JP4683382B2 - Electric vehicle control device - Google Patents

Description

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

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

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

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

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

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

In order to achieve the above object, the invention according to claim 1 converts the voltage of a DC power supply to generate a system voltage in the power supply line, the inverter connected to the power supply line, and the inverter driven by the inverter In a control device for an electric vehicle including at least one motor drive unit (hereinafter referred to as “MG unit”) composed of an AC motor, a command value of a motor current flowing through the AC motor is set by a motor command current setting unit. The motor current detection unit detects the motor current by the motor current detection unit, and outputs the command signal to the MG unit based on the command value of the motor current and the detection value of the motor current by the current control unit to control the motor current. run, an input power different from the power required to torque generation of the AC motor by the system voltage control means Create and outputs a command signal to the motor command current setting means to perform the inhibiting system voltage stabilization control the fluctuation of the system voltage. Furthermore, the current control means sets a transient characteristic of the motor current based on the command value of the motor current and the detected value of the motor current during the system voltage stabilization control, and performs motor current control based on the transient characteristic . By setting the control gain , the command signal is output to the MG unit so that the motor current converges to the command value.

  In this configuration, since the system voltage stabilization control is executed, the input power of the MG unit (AC motor) can be operated to suppress fluctuations in the system voltage. Even when the power balance of the motor changes greatly, the system voltage (power line voltage) can be effectively stabilized. 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.

  In addition, during system voltage stabilization control, the system voltage is controlled by operating input power (that is, reactive power) that is different from the power required for generating torque of the AC motor, so that the torque of the AC motor is substantially constant (for example, The system voltage can be controlled by operating the input power of the AC motor while maintaining the torque command value), and fluctuations in the system voltage can be suppressed without adversely affecting the driving state of the vehicle.

By the way, when operating the input power (that is, reactive power) different from the power required for generating the torque of the AC motor during the system voltage stabilization control, for example, as shown in FIG. 4, it contributes to the torque generation. A power control current vector for changing the reactive power by a predetermined amount with respect to the torque control current vector to be obtained is obtained, and the power control current vector is synthesized with the torque control current vector to obtain a final command current vector. This command current vector is a current vector that generates the same torque as the torque control current vector, and is a current vector on a constant torque curve A (curve representing a current that generates the same torque) that passes through the torque control current vector.

  After obtaining the command current vector in this way, the MG unit is controlled so that the deviation between the command current vector (motor current command value) and the detected current vector (motor current detection value) becomes small. It converges to the command current vector. In this case, if the current vector changes along the constant torque curve A as shown by the arrow B in FIG. 4 during the transition in which the current vector changes to the command current vector, torque fluctuation hardly occurs. As indicated by the arrow C, if the current vector deviates significantly from the constant torque curve A, an unpleasant torque fluctuation (see FIG. 5) may occur.

  As a countermeasure against this, the present invention sets a motor current transient characteristic based on the motor current command value and the detected motor current value during the system voltage stabilization control, and sets the motor current to the command value based on the transient characteristic. A command signal is output to the MG unit so as to converge. In this way, during the system voltage stabilization control, the MG unit is controlled so that the deviation between the command current vector (motor current command value) and the detected current vector (motor current detection value) becomes small. When the current vector is converged to the command current vector, the transient characteristic of the current vector is set so that the current vector changes along the constant torque curve, and the current vector is converged to the command current vector by the transient characteristic. It is possible to prevent unpleasant torque fluctuations from occurring during a transition in which the current vector changes to the command current vector.

  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 2. The input power manipulated variable of the MG unit is calculated on the basis of the target value and the detected system voltage, and a command signal is output to the motor command current setting means based on the input power manipulated variable to control the system voltage. May be. In this way, the input power of the MG unit can be controlled so as to reduce the deviation between the target value of the system voltage and the detected value of the system voltage, and fluctuations in the system voltage can be reliably suppressed.

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

  By the way, when system voltage stabilization control is performed to control system voltage fluctuation by manipulating the input power of the MG unit (AC motor), the system voltage is controlled by the input power operation of the MG unit and the system voltage of the conversion means is changed. Controls can interfere with each other.

