JP2007215394A - Controller for electric automobile - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve the voltage stabilization effects of a power supply line in a system for driving an AC motor via an inverter with a system voltage, by allowing the power supply line to generate the system voltage, while stepping up a voltage of a DC power supply using a step-up converter. <P>SOLUTION: Second system-voltage stabilization control for suppressing variations in system voltage is executed by controlling the step-up converter 21, while executing first system-voltage stabilization control for suppressing the variations in system voltage by operating input power of the AC motor 14. the frequency band for suppressing the variations in system voltage by the first system-voltage stabilization control is separated from a frequency band for suppressing the variations in system voltage by the second system-voltage stabilization control. Consequently, while preventing interference between the first/second system-voltage stabilization control, the system voltage can be stabilized effectively by using both of the first/second system-voltage stabilization 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 are disclosed. An AC motor driven by an engine to generate electric power, and a DC voltage obtained by boosting a voltage of a DC power source (secondary battery) by a boost converter is generated in the power line, and each power line is connected to each of the power lines via an inverter. An AC motor is connected and the DC voltage boosted by the boost converter is converted to AC voltage by an inverter to drive the AC motor, or the AC voltage generated by the AC motor is converted to DC voltage by the inverter and this DC voltage is converted. Some are stepped down by a step-up converter and collected by a battery.

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

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

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

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

  In order to achieve the above object, the invention according to claim 1 converts the voltage of a DC power supply to generate a system voltage in the power supply line, the inverter connected to the power supply line, and the inverter driven by the inverter In a control apparatus for an electric vehicle having at least one motor drive unit (hereinafter referred to as “MG unit”) composed of an AC motor, the system voltage is controlled by operating the input power of the MG unit by the first system voltage control means. The second system voltage stabilization control is executed to control the fluctuation of the system voltage, and the second system voltage control means controls the conversion means to control the fluctuation of the system voltage. A frequency band and a first frequency band that execute system voltage stabilization control and suppress fluctuations in system voltage by the first system voltage stabilization control. It is obtained by the system voltage stabilization control configured to separate the suppressing frequency band variations in system voltage.

  In this configuration, the system power can be suppressed by operating the input power of the MG unit by the first system voltage stabilization control and the conversion means is controlled by the second system voltage stabilization control. Since fluctuations in voltage can be suppressed, the system voltage (power line voltage) can be effectively stabilized even when the power balance of the AC motor changes greatly due to changes in the driving state of the vehicle or the like. In addition, the voltage stabilizing effect of the power supply line can be enhanced without increasing the performance of the conversion means and increasing the capacity of the smoothing means, and the requirements for downsizing and cost reduction of the system can be satisfied.

  By the way, when the first system voltage stabilization control (control of the system voltage by operating the input power of the MG unit) and the second system voltage stabilization control (control of the system voltage by the conversion means) are used in combination, There is a possibility that the system voltage stabilization control and the second system voltage stabilization control interfere with each other.

  As a countermeasure against this, the present invention separates the frequency band in which the fluctuation of the system voltage is suppressed by the first system voltage stabilization control and the frequency band in which the fluctuation of the system voltage is suppressed by the second system voltage stabilization control. I have to. In this way, for example, the high-frequency fluctuation of the system voltage is suppressed by the first system voltage stabilization control, and the low-frequency fluctuation of the system voltage is suppressed by the second system voltage stabilization control. Since the fluctuation of the system voltage can be suppressed by executing any one of the system voltage stabilization controls according to the frequency band, the interference between the first system voltage stabilization control and the second system voltage stabilization control The system voltage can be effectively stabilized by using the first system voltage stabilization control and the second system voltage stabilization control in combination.

  Further, during the first system voltage stabilization control, 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, the system voltage is controlled by manipulating the input power (that is, reactive power) different from the power necessary for generating the torque of the AC motor during the first system voltage stabilization control. It is good to do. 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.

