JP2007185084A - Control device of electric vehicle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve voltage stabilization effect of a power line of a system generating system voltage in the power line, by boosting voltage of a DC power source with a boosting converter and driving an AC motor through an inverter by system voltage. <P>SOLUTION: Input power of the AC motor 14 is operated so that a difference ΔVs becomes small between a target value Vs* and a detection value Vsf of system voltage, and system voltage stabilization control is performed for suppressing fluctuation of system voltage. Conversion power control for controlling conversion power is performed so that a difference ΔPi becomes small between a command value Pif* and a detection value Pi of conversion power (output power of boosting converter 21). A conversion power correction amount Px is operated from an input power operation amount Pm of system voltage stabilization control, and conversion power is corrected by reflecting the conversion power correction amount Px on conversion power control. Thus, dispersion (dispersion of system voltage) is corrected in conversion power due to a control error of conversion power control. <P>COPYRIGHT: (C)2007,JPO&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 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 an electric vehicle control apparatus including at least one motor drive unit (hereinafter referred to as “MG unit”) composed of an AC motor, system voltage control means operates the input power of the MG unit to change the system voltage. System voltage stabilization control is performed to control the power to be suppressed, and conversion power control is performed to control input power or output power (hereinafter referred to as “conversion power”) of the conversion means by the conversion power control means. Further, the correction amount calculation means calculates the correction amount of the conversion power based on the control information related to the system voltage stabilization control, and the conversion power correction means reflects the conversion power correction amount in the conversion power control to correct the conversion power. It is a configuration.

  In this configuration, the system voltage stabilization control by the system voltage control means can manipulate the input power of the MG unit to suppress the fluctuation of the system voltage. Even when the balance greatly changes, the system voltage (power supply line voltage) 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 addition, when system voltage stabilization control is performed to control system voltage fluctuation 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. Although there is a possibility of interference, the present invention performs system conversion power control for controlling the conversion power (input power or output power of the conversion means) by the conversion power control means, so that the system voltage due to the input power operation of the MG unit is controlled. Can be prevented from interfering with the control of the system voltage by the conversion means.

  By the way, this conversion is performed when the control accuracy of the conversion power control decreases due to some cause (for example, variation in manufacturing of AC motor device constants, change over time, etc.) and the variation in system voltage (offset amount with respect to the target value) increases. When the system voltage variation due to power control error is corrected by the above-mentioned system voltage stabilization control (control of system voltage by MG unit input power operation), the burden on system voltage stabilization control increases accordingly. As a result, the dynamic range of the system voltage stabilization control is narrowed, and the system voltage stabilization function may not be fully exhibited.

  As a countermeasure, the present invention calculates the correction amount of the converted power based on the control information related to the system voltage stabilization control, and corrects the converted power by reflecting this correction amount of the converted power in the converted power control. In other words, if the control accuracy of the conversion power control decreases and the control error increases, the variation of the conversion power increases accordingly, the variation of the system voltage increases, and the system voltage stabilizes to correct the variation of the system voltage. The control information (for example, input power manipulated variable) related to the activation control changes. Therefore, if the control information related to the system voltage stabilization control is used, the conversion power correction amount that accurately reflects the control error of the conversion power control can be calculated, and the conversion power correction amount is reflected in the conversion power control. Thus, it is possible to reduce the control error of the conversion power control and correct the conversion power with high accuracy, and to reduce the variation of the conversion power (system voltage variation). This makes it possible to correct the conversion power variation (system voltage variation) due to the control error of the conversion power control on the conversion power control side, thus reducing the burden on the system voltage stabilization control and reducing the system voltage. The dynamic range of the stabilization control can be prevented from being narrowed, and the system voltage stabilization function can be fully exhibited.

  In this case, as in claim 2, when the MG unit is in a steady state, the correction amount of the converted power is preferably calculated based on the control information related to the system voltage stabilization control. When the MG unit is in a steady state, the AC motor's power balance hardly changes, so there is almost no change in the conversion power (system voltage fluctuation) due to the change in the AC motor's power balance. Only the variation in the conversion power due to (system voltage variation) occurs. Therefore, if the correction amount of the conversion power is calculated based on the control information related to the system voltage stabilization control when the MG unit is in a steady state, it is hardly affected by the change in the conversion power due to the change in the power balance of the AC motor. Thus, it is possible to obtain the correction amount of the conversion power that accurately reflects the variation of the conversion power (system voltage variation) due to the control error of the conversion power control.

