JP4775656B2 - Electric vehicle control device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a control device which improves the effect of power line voltage stabilization in a system which generates a system voltage in a power line by increasing voltage in a DC voltage source via a step-up converter, and actuates an AC motor via an inverter using the system voltage. <P>SOLUTION: This control device calculates an input power operation amount Pm which reduces a deviation &Delta;Vs between a system voltage target value Vs* and a detection value Vsf, and determines a command current vector (id2*, iq2*) for changing only a reactive power in the AC motor 14 according to this input power operation amount Pm and a torque control current vector (idt2*, iqt2*). To suppress system voltage variations, this device obtains three-phase voltage command signals UU2, UV2 and UW2 based on the command current vector (id2*, iq2*), outputs them to an inverter 28, and then manipulates the input power of the AC motor 14 in a way that the deviation &Delta;Vs between the system voltage target value Vs* and the detection value Vsf is reduced, keeping the torque of the AC motor 14 constant. <P>COPYRIGHT: (C)2007,JPO&amp;INPIT

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 the control apparatus for an electric vehicle comprising at least one or more motor drive units consisting of an AC motor (hereinafter referred to as "MG unit"), the detection value and the target value of said system voltage input power of M G unit System voltage control means that operates to reduce the deviation of the system voltage and suppresses fluctuations in the system voltage, and the system voltage control means changes the operation amount of the input power while keeping the torque of the AC motor constant. And a means for obtaining a d-axis command current and a q-axis command current.

  In this configuration, since it is possible to control the fluctuation of the system voltage by manipulating the input power of the MG unit, even when the power balance of the AC motor greatly changes due to a change in the driving state of the vehicle, the system voltage ( The voltage of the power line can be effectively stabilized. In addition, the voltage stabilization effect of the power supply line can be enhanced without increasing the performance of the conversion means and increasing the capacity of the smoothing capacitor, thereby satisfying the demands for system downsizing and cost reduction.

  In this case, if the torque of the AC motor largely fluctuates due to the operation of the input power of the MG unit, the driving state of the vehicle may be adversely affected. As a countermeasure, it is preferable to control the system voltage by operating an input power (that is, a reactive power) different from the power required for generating the torque of the AC motor, as in claim 2. In this way, the system voltage can be controlled by operating the input power of the AC motor while keeping the torque of the AC motor constant (for example, the torque command value) without adversely affecting the driving state of the vehicle. Variations in system voltage can be suppressed.

  The specific control method of the system voltage is as set forth in claim 3, wherein the target value of the system voltage is set by the target voltage setting means, and the system voltage is detected by the voltage detection means to detect the target value of the system voltage. The operation amount of the input power of the MG unit may be calculated by the operation amount calculation means based on the system voltage, and the system voltage may be controlled by operating the input power of the MG unit based on the operation amount. 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 4, 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, if control for suppressing fluctuations in system voltage is performed 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 may interfere with each other. There is.

  As a countermeasure, the conversion power control means may control the input power or output power of the conversion means as in claim 5. Specifically, as in claim 6, a command value of input power or output power (hereinafter referred to as “converted power”) of the converting means is calculated by the converted power command value calculating means, and the converted power is converted to the converted power detecting means. And a control amount of the input power or output power of the conversion means is calculated by the conversion power control amount calculation means based on the command value of the conversion power and the detected conversion power, and the conversion power of the conversion means is calculated based on this control amount. Input power or output power may be controlled. In this way, even if the conversion power (input power or output power of the conversion means) fluctuates due to the control of the system voltage by the input power operation of the MG unit, the conversion power command value and the detected conversion power By controlling the input power or output power of the conversion means so as to reduce the deviation, it is possible to prevent interference between 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.

  Moreover, the command value of the conversion power is the power including the total value of the input power of all the MG units connected to the power supply line (for example, the total value of the input power of the MG unit is 100V commercial power). 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 8. 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. It is possible to calculate, and by limiting the band, interference with control of the system voltage due to operation of the input power of the MG unit can be prevented.

  The conversion power may be detected by calculating the conversion power based on the target value of the system voltage or the detected system voltage and the detected output current of the conversion means. In this way, the conversion power can be calculated with high accuracy.

  In this case, as in claim 10, there is provided a 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.