  According to a specific control method of the first 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. Based on the target voltage value and the detected system voltage, the operation amount of the input power of the MG unit is calculated by the operation amount calculation means, and the system voltage is controlled by operating the input power of the MG unit based on the operation amount. You may do it. 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, when controlling the AC motor by the sine wave PWM control system as in claim 4, 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.

  On the other hand, when the AC motor is controlled by the rectangular wave control method as in claim 5, 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 that is an internal combustion engine, a first AC motor 13, and a second AC motor 14 are mounted, and the engine 12 and the second AC motor 14 serve as a power source for driving the wheels 11. The power of the crankshaft 15 of the engine 12 is divided into two systems by the planetary gear mechanism 16. The planetary gear mechanism 16 includes a sun gear 17 that rotates at the center, a planetary gear 18 that revolves while rotating on the outer periphery of the sun gear 17, and a ring gear 19 that rotates on the outer periphery of the planetary gear 18. The crankshaft 15 of the engine 12 is connected through a carrier that is not connected, the rotary shaft of the second AC motor 14 is connected to the ring gear 19, and the first AC motor 13 mainly used as a generator is connected to the sun gear 17. Are connected.

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

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

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

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

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

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

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

  First, the rotor rotational position θ1 of the first AC motor 13 (the output signal of the rotor rotational position sensor 39) is input to the first rotational speed calculator 45, and the rotational speed N1 of the first AC motor 13 is calculated. . 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. While maintaining the (torque command value T2 *), the input power of the second AC motor 14 is operated to execute the first system voltage stabilization control for suppressing the fluctuation of the system voltage, and the boost converter 21 is controlled. Then, the second system voltage stabilization control for suppressing the fluctuation of the system voltage is executed. Further, the first system is separated by separating the frequency band in which the system voltage fluctuation is suppressed by the first system voltage stabilization control and the frequency band in which the system voltage fluctuation is suppressed by the second system voltage stabilization control. Interference between the voltage stabilization control and the second system voltage stabilization control is prevented.

  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 second AC motor 14. Calculate the speed 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 inputs the target value Vs * of the system voltage to the first high-pass filter 51 to obtain the system voltage. The high-pass filter process for passing only the high-frequency component of the target value Vs * of the system is performed, and the system voltage target value Vs * is input to the first low-pass filter 52 to obtain the system voltage target value Vs *. A low-pass filter process for passing only the low-frequency component is applied. As a result, the target value Vs * of the system voltage is converted into the target value VsH * (high frequency component) of the system voltage after high-pass filtering and the target value VsL * (low frequency component) of the system voltage after low-pass filtering. To separate.

  On the other hand, the detected value Vs of the system voltage detected by the voltage sensor 25 is input to the low-pass filter 53 for noise removal, and the noise component (high frequency component) of the detected value Vs of the system voltage is removed to make it more than the noise component. A low-pass filter process for passing only low-frequency components is performed. The system voltage detection value Vsf after the low-pass filter processing is input to the second high-pass filter 56, and only high-frequency components of the system voltage detection value Vsf are allowed to pass through. The detected value Vsf is input to the second low-pass filter 57, and a low-pass filter process for passing only the low frequency component of the detected value Vsf of the system voltage is performed. As a result, the system voltage detection value Vsf is separated into a system voltage detection value VsfH (high-frequency component) after high-pass filtering and a system voltage detection value VsfL (low-frequency component) after low-pass filtering. .

  Thereafter, the deviation unit 58 obtains a deviation ΔVsH (that is, a fluctuation in the high frequency range of the system voltage) between the target value VsH * of the system voltage after the high-pass filter processing and the detected value VsfH of the system voltage after the high-pass filter processing. The deviation ΔVsH is input to the PI controller 59 (power manipulated variable calculation means), and the input power manipulated variable of the second AC motor 14 is controlled by PI control so that the deviation ΔVsH (that is, fluctuation in the high frequency range of the system voltage) is reduced. Pm is calculated.

