JP2010158088A - Vehicle and control method therefor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To suppress heating from the switching element of a voltage regulator circuit, in a vehicle equipped with the voltage regulator circuit that regulates the voltage on the drive circuit side relative to the voltage on the secondary battery side. <P>SOLUTION: When slip due to idling of driving wheels is not determined, or the element temperature Tc of a transistor of a boost circuit is equal to or lower than a predetermined temperature Tref, a first frequency CF1 is set as the carrier frequency CF (S110, S120, S140). When the element temperature Tc is higher than the predetermined temperature Tref and slip due to idling of the driving wheels 63a, 63b is determined; and a second frequency CF2 lower than the first frequency CF1 is set as the carrier frequency CF (S110, S140, S150). By using the carrier frequency CF set, switching of the boost circuit is controlled so that the voltage VH of a high-voltage system becomes equal to the target voltage VH* (S160). As a result of this, heating from the transistor of the boost circuit due to switching can be suppressed. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a vehicle and a control method thereof, and more particularly to a vehicle including an electric motor that outputs power to drive wheels and a control method thereof.

Conventionally, as this type of vehicle, a vehicle equipped with a power converter including an inverter circuit that drives a motor by supplying electric power from a battery has been proposed (see, for example, Patent Document 1). In this vehicle, when the temperature of the switching element of the inverter circuit is high, the frequency of the carrier signal when outputting the PWM control signal to the inverter circuit is set lower than when the temperature of the switching element is low, thereby switching the switching element. Loss is reduced and temperature rise due to heat generation is suppressed.
JP-A-9-121595

  In addition to the configuration of the vehicle described above, there is a voltage adjustment circuit that adjusts the voltage of the electric power from the battery by switching the switching element and supplies it to the inverter circuit side of the electric motor. It is desirable to suppress the heat generation. On the other hand, it is conceivable to lower the switching frequency when the temperature of the switching element of the voltage adjustment circuit is high. For example, when an abnormality occurs in the sensor that detects the temperature of the switching element of the voltage adjustment circuit, such a sensor On the other hand, it may be desirable to suppress the heat generation of the switching element of the voltage adjustment circuit by another method, such as when a certain amount of time is required until the temperature rise due to the heat generation of the element is reflected.

  A vehicle and a control method thereof according to the present invention include a voltage adjustment circuit that adjusts a voltage on a drive circuit side with respect to a voltage on a secondary battery side, and mainly aims to suppress heat generation of a switching element of the voltage adjustment circuit. And

  The vehicle and the control method thereof according to the present invention employ the following means in order to achieve at least the above-described main object.

The vehicle of the present invention
A vehicle including an electric motor that outputs power to drive wheels,
A drive circuit for driving the electric motor;
A secondary battery,
Voltage adjusting means connected to the secondary battery and the drive circuit, having a switching element, and adjusting the voltage on the drive circuit side with respect to the voltage on the secondary battery side by switching of the switching element;
Slip determination means for determining slip due to idling of the drive wheel;
When slip is not determined by the slip determining means, a first frequency is set as an execution frequency for switching the switching element of the voltage adjusting means, and when slip is determined by the slip determining means, the execution frequency is set. Execution frequency setting means for setting a second frequency lower than the first frequency to
The voltage adjusting means is controlled so that the switching element is switched at the set execution frequency to adjust the voltage on the drive circuit side, and a driving force based on a required driving force required for traveling from the motor is obtained. Control means for controlling the drive circuit to output and travel;
It is a summary to provide.

  In the vehicle of the present invention, the first frequency is set as the execution frequency for switching the switching element of the voltage adjusting means when the drive wheel slip is not determined, and when the drive wheel slip is determined. A second frequency lower than the first frequency is set as the frequency, the voltage adjusting means is controlled so that the voltage on the drive circuit side is adjusted by switching the switching element at the set execution frequency, and the motor is driven to travel. The drive circuit is controlled so that the vehicle travels by outputting a drive force based on the required drive force. When slipping due to idling of the drive wheel occurs, the switching element of the voltage adjusting means easily generates heat due to the current from the secondary battery, but when the slip of the drive wheel is determined, the slip of the drive wheel is not determined Since the switching element is switched at a lower frequency, excessive heat generation of the switching element of the voltage adjusting means can be suppressed.

  The vehicle according to the present invention includes an element temperature detecting unit that detects an element temperature that is a temperature of the switching element of the voltage adjusting unit, and the execution frequency setting unit is configured so that the detected element temperature is equal to or lower than a predetermined temperature. Regardless of whether or not slip is determined by the slip determination means, the first frequency may be set as the execution frequency. In this case, the predetermined temperature is equal to the switching voltage regardless of the element temperature when the terminal voltage of the switching element when a slip occurs due to idling of the driving wheel in a state where the switching element is switched at the first frequency. The voltage between the terminals of the switching element when the slip occurs due to idling of the drive wheel in a state where the switching element is switched at the second frequency while being within the withstand voltage range of the element is the predetermined temperature as the predetermined temperature. The temperature may be predetermined by experiment or analysis so that the loss due to the switching element is reduced under the condition that the withstand voltage of the switching element is within the element temperature. By so doing, loss due to switching of the switching element of the voltage adjusting means is reduced, and heat generation of the switching element can be more appropriately suppressed.

  In the vehicle of the present invention, the internal combustion engine, a generator capable of exchanging electric power with the secondary battery and capable of inputting and outputting power, a drive shaft connected to the drive wheels, and an output shaft of the internal combustion engine A three-axis power input / output means which is connected to three axes of the generator and the rotating shaft of the generator and inputs / outputs power to / from the remaining shaft based on power input / output to / from any two of the three axes And the electric motor can input and output power to the drive shaft. Here, the “three-axis power input / output means” may be a single pinion type or double pinion type planetary gear mechanism, or may be a differential gear.

The vehicle control method of the present invention includes:
An electric motor that outputs power to the driving wheel; a driving circuit that drives the electric motor; a secondary battery; a switching element that is connected to the secondary battery and the driving circuit; A voltage adjusting means for adjusting the voltage on the drive circuit side with respect to the voltage on the battery side, and a vehicle control method comprising:
(A) determining slip due to idling of the drive wheel;
(B) A first frequency is set as an execution frequency for switching the switching element of the voltage adjusting means when the drive wheel slip is not determined, and when the drive wheel slip is determined, the execution wheel is switched. Setting a second frequency lower than the first frequency to the frequency;
(C) controlling the voltage adjusting means so that the switching element is switched at the set execution frequency to adjust the voltage on the drive circuit side, and based on the required driving force required for traveling from the electric motor Controlling the drive circuit so that the driving force is output and the vehicle travels;
This is the gist.