  Further, according to a specific control method of the system voltage stabilization control, 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, as in claim 3. An operation amount of the input power of the MG unit is calculated by the operation amount calculation means based on the target value of the current and the detected system voltage, and the system voltage is controlled by operating the input power of the MG unit based on the operation amount. Anyway. 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.

  Further, the specific control method of the conversion power control is, as in claim 4, calculating the conversion power command value by the conversion power command value calculation means and detecting the conversion power by the conversion power detection means to convert the conversion power. The control amount of the conversion power may be calculated by the conversion power control amount calculation means based on the command value of the power and the detected conversion power, and the conversion power may be controlled based on this 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.

  In addition, during system voltage stabilization control, if the torque of the AC motor greatly 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 manipulating input power (that is, reactive power) different from the power necessary for generating torque of the AC motor, as in claim 5. 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.

  In this case, when the AC motor is controlled by the sinusoidal PWM control method as in claim 6, the input power of the MG unit is controlled by operating the current vector energized to the AC motor or the voltage vector applied to the AC motor. It is better to operate. When controlling an AC motor with a sinusoidal PWM control method, the AC motor torque is kept constant by operating the current vector and voltage vector so that only the reactive power that does not contribute to torque generation of the AC motor is changed. In this state, the system voltage can be controlled by operating the input power of the AC motor.

  In addition, when controlling the AC motor by the rectangular wave control method as in claim 7, the input power of the MG unit is controlled by manipulating the duty ratio and / or phase of the rectangular wave when the AC motor is energized. It is better to operate. When controlling an AC motor using the rectangular wave control method, the system voltage is controlled by operating the input power of the AC motor while maintaining the constant torque of the AC motor by operating the duty ratio and phase of the rectangular wave. can do.

  Hereinafter, the best mode for carrying out the present invention will be described using two Examples 1 and 2.

A first embodiment of the present invention will be described with reference to FIGS.
First, a schematic configuration of an electric vehicle drive system will be described with reference to FIG. An engine 12 (internal combustion engine) and a second 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 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 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 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.

  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), 3, the power control current vector ip * (d-axis power control current idp *, q-axis power control current iqp) that changes the reactive power that does not contribute 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 by a map or a mathematical expression.

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.

  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 then added to the total power Pi * by the adder 70. A corrected total power Pix * is obtained by adding a conversion power correction amount Px described later. The corrected total power Pix * is input to the second low-pass filter 63 (second low-pass means), and low-pass filter processing is performed to pass only the low-frequency component of the corrected total power Pix *. The total power Pif * after the low-pass filter processing is set as a command value Pif * for the conversion power. The adder 62, the adder 70, 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.

  By the way, this conversion power control is performed when the control accuracy of the conversion power control is reduced due to some cause (for example, manufacturing variation or change with time of AC motor device constant) and the system voltage variation (offset amount with respect to the target value) is large. If the variation in the system voltage due to the control error is corrected by the above-described system voltage stabilization control (control of the system voltage by the input power operation of the second MG unit 30), the burden on the system voltage stabilization control is correspondingly increased. As a result, the dynamic range of the system voltage stabilization control is narrowed, and the system voltage stabilization function may not be sufficiently exhibited.

  As a countermeasure, the motor control device 37 calculates a conversion power correction amount Px based on control information (for example, input power operation amount Pm) related to system voltage stabilization control, and reflects this conversion power correction amount Px in the conversion power control. Thus, the converted power (the output power of the boost converter 21) is corrected. In other words, if the control accuracy of the conversion power control decreases and the control error increases, the variation of the conversion power increases accordingly, the variation of the system voltage increases, and the system voltage stabilizes to correct the variation of the system voltage. The input power manipulated variable Pm of the control is changed. Therefore, if the input power manipulated variable Pm of the system voltage stabilization control is used, the conversion power correction amount Px that accurately reflects the control error of the conversion power control can be calculated, and this conversion power correction amount Px can be calculated as the conversion power control amount Px. By reflecting in the above, it is possible to correct the conversion power by reducing the control error of the conversion power control, and to reduce the variation of the conversion power (the variation of the system voltage).