  As a countermeasure, the conversion power control means may control the input power or output power (hereinafter referred to as “conversion power”) of the conversion means as in claim 4. Specifically, as in claim 5, the conversion power command value is calculated by the conversion power command value calculation means, the conversion power is detected by the conversion power detection means, and the conversion power detected as the conversion power command value is detected. The control amount of the conversion power may be calculated based on the power, and the conversion power may be controlled based on the control amount of the conversion power. 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 The conversion power can be controlled so as to reduce the deviation between the detected conversion power and the detected conversion power, and interference between the control of the system voltage by the input power operation of the MG unit and the control of the system voltage by the conversion means can be prevented. .

  Moreover, the command value of the conversion power is the input power of all electric loads including the MG unit connected to the power supply line (for example, a commercial 100V electric device is added to the total value of the input power of the MG unit). The command value of the converted power may be calculated based on the power obtained by adding a power load other than the MG unit such as a DCAC converter to be driven. When the input power of the MG unit is controlled, the total value of the input power of all the electric loads including the MG unit changes. Therefore, the converted power command value is based on the total value of the input power of all the electric loads including the MG unit. Is calculated, it is possible to calculate the command value of the converted power that accurately reflects the influence of the input power operation of the MG unit.

  In this case, as in the seventh aspect, the second low-pass means for passing a component having a frequency equal to or lower than a predetermined frequency out of the input power of all electric loads including the MG unit connected to the power supply line is provided. You may make it calculate the command value of conversion electric power based on the electric power below the predetermined frequency which passed the 2nd low-pass means. In this way, the command value of the conversion power is set based on the power obtained by removing the noise component (high frequency component) included in the total value of the input power of all electric loads including the MG unit by the second low-pass means. Since calculation can be performed with high accuracy and the speed of the conversion means can be prevented by limiting the band, the performance of the conversion means can be reduced and the size can be reduced, which is advantageous for mounting in a vehicle.

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

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

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

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

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

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

  Next, control of the first and second AC motors 13 and 14 will be described with reference to FIGS. As shown in FIG. 2, 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 each rotating the rotor to detect the rotational position of the rotor. Position sensors 39 and 40 are mounted. 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.

  As shown in FIG. 2, when the motor control device 37 controls the torque of the first AC motor 13, the torque command value T1 * output from the main control device 31 and the U of the first AC motor 13 are controlled. Based on the phase current iU1 and the W-phase current iW1 (output signals of the current sensors 41 and 42) and the rotor rotational position θ1 of the first AC motor 13 (output signal of the rotor rotational position sensor 39), a sinusoidal PWM control method is used. Three-phase voltage command signals UU1, UV1, 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), a detected current vector i1 (d-axis detected current id1, q-axis detected current iq1) which is a detected value of the motor current actually flowing to the first AC motor 13 is obtained. The d-axis command voltage Vd1 * is calculated by PI control or the like so that the deviation Δid1 between the d-axis torque control current idt1 * and the d-axis detection current id1 becomes small, and the q-axis torque control current iqt1 * and the q-axis The q-axis command voltage Vq1 * is calculated by PI control or the like so that the deviation Δiq1 from the detected current iq1 becomes small. 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.

In this way, torque control for controlling the torque of the first AC motor 13 is executed so as to realize the torque command value T1 * output from the main control device 31.
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 used in a sinusoidal PWM control system. UU2, UV2 and UW2 are generated.

  At that time, the torque of the second AC motor 14 is substantially reduced by controlling the current vector so that only the input power (that is, the reactive power) different from the power required for generating the torque of the second AC motor 14 is changed. The system voltage stabilization control is performed to control the input power of the second MG unit 30 (second AC motor 14) while maintaining constant (torque command value T2 *) to suppress the fluctuation of the system voltage.

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

  Further, the system voltage target value calculation unit 50 (target voltage setting 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 the low-pass filter processing is obtained by the deviation unit 52, and this deviation ΔVs is input to the PI controller 53 to obtain the target of the system voltage. The input electric power manipulated variable Pm of the second AC motor 14 is calculated by PI control or the like so that the deviation ΔVs between the value Vs * and the detected value Vsf of the system voltage after the low-pass filter processing becomes small.

  Thereafter, the input power manipulated variable Pm, the torque control current vector it2 * (d-axis torque control current idt2 *, q-axis torque control current iqt2 *) and the torque command value T2 * are converted into a command current calculation unit 54 (motor command current setting means). ). As shown in FIG. 3, the command current calculation unit 54 is a power control current calculation unit 69 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. After obtaining ip2 * (d-axis power control current idp2 *, q-axis power control current iqp2 *), the adder 70 performs torque control current vector it2 * (d-axis torque control current itt2 *, q-axis torque control current iqt2 *) And the power control current vector ip2 * (d-axis power control current idp2 *, q-axis power control current iqp2 *) and a command current vector i2 that is a command value of the motor current flowing to the second AC motor 14 * (D-axis command current id2 *, q-axis command current iq2 *) is obtained.

