command voltage Vq1 * are converted into three-phase voltage command signals UU1, UV1, UW1, and these three-phase voltage command signals UU1, UV1, UW1 are output to the first inverter 27. To do.

  On the other hand, when the motor control device 37 controls the torque of the second AC motor 14, the torque command value T2 * output from the main control device 31, the U-phase currents iU2 and W of the second AC motor 14, and the like. Based on the phase current iW2 (output signals of the current sensors 43 and 44) and the rotor rotational position θ2 of the second AC motor 14 (output signal of the rotor rotational position sensor 40), a three-phase voltage command signal is applied in a sinusoidal PWM control system. UU2, UV2 and UW2 are generated.

  At that time, the torque of the second AC motor 14 is kept constant by manipulating the current vector so as to change only the input power (that is, reactive power) different from the power necessary for generating the torque of the second AC motor 14. The system voltage stabilization control that suppresses the fluctuation of the system voltage by operating the input power of the second AC motor 14 while maintaining the (torque command value T2 *) is executed.

  In the system voltage stabilization control of this embodiment, the current vector is delayed when the rotational speed N2 of the second AC motor 14 is higher than the predetermined value Nref or when the torque command value T2 * is higher than the predetermined value Tref. By operating the input power by operating in the negative direction (d-axis negative direction), it is possible to reliably realize the input power operation amount Pm necessary for stabilizing the system voltage. On the other hand, when the rotational speed N2 of the second AC motor 14 is equal to or smaller than the predetermined value Nref and the torque command value T2 * (information on generated torque) is equal to or smaller than the predetermined value Tref, the current vector is advanced (the d-axis plus). The torque fluctuation is reduced by operating the input power by operating in the direction).

  Specifically, first, the rotor rotational position θ2 of the second AC motor 14 (the output signal of the rotor rotational position sensor 40) is input to the second rotational speed calculation unit 48 (rotational speed detection means), and the second The rotational speed N2 of the AC motor 14 is calculated. Thereafter, in the dq coordinate system set as the rotation coordinate of the rotor of the second AC motor 14, the second torque control current is used for the current feedback control of the d-axis current id2 and the q-axis current iq2 independently. Calculation unit 49 maps torque control current vector it2 * (d-axis torque control current idt2 *, q-axis torque control current iqt2 *) according to torque command value T2 * of second AC motor 14 and rotation speed N2. Or it calculates by numerical formula etc.

  Further, the system voltage target value calculation unit 50 (target voltage calculation means) calculates the target value Vs * of the system voltage, and the detected value Vs of the system voltage detected by the voltage sensor 25 is used as the first low-pass filter 51 (first The low-pass filter process is performed to pass only the low-frequency component of the detected value Vs of the system voltage. Thereafter, a deviation ΔVs between the target value Vs * of the system voltage and the detected value Vsf of the system voltage after low-pass filter processing is obtained by the deviation unit 52, and this deviation ΔVs is input to the PI controller 53 (power manipulated variable calculation means). Then, the input power manipulated variable Pm of the second AC motor 14 is calculated by PI control so that the deviation ΔVs between the target value Vs * of the system voltage and the detected value Vsf of the system voltage after the low-pass filter processing becomes small.

  Thereafter, the input power manipulated variable Pm and the torque control current vector it2 * (d-axis torque control current itt2 *, q-axis torque control current iqt2 *) are input to the command current calculation unit 54 (system voltage control means), As shown in FIG. 3, the power control current vector ip * (d-axis power control current idp *, q-axis power control current iqp) changes the reactive power not contributing to the torque generation of the second AC motor 14 by the input power manipulated variable Pm. *).

  At this time, when the rotational speed N2 of the second AC motor 14 is equal to or less than the predetermined value Nref and the torque command value T2 * of the second AC motor 14 is equal to or less than the predetermined value Tref, the leading power control current vector ip * (Power control current vector ip * oriented in the positive direction of the d-axis) is obtained. On the other hand, when the rotational speed N2 of the second AC motor 14 is higher than the predetermined value Nref or the torque command value T2 * is larger than the predetermined value Tref, the delay-side power control current vector ip * (d-axis Find the power control current vector ip *) pointing in the negative direction.