  Specifically, first, the input power operation amount Pm output from the PI controller 53 is input to the correction amount calculation unit 69 (correction amount calculation means) to calculate the converted power correction amount Px. The calculation of the conversion power correction amount Px is executed according to the conversion power correction amount calculation program shown in FIG. When this program is started, first, in step 201, whether or not the first and second MG units 29 and 30 are in a steady state, for example, all the following conditions (1) to (3) are satisfied. Judgment is made based on whether or not it is satisfied.

(1) The torque command value (or estimated torque) of the first and second AC motors 13 and 14 is constant.
(2) The vehicle speed must be constant
(3) The brake is in a non-operating state. If all the conditions (1) to (3) are satisfied, it is determined that the first and second MG units 29 and 30 are in a steady state. If there is a condition that does not satisfy any one of the conditions (3) to (3), it is determined that at least one of the first and second MG units 29 and 30 is not in a steady state.

If it is determined in step 201 that the first and second MG units 29 and 30 are in a steady state, the process proceeds to step 202 where the current input power operation amount Pm is converted to the current conversion power correction amount Px ( Adopt as i).
Px (i) = Pm

  When the first and second MG units 29 and 30 are in a steady state, the power balance of the first and second AC motors 13 and 14 hardly changes. Therefore, the converted power due to the change in the power balance of the AC motors 13 and 14 Fluctuation (system voltage fluctuation) hardly occurs, and only the conversion power variation (system voltage variation) due to the control error of the conversion power control occurs. Therefore, if the input power manipulated variable Pm is adopted as the conversion power correction amount Px when the first and second MG units 29 and 30 are in a steady state, the conversion power of the AC motors 13 and 14 due to the change in the power balance is reduced. It is possible to set the conversion power correction amount Px that accurately reflects the variation in the conversion power (the variation in the system voltage) due to the control error of the conversion power control without being affected by the fluctuation.

On the other hand, if it is determined in step 201 that at least one of the first and second MG units 29 and 30 is not in a steady state, the process proceeds to step 203 and the previous conversion power correction amount Px (i-1 ) Is directly adopted as the conversion power correction amount Px (i) of this time.
Px (i) = Px (i-1)

  Each time the first and second MG units 29 and 30 are in a steady state and the conversion power correction amount Px is updated, the conversion power correction amount Px is learned, and the learned value is used for the subsequent conversion power control. In the case of the system to be reflected in the above, the converted power correction amount Px is set to “0” in the above step 203.

  After the conversion power correction amount Px is calculated by the correction amount calculation unit 69 as described above, the conversion power correction amount Px is added to the total power Pi * by the adder 70 (conversion power correction means) as shown in FIG. Then, the corrected total power Pix * is obtained, and the converted power command value Pif * is calculated based on the corrected total power Pix *, so that the converted power correction amount Px is reflected in the converted power control and the converted power (boost converter) is calculated. 21 output power) is corrected.

  In the first embodiment described above, the second MG unit is operated by manipulating the current vector supplied to the 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 for suppressing the fluctuation of the system voltage (the voltage of the power supply line 22) is performed by operating the input power of the 30 (second AC motor 14), the change of the driving state of the vehicle, etc. Even when the power balance of the two AC motors 13 and 14 greatly changes, 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.

  Further, when system voltage stabilization control is performed to suppress fluctuations in system voltage by operating input power of the second MG unit 30 (second AC motor 14), input power operation of the second MG unit 30 is performed. In the first embodiment, the input power Pi1 of the first AC motor 13 and the input power of the second AC motor may be interfered with each other. A command value Pif * of the conversion power is obtained from the total power Pi * obtained by adding up Pi2, and the target value Vs * (or detection value Vsf) of the system voltage is multiplied by the detection value icf of the output current of the boost converter 21. Conversion power control is performed to obtain the detected value Pi of the conversion power and control the output power of the boost converter 21 so that the deviation ΔPi between the command value Pif * of the conversion power and the detection value Pi becomes small. Thus, the interference between the control of the system voltage by the input power operation of the second MG unit 30 and the control of the system voltage by the boost converter 21 can be prevented.

  However, if the variation in the system voltage due to the control error of the conversion power control is corrected by the above-described system voltage stabilization control (control of the system voltage by the operation of the input power of the second MG unit 30), the system voltage is stabilized correspondingly. There is a possibility that the burden on control increases, the dynamic range of system voltage stabilization control becomes narrow, and the function of system voltage stabilization cannot be fully exhibited.