  In the vehicle control method of the present invention, when the slip of the drive wheel is not determined, the first frequency is set as the execution frequency for switching the switching element of the voltage adjusting means, and the slip of the drive wheel is determined. Sometimes, the execution frequency is set to a second frequency lower than the first frequency, the voltage adjusting means is controlled so that the switching element is switched at the set execution frequency and the voltage on the drive circuit side is adjusted, and the electric motor The driving circuit is controlled so that the driving force based on the required driving force required for traveling is output from the vehicle. When slipping due to idling of the drive wheel occurs, the switching element of the voltage adjusting means easily generates heat due to the current from the secondary battery, but when the slip of the drive wheel is determined, the slip of the drive wheel is not determined Since the switching element is switched at a lower frequency, excessive heat generation of the switching element of the voltage adjusting means can be suppressed.

  Next, the best mode for carrying out the present invention will be described using examples.

  FIG. 1 is a configuration diagram showing an outline of the configuration of a hybrid vehicle 20 as one embodiment of the present invention, and FIG. 2 is a configuration diagram showing an outline of the configuration of an electric drive system including motors MG1 and MG2. As shown in FIG. 1, the hybrid vehicle 20 according to the embodiment includes an engine 22, a three-shaft power distribution and integration mechanism 30 connected to a crankshaft 26 as an output shaft of the engine 22 via a damper 28, A motor MG1 capable of generating electricity connected to the distribution integration mechanism 30, a motor MG2 connected to a ring gear shaft 32a as a drive shaft connected to the power distribution integration mechanism 30 via a reduction gear 35, and a direct current to an alternating current Inverters 41 and 42 that can be converted into motors MG1 and MG2 and a voltage booster circuit 55 that can convert the power from the battery 50 and supply it to the inverters 41 and 42, and a hybrid that controls the entire vehicle And an electronic control unit 70.

  The engine 22 is an internal combustion engine that outputs power using a hydrocarbon-based fuel such as gasoline or light oil. The engine electronic control unit (hereinafter referred to as engine ECU) 24 performs fuel injection control, ignition control, and intake air amount adjustment. Under control of operation such as control. The engine ECU 24 receives signals from various sensors that detect the operating state of the engine 22, for example, a crank position from a crank position sensor (not shown) that detects the crank angle of the crankshaft 26 of the engine 22. The engine ECU 24 is in communication with the hybrid electronic control unit 70, controls the operation of the engine 22 by a control signal from the hybrid electronic control unit 70, and, if necessary, transmits data related to the operating state of the engine 22 to the hybrid electronic control. Output to unit 70. The engine ECU 24 also calculates the rotational speed of the crankshaft 26, that is, the rotational speed Ne of the engine 22, based on a crank position from a crank position sensor (not shown).

  The power distribution and integration mechanism 30 includes an external gear sun gear 31, an internal gear ring gear 32 arranged concentrically with the sun gear 31, a plurality of pinion gears 33 that mesh with the sun gear 31 and mesh with the ring gear 32, A planetary gear mechanism is provided that includes a carrier 34 that holds a plurality of pinion gears 33 so as to rotate and revolve, and that performs differential action using the sun gear 31, the ring gear 32, and the carrier 34 as rotational elements. In the power distribution and integration mechanism 30, the crankshaft 26 of the engine 22 is connected to the carrier 34, the motor MG1 is connected to the sun gear 31, and the reduction gear 35 is connected to the ring gear 32 via the ring gear shaft 32a. When functioning as a generator, power from the engine 22 input from the carrier 34 is distributed according to the gear ratio between the sun gear 31 side and the ring gear 32 side, and when the motor MG1 functions as an electric motor, the engine input from the carrier 34 The power from 22 and the power from the motor MG1 input from the sun gear 31 are integrated and output to the ring gear 32 side. The power output to the ring gear 32 is finally output from the ring gear shaft 32a to the drive wheels 63a and 63b of the vehicle via the gear mechanism 60 and the differential gear 62.

  As shown in FIG. 2, each of the motor MG1 and the motor MG2 is configured as a well-known synchronous generator motor including a rotor having a permanent magnet attached to an outer surface and a stator wound with a three-phase coil. . The inverters 41 and 42 are composed of six transistors T11 to T16 and T21 to 26 and six diodes D11 to D16 and D21 to D26 connected in parallel to the transistors T11 to T16 and T21 to T26 in the reverse direction. Yes. Two transistors T11 to T16 and T21 to T26 are arranged in pairs so that each of the inverters 41 and 42 becomes a source side and a sink side with respect to the positive electrode bus 54a and the negative electrode bus 54b shared by the power line 54. Each of the three-phase coils (U-phase, V-phase, W-phase) of the motors MG1, MG2 is connected to each connection point between the paired transistors. Therefore, a rotating magnetic field is formed in the three-phase coil by controlling the ratio of the on-time of the transistors T11 to T16 and T21 to T26 that make a pair while a voltage is acting between the positive electrode bus 54a and the negative electrode bus 54b. The motors MG1, MG2 can be driven to rotate. Since the inverters 41 and 42 share the positive bus 54a and the negative bus 54b, the electric power generated by either the motor MG1 or MG2 can be supplied to another motor. A smoothing capacitor 57 is connected to the positive bus 54a and the negative bus 54b.

  As shown in FIG. 2, the booster circuit 55 includes two transistors T31 and T32 (for example, bipolar transistors, MOSFETs, IGBTs, and IGBTs in the embodiment, IGBT) and two diodes D31 connected in parallel to the transistors T31 and T32. , D32 and the reactor L. The two transistors T31 and T32 are connected to the positive bus 54a and the negative bus 54b of the inverters 41 and 42, respectively, and the reactor L is connected to the connection point. Further, a positive terminal and a negative terminal of battery 50 are connected to reactor L and negative bus 54b, respectively. Therefore, by turning on / off the transistors T31 and T32, the voltage of the DC power of the battery 50 is boosted and supplied to the inverters 41 and 42, or the DC voltage acting on the positive bus 54a and the negative bus 54b is lowered. The battery 50 can be charged. A smoothing capacitor 58 is connected to the reactor L and the negative electrode bus 54b. Hereinafter, the power line 54 side of the booster circuit 55 is referred to as a high voltage system, and the battery 50 side of the booster circuit 55 is referred to as a low voltage system.