  Further, when the system voltage is controlled by manipulating the input power of the MG unit, the current vector energized to the AC motor or the voltage vector applied to the AC motor is manipulated as in claim 11 to control the system voltage. It is better to operate the input power. When operating the input power of the MG unit by current vector control or voltage vector control, the current vector or voltage vector is changed so that only the input power (that is, reactive power) different from the power required for generating torque of the AC motor is changed. , The system voltage can be controlled by operating the input power of the AC motor while keeping the torque of the AC motor constant.

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 (internal combustion engine) and an AC motor 14 are mounted as power sources 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 non-carrier, the rotating shaft of the AC motor 14 is connected to the ring gear 19, and the AC motor 13 mainly used as a generator is connected to the sun gear 17.

  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 transmits and receives 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 AC motors 13 and 14. The operations of the engine 12 and the AC motors 13 and 14 are controlled by 36 and 37 according to the driving state of the vehicle.

  Next, control of 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 boosted by the DC voltage (boost converter 21) of the power supply line 22 based on the three-phase voltage command signals UU1, UV1, UW1 output from the motor control device 37. 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 AC motors 13 and 14 function as generators when driven by the inverters 27 and 28 with negative torque. For example, when the vehicle decelerates, AC power generated by the AC motor 14 by the deceleration energy is converted into DC power by the inverter 28 and charged to the DC power source 20. Normally, a part of the power of the engine 12 is transmitted to the AC motor 13 via the planetary gear 18 and is generated by the AC motor 13 to extract the power of the engine 12, and the generated power is supplied to the AC motor 14 to generate AC. The motor 14 functions as an electric motor. In the overdrive state, the AC motor 13 functions as an electric motor to draw out the power of the engine 12. In this case, the AC motor 14 functions as a generator, and the generated electric power is supplied to the 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 (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), a three-phase voltage command signal 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. Control is performed so as to suppress fluctuations in the system voltage by operating the input power of the second AC motor 14 while maintaining the torque command value T2 *.

  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 to rotate the rotational speed of the second AC motor 14. Calculate N2. 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. *) To obtain the torque control current vector it2 * (d-axis torque control current idt2 *, q-axis torque control current iqt2 *) and power control current vector ip * (d-axis power control current idp *, q-axis power control current iqp *) And the final command current vector i2 * (d-axis command current id2 *, q-axis command current iq2 *).
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, a torque control current vector it2 * (d-axis torque control current itt2 *, q according to the torque command value T2 * and the rotational speed N2 of the second AC motor 14 is set. The shaft torque control current iqt2 *) is calculated using a map or mathematical formula.

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、それぞれ交流モータ１４の機器定数である。 Thereafter, the process proceeds to step 102, where the d-axis power control current idp * corresponding 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 *) is mapped. Or after calculating by a numerical formula etc., it progresses to step 103 and calculates q-axis power control current iqp * by following Formula using d-axis power control current idp *.

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

  Through the processing of these steps 102 and 103, the power control current vector ip * (d-axis power control) is changed by changing the input power manipulated variable Pm while keeping the torque of the second AC motor 14 constant (torque command value T2 *). Current idp *, q-axis power control current iqp *).

Thereafter, the process proceeds to step 104, 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 idp *, q-axis power). And a control current iqp *) to obtain a final command current vector i2 * (d-axis command current id2 *, q-axis command current iq2 *).
i2 * (id2 *, iq2 *) = it2 * (idt2 *, iqt2 *) + ip * (idp *, iqp *)

  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.

  Thus, the second MG unit 30 is configured such 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 *). The input power of (second AC motor 14) is manipulated to suppress fluctuations in system voltage.

  Furthermore, the motor control device 37 prevents the interference between the control of the system voltage by the operation of the input power of the second MG unit 30 (second AC motor 14) and the control of the system voltage by the boost converter 21 described above. Therefore, the duty ratio Dc of the switching element (not shown) of the boost converter 21 is controlled 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. To do.

  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.

  Thus, the output power of boost converter 21 is controlled so that deviation ΔPi between converted power command value Pif * and detected value Pi becomes small, and input to second MG unit 30 (second AC motor 14). Interference between the control of the system voltage by operating the power and the control of the system voltage by the boost converter 21 is 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 fluctuation of the voltage (voltage of the power supply line 22) is suppressed, the system voltage is effectively stabilized even when the power balance of the two AC motors 13 and 14 changes greatly due to changes in the driving state of the vehicle, etc. It can be made. 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.