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, as shown in FIG. The power control current vector ip * (d-axis power control current idp *, q-axis power control current iqp *) for changing the reactive power not contributing to the torque generation of the second AC motor 14 by the input power manipulated variable Pm is obtained, and the torque is obtained. The 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 control current iqp *) are synthesized. The final command current vector i2 * (d-axis command current id2 *, q-axis command current iq2 *) is obtained.
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.

  By the processing of these steps 102 and 103, the input power (reactive power) of the second AC motor 14 is changed to the input power manipulated variable Pm while the torque of the second AC motor 14 is kept constant (torque command value T2 *). The power control current vector ip * (d-axis power control current idp *, q-axis power control current iqp *) to be changed only by the amount is obtained.

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 shown in FIG. 2, the second current vector control unit 55 uses the U-phase and W-phase currents iU2 and iW2 (current sensors 43 and 44) of the second AC motor 14. ) 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, q-axis current iq2) is calculated, d The d-axis command voltage Vd2 * is calculated by PI control so that the deviation Δid2 between the axis command current id2 * and the actual d-axis current id2 is small, and between the q-axis command current iq2 * and the actual q-axis current iq2 The q-axis command voltage Vq2 * is calculated by PI control so that the deviation Δiq2 becomes small. 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, torque control for controlling the torque of the second AC motor 14 so as to realize the torque command value T2 * output from the main control device 31 is executed, and the torque of the second AC motor 14 is also executed. Is kept constant (torque command value T2 *), and the second MG unit 30 (the second MG unit 30) is adjusted so that the deviation ΔVsH between the target value VsH * of the system voltage after the high-pass filter processing and the detected value VsfH becomes small. The first system voltage stabilization control is performed to control the fluctuation of the system voltage in the high frequency range by operating the input power of the AC motor 14). In this case, the second torque control current calculation unit 49, the command current calculation unit 54, the second current vector control unit 55, and the like serve as motor control means, and the PI controller 59, the command current calculation unit 54, the first The second current vector control unit 55 and the like serve as first system voltage control means.

  Further, the deviation device 60 obtains a deviation ΔVsL (that is, fluctuation in the low frequency range of the system voltage) between the target value VsL * of the system voltage after the low-pass filter processing and the detected value VsfL of the system voltage after the low-pass filter processing. The deviation ΔVsL is input to the PI controller 61, and the energization duty ratio Dc of a switching element (not shown) of the boost converter 21 is calculated by PI control so that the deviation ΔVsL (that is, fluctuation in the low frequency range of the system voltage) is reduced. Thereafter, the boost drive signal calculation unit 68 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 manner, the boost converter 21 is feedback-controlled so as to reduce the deviation ΔVsL between the target value VsL * of the system voltage after the low-pass filter process and the detected value VsfL, thereby suppressing the fluctuation in the low frequency range of the system voltage. 2 system voltage stabilization control is executed. In this case, the PI controller 61, the boost drive signal calculation unit 68, and the like serve as second system voltage control means.

  In the first embodiment described above, the second MG unit 30 is set so that the deviation ΔVsH (that is, the fluctuation in the high frequency range of the system voltage) between the target value VsH * of the system voltage after the high-pass filter processing and the detected value VsfH becomes small. The first system voltage stabilization control for suppressing the fluctuation of the system voltage (the voltage of the power supply line 22) by operating the input power of the (second AC motor 14) and the system voltage after the low-pass filter processing are performed. Since the second system voltage stabilization control for controlling the boost converter 21 is executed so that the deviation ΔVsL between the target value VsL * and the detected value VsfL (that is, the fluctuation in the low frequency range of the system voltage) is reduced. Even when the power balance of the two AC motors 13 and 14 changes greatly due to a change in the driving state of the vehicle, the system voltage can be effectively stabilized. Kill. 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, in the first embodiment, the frequency band that suppresses the fluctuation of the system voltage by the first system voltage stabilization control and the frequency band that suppresses the fluctuation of the system voltage by the second system voltage stabilization control are separated. Since the fluctuation in the high frequency range of the system voltage is suppressed by the first system voltage stabilization control and the fluctuation in the low frequency range of the system voltage is suppressed by the second system voltage stabilization control, the first system The system voltage is effectively stabilized by using the first system voltage stabilization control and the second system voltage stabilization control together while preventing the interference between the voltage stabilization control and the second system voltage stabilization control. It can be made.