Thereafter, the torque control current vector it2 * (d-axis torque control current idt2 *, q-axis torque control current iqt2 *) and the power control current vector ip * (d-axis power control current idp *, q-axis) The command current vector i2 * (d-axis command current id2 *, q-axis command current iq2 *) on the advance side or the lag side is obtained by combining the power control current iqp *).
i2 * (id2 *, iq2 *) = it2 * (idt2 *, iqt2 *) + ip * (idp *, iqp *)

  The calculation of the command current vector i2 * is executed according to the command current vector calculation program shown in FIG. When this program is started, first, in step 101, the rotational speed N2 of the second AC motor 14 is calculated based on the rotor rotational position θ2 of the second AC motor 14 (the output signal of the rotor rotational position sensor 40). After that, the routine proceeds to step 102 where the torque control current vector it2 * (d-axis torque control current itt2 *, q-axis torque control current iqt2 * corresponding to the torque command value T2 * of the second AC motor 14 and the rotational speed N2 is obtained. ) Is calculated by a map or a mathematical expression.

  Thereafter, the routine proceeds to step 103, where it is determined whether or not the rotational speed N2 of the second AC motor 14 is equal to or less than a predetermined value Nref and the torque command value T2 * of the second AC motor 14 is equal to or less than a predetermined value Tref. .

  As a result, if it is determined that the rotational speed N2 of the second AC motor 14 is less than or equal to the predetermined value Nref and the torque command value T2 * of the second AC motor 14 is less than or equal to the predetermined value Tref, step 104 is performed. Referring to the map of the forward d-axis power control current idp *, according to the input power manipulated variable Pm and the torque control current vector it2 * (d-axis torque control current idt2 *, q-axis torque control current iqt2 *) The forward d-axis power control current idp * is calculated. This map of the d-axis power control current idp * on the advancing side is the advancing side where the power control current vector ip * that changes the reactive power of the second AC motor 14 by the input power manipulated variable Pm is directed in the positive direction of the d-axis. The d-axis power control current idp * on the advancing side is set so as to be the power control current vector ip *.

  On the other hand, if it is determined in step 103 that the rotational speed N2 of the second AC motor 14 is higher than the predetermined value Nref, or the torque command value T2 * of the second AC motor 14 is higher than the predetermined value Tref. If it is determined that the value is larger, the process proceeds to step 105, and the input power manipulated variable Pm and the torque control current vector it2 * (d-axis torque control current itt2 * are referred to with reference to the map of the d-axis power control current idp * on the delay side. , Q-axis torque control current iqt2 *), the d-axis power control current idp * on the delay side is calculated. The map of the delay side d-axis power control current idp * shows that the power control current vector ip * for changing the reactive power of the second AC motor 14 by the input power manipulated variable Pm is the delay side where the d-axis negative direction is directed to the negative direction of the d axis. The d-axis power control current idp * on the delay side is set so that the power control current vector ip * of

ここで、φは鎖交磁束、Ｌd はｄ軸インダクタンス、Ｌq はｑ軸インダクタンスであり、それぞれ第２の交流モータ１４の機器定数である。 Thereafter, the process proceeds to step 106, where the advance side or delay side d-axis power control current idp * is used to calculate the advance side or delay side q-axis power control current iqp * by the following equation.

Here, φ is an interlinkage magnetic flux, Ld is a d-axis inductance, and Lq is a q-axis inductance, which are device constants of the second AC motor 14, respectively.

  By the processing of these steps 104 to 106, the input power (reactive power) of the second AC motor 14 is changed to the input power manipulated variable Pm while the torque of the second AC motor 14 is kept constant (torque command value T2 *). A lead-side or lag-side power control current vector ip * (d-axis power control current idp *, q-axis power control current iqp *) that is changed only by the distance is obtained.