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。 Specifically, as shown in FIG. 4, first, the d-axis power corresponding to 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 *). The control current idp2 * is calculated by a map or a mathematical expression, and the q-axis power control current iqp2 * is calculated by the following expression using the d-axis power control current idp2 *.

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.

  As a result, a power control current vector ip2 * (d-axis power control current idp2 *, which changes the reactive power by the input power manipulated variable Pm with respect to the torque control current vector it2 * contributing to the torque generation of the second AC motor 14. q-axis power control current iqp2 *) is obtained.

After this, torque control current vector it2 * (d-axis torque control current idt2 *, q-axis torque control current iqt2 *) and power control current vector ip2 * (d-axis power control current idp2 *, q-axis power control current iqp2 *) To obtain a final command current vector i2 * (d-axis command current id2 *, q-axis command current iq2 *).
i2 * (id2 *, iq2 *) = it2 * (idt2 *, iqt2 *) + ip2 * (idp2 *, iqp2 *)

  This command current vector i2 * is a current vector that generates the same torque as the torque control current vector it2 *, and is on a constant torque curve A (curve representing a current that generates the same torque) that passes through the torque control current vector it2 *. It becomes a current vector.

  After obtaining the command current vector i2 * in this way, as shown in FIG. 2, the command current vector i2 * (d-axis command current id2 *, q-axis command current iq2 *) is converted into the second current vector control unit 55. (Current control means), and the second current vector control unit 55 controls the MG unit 30 so that the deviation between the command current vector i2 * and the detected current vector i2 is small, and commands the current vector i2. It converges to the current vector i2 *. In this case, if the current vector i2 changes along the constant torque curve A as shown by the arrow B in FIG. 4 during the transition in which the current vector i2 changes to the command current vector i2 *, torque fluctuation hardly occurs. As shown by the arrow C in FIG. 4, when the current vector i2 deviates greatly from the constant torque curve A, an unpleasant torque fluctuation (see FIG. 5) may occur.

  As a countermeasure, in this embodiment, the second current vector control unit 55 controls the MG unit 30 so that the deviation between the command current vector i2 * and the detected current vector i2 becomes small, and the current vector i2 is set to the command current. Set the transient characteristics of the current vector i2 (response characteristics of the d-axis current id2 and response characteristics of the q-axis current iq2) so that the current vector i2 changes along the constant torque curve A when converging to the vector i2 *. Thus, the current vector i2 is converged to the command current vector i2 * by the transient characteristic.

  Specifically, as shown in FIG. 6, the second current vector control unit 55 is a coordinate conversion unit 71 (motor current detection means), and a U-phase current, a W-phase current iU2 of the second AC motor 14, Detection of motor current actually flowing to the second AC motor 14 based on 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 detection current vector i2 (d-axis detection current id2, q-axis detection current iq2) which is a value is calculated.

  Thereafter, a deviation Δid2 between the d-axis command current id2 * and the d-axis detection current id2 is obtained by the deviation unit 72, and this deviation Δid2 is input to the d-axis current FB (feedback) control unit 73, and the deviation unit 74 q A deviation Δiq2 between the axis command current iq2 * and the q-axis detection current iq2 is obtained, and this deviation Δiq2 is input to the q-axis current FB control unit 75.

  Further, the d-axis current control response calculation unit 76 calculates a d-axis current response characteristic value Rd corresponding to the d-axis command current id2 * and the d-axis detection current id2 by a map or a mathematical formula, and calculates a q-axis current control response. The unit 77 calculates a q-axis current response characteristic value Rq according to the q-axis command current iq2 * and the q-axis detection current iq2 by using a map or a mathematical expression. The map of the d-axis current response characteristic value Rd and the map of the q-axis current response characteristic value Rq are created in advance based on test data, design data, etc., and the current vector i2 (d-axis current id2, q-axis current iq2). The d-axis current response characteristic value Rd and the q-axis current response characteristic value Rq are set so as to be correlated with each other so that the value changes along the constant torque curve A.