  The inverters 41 and 42 and the booster circuit 55 are all controlled by a motor electronic control unit (hereinafter referred to as a motor ECU) 40, thereby driving and controlling the motors MG1 and MG2. The motor ECU 40 detects signals necessary for driving and controlling the motors MG1 and MG2, such as signals from rotational position detection sensors 43 and 44 that detect the rotational positions of the rotors of the motors MG1 and MG2, and current sensors (not shown). The phase current applied to the motors MG1 and MG2, the element temperature Tc from the temperature sensor 56 for detecting the temperature of the transistors T31 and T32 of the booster circuit 55, the voltage of the capacitor 57 from the voltage sensor 57a (hereinafter referred to as a high voltage system) The voltage VH of the capacitor 58 is input from the voltage sensor 58a. The motor ECU 40 outputs switching control signals to the transistors T11 to T16 and T21 to T26 of the inverters 41 and 42 and switching control signals to the transistors T31 and T32 of the booster circuit 55. The motor ECU 40 is in communication with the hybrid electronic control unit 70, controls the driving of the motors MG1 and MG2 by a control signal from the hybrid electronic control unit 70, and, if necessary, data on the operating state of the motors MG1 and MG2. Output to the hybrid electronic control unit 70. The motor ECU 40 also calculates the rotational speeds Nm1 and Nm2 of the motors MG1 and MG2 based on signals from the rotational position detection sensors 43 and 44. In the embodiment, the rotational position detection sensors 43 and 44 compare the rotational positions of the rotors of the motors MG1 and MG2 in comparison with the accuracy and responsiveness of the temperature sensor 56 that detects the element temperature Tc of the switching elements T31 and T32. A sensor (for example, a resolver or the like) that can detect with high accuracy and high responsiveness is used.

  The battery 50 is configured as a secondary battery such as a nickel metal hydride battery or a lithium ion battery, and is managed by a battery electronic control unit (hereinafter referred to as a battery ECU) 52. The battery ECU 52 receives signals necessary for managing the battery 50, for example, a voltage between terminals from a voltage sensor (not shown) installed between terminals of the battery 50, and a power line 54 connected to the output terminal of the battery 50. The charging / discharging current Ib from the attached current sensor 51a, the battery temperature Tb from the temperature sensor 51b attached to the battery 50, and the like are input. Output to the control unit 70. Further, the battery ECU 52 calculates the storage amount SOC based on the integrated value of the charge / discharge current Ib detected by the current sensor 51a in order to manage the battery 50, or based on the calculated storage amount SOC and the battery temperature Tb. The input / output limits Win and Wout, which are the maximum allowable power that may charge / discharge the battery 50, are calculated. The input / output limits Win and Wout of the battery 50 are set to basic values of the input / output limits Win and Wout based on the battery temperature Tb, and the output limit correction coefficient and the input limit are set based on the storage amount SOC of the battery 50. It can be set by setting a correction coefficient and multiplying the basic value of the set input / output limits Win and Wout by the correction coefficient. The charge / discharge current Ib was positive on the discharge side and negative on the charge side.

  The hybrid electronic control unit 70 is configured as a microprocessor centered on the CPU 72, and in addition to the CPU 72, a ROM 74 for storing processing programs, a RAM 76 for temporarily storing data, an input / output port and communication not shown. And a port. The hybrid electronic control unit 70 includes an ignition signal from an ignition switch 80, a shift position SP from a shift position sensor 82 that detects the operation position of the shift lever 81, and an accelerator pedal position sensor 84 that detects the amount of depression of the accelerator pedal 83. The accelerator pedal opening Acc from the vehicle, the brake pedal position BP from the brake pedal position sensor 86 for detecting the depression amount of the brake pedal 85, the vehicle speed V from the vehicle speed sensor 88, and the like are input via the input port. As described above, the hybrid electronic control unit 70 is connected to the engine ECU 24, the motor ECU 40, and the battery ECU 52 via the communication port, and exchanges various control signals and data with the engine ECU 24, the motor ECU 40, and the battery ECU 52. ing. In the embodiment, the vehicle speed V from the vehicle speed sensor 88 can be used as the vehicle body speed.

  The hybrid vehicle 20 of the embodiment thus configured calculates the required torque to be output to the ring gear shaft 32a as the drive shaft based on the accelerator opening Acc and the vehicle speed V corresponding to the depression amount of the accelerator pedal 83 by the driver. Then, the operation of the engine 22, the motor MG1, and the motor MG2 is controlled so that the required power corresponding to the required torque is output to the ring gear shaft 32a. As operation control of the engine 22, the motor MG1, and the motor MG2, the operation of the engine 22 is controlled so that power corresponding to the required power is output from the engine 22, and all of the power output from the engine 22 is the power distribution and integration mechanism 30. Torque conversion operation mode for driving and controlling the motor MG1 and the motor MG2 so that the torque is converted by the motor MG1 and the motor MG2 and output to the ring gear shaft 32a, and the required power and the power required for charging and discharging the battery 50. The engine 22 is operated and controlled so that suitable power is output from the engine 22, and all or part of the power output from the engine 22 with charging / discharging of the battery 50 is the power distribution and integration mechanism 30, the motor MG1, and the motor. The required power is converted to the ring gear shaft 32 with torque conversion by MG2. Charge / discharge operation mode in which the motor MG1 and the motor MG2 are driven and controlled so as to be output to each other, and a motor operation mode in which the operation of the engine 22 is stopped and the power corresponding to the required power from the motor MG2 is output to the ring gear shaft 32a. and so on. The torque conversion operation mode and the charge / discharge operation mode are modes in which the engine 22 and the motors MG1, MG2 are controlled so that the required power is output to the ring gear shaft 32a with the operation of the engine 22. Since there is no difference in the control, both are hereinafter referred to as the engine operation mode. In the drive control routine (not shown) executed by the hybrid electronic control unit 70, the required torque Tr * to be output to the ring gear shaft 32a as the drive shaft is set and set based on the accelerator opening Acc and the vehicle speed V. Engine operation mode based on the required power Pe * required for the engine 22 as the sum of the required power corresponding to the required torque Tr * and the charge / discharge required power required by the battery 50 and the remaining capacity (SOC) of the battery 50 Alternatively, the motor operation mode is selected, and in the engine operation mode, the required power Pe * is efficiently output from the engine 22, and the required torque Tr * is output to the ring gear shaft 32a within the range of the input / output limits Win and Wout of the battery 50. Target operating point of engine 22 (target rotational speed Ne *, target torque e *) and torque commands Tm1 * and Tm2 * of the motors MG1 and MG2 are set and transmitted to the engine ECU 24 and the motor ECU 40. In the motor operation mode, the ring gear shaft is within the range of the input / output limits Win and Wout of the battery 50. A torque command Tm2 * of the motor MG2 is set so that the required torque Tr * is output to 32a and transmitted to the motor ECU 40. In the engine operation mode, the engine ECU 24 controls the engine 22 so that the engine 22 is operated at the received target operation point, and the motor ECU 40 is an inverter so that the motors MG1 and MG2 are driven by the received torque commands Tm1 * and Tm2 *. Switching control of 41 and 42