After this, the routine proceeds to step 107 where the torque control current vector it2 * (d-axis torque control current idt2 *, q-axis torque control current iqt2 *) and the power control current vector ip * (d-axis power control current) on the advance side or the lag side. idp * and q-axis power control current iqp *) are combined to determine the lead-side or lag-side command current vector i2 * (d-axis command current id2 *, q-axis command current iq2 *).
i2 * (id2 *, iq2 *) = it2 * (idt2 *, iqt2 *) + ip * (idp *, iqp *)

  As a result, when the rotational speed N2 of the second AC motor 14 is equal to or smaller than the predetermined value Nref and the torque command value T2 * is equal to or smaller than the predetermined value Tref, the command current vector i2 is further advanced than the torque control current vector it2 *. By setting *, the input power is manipulated by manipulating the current vector forward. On the other hand, when the rotational speed N2 of the second AC motor 14 is higher than the predetermined value Nref or the torque command value T2 * is larger than the predetermined value Tref, the command current is delayed to the torque control current vector it2 *. By setting the vector i2 *, the input power is manipulated by manipulating the current vector to the lag side.

  After calculating the command current vector i2 * as described above, the second current vector control unit 55 performs U-phase and W-phase currents iU2 and iW2 of the second AC motor 14 as shown in FIG. Based on (the output signals of the current sensors 43 and 44) and the rotor rotational position θ2 of the second AC motor 14 (the output signal of the rotor rotational position sensor 40), the actual current vector i2 (d-axis current id2 and q-axis current iq2). ) To calculate the d-axis command voltage Vd2 * by PI control so that the deviation Δid2 between the d-axis command current id2 * and the actual d-axis current id2 becomes small, and the q-axis command current iq2 * and the actual The q-axis command voltage Vq2 * is calculated by PI control so that the deviation Δiq2 from the q-axis current iq2 becomes small. Then, the d-axis command voltage Vd2 * and the q-axis command voltage Vq2 * are converted into three-phase voltage command signals UU2, UV2, UW2, and these three-phase voltage command signals UU2, UV2, UW2 are output to the second inverter 28. To do.

  In this way, the second MG is set so that the deviation ΔVs between the target value Vs * of the system voltage and the detected value Vsf is reduced while the torque of the second AC motor 14 is kept constant (torque command value T2 *). System voltage stabilization control is performed by operating the input power of the unit 30 (second AC motor 14) to suppress fluctuations in system voltage.

  Further, the motor control device 37 prevents the above-described system voltage stabilization control (control of the system voltage by operating the input power of the second MG unit 30) and the control of the system voltage by the boost converter 21. Conversion for controlling the duty ratio Dc of a switching element (not shown) of the boost converter 21 so that the deviation ΔPi between the command value Pi * of the output power (hereinafter referred to as “converted power”) of the boost converter 21 and the detected value Pi becomes small. Perform power control.

  Specifically, when calculating the converted power command value Pi *, first, the torque command value T1 * and the rotational speed N1 of the first AC motor 13 are input to the first shaft output calculation unit 56. The shaft output PD1 of the first AC motor 13 is calculated, and the torque command value T1 * and the rotational speed N1 of the first AC motor 13 are input to the first output loss calculation unit 57 to input the first AC motor 13. After the output loss PL1 is calculated, the adder 58 adds the output loss PL1 to the shaft output PD1 of the first AC motor 13 to obtain the input power Pi1 of the first AC motor 13. At this time, when the first AC motor 13 functions as a generator, the calculation result of the input power Pi1 of the first AC motor 13 becomes a negative value.