  For example, as shown in FIG. 7, (1) the current vector i2 is changed from the current detected current vector i2 to the command current vector id2 * along the constant torque curve A along the path B1 (the change amount Δid2 of the d-axis current id2 is q-axis When changing the current iq2 by a path larger than the change amount Δiq2), the d-axis current response characteristic value Rd and the d-axis current control characteristic value Rd are set so as to make the d-axis current control responsiveness faster and the q-axis current control responsiveness slower. q-axis current response characteristic value Rq is set. On the other hand, (2) the current vector i2 is changed from the current detected current vector i2 to the command current vector id2 * along the path B2 along the constant torque curve A (the change amount Δid2 of the d-axis current id2 is greater than the change amount Δiq2 of the q-axis current iq2). When the change is made in a small path), the d-axis current response characteristic value Rd and the q-axis current response characteristic value Rq are set so that the d-axis current control response is generally delayed and the q-axis current control response is increased. Set.

  Thereafter, as shown in FIG. 6, the d-axis current response characteristic value Rd is input to the d-axis current control gain calculation unit 78, and the d-axis current control gain Gd corresponding to the d-axis current response characteristic value Rd is mapped or The d-axis current control gain Gd is input to the d-axis current FB control unit 73 and the q-axis current response characteristic value Rq is input to the q-axis current control gain calculation unit 79 to calculate the q-axis current. The q-axis current control gain Gq corresponding to the response characteristic value Rq is calculated by a map or a mathematical formula, and this q-axis current control gain Gq is input to the q-axis current FB control unit 75.

  As a result, the d-axis current FB control unit 73 uses the d-axis current control gain Gd to reduce the deviation Δid2 between the d-axis command current id2 * and the d-axis detected current id2 by PI control or the like. Vd2 * is calculated and the q-axis current FB control unit 75 uses the q-axis current control gain Gq to reduce the deviation Δiq2 between the q-axis command current iq2 * and the q-axis detection current iq2 by PI control or the like. Calculates q-axis command voltage Vq2 *.

  The output form of the current control gain calculation units 78 and 79 may be appropriately changed according to the control algorithm of the current FB control units 73 and 75. For example, the control algorithm of the current FB control units 73 and 75 is PI control. In this case, the d-axis current control gain calculation unit 78 calculates the P gain GPd and the I gain GId as the d-axis current control gain Gd, and the q-axis current control gain calculation unit 79 calculates the P gain GPq as the q-axis current control gain Gq. And I gain GIq. When the control algorithm of the current FB control units 73 and 75 is the state FB, the d-axis current control gain calculation unit 78 calculates the FB gain Gd as the d-axis current control gain Gd, and the q-axis current control gain calculation unit. In 79, the FB gain Gq is calculated as the q-axis current control gain Gq.

  Thereafter, the d-axis command voltage Vd2 * and the q-axis command voltage Vq2 * are converted into three-phase voltage command signals UU2, UV2, UW2 by the coordinate conversion unit 80, and these three-phase voltage command signals UU2, UV2, UW2 are converted into the first. 2 to the inverter 28.

  As described above, torque control for controlling the torque of the second AC motor 14 is executed so as to realize the torque command value T2 * output from the main control device 31, and the torque of the second AC motor 14 is also executed. Input to the second MG unit 30 (second AC motor 14) so that the deviation ΔVs between the target value Vs * of the system voltage and the detected value Vsf is reduced while the torque is kept substantially constant (torque command value T2 *). System voltage stabilization control that controls power to suppress system voltage fluctuations is executed. In this case, the PI controller 53 and the like serve as system voltage control means.

  Further, the motor control device 37 executes conversion power control for controlling the output power of the boost converter 21 so that the deviation ΔPi between the command value Pif * of the output power of the boost converter 21 and the detected value Pi becomes small.

  Specifically, as shown in FIG. 2, when calculating the command value Pif * of the output power of the boost converter 21, first, the torque command value T1 * and the rotational speed N1 of the first AC motor 13 are set to the first value. The first shaft output calculation unit 56 inputs the shaft output PD1 of the first AC motor 13 and calculates the torque command value T1 * and the rotational speed N1 of the first AC motor 13 as the first output loss calculation unit. 57, the output loss PL1 of the first AC motor 13 is calculated, and the adder 58 adds the output loss PL1 to the shaft output PD1 of the first AC motor 13 to input the first AC motor 13. The electric power Pi1 is obtained. At this time, when the first AC motor 13 functions as a generator, the calculation result of the input power Pi1 of the first AC motor 13 becomes a negative value.