  Next, the operation of the hybrid vehicle 20 of the embodiment configured as described above, particularly the operation when traveling with the adjustment of the high-voltage system voltage VH by the booster circuit 55 when the motor operation mode is selected will be described. . FIG. 3 is a flowchart showing an example of a motor control routine executed by the motor ECU 40. This routine is repeatedly executed at predetermined time intervals (for example, every several msec) in parallel with a drive control routine (not shown) executed by the hybrid electronic control unit 70 when the motor operation mode is selected.

  When the motor control routine shown in FIG. 3 is executed, the CPU (not shown) of the motor ECU 40 first starts the torque command Tm2 * of the motor MG2, the element temperature Tc of the transistors T31 and T32 of the booster circuit 55 from the temperature sensor 56, and the voltage sensor. A process of inputting data necessary for control such as the high voltage system voltage VH from 57a, the high voltage system target voltage VH *, and the slip determination flag F is executed (step S100). Here, the torque command Tm2 * of the motor MG2 is set by a communication control routine (not shown) from the hybrid electronic control unit 70 by communication. In the embodiment, the target voltage VH * is input with torque commands Tm1 * and Tm2 * of the motors MG1 and MG2 set by a drive control routine (not shown) and the rotational speeds Nm1 and Nm2 of the motors MG1 and MG2. Based on the command Tm1 * and the rotational speed Nm1, the voltage set using a predetermined map within the rated voltage range of the motor MG1, the torque command Tm2 *, and the rated voltage of the motor MG2 based on the rotational speed Nm2. The voltage set as the larger one of the voltages set using a predetermined map within the range is input. Further, the slip determination flag F is set to an initial value of 0, and is set to a value of 1 when slippage occurs due to idling of the drive wheels 63a and 63b, and the drive wheels 63a and 63b are brought into a grip state. The flag is sometimes set to the value 0, and the flag set by the slip determination routine illustrated in FIG. 4 is input. Hereinafter, the description of the motor control will be temporarily interrupted, and the slip determination will be described. The slip determination routine in FIG. 4 is repeatedly executed by the motor ECU 40 every predetermined time (for example, every several msec) in parallel with the motor control routine.

  When the slip determination routine of FIG. 4 is executed, the CPU (not shown) of the motor ECU 40 detects the rotational speed Nm2 of the motor MG2 calculated based on the rotational position of the rotor of the motor MG2 detected by the rotational position detection sensor 44. The vehicle speed V detected by the vehicle speed sensor 88 and input from the hybrid electronic control unit 70 through communication is input (step S200), and the motor MG2 input when this routine is executed last time from the input rotation speed Nm2 of the motor MG2. The rotation speed change amount ΔNm2 of the motor MG2 is calculated by subtracting the rotation speed Nm2 (previous Nm2) (step S210), and conversion for converting the rotation speed Nm2 of the motor MG2 into the rotation speeds of the drive wheels 63a and 63b. Decreasing the vehicle speed V as the vehicle speed from the product of the coefficient kw Ri drive wheels 63a, calculates the slip speed Vs of 63 b (step S220). Subsequently, the slip determination flag F is checked (step S230), and when the slip determination flag F is 0, in order to determine the occurrence of slip due to the calculated rotation speed change amount ΔNm2 of the motor MG2 and the idling of the drive wheels 63a and 63b. Is compared with a predetermined threshold value Nref (step S240). When the rotational speed change amount ΔNm2 is less than the threshold value Nref, it is determined that no slip has occurred in the drive wheels 63a and 63b, and the slip determination routine is terminated. When the rotational speed change amount ΔNm2 is equal to or greater than the threshold value Nref, it is determined that the drive wheels 63a and 63b have slipped, a value 1 is set in the slip determination flag F (step S250), and the slip determination routine ends. When the slip determination flag F is 1, the predetermined threshold value Vref is compared with the calculated slip speed Vs to determine that the slip of the drive wheels 63a and 63b has converged to the grip state. (Step S260) When the slip speed Vs is equal to or higher than the threshold value Vref, it is determined that the slip of the drive wheels 63a and 63b has not converged, and the slip determination routine is terminated as it is, and when the slip speed Vs is less than the threshold value Vref, It is determined that the slip of the drive wheels 63a and 63b has converged, a value 0 is set in the slip determination flag F (step S270), and the slip determination routine is terminated. The slip determination has been described above.

  Returning to the description of the motor control routine of FIG. When the data is input, the input slip determination flag F is checked (step S110). When the slip determination flag F is 0, that is, when slipping due to idling of the drive wheels 63a and 63b does not occur, the transistor T31 of the booster circuit 55 is input. The first frequency CF1 is set as the carrier frequency CF as a frequency for switching T32 (step S120), and the high-voltage system voltage VH becomes the target voltage VH * by switching the transistors T31 and T32 with the set carrier frequency CF. Switching control of the booster circuit 55 is performed (step S160), and switching control of the transistors T21 to T26 of the inverter 42 is performed so that the motor MG2 is driven by the input torque command Tm2 * (step S170). The motor control routine is terminated. Here, in the embodiment, the first frequency CF1 is determined in advance by experiment or analysis as a frequency that is high enough that noise (for example, sound volume) due to switching of the switching elements T31 and T32 does not give the driver or passenger an uncomfortable feeling. Values (for example, 9 kHz, 10 kHz, etc.) were used. By such control, it is possible to travel by outputting the required torque Tr * to the ring gear shaft 32a as the drive shaft within the range of the input / output limits Win and Wout of the battery 50 while suppressing the uncomfortable feeling to the driver and the occupant.