  Further, the torque command value T2 * and the rotational speed N2 of the second AC motor 14 are input to the second shaft output calculation unit 59 to calculate the shaft output PD2 of the second AC motor 14, and the second AC The torque command value T2 * and the rotational speed N2 of the motor 14 are input to the second output loss calculation unit 60 to calculate the output loss PL2 of the second AC motor 14, and then the adder 61 uses the second AC motor 14 to calculate the output loss PL2. The output power PL2 is added to the shaft output PD2 and the input power Pi2 of the second AC motor 14 is obtained. At this time, when the second AC motor 14 functions as a generator, the calculation result of the input power Pi2 of the second AC motor 14 becomes a negative value.

  Thereafter, the total power Pi * is obtained by summing the input power Pi1 of the first AC motor 13 and the input power Pi2 of the second AC motor by the adder 62, and the total power Pi * is obtained as the second low-pass filter. 63 (second low-pass means) is input and subjected to low-pass filter processing to pass only the low-frequency component of the total power Pi *, and the total power Pif * after this low-pass filter processing is converted into the converted power. The command value is Pif *. The adder 62 and the second low-pass filter 63 serve as converted power command value calculation means.

  On the other hand, when calculating the detected value Pi of the converted power, the detected value ic of the output current of the boost converter 21 detected by the current sensor 26 is input to the third low-pass filter 64 (third low-pass means). A low-pass filter process for passing only the low frequency component of the detected value ic of the output current of the boost converter 21 is performed, and the target value Vs * of the system voltage and the low-pass filter are converted by the conversion power detection unit 65 (conversion power detection means). The detection value Pi of the converted power is obtained by multiplying the detected output current value cf of the boost converter 21 after processing. The detected value Pi of the converted power may be obtained by multiplying the detected value Vsf of the system voltage and the detected value icf of the output current.

  Thereafter, a deviation ΔPi between the converted power command value Pif * and the detected value Pi is obtained by the deviation unit 66, and this deviation ΔPi is input to the PI controller 67 (converted power control amount calculation means). The energization duty ratio Dc of the switching element (not shown) of the boost converter 21 is calculated by PI control so that the deviation ΔPi between Pif * and the detected value Pi becomes small. Thereafter, the boost drive signal calculation unit 68 (conversion power control means) calculates the boost drive signals UCU and UCL based on the energization duty ratio Dc, and outputs the boost drive signals UCU and UCL to the boost converter 21.

  In this way, the conversion power control is performed to control the output power of the boost converter 21 so that the deviation ΔPi between the conversion power command value Pif * and the detected value Pi becomes small, and the system voltage stabilization control (second The control of the system voltage by the input power operation of the MG unit 30) and the control of the system voltage by the boost converter 21 are prevented.

  In the present embodiment described above, the system is operated by operating the input power of the second MG unit 30 (second AC motor 14) so that the deviation ΔVs between the target value Vs * of the system voltage and the detected value Vsf becomes small. Since the system voltage stabilization control that suppresses fluctuations in the voltage (voltage of the power supply line 22) is executed, even when the power balance of the two AC motors 13 and 14 changes greatly due to a change in the driving state of the vehicle or the like. The system voltage can be stabilized effectively. In addition, the voltage stabilization effect of the power supply line 22 can be enhanced without increasing the performance of the boost converter 21 and increasing the capacity of the smoothing capacitor 24, thereby satisfying the demands for system downsizing and cost reduction. it can.

  By the way, as shown in FIG. 5, the current limit value when controlling AC motors 13 and 14 can be represented by a current limit circle, and the voltage limit value can be represented by a voltage limit ellipse. The range inside the current limit circle and inside the voltage limit ellipse is the current vector operable range. As the rotational speed of the AC motors 13 and 14 increases, the voltage limit ellipse becomes smaller and the current vector operable range becomes smaller. There is a characteristic that it is narrowed in the negative direction of the d-axis (the direction in which the d-axis current decreases).