  In addition, in the present embodiment, the system voltage is controlled by operating the input power (that is, reactive power) different from the power necessary for generating the torque of the second AC motor 14, so that the second AC motor 14 The system voltage can be controlled by operating the input power of the second AC motor 14 while keeping the torque of the motor constant (torque command value T2 *), and the system voltage can be controlled without adversely affecting the driving state of the vehicle. Variations can be suppressed.

  In this 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 control is performed to suppress the fluctuation of the system voltage by operating the input power of the second MG unit 30 (second AC motor 14), the second MG unit 30 (second AC motor 14). There is a possibility that the control of the system voltage by the operation of the input power and the control of the system voltage by the boost converter 21 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 command value Pi * and the detected value Pi of these converted powers. Since the output power of the boost converter 21 is controlled so that the deviation ΔP i from the output voltage becomes smaller, the system voltage is controlled by the input power operation of the second MG unit 30 (second AC motor 14) and the boost converter 21 is controlled. Interference with the control of the system voltage due to can be prevented.

  In this embodiment, the output power of the boost converter 21 is controlled so that the deviation ΔPi between the command value Pi * of the converted power and the detected value Pi is small. However, the command value Pi * of the converted power is detected. The value Pi may be set as the input side of the boost converter 21, and the input power of the boost converter 21 may be controlled so that the deviation ΔPi becomes 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, the input power of the second MG unit 30 (second AC motor 14) is manipulated to suppress fluctuations in the system voltage. However, the first MG unit 29 (first You may make it control the fluctuation | variation of a system voltage by operating the input electric power of AC 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. Also good.

  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 on which only one set of MG units including an inverter and an AC motor is mounted, or a vehicle on which three or more sets of MG units are mounted.

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.

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 control device, 50 ... system voltage target value calculation unit (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... Totalizer (converted power command value calculation means), 63. , Low-pass filter (second low-pass means), 64 ... third low-pass filter (third low-pass means), 65 ... converted power detector (converted power detector), 67 ... PI controller Conversion power control amount calculation means), 68 ... voltage boosting drive signal computation unit (conversion power control means)

Claims (11)

At least one motor drive unit (hereinafter referred to as “hereinafter referred to as“ a drive unit ”) including a conversion unit that converts a voltage of a DC power source to generate a system voltage on a power line, an inverter connected to the power line, and an AC motor driven by the inverter. An electric vehicle control device provided with "MG unit"),
Comprising a Cie stem voltage control means to suppress fluctuation of the operation to the system voltage so that the deviation between the target value and the detection value decreases the system voltage input power of the MG unit,
The system voltage control means includes means for obtaining a d-axis command current and a q-axis command current for changing an operation amount of the input power while maintaining a constant torque of the AC motor. apparatus.   2. The control apparatus for an electric vehicle according to claim 1, wherein the system voltage control means controls the system voltage by operating input power different from the power required for generating torque of the AC motor. 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;
3. The system voltage control unit according to claim 1, wherein the system voltage control unit controls the system voltage by operating input power of the MG unit based on an operation amount calculated by the power operation amount calculation unit. Control device for electric vehicles. 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 calculating means calculates an operation amount of input power of the MG unit using a system voltage having a frequency equal to or lower than a predetermined frequency that has passed through the first low-pass means. The control apparatus of the electric vehicle as described.   The control apparatus for an electric vehicle according to any one of claims 1 to 4, further comprising conversion power control means for controlling input power or output power of the conversion means. Conversion power command value calculation means for calculating a command value of input power or output power (hereinafter referred to as “conversion power”) of the conversion means;
Converted power detection means for detecting the converted power;
Conversion power control amount calculation for calculating a control amount of input power or output power of the conversion means based on the conversion power command value calculated by the conversion power command value calculation means and the conversion power detected by the conversion power detection means Means and
6. The control apparatus for an electric vehicle according to claim 5, wherein the conversion power control means controls input power or output power of the conversion means 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. 6. The control apparatus for an electric vehicle according to 6. 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;
8. The electric power according to claim 7, 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 6 to 8, 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;
10. The control apparatus for an electric vehicle according to claim 9, wherein the converted power detection means calculates the converted power using an output current having a frequency equal to or lower than a predetermined frequency that has passed through the third low-pass means. .   The said system voltage control means operates the input electric power of the said MG unit by operating the electric current vector which supplies with electricity to the said AC motor, or the voltage vector applied to the said AC motor, The any one of Claim 1 thru | or 10 characterized by the above-mentioned. A control apparatus for an electric vehicle according to claim 1.

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