  When the slip determination flag F is 1, that is, when slipping due to idling of the drive wheels 63a and 63b occurs, the torque command Tm2 * of the motor MG2 is corrected so that the slip of the drive wheels 63a and 63b is suppressed ( In step S130, the input element temperature Tc of the transistors T31 and T32 of the booster circuit 55 is compared with a predetermined temperature Tref (step S140). In the embodiment, the torque command Tm2 * is corrected when the driving wheel 63a, 63b is determined to have slipped, that is, the elapsed time t after the value 1 is set in the slip determination flag F and the torque command Tm2 *. Based on a predetermined map based on this, it was performed. In the embodiment, the predetermined temperature Tref is a temperature that is predetermined by experiment or analysis as a temperature at which the transistor T32 may be overheated due to slippage due to idling of the drive wheels 63a and 63b.

  When the element temperature Tc of the transistors T13 and T32 of the booster circuit 55 is equal to or lower than the predetermined temperature Tref, the first frequency CF1 is set to the carrier frequency CF of the booster circuit 55 (step S120), and when the element temperature Tc is higher than the predetermined temperature Tref The second frequency lower than the first frequency CF1 is set to the carrier frequency CF of the booster circuit 55 (step S150), and the boosted voltage VH is boosted to the target voltage VH * using the set carrier frequency CF. The switching control of the circuit 55 is performed (step S160), and the switching control of the inverter 42 is performed so that the motor MG2 is driven by the torque command Tm2 * (step S170), and the motor control routine is ended. Here, in the embodiment, the second frequency CF2 is a value determined in advance by experiment or analysis so that the transistor T32 is prevented from overheating when slipping occurs due to idling of the drive wheels 63a and 63b (for example, 7 kHz or 8 kHz). As described above, when slip occurs in the drive wheels 63a and 63b in the state where the element temperature Tc is higher than the predetermined temperature Tref, the carrier frequency CF is reduced from the first frequency CF1 to the second frequency CF2, so that the transistors T31 and T32 are used. Excessive heat generation due to switching can be suppressed.

  FIG. 5 shows an example of temporal changes in the charge / discharge current Ib of the battery 50, the carrier frequency CF of the booster circuit 55, and the temperature of the transistor T32 when the element temperature Tc of the transistors T31 and T32 is higher than the predetermined temperature Tref. In the figure, the solid line shows the embodiment, and the broken line shows a comparative example in the case of switching control of the booster circuit 55 uniformly using the first frequency CF1. As shown in the figure, when the slip of the drive wheels 63a and 63b is determined at time t1, the carrier frequency CF is reduced from the first frequency CF1 to the second frequency CF2, so that the slip of the drive wheels 63a and 63b at time t2. The temperature rise due to the heat generation of the transistor T32 until is converged is suppressed. Therefore, when an abnormality occurs in the temperature sensor 56 that detects the element temperature Tc of the transistors T31 and T32, or due to the accuracy and responsiveness of the temperature sensor 56, the temperature rise due to heat generation of the transistor T32 due to the slip of the drive wheels 63a and 63b. Even when a certain amount of time is required until the element temperature Tc is reflected, in the embodiment, the rotational position detection sensor 44 (for example, a resolver) that can detect the rotational position of the rotor of the motor MG2 with relatively high accuracy and high responsiveness. Etc.) and the carrier frequency CF of the booster circuit 55 is reduced at an early stage by determining the slip of the drive wheels 63a and 63b, so that the heat generated by switching of the transistors T31 and T32 can be more reliably suppressed. . As a result, it is possible to reduce the size of the power module to which the transistors T31 and T32 and the diodes D31 and D32 are attached.

  According to the hybrid vehicle 20 of the embodiment described above, when the slip due to idling of the drive wheels 63a and 63b is not determined or when the element temperature Tc of the transistors T31 and T32 of the booster circuit 55 is equal to or lower than the predetermined temperature Tref, When the frequency CF1 is set to the carrier frequency CF and the slip due to the idling of the drive wheels 63a and 63b is determined in the state where the element temperature Tc is higher than the predetermined temperature Tref, the second frequency CF2 lower than the first frequency CF1 is set to the carrier frequency CF. Since the switching control of the booster circuit 55 is performed using the set carrier frequency CF so that the high voltage system voltage VH becomes the target voltage VH *, heat generation due to switching of the transistors T31 and T32 of the booster circuit 55 is suppressed. can do.

  In the hybrid vehicle 20 of the embodiment, even when the slip determination flag F is the value 1, the first frequency CF1 is set to the carrier frequency CF when the element temperature Tc is equal to or lower than the predetermined temperature Tref. When 1, the second frequency CF2 may be set to the carrier frequency CF regardless of the element temperature Tc.

  In the hybrid vehicle 20 of the embodiment, the rotational speed change amount ΔNm2 is calculated by subtracting the previous Nm2 from the rotational speed Nm2 of the motor MG2 calculated based on the signal from the rotational position detection sensor 44, and the driving wheels 63a and 63b. Although the occurrence of slip is determined, the slip speed Vs of the drive wheels 63a and 63b obtained by subtracting the vehicle speed V from the product obtained by multiplying the rotation speed Nm2 of the motor MG2 by the conversion factor kw is the slip of the drive wheels 63a and 63b. It is good also as what determines the generation | occurrence | production of the slip of driving wheel 63a, 63b when it becomes more than the threshold value Vref2 which can be determined with the wheel speed sensor (not shown) attached to driving wheel 63a, 63b, respectively. Any method, such as judging the occurrence of slip when at least one of the wheel speeds from Ri drive wheels 63a, may be as to determine the occurrence of a slip due to idling of 63 b.

  In the hybrid vehicle 20 of the embodiment, the slip speed Vs of the drive wheels 63a and 63b obtained by subtracting the vehicle speed V as the vehicle body speed from the vehicle speed sensor 88 from the product obtained by multiplying the rotation speed Nm2 of the motor MG2 by the conversion factor kw is a threshold value. Although it is determined that the slip of the drive wheels 63a and 63b has converged and become in the grip state when it becomes less than Vref, the wheel speed attached to the driven wheel (not shown) is used instead of the vehicle speed V from the vehicle speed sensor 88. It is also possible to determine the convergence of slip due to idling of the drive wheels 63a, 63b by any method, such as determining that the drive wheels 63a, 63b are in the grip state using the average wheel speed from the sensor as the vehicle body speed. .