  For this reason, during the system voltage stabilization control, when the rotational speed of the second AC motor 14 is increased and the current vector operable range is narrowed in the negative direction of the d-axis, the current vector is advanced ( If it is attempted to operate the input power by operating in the positive direction of the d-axis), there is a possibility that the input power manipulated variable Pm necessary for stabilizing the system voltage cannot be realized within the current vector operable range. Further, when the torque command value T2 * of the second AC motor 14 becomes large and the current vector (torque control current vector it2 *) becomes long, the current vector is manipulated to the advance side (positive direction of the d-axis). If an attempt is made to manipulate the input power, the input power manipulated variable Pm necessary for stabilizing the system voltage may not be realized within the current vector operable range.

  As these countermeasures, in this embodiment, in the system voltage stabilization control, the rotational speed N2 of the second AC motor 14 is higher than the predetermined value Nref or the torque command value T2 * is larger than the predetermined value Tref. In this case, the current vector is delayed by combining the torque control current vector it2 * with the power control current vector ip * on the lag side and setting the command current vector i2 * on the lag side with respect to the torque control current vector it2 *. Side to operate the input power. As a result, when the rotational speed N2 of the second AC motor 14 becomes higher than the predetermined value Nref and the operable range of the current vector is narrowed in the negative direction of the d-axis, or the torque command of the second AC motor 14 When the value T2 * becomes larger than the predetermined value Tref and the current vector (torque control current vector it2 *) becomes longer, the input power can be manipulated by operating the current vector to the lag side. The input power manipulated variable Pm necessary for system voltage stabilization can be realized within the operable range, and the system voltage stabilization function can be sufficiently exhibited.

  On the other hand, when the rotational speed N2 of the second AC motor 14 is equal to or less than the predetermined value Nref and the torque command value T2 * is equal to or less than the predetermined value Tref, the power control current vector ip * on the leading side is advanced to the torque control current vector it2 *. And the command current vector i2 * is set to the advance side of the torque control current vector it2 *, thereby operating the current vector to the advance side and operating the input power. When operating the input power of the second AC motor 14 while keeping the torque of the second AC motor 14 constant, that is, when operating the current vector along a constant torque curve (see FIG. 3), the current vector Since the torque fluctuation tends to be smaller when operated in the forward direction rather than operating in the delayed direction, the rotational speed N2 of the first AC motor 14 is less than the predetermined value Nref and the torque command value T2 * is the predetermined value. By controlling the input power by operating the current vector forward when Tref or less, torque fluctuation is reduced in the low rotation / low torque region (region where the influence of torque variation is large) of the second AC motor 14. can do.

  In the above embodiment, the torque command value T2 * is used as information on the torque generated by the second AC motor 14, but instead of this, based on the operating state of the second AC motor 14, etc. You may make it use the estimated torque estimated.

  Further, in this embodiment, in the system that controls the second AC motor 14 by the sine wave PWM control method, only reactive power that does not contribute to the torque generation of the second AC motor 14 is controlled during the system voltage stabilization control. By operating the current vector so as to change, the system voltage is controlled by operating the input power of the second AC motor 14 while keeping the torque of the second AC motor 14 constant (torque command value T2 *). As a result, system voltage fluctuations can be suppressed without adversely affecting the driving state of the vehicle.

  In the above embodiment, by operating the current vector of the second AC motor 14, the input power of the second AC motor 14 is operated while the torque of the second AC motor 14 is kept constant. However, by manipulating the voltage vector of the second AC motor 14, the input power of the second AC motor 14 may be manipulated while keeping the torque of the second AC motor 14 constant.

  In this embodiment, since the input power manipulated variable Pm of the second AC motor 14 is calculated using the detected value Vsf of the system voltage after the low-pass filter process, when calculating the input power manipulated variable Pm. Furthermore, the detection value Vsf of the system voltage after the noise component (high frequency component) included in the detection value Vs of the system voltage is removed by the low-pass filter process can be used, and the calculation accuracy of the input power manipulated variable Pm can be improved. Can do.

  By the way, when the system voltage stabilization control is performed to control the fluctuation of the system voltage by operating the input power of the second MG unit 30 (second AC motor 14), the input power operation of the second MG unit 30 is performed. There is a possibility that the control of the system voltage by the control and the control of the system voltage by the boost converter 20 interfere with each other.