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

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

  On the other hand, when the detected value Pi of the output power of the boost converter 21 is calculated, the detected value ic of the output current of the boost converter 21 detected by the current sensor 26 is used as a third low-pass filter 64 (third low-pass means). And 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 conversion power detection unit 65 (conversion power detection means) performs a system voltage target value Vs. The detected value Pi of the converted power is obtained by multiplying * by the detected value icf of the output current of the boost converter 21 after the low-pass filter processing. The detection value Pi of the output power may be obtained by multiplying the detection value Vsf of the system voltage and the detection value iff of the output current.

  Thereafter, the deviation ΔPi between the command value Pif * of the output power of the boost converter 21 and the detected value Pi is obtained by the deviation unit 66, and this deviation ΔPi is input to the PI controller 67 to output the command of the output power of the boost converter 21. The energization duty ratio Dc of the switching element of the boost converter 21 is calculated by PI control or the like so that the deviation ΔPi between the value Pif * and the detected value Pi becomes small. 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.

  Thus, by executing the conversion power control for controlling the output power of the boost converter 21 so that the deviation ΔPi between the command value Pif * of the output power of the boost converter 21 and the detected value Pi becomes small, the system voltage is stabilized. Control (system voltage control by operation of input power of second MG unit 30) and system voltage control by boost converter 21 are prevented from interfering with each other. In this case, the PI controller 67, the boost drive signal calculation unit 68, and the like serve as conversion power control means.

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

  In the present embodiment, the second AC motor 14 is controlled by controlling the current vector so that only the reactive power that does not contribute to the torque generation of the second AC motor 14 is changed during the system voltage stabilization control. Since the system voltage is controlled by controlling the input power of the second AC motor 14 while maintaining the torque of the motor at a substantially constant (torque command value T2 *), the system does not adversely affect the driving state of the vehicle. Voltage fluctuation can be suppressed.

  Furthermore, in this embodiment, during the system voltage stabilization control, the MG unit 30 is controlled so that the deviation between the command current vector i2 * and the detected current vector i2 becomes small, and the current vector i2 is set to the command current vector i2 *. Is set so that the current vector i2 changes along the constant torque curve A when the current vector i converges, and the transient characteristics (response characteristics of the d-axis current id2 and response characteristics of the q-axis current iq2) are set. Since the current vector i2 is converged to the command current vector i2 * due to the transient characteristics, it is possible to prevent unpleasant torque fluctuations from occurring during a transient in which the current vector i2 changes to the command current vector i2 *.

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

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

  In this embodiment, the total power Pif * after the low-pass filter processing is performed on the total power Pi * of the input power Pi1 of the first AC motor 13 and the input power Pi2 of the second AC motor 13 is used as the command value for the conversion power. Since Pif * is used, the total power Pif * after the noise component (high frequency component) is removed by the low-pass filter processing can be used as the converted power command value Pif *. It can be set with high accuracy. In addition, since the speed of the boost converter 21 can be prevented by limiting the bandwidth, the required performance of the boost converter 21 can be reduced and the size can be reduced, which is advantageous for mounting in a vehicle.

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

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

  In the above-described embodiment, the system voltage stabilization control is performed by controlling the input power of the second MG unit 30 (second AC motor 14) to suppress fluctuations in the system voltage. The input power of one MG unit 29 (first AC motor 13) may be controlled to suppress fluctuations in system voltage. Or, 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 controlled to suppress fluctuations in the system voltage. May be.