  As a countermeasure, in the first embodiment, when the first and second MG units 29 and 30 are in a steady state, the conversion power correction amount Px is calculated from the input power operation amount Pm of the system voltage stabilization control. Conversion power correction amount Px that accurately reflects variations in converted power (variations in system voltage) due to control errors in conversion power control without being substantially affected by variations in converted power due to changes in the power balance of AC motors 13 and 14. And the conversion power correction amount Px is reflected in the conversion power control, so that the conversion power control error is reduced and the conversion power is corrected. Variation (system voltage variation) can be corrected on the conversion power control side. As a result, the burden on the system voltage stabilization control can be reduced, the dynamic range of the system voltage stabilization control can be prevented from being narrowed, and the system voltage stabilization function can be fully exhibited.

  In the first embodiment, in the system in which the second AC motor 14 is controlled by the sinusoidal 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 manipulating the current vector so as to change the system voltage, the system voltage can be adjusted by manipulating the input power of the second AC motor 14 while keeping the torque of the second AC motor 14 constant (torque command value T2 *). Since the control is performed, fluctuations in the system voltage can be suppressed without adversely affecting the driving state of the vehicle.

  In the first 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 operating the voltage vector of the second AC motor 14, the input power of the second AC motor 14 may be operated while the torque of the second AC motor 14 is kept constant. .

  Next, a second embodiment of the present invention will be described with reference to FIGS. However, substantially the same parts as those in the first embodiment are denoted by the same reference numerals, and the description will be simplified. The parts different from the first embodiment will be mainly described.

  In the first embodiment, the second AC motor 14 is controlled by the sine wave PWM control method. However, in the second embodiment, the second AC motor 14 is controlled by the rectangular wave control method. .

  As shown in FIG. 6, when the motor control device 37 controls the torque of the second AC motor 14, the torque control value T2 * output from the main control device 31 and the U of the second AC motor 14 are controlled. Three-phase voltage command signals UU2, UV2, and UW2 are generated by a rectangular wave control method based on the phase current iU2 and the W-phase current iW2 and the rotor rotational position θ2 of the second AC motor 14. The rectangular wave control method is a method in which the AC motor 14 is controlled by commutating energization at every predetermined angle using the electrical angle of the AC motor 14.

  At that time, as shown in FIG. 9A, the pulse width is manipulated by manipulating the duty ratio Duty of the rectangular wave energizing the second AC motor 14, or as shown in FIG. By manipulating the wave phase φ, the input power of the second AC motor 14 is manipulated while keeping the torque of the second AC motor 14 constant (torque command value T2 *), thereby suppressing fluctuations in the system voltage. Control to do.

  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 rotational speed calculation unit 48, and the rotational speed N2 of the second AC motor 14 is calculated. While calculating, the U-phase and W-phase currents iU2 and iW2 (output signals of the current sensors 43 and 44) and the rotor rotational position θ2 of the second AC motor 14 and the rotor rotational position θ2 are input to the torque estimator 71, and the second AC The torque T2 generated by the current flowing through the motor 14 is estimated.

  Thereafter, as shown in FIG. 7, a deviation device 74 of the torque control unit 72 (motor control means) obtains a deviation ΔT2 between the torque command value T2 * of the second AC motor 14 and the estimated torque T2, and this deviation is obtained. ΔT2 is input to the PI controller 75, and the phase φt of the rectangular wave is calculated by PI control so that the deviation ΔT2 between the torque command value T2 * and the estimated torque T2 becomes small. The duty ratio Dt of the rectangular wave corresponding to the torque command value T2 * of the AC motor 14 and the rotational speed N2 is calculated by a map or a mathematical expression.

  Further, the input power operation amount Pm, the estimated torque T2 and the rotation speed N2 output from the PI controller 53 are input to the rectangular wave operation amount calculation unit 77 of the power control unit 73 (system voltage control means) to perform duty ratio operation. The amount Dp and the phase operation amount φp are calculated as follows. First, as shown in FIG. 8, the second AC motor 14 is calculated by calculating a rectangular wave duty ratio manipulated variable Dp according to the input power manipulated variable Pm, the estimated torque T2 and the rotational speed N2 using a map or a mathematical expression. The duty ratio manipulated variable Dp for changing the input power by the input power manipulated variable Pm is obtained. Further, a phase operation amount φp of a rectangular wave corresponding to the input power operation amount Pm, the estimated torque T2 of the second AC motor 14 and the rotational speed N2 is calculated by a map or a mathematical formula or the like, and the phase corresponding to the duty ratio operation amount Dp. By obtaining the operation amount φp, as shown in FIG. 8, the phase operation amount φp is obtained so as to suppress the torque fluctuation of the second AC motor 14 caused by the operation of the duty ratio by the duty ratio operation amount Dp.