  As a countermeasure, in this embodiment, the command value Pif * of the converted power is obtained from the total power Pi * obtained by summing the input power Pi1 of the first AC motor 13 and the input power Pi2 of the second AC motor, and the system The voltage target value Vs * (or the detected value Vsf) is multiplied by the detected value icf of the output current of the boost converter 21 to obtain the detected value Pi of the converted power, and the converted power command value Pif * and the detected value Pi. Since the conversion power control for controlling the output power of the boost converter 21 is executed so that the deviation ΔPi from the second MG unit 30 becomes smaller, the system voltage control by the input power operation of the second MG unit 30 and the system by the boost converter 21 are performed. Interference with voltage control can be prevented.

  In the above embodiment, the output power of the boost converter 21 is controlled so that the deviation ΔPi between the command value Pif * of the output power of the boost converter 21 and the detected value Pi becomes small. The input power of boost converter 21 may be controlled so that deviation ΔPi between power command value Pif * and detected value Pi is small.

  In this embodiment, the total power Pif * after the low-pass filter processing is performed on the total power Pi * of the input power Pi1 of the first AC motor 13 and the input power Pi2 of the second AC motor 13 is used as the command value for the conversion power. Since Pif * is used, the total power Pif * after the noise component (high frequency component) is removed by the low-pass filter processing can be used as the converted power command value Pif *. It can be set with high accuracy.

  Furthermore, in this embodiment, the detected value Pi of the converted power is calculated using the detected value icf of the output current of the boost converter 21 after the low-pass filter process. Therefore, when the detected value Pi of the converted power is calculated. The detection value icf of the output current after the noise component (high frequency component) contained in the detection value ic of the output current is removed by the low-pass filter processing can be used, and the calculation accuracy of the detection value Pi of the converted power is improved. Can do.

  In the above embodiment, when the system voltage stabilization control is performed, the input power of the second MG unit 30 (second AC motor 14) is manipulated to suppress the fluctuation of the system voltage. You may make it control the fluctuation | variation of a system voltage by operating the input electric power of 1 MG unit 29 (1st alternating current motor 13). Alternatively, although not shown, for example, in a vehicle having an all-wheel drive configuration in which the third MG unit is mounted on the driven wheel, the input power of the third MG unit is operated to suppress fluctuations in the system voltage. May be.

  In the above embodiment, the present invention is applied to a so-called split type hybrid vehicle in which engine power is divided by a planetary gear mechanism. However, the present invention is not limited to this split type hybrid vehicle, and other types such as a parallel type or The present invention may be applied to a series type hybrid vehicle. Further, in the above embodiment, the present invention is applied to a vehicle using an AC motor and an engine as a power source. However, the present invention may be applied to a vehicle using only an AC motor as a power source. Further, the present invention may be applied to a vehicle equipped with only one MG unit composed of an inverter and an AC motor, or a vehicle equipped with three or more MG units.

It is a schematic block diagram of the drive system of the electric vehicle in one Example of this invention. It is a block diagram which shows the structure of the control system of an AC motor. It is a figure for demonstrating the calculation method of a command electric current vector. It is a flowchart which shows the flow of a process of a command electric current vector calculation program. It is a figure for demonstrating the operable range of an electric current vector.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 13,14 ... AC motor, 20 ... DC power supply, 21 ... Boost converter (conversion means), 22 ... Power supply line, 23 ... Ground line, 24 ... Smoothing capacitor, 25 ... Voltage sensor (voltage detection means), 26 ... Current sensor (Current detection means), 27, 28 ... Inverter, 29, 30 ... MG unit, 37 ... Motor controller, 48 ... Rotational speed calculation section (Rotation speed detection means), 50 ... System voltage target value calculation section (Target voltage calculation) Means), 51... First low-pass filter (first low-pass means), 53... PI controller (power manipulated variable calculation means), 54... Command current calculation section (system voltage control means), 62. (Converted power command value calculating means), 63 ... second low-pass filter (second low-pass means), 64 ... third low-pass filter (third low-pass means), 65 ... converted power detection Part (conversion power detection means), 67 ... PI controller (conversion power control amount calculation means), 68 ... voltage boosting drive signal computation unit (conversion power control means)