  In the first embodiment, the second system voltage stabilization control that controls the boost converter 21 so as to reduce the deviation ΔVsL between the target value VsL * of the system voltage and the detected value VsfL to suppress the fluctuation of the system voltage. , The feedback control of the output power (or input power) of the step-up converter 21 and the feedback control of the current are not necessary, and the current sensor for detecting the current flowing in the power supply line may be omitted. It is good also as a structure which provided the current sensor.

  In the first embodiment, in the system in which the second AC motor 14 is controlled by the sine wave PWM control method, the first AC voltage stabilization control does not contribute to the torque generation of the second AC motor 14. By operating the current vector so as to change only the reactive power, the input power of the second AC motor 14 is operated while the torque of the second AC motor 14 is kept constant (torque command value T2 *). Since the system voltage is controlled, 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. 5, 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, the torque of the second AC motor 14 is kept constant by manipulating the duty ratio Duty of the rectangular wave energizing the second AC motor 14 to manipulate the pulse width or manipulating the phase φ of the rectangular wave. While maintaining the (torque command value T2 *), the input power of the second AC motor 14 is operated to execute the first system voltage stabilization control for suppressing the fluctuation of the system voltage, and the boost converter 21 is controlled. The second system voltage stabilization control for suppressing the fluctuation of the system voltage is executed, the frequency band for suppressing the fluctuation of the system voltage by the first system voltage stabilization control and the system voltage by the second system voltage stabilization control. The frequency band that suppresses fluctuations is separated.

  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 second AC motor 14. While calculating the speed N2, the U-phase and W-phase currents iU2 and iW2 (output signals of the current sensors 43 and 44) of the second AC motor 14 and the rotor rotational position θ2 are input to the torque estimating unit 74, The torque T2 generated by the current flowing through the two AC motors 14 is estimated.

  Thereafter, as shown in FIG. 6, a deviation device 77 of the torque controller 75 (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 78, 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 manipulated variable Pm, the estimated torque T2 and the rotational speed N2 outputted from the PI controller 59 are inputted to the rectangular wave manipulated variable calculator 80 of the power controller 76 (first system voltage controller), The duty ratio manipulated variable Dp and the phase manipulated variable φp are calculated as follows. First, as shown in FIG. 7, the second AC motor 14 is calculated by calculating a rectangular wave duty ratio operation amount Dp according to the input power operation amount 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. 7, 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.

  Further, the rectangular wave manipulated variable calculation unit 80 includes limit means (not shown) for limiting (guard processing) the duty ratio manipulated variable Dp and the phase manipulated variable φp with predetermined limit values. 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 81 of the power control unit 76 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 82 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 calculation unit 83 of the torque control unit 75 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.

  Thus, torque control for controlling the torque of the second AC motor 14 so as to realize the torque command value T2 * output from the main control device 31 is executed, and the torque of the second AC motor 14 is also executed. Is kept constant (torque command value T2 *), and the second MG unit 30 (the second MG unit 30) is adjusted so that the deviation ΔVsH between the target value VsH * of the system voltage after the high-pass filter processing and the detected value VsfH becomes small. The first system voltage stabilization control is performed to control the fluctuation of the system voltage in the high frequency range by operating the input power of the AC motor 14).