  The rectangular wave manipulated variable calculator 77 includes limit means (not shown) for limiting (guard processing) the duty ratio manipulated variable Dp and the phase manipulated variable φp with a predetermined limit value. The amount Dp and the phase operation amount φp are prevented from exceeding excessively exceeding the limit values.

  In calculating the duty ratio manipulated variable Dp and the phase manipulated variable φp, a torque command value T2 * may be used instead of the estimated torque T2. Further, the torque of the second AC motor 14 generated by the operation of the duty ratio is calculated by calculating the phase operation amount φp based on the final duty ratio Duty (= Dt + Dp) and the torque command value T2 *, which will be described later. The phase operation amount φp may be obtained so as to suppress the fluctuation.

  Thereafter, the adder 78 of the power control unit 73 adds the phase operation amount φp to the phase φt of the rectangular wave to obtain the final phase φ (= φt + φp) of the rectangular wave, and the adder 79 determines the rectangular wave phase φt. After the duty ratio manipulated variable Dp is added to the duty ratio Dt to obtain the final rectangular wave duty ratio Duty (= Dt + Dp), the rectangular wave computing unit 80 of the torque control unit 72 uses the rectangular wave phase φ and Based on the duty ratio Duty, the rotor rotational position θ2 of the second AC motor 14 and the rotational speed N2, three-phase voltage command signals UU2, UV2, UW2 (rectangular wave command signals) are calculated, and these three-phase voltage command signals UU2, UV2, and UW2 are output to the second inverter 28.

  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.

  In addition, the motor control device 37 performs the 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, as in the first embodiment. In order to prevent interference with the power converter, the duty ratio Dc of the switching element (not shown) of the boost converter 21 is reduced so that the deviation ΔPi between the command value Pi * of the converted power (output power of the boost converter 21) and the detected value Pi becomes small. The conversion power control for controlling is executed.

  Further, in the same manner as in the first embodiment, the motor control device 37 controls the control information (system voltage stabilization control) in order to correct the variation in the conversion power (system voltage variation) due to the control error in the conversion power control. For example, the conversion power correction amount Px is calculated based on the input power operation amount Pm), and the conversion power correction amount Px is reflected in the conversion power control to correct the conversion power (the output power of the boost converter 21).

  In the second embodiment described above, the duty ratio Duty and the phase φ of the rectangular wave energized to the second AC motor 14 are manipulated so that the deviation ΔVs between the target value Vs * of the system voltage and the detected value Vsf becomes small. As a result, the system voltage stabilization control that controls the fluctuation of the system voltage (the voltage of the power supply line 22) by operating the input power of the second MG unit 30 (second AC motor 14) is executed. The same effect as the first embodiment can be obtained.

  In the second embodiment, in the system in which the second AC motor 14 is controlled by the rectangular wave control method, the input power of the second AC motor 14 is input by the input power manipulated variable Pm during the system voltage stabilization control. Since the duty ratio manipulated variable Dp to be changed is obtained and the phase manipulated variable φp is obtained so as to suppress the torque fluctuation of the second AC motor 14 generated by the duty ratio manipulated by the duty ratio manipulated variable Dp. The system voltage can be 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 *), which adversely affects the driving state of the vehicle. Thus, fluctuations in the system voltage can be suppressed.

  Further, in the second embodiment, as in the first embodiment, the conversion power correction amount Px is calculated based on the control information (for example, the input power operation amount Pm) related to the system voltage stabilization control, and this conversion power correction is performed. Since the amount Px is reflected in the conversion power control and the conversion power (the output power of the boost converter 21) is corrected, the burden on the system voltage stabilization control is reduced, and the dynamic range of the system voltage stabilization control is increased. The narrowing can be prevented, and the system voltage stabilizing function can be sufficiently exhibited.

  In the first and second embodiments, the conversion power correction amount Px is calculated based on the input power operation amount Pm of the system voltage stabilization control. However, other control information related to the system voltage stabilization control (for example, The conversion power correction amount Px is calculated based on the deviation ΔVs between the target value Vs * and the detected value Vsf of the system voltage, the power control vector ip *, the command current vector i2 *, the duty ratio operation amount Dp, the phase operation amount φp, etc. You may make it calculate.