Claims (9)

At least one motor drive unit (hereinafter referred to as “MG unit”) comprising conversion means for converting a voltage of a DC power source to generate a system voltage on a power supply line, an inverter connected to the power supply line, and an AC motor driven by the inverter. In a control device of an electric vehicle provided with
System voltage control means for performing system voltage stabilization control for controlling the input voltage different from the power necessary for generating torque of the AC motor of the MG unit to suppress fluctuations in the system voltage;
Rotation speed detection means for detecting the rotation speed of the AC motor,
The system voltage control means, when the rotation speed of the AC motor detected by the rotation speed detection means during the system voltage stabilization control is less than a predetermined value and the generated torque of the AC motor is less than a predetermined value, The current or voltage to be supplied to the AC motor is operated by selecting the leading side, and the rotational speed of the AC motor detected by the rotational speed detecting means is higher than a predetermined value or the generated torque of the AC motor is higher than a predetermined value. control device that electric vehicles be characterized in that this operation by selecting the delayed side of the current or voltage energizing the alternating current motor is greater. Target voltage setting means for setting a target value of the system voltage;
Voltage detecting means for detecting the system voltage;
Power manipulated variable calculating means for calculating the manipulated variable of input power of the MG unit based on the target value of the system voltage set by the target voltage setting means and the system voltage detected by the voltage detecting means;
The system voltage control means controls the system voltage by operating input power of the MG unit based on an input power operation amount calculated by the power operation amount calculation means. Electric vehicle control device. A first low-pass means for passing a component having a predetermined frequency or less out of the system voltage detected by the voltage detection means;
The power operation amount calculation unit calculates the operation amount of the input power of the MG unit using a system voltage of a predetermined frequency or less that has passed through the first low-pass unit. The control apparatus of the electric vehicle as described.   The control apparatus for an electric vehicle according to any one of claims 1 to 3, further comprising conversion power control means for controlling input power or output power (hereinafter referred to as "conversion power") of the conversion means. Converted power command value calculating means for calculating a command value of the converted power;
Converted power detection means for detecting the converted power;
A conversion power control amount calculation means for calculating a control amount of the conversion power based on the command value of the conversion power calculated by the conversion power command value calculation means and the conversion power detected by the conversion power detection means;
5. The control apparatus for an electric vehicle according to claim 4, wherein the conversion power control means controls the conversion power based on a control amount calculated by the conversion power control amount calculation means.   The converted power command value calculation means calculates the command value of the converted power based on power including at least a total value of input power of all MG units connected to the power supply line. 5. The control apparatus for an electric vehicle according to 5. A second low-pass means for passing a component having a frequency equal to or lower than a predetermined frequency out of power including at least a total value of input power of all MG units connected to the power line;
7. The electric power according to claim 6, wherein the converted power command value calculating means calculates a command value of the converted power based on power equal to or lower than a predetermined frequency that has passed through the second low-pass means. Automotive control device. Current detection means for detecting the output current of the conversion means,
The conversion power detection means is configured to convert the conversion voltage based on a system voltage target value set by the target voltage setting means or a system voltage detected by the voltage detection means, and an output current of the conversion means detected by the current detection means. The electric vehicle control device according to any one of claims 5 to 7, wherein electric power is calculated. A third low-pass means for passing a component having a predetermined frequency or less in the output current of the conversion means detected by the current detection means;
9. The control apparatus for an electric vehicle according to claim 8, wherein the converted power detection means calculates the converted power using an output current of a predetermined frequency or less that has passed through the third low-pass means. .

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