  In the hybrid vehicle 20 of the embodiment, the predetermined temperature Tref is set to a temperature predetermined by experiment or analysis as the temperature at which the transistor T32 may be overheated due to slippage due to idling of the drive wheels 63a and 63b. Considering the first to fourth characteristics of the circuit 55, a temperature predetermined by experiment or analysis may be used as a temperature at which the switching time of the transistors T31 and T32 can be shortened as much as possible. FIG. 6 is an explanatory diagram for explaining the switching time of the booster circuit 55, the loss due to switching, and the first characteristic. As shown in the figure, the switching time of the booster circuit 55 is a time required to switch the transistor T32 on and off, and the longer this time, the greater the loss due to switching. The first characteristic is that the larger the absolute value (| dIc / dt |) of the time differential value of the current Ic flowing between the terminals of the transistor T32 (between the collector and the emitter) when the transistor T32 is turned on / off, the greater the transistor T32. This is a characteristic showing that the surge voltage Vcsg acting on the transistor T32 tends to increase when the transistor is turned from on to off. FIG. 7 is an explanatory diagram for explaining the second to fourth characteristics of the booster circuit 55. As illustrated, the second characteristic is a characteristic that the withstand voltage Vcd between the terminals of the transistor T32 tends to increase as the temperature of the transistor T32 increases, and the third characteristic indicates the carrier frequency CF of the booster circuit 55. Is a characteristic that shows that the surge current Icsg flowing between the terminals of the transistor T32 tends to increase when the transistor T32 is turned off from on, and the fourth characteristic is that the current Ic flowing between the terminals of the transistor T32 increases. This is a characteristic showing that the surge voltage Vcsg of the transistor T32 tends to increase when the transistor T32 is turned off. The second characteristic is based on the fact that the pulsation (ripple) width of the current Ic due to the action of the reactor L increases as the carrier frequency CF decreases.

  Here, a case where the carrier frequency CF is reduced to the second frequency CF2 regardless of the element temperature Tc of the transistors T31 and T32 when slipping due to idling of the driving wheels 63a and 63b occurs is considered as a comparative example for this modification example. How the switching times of the transistors T31 and T32 are set in this comparative example will be described. First, because of the first characteristic, when the switching time of the booster circuit 55 is shortened, the surge voltage Vcsg of the transistor T32 increases. Therefore, the switching time of the booster circuit 55 is such that the inter-terminal voltage Vc of the transistor T32 becomes the withstand voltage Vcd. Can be shortened with a certain margin secured. The reason for shortening the switching time is to reduce loss due to switching. Further, due to the second characteristic, the withstand voltage Vcd of the transistor T32 decreases when the temperature of the transistor T32 decreases, and therefore, in the comparative example, the temperature of the transistor T32 is extremely low (for example, −20 ° C. or −30 ° C.). It is necessary to determine the switching time by limiting the withstand voltage Vcd. Furthermore, due to the third characteristic, as one of the cases where the current Ic of the transistor T32 in the comparative example becomes the largest, the driving wheel 63a in a state in which the booster circuit 55 is switching-controlled with a relatively low carrier frequency CF as the second frequency CF2. , 63b takes into account the surge current Icsg of the transistor T32 when a slip occurs, and the fourth characteristic shows that the surge voltage Vcsg corresponding to the surge current Icsg at this time is the highest in the comparative example. It needs to be considered as one of the cases where it grows. In view of these, the switching time of the booster circuit 55 in the comparative example is such that the driving wheels 63a and 63b are in a state where the temperature of the transistor T32 is extremely low and the booster circuit 55 is switching-controlled with the carrier frequency CF as the second frequency CF2. The time as short as possible can be set under the condition that the surge voltage Vcsg corresponding to the surge current Icsg of the transistor T32 when the slip occurs is within the range of the withstand voltage Vcd at the extremely low temperature. FIG. 8 shows an example of how the switching times of the transistors T31 and T32 are set in the modified example and a comparative example corresponding to the modified example. In the figure, the solid line indicates a modification, and the alternate long and short dash line indicates a comparative example.

  In contrast to the comparative example described above, in the modified example, when slip occurs in the drive wheels 63a and 63b, the relatively high first frequency CF1 is set to the carrier frequency when the element temperature Tc of the transistors T31 and T32 is equal to or lower than the predetermined temperature Tref. When the element temperature Tc is higher than the predetermined temperature Tref, the relatively high second frequency CF2 is set as the carrier frequency CF. For this reason, as shown in FIG. 8, the switching time of the transistors T31 and T32 in the modification is a state in which the temperature of the transistor T32 is extremely low and the booster circuit 55 is controlled to be switched at the carrier frequency CF as the first frequency CF1. Thus, the surge current Vsg corresponding to the surge current Ic1sg of the transistor T32 when the drive wheels 63a and 63b slip is within the range of the withstand voltage Vc1d at the extremely low temperature, and the temperature of the transistor T32 is at the predetermined temperature Tref. In addition, the surge voltage Vsg corresponding to the surge current Ic2sg of the transistor T32 when the slip occurs in the drive wheels 63a and 63b in a state where the booster circuit 55 is switching-controlled at the carrier frequency CF as the second frequency CF2 corresponds to the predetermined temperature Tref. Range of withstand voltage Vc2d Under conditions such that within, it is possible to set the shortest possible time. In other words, the predetermined temperature Tref in the modification can be a temperature that can shorten the switching time of the booster circuit 55 as much as possible in consideration of the first to fourth characteristics of the booster circuit 55. That is, the predetermined temperature Tref in the modified example takes into consideration the first to fourth characteristics of the booster circuit 55, and the drive wheels 63a and 63b in a state where the booster circuit 55 is switching-controlled with the carrier frequency CF as the first frequency CF1. The voltage Vc between the terminals of the transistor T32 when slipping due to idling occurs within the range of the withstand voltage Vcd of the transistor T32 regardless of the element temperature Tc of the transistors T31 and T32, and the booster circuit 55 is set to the second frequency CF2. The voltage Vc between the terminals of the transistor T32 when the slip due to the idling of the driving wheels 63a and 63b occurs in the state where the switching control is performed with the carrier frequency CF of the transistor T32 is the transistor T32 in the state where the element temperature Tc of the transistors T31 and T32 is the predetermined temperature Tref. Under conditions where the withstand voltage Vcd is within the range, So that it is possible to use a temperature which is predetermined by experiments or analysis as the temperature at which the loss due to the switching of the static T31, T32 is as small as possible. Since the predetermined temperature Tref is set in advance in this manner, the switching time of the transistors T31 and T32 can be shortened and the loss due to switching can be reduced as compared with the comparative example, and thus the heat generation due to the switching of the transistors T31 and T32 can be more appropriately suppressed. be able to.