  In each of the first and second embodiments, the total power Pi * is corrected by the conversion power correction amount Px and the conversion power command value Pif * is corrected to reflect the conversion power correction amount Px in the conversion power control. However, the method of reflecting the conversion power correction amount Px in the conversion power control may be changed as appropriate. For example, the conversion power correction amount Px may be used to correct the detected value Pi of the conversion power, or the conversion power correction amount. The deviation ΔPi between the command value Pif * and the detected value Pi may be corrected by Px.

  Further, in each of the first and second embodiments, the output power of the boost converter 21 is controlled so that the deviation ΔPi between the command value Pi * of the output power of the boost converter 21 and the detected value Pi becomes small during the conversion power control. However, the input power of the boost converter 21 may be controlled so that the deviation ΔPi between the command value Pi * of the input power of the boost converter 21 and the detected value Pi becomes small.

  Further, in each of the first and second embodiments, during the system voltage stabilization control, the input power of the second MG unit 30 (second AC motor 14) is operated so as to suppress fluctuations in the system voltage. However, the fluctuation of the system voltage may be suppressed by operating the input power of the first MG unit 29 (first 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 each of the first and second embodiments, the present invention is applied to a so-called split type hybrid vehicle in which the engine power is divided by a planetary gear mechanism. However, the present invention is not limited to this split type hybrid vehicle, and other methods are used. The present invention may be applied to a certain parallel type or series type hybrid vehicle. Further, in each of the first and second embodiments, 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 Example 1 of this invention. FIG. 3 is a block diagram illustrating a configuration of a control system of the AC motor according to the first embodiment. 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 flowchart which shows the flow of a process of the conversion electric power correction amount calculation program. It is a block diagram which shows the structure of the control system of the alternating current motor of Example 2. It is a block diagram which shows the structure of a torque control part and an electric power control part. It is a figure for demonstrating the calculation method of a duty ratio operation amount and a phase operation amount. (A) is a figure for demonstrating operation of a duty ratio, (b) is a figure for demonstrating operation of a phase.

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, 50 ... system voltage target value calculation unit (target voltage calculation means), 53 ... PI controller (power operation amount calculation) Means), 54 ... command current calculation unit (system voltage control means), 62 ... totalizer (converted power command value calculation means), 65 ... conversion power detection unit (converted power detection means), 67 ... PI controller (conversion power) Control amount calculation means), 68 ... boost drive signal calculation section (conversion power control means), 69 ... correction amount calculation section (correction amount calculation means), 70 ... adder (conversion power correction means), 72 ... torr Control unit (motor control means), 73 ... power control unit (system voltage control means)

Claims (7)

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 power of the MG unit to control fluctuation of the system voltage;
Conversion power control means for executing conversion power control for controlling input power or output power (hereinafter referred to as “conversion power”) of the conversion means;
A correction amount calculating means for calculating a correction amount of the converted power based on control information related to the system voltage stabilization control;
A control device for an electric vehicle, comprising: conversion power correction means for correcting the conversion power by reflecting the correction amount of the conversion power calculated by the correction amount calculation means in the conversion power control.   2. The electric vehicle according to claim 1, wherein the correction amount calculation means calculates the correction amount of the converted power based on control information related to the system voltage stabilization control when the MG unit is in a steady state. Control device. 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 the input power of the MG unit based on the operation amount of the input power calculated by the power operation amount calculation means. The control apparatus of the electric vehicle described in 1. A converted power command value calculating means for calculating the 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;
The control apparatus for an electric vehicle according to any one of claims 1 to 3, wherein the conversion power control means controls the conversion power based on a control amount calculated by the conversion power control amount calculation means.   5. The electric vehicle according to claim 1, wherein the system voltage control unit controls the system voltage by operating input power different from power necessary for generating torque of the AC motor. Control device. Motor control means for controlling the AC motor by a sinusoidal PWM control system;
The system voltage control means operates the input power of the MG unit by operating a current vector energized to the AC motor or a voltage vector applied to the AC motor in the sine wave PWM control method. The control apparatus for an electric vehicle according to claim 5. Motor control means for controlling the AC motor by a rectangular wave control method;
The system voltage control means manipulates input power of the MG unit by manipulating a duty ratio and / or phase of a rectangular wave when the AC motor is energized by the rectangular wave control method. Item 6. The control device for an electric vehicle according to Item 5.

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