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

It is a schematic block diagram of the drive system of the electric vehicle in one Example of this invention. It is a block diagram which shows the structure of the motor control apparatus in one Example of this invention. It is a block diagram which shows the structure of the command electric current calculating part in one Example of this invention. It is a figure for demonstrating the calculation method of the command current vector in one Example of this invention. It is a time chart which shows a torque fluctuation when it deviates from a constant torque curve at the time of a transition where a current vector changes to a command current vector. It is a block diagram which shows the structure of the 2nd current vector control part in one Example of this invention. It is a figure for demonstrating an example of the setting method of d-axis current response characteristic value Rd and q-axis current response characteristic value Rq in one Example of this invention.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 13,14 ... AC motor, 20 ... DC power supply, 21 ... Boost converter (conversion means), 22 ... Power supply 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, 49 ... second torque control current calculation unit, 50 ... system voltage target value calculation unit (target voltage setting means), 51 ... first Low-pass filter (first low-pass means), 53... PI controller (system voltage control means), 54... Command current calculator (motor command current setting means), 55. Control means), 62 ... totalizer (converted power command value calculating means), 63 ... second low-pass filter (second low-pass means), 64 ... third low-pass filter (third low-pass filter) Stage), 65 ... conversion power detection part (conversion power detection means), 67 ... PI controller (conversion power control means), 68 ... boost drive signal calculation part (conversion power control means), 71 ... coordinate conversion part (motor current) Detecting means), 73 ... d-axis current FB control unit, 75 ... q-axis current FB control unit, 76 ... d-axis current control response calculation unit, 77 ... q-axis current control response calculation unit, 78 ... d-axis current control gain calculation 79, q-axis current control gain calculation unit

Claims (9)

At least one motor drive unit (hereinafter referred to as “MG unit”) comprising conversion means for converting a voltage of a DC power source to generate a system voltage on a power supply line, an inverter connected to the power supply line, and an AC motor driven by the inverter. In a control device of an electric vehicle provided with
Motor command current setting means for setting a command value of a motor current flowing through the AC motor;
Motor current detection means for detecting the motor current;
A motor current for controlling the motor current by outputting a command signal to the MG unit based on a motor current command value set by the motor command current setting means and a motor current detection value detected by the motor current detection means Current control means for performing control;
A system that outputs a command signal to the motor command current setting means so as to execute a system voltage stabilization control that suppresses fluctuations in the system voltage by operating an input power different from the power required for generating torque of the AC motor Voltage control means,
Wherein said current control means, said during system voltage stabilization control, based on the transient characteristics by setting the transient characteristics of the motor current based on the command value of the motor current and the detected value of the motor current An electric vehicle control device that outputs a command signal to the MG unit so as to converge the motor current to a command value by setting a control gain of motor current control . Target voltage setting means for setting a target value of the system voltage;
Voltage detecting means for detecting the system voltage,
The system voltage control means calculates an input power operation amount of the MG unit based on a system voltage target value set by the target voltage setting means and a system voltage detected by the voltage detection means, and the input power operation 2. The control apparatus for an electric vehicle according to claim 1, wherein the system voltage is controlled by outputting a command signal to the motor command current setting means based on a quantity. A first low-pass means for passing a component having a predetermined frequency or less out of the system voltage detected by the voltage detection means;
The said system voltage control means calculates the input electric power manipulated variable of the said MG unit using the system voltage below the predetermined | prescribed frequency which passed the said 1st low-pass means. Electric vehicle control device.   The control apparatus for an electric vehicle according to any one of claims 1 to 3, further comprising conversion power control means for controlling input power or output power (hereinafter referred to as "conversion power") of the conversion means. Converted power command value calculating means for calculating a command value of the converted power;
Conversion power detection means for detecting the conversion power,
The converted power control means calculates the control amount of the converted power based on the converted power command value calculated by the converted power command value calculating means and the converted power detected by the converted power detection means, and the converted power 5. The control apparatus for an electric vehicle according to claim 4, wherein the converted electric power is controlled based on a control amount of the electric vehicle.   6. The converted power command value calculation means calculates the converted power command value based on input power of all electric loads including the MG unit connected to the power supply line. Electric vehicle control device. A second low-pass means for passing a component having a frequency equal to or lower than a predetermined frequency out of input power of all electric loads including the MG unit connected to the power line;
7. The electric power according to claim 6, wherein the converted power command value calculating means calculates a command value of the converted power based on power equal to or lower than a predetermined frequency that has passed through the second low-pass means. Automotive control device. At least one of target voltage setting means for setting a target value of the system voltage and voltage detection means for detecting the system voltage;
Current detection means for detecting the output current of the conversion means,
The conversion power detection means is configured to convert the conversion voltage based on a system voltage target value set by the target voltage setting means or a system voltage detected by the voltage detection means, and an output current of the conversion means detected by the current detection means. The electric vehicle control device according to any one of claims 5 to 7, wherein electric power is calculated. A third low-pass means for passing a component having a predetermined frequency or less in the output current of the conversion means detected by the current detection means;
9. The control apparatus for an electric vehicle according to claim 8, wherein the converted power detection means calculates the converted power using an output current of a predetermined frequency or less that has passed through the third low-pass means. .

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