  In the hybrid vehicle 20 of the embodiment, the power of the motor MG2 is shifted by the reduction gear 35 and output to the ring gear shaft 32a. However, as illustrated in the hybrid vehicle 120 of the modified example of FIG. May be connected to an axle (an axle connected to the wheels 64a and 64b in FIG. 9) different from an axle to which the ring gear shaft 32a is connected (an axle to which the drive wheels 63a and 63b are connected).

  In the embodiment, the power of the engine 22 and the motor MG1 is output to the ring gear shaft 32a as a drive shaft connected to the drive wheels 63a and 63b via the power distribution and integration mechanism 30, and the power of the motor MG2 is output to the ring gear shaft 32a. However, as exemplified in the electric vehicle 220 of the modified example of FIG. 10, the power from the motor MG for driving is not provided with the engine 22 and the motor MG1, and the driving wheel 63a is used. , 63b, and may be applied to a traveling vehicle.

  Moreover, it is not limited to what is applied to such electric vehicles, such as a hybrid vehicle, It is good also as vehicles, such as trains other than a motor vehicle, and the form of the control method of such a vehicle.

Here, the correspondence between the main elements of the embodiment and the main elements of the invention described in the column of means for solving the problems will be described. In the embodiment, the motor MG2 corresponds to a “motor”, the inverter 42 corresponds to a “drive circuit”, the battery 50 corresponds to a “secondary battery”, the booster circuit 55 corresponds to a “voltage adjusting unit”, The motor ECU 40 that executes the slip determination routine of FIG. 4 for determining the slip due to the idling of the drive wheels 63a and 63b based on the rotational speed Nm2 of the motor MG2 and the vehicle speed V and setting the slip determination flag F becomes “slip determination means”. Equivalent,
When the slip determination flag F is 0 or when the element temperature Tc of the transistors T31 and T32 is equal to or lower than the predetermined temperature Tref, the first frequency CF1 is set as the carrier frequency CF and the slip determination flag F is 1 and the transistors T31 and T32 The motor ECU 40 that executes the processes of steps S110 and S120 to S150 of the motor control routine of FIG. 3 for setting the carrier frequency CF to the second frequency CF2 lower than the first frequency CF1 when the element temperature Tc is higher than the predetermined temperature Tref. Corresponding to “execution frequency setting means”, switching control of the booster circuit 55 is performed using the set carrier frequency CF so that the high voltage system voltage VH becomes the target voltage VH *, and the ring gear shaft 32a as a drive shaft is requested. Motor MG2 set to output torque Tr * Motor ECU40 executing the processing in torque command Tm2 at step motor control routine of FIG. 3 for switching controls the inverter 42 to the motor MG2 is driven S160, S170 corresponds to the "control means". Further, the temperature sensor 56 corresponds to “element temperature detection means”, the engine 22 corresponds to “internal combustion engine”, the motor MG1 corresponds to “generator”, and the power distribution and integration mechanism 30 corresponds to “three-shaft power input”. It corresponds to “output means”.

  Here, the “motor” is not limited to the motor MG2 configured as a synchronous generator motor, and may be any type of motor as long as it outputs driving wheel power, such as an induction motor. The “drive circuit” is not limited to the inverter 42, and any circuit that drives the motor may be used. The “secondary battery” is not limited to the battery 50 configured as a nickel metal hydride battery or a lithium ion battery, and may be of any type as long as it is a secondary battery. The “voltage adjusting means” is not limited to the booster circuit 55, and is connected to a secondary battery and a drive circuit, such as a DC / DC converter, and has a switching element. Any device that adjusts the voltage on the drive circuit side with respect to the voltage may be used. The “slip determination means” is not limited to the motor ECU 40 that determines slip due to idling of the drive wheels 63a and 63b based on the rotational speed Nm2 of the motor MG2 and the vehicle speed V and sets the slip determination flag F. Any combination of a plurality of electronic control units or a different method may be used as long as it determines slip due to idling of driving wheels. As the “execution frequency setting means”, the first frequency CF1 is set as the carrier frequency CF and the slip determination is performed when the slip determination flag F is 0 or when the element temperature Tc of the transistors T31 and T32 is equal to or lower than the predetermined temperature Tref. It is not limited to the motor ECU 40 that sets the carrier frequency CF to the second frequency CF2 lower than the first frequency CF1 when the flag F is 1 and the element temperature Tc of the transistors T31 and T32 is higher than the predetermined temperature Tref. When slip is not determined by the slip determining means, such as a combination of electronic control units, the first frequency is set as the execution frequency for switching the switching element of the voltage adjusting means, and slip is determined by the slip determining means. When the frequency for execution is first As long as the setting of the second frequency lower than the frequency, it may be used as any kind. As a “control means”, the booster circuit 55 is switched and controlled using the set carrier frequency CF so that the high voltage system voltage VH becomes the target voltage VH *, and the required torque Tr * is applied to the ring gear shaft 32a as the drive shaft. It is not limited to the motor ECU 40 that performs switching control of the inverter 42 so that the motor MG2 is driven by the torque command Tm2 of the motor MG2 that is set to be output, but is set by a combination of a plurality of electronic control units. The voltage adjusting means is controlled so that the switching element is switched at the execution frequency and the voltage on the drive circuit side is adjusted, and the driving force based on the required driving force required for running is output from the motor to drive the vehicle. Any device can be used as long as it controls the circuit. Further, the “element temperature detection means” is not limited to the temperature sensor 56, and any element can be used as long as it detects the element temperature which is the temperature of the switching element of the voltage adjustment means. The “internal combustion engine” is not limited to an internal combustion engine that outputs power using a hydrocarbon fuel such as gasoline or light oil, and may be any type of internal combustion engine such as a hydrogen engine. The “generator” is not limited to the motor MG1 configured as a synchronous generator motor, and may be any type of generator such as an induction motor that can input and output power. The “three-axis power input / output means” is not limited to the power distribution / integration mechanism 30 described above, but includes four or more shafts using a double pinion type planetary gear mechanism or a combination of a plurality of planetary gear mechanisms. Connected to the three axes of the drive shaft connected to the drive wheel, the output shaft of the internal combustion engine, and the rotating shaft of the generator, such as those connected to the motor and those having a differential action different from the planetary gear such as a differential gear Any power can be used as long as power is input / output to the remaining shafts based on power input / output to / from any two of the three axes.