  Further, in the same manner as in the first embodiment, the boost converter 21 is feedback-controlled so that the deviation ΔVsL between the target value VsL * of the system voltage after the low-pass filter process and the detected value VsfL becomes small, thereby reducing the low frequency of the system voltage. The second system voltage stabilization control is performed to suppress the fluctuation of the area.

  Also in the second embodiment described above, the frequency band in which the fluctuation of the system voltage is suppressed by the first system voltage stabilization control and the frequency band in which the fluctuation of the system voltage is suppressed by the second system voltage stabilization control are separated. Then, the fluctuation in the high frequency range of the system voltage is suppressed by the first system voltage stabilization control, and the fluctuation in the low frequency range of the system voltage is suppressed by the second system voltage stabilization control. The system voltage is effectively reduced by using both the first system voltage stabilization control and the second system voltage stabilization control while preventing the interference between the system voltage stabilization control and the second system voltage stabilization control. Can be stabilized.

  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 changed to the input power operation during the first system voltage stabilization control. The duty ratio manipulated variable Dp to be changed by the quantity Pm is obtained, and the phase manipulated variable φp is obtained so as to suppress the torque fluctuation of the second AC motor 14 caused by the duty ratio manipulated by the duty ratio manipulated variable Dp. Therefore, 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 *), and the vehicle is in the driving state. System voltage fluctuations can be suppressed without adverse effects.

  In each of the first and second embodiments, during the first system voltage stabilization control, the input power of the second MG unit 30 (second AC motor 14) is manipulated to suppress fluctuations in the system voltage. However, the input power of the first MG unit 29 (first AC motor 13) may be manipulated to suppress fluctuations in the system voltage. Alternatively, although not shown, for example, in a vehicle having an all-wheel drive configuration in which the third MG unit is mounted on the driven wheel, the input power of the third MG unit is operated to suppress fluctuations in the system voltage. May be.

  In 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. It is a block diagram which shows the structure of the control system of an AC motor. It is a figure for demonstrating the calculation method of a command electric current vector. It is a flowchart which shows the flow of a process of a command electric current vector calculation program. It is a 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.

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), 27, 28 ... Inverter, 29, 30 ... MG unit, 37 ... motor control device, 49 ... second torque control current calculation unit (motor control means), 50 ... system voltage target value calculation unit (target voltage calculation means), 51 ... first High pass filter, 52... First low pass filter, 54... Command current calculation unit (motor control means, first system voltage control means), 55... Second current vector control unit (motor control means, first system) Voltage control means), 56 ... second high-pass filter, 57 ... second low-pass filter, 59 ... PI controller (power manipulated variable calculation means, first system voltage) , 61... PI controller (second system voltage control means), 68... Boost drive signal calculation section (second system voltage control means), 75... Torque control section (motor control means), 76. Control unit (first system voltage control means)

Claims (5)

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
First system voltage control means for executing first system voltage stabilization control for controlling the input power of the MG unit to control fluctuation of the system voltage;
Second system voltage control means for performing second system voltage stabilization control for controlling the conversion means to control fluctuation of the system voltage, and
The frequency band for suppressing the fluctuation of the system voltage by the first system voltage stabilization control is separated from the frequency band for suppressing the fluctuation of the system voltage by the second system voltage stabilization control. Electric vehicle control device.   2. The electric vehicle control according to claim 1, wherein the first system voltage control unit controls the system voltage by operating an input power different from an electric power necessary for generating torque of the AC motor. apparatus. 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 first system voltage control means controls the system voltage by operating input power of the MG unit based on an operation amount of input power calculated by the power operation amount calculation means. The control apparatus of the electric vehicle of 1 or 2. Motor control means for controlling the AC motor by a sinusoidal PWM control system;
The first 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 by the sine wave PWM control method. The control apparatus for an electric vehicle according to any one of claims 1 to 3. Motor control means for controlling the AC motor by a rectangular wave control system;
The first 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. The control apparatus for an electric vehicle according to any one of claims 1 to 3.

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