  The correspondence between the main elements of the embodiment and the main elements of the invention described in the column of means for solving the problem is the same as that of the embodiment described in the column of means for solving the problem. It is an example for specifically explaining the best mode for doing so, and does not limit the elements of the invention described in the column of means for solving the problem. That is, the interpretation of the invention described in the column of means for solving the problems should be made based on the description of the column, and the examples are those of the invention described in the column of means for solving the problems. It is only a specific example.

  The best mode for carrying out the present invention has been described with reference to the embodiments. However, the present invention is not limited to these embodiments, and various modifications can be made without departing from the gist of the present invention. Of course, it can be implemented in the form.

  The present invention can be used in the vehicle manufacturing industry.

1 is a configuration diagram showing an outline of a configuration of a hybrid vehicle 20 as an embodiment of the present invention. It is a block diagram which shows the outline of a structure of the electric drive system containing motor MG1, MG2. It is a flowchart which shows an example of the motor control routine performed by motor ECU40 when the motor operation mode is selected. 4 is a flowchart illustrating an example of a slip determination routine executed by a motor ECU 40. It is explanatory drawing which shows an example of the time change of the charging / discharging electric current Ib of the battery 50, the carrier frequency CF of the booster circuit 55, and the temperature of the transistor T32 when the element temperature Tc of the transistors T31 and T32 is higher than the predetermined temperature Tref. FIG. 6 is an explanatory diagram for explaining a switching time of the booster circuit 55, a loss due to switching, and a first characteristic. 6 is an explanatory diagram for explaining second to fourth characteristics of the booster circuit 55. FIG. It is explanatory drawing which shows an example of a mode that the switching time of the pressure | voltage rise circuit 55 is set in a modification and the comparative example with respect to this modification. FIG. 11 is a configuration diagram showing an outline of a configuration of a hybrid vehicle 120 according to a modification. It is a block diagram which shows the outline of a structure of the electric vehicle 220 of a modification.

Explanation of symbols

  20, 120 Hybrid vehicle, 22 engine, 24 electronic control unit (engine ECU) for engine, 26 crankshaft, 28 damper, 30 power distribution integration mechanism, 31 sun gear, 32 ring gear, 32a ring gear shaft, 33 pinion gear, 34 carrier, 35 Reduction gear, 40 motor electronic control unit (motor ECU), 41, 42 inverter, 43, 44 rotational position detection sensor, 50 battery, 51a current sensor, 51b temperature sensor, 52 battery electronic control unit (battery ECU), 54 Power line, 54a Positive bus, 54b Negative bus, 55 Booster circuit, 56 Temperature sensor, 57, 58 Capacitor, 57a, 58a Voltage sensor, 60 gear mechanism, 62 Differential gear, 63a, 63b Driving wheel, 64a, 64b wheel, 70 hybrid electronic control unit, 72 CPU, 74 ROM, 76 RAM, 80 ignition switch, 81 shift lever, 82 shift position sensor, 83 accelerator pedal, 84 accelerator pedal position sensor, 85 brake pedal, 86 Brake pedal position sensor, 88 Vehicle speed sensor, 220 Electric vehicle, D11-D16, D21-D26, D31, D32 Diode, T11-T16, T21-T26, T31, T32 Transistor, L reactor, MG1, MG2, MG motor.

Claims (5)

A vehicle including an electric motor that outputs power to drive wheels,
A drive circuit for driving the electric motor;
A secondary battery,
Voltage adjusting means connected to the secondary battery and the drive circuit, having a switching element, and adjusting the voltage on the drive circuit side with respect to the voltage on the secondary battery side by switching of the switching element;
Slip determination means for determining slip due to idling of the drive wheel;
When slip is not determined by the slip determining means, a first frequency is set as an execution frequency for switching the switching element of the voltage adjusting means, and when slip is determined by the slip determining means, the execution frequency is set. Execution frequency setting means for setting a second frequency lower than the first frequency to
The voltage adjusting means is controlled so that the switching element is switched at the set execution frequency to adjust the voltage on the drive circuit side, and a driving force based on a required driving force required for traveling from the motor is obtained. Control means for controlling the drive circuit to output and travel;
A vehicle comprising: The vehicle according to claim 1,
An element temperature detecting means for detecting an element temperature which is a temperature of the switching element of the voltage adjusting means;
The execution frequency setting means sets the first frequency to the execution frequency regardless of whether or not slip is determined by the slip determination means when the detected element temperature is equal to or lower than a predetermined temperature. Is,
vehicle. The vehicle according to claim 2,
The predetermined temperature is the resistance of the switching element regardless of the element temperature regardless of the element temperature when the slippage due to idling of the drive wheel occurs in the state where the switching element is switched at the first frequency. A voltage between the terminals of the switching element when the slip occurs due to idling of the drive wheel in a state where the switching element is switched at the second frequency within the voltage range is the element temperature as the predetermined temperature. The temperature is predetermined by experiment or analysis so that the loss due to the switching element is reduced under a condition that is within the withstand voltage range of the switching element.
vehicle. A vehicle according to any one of claims 1 to 3,
An internal combustion engine;
A generator capable of exchanging power with the secondary battery and capable of inputting and outputting power;
Based on the power input / output to / from any two of the three shafts, which are connected to three shafts of a drive shaft coupled to the drive wheels, an output shaft of the internal combustion engine, and a rotating shaft of the generator. 3-axis power input / output means for inputting / outputting power to the remaining shafts;
With
The electric motor inputs and outputs power to the drive shaft;
vehicle. An electric motor that outputs power to the driving wheel; a driving circuit that drives the electric motor; a secondary battery; a switching element that is connected to the secondary battery and the driving circuit; A voltage adjusting means for adjusting the voltage on the drive circuit side with respect to the voltage on the battery side, and a vehicle control method comprising:
(A) determining slip due to idling of the drive wheel;
(B) The first frequency is set as an execution frequency for switching the switching element of the voltage adjusting means when the drive wheel slip is not determined, and when the drive wheel slip is determined, the execution wheel is switched. Setting a second frequency lower than the first frequency to the frequency;
(C) controlling the voltage adjusting means so that the switching element is switched at the set execution frequency to adjust the voltage on the drive circuit side, and based on the required driving force required for running from the electric motor Controlling the drive circuit so that the driving force is output and the vehicle travels;
Vehicle control method.

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