JP7463729B2 - Control device for four-wheel drive electric vehicle - Google Patents

Description

This disclosure relates to a control device for a four-wheel drive electric vehicle.

Patent document 1 discloses a driving force control device for an electric vehicle equipped with at least two electric motors for driving the left and right wheels. The driving force control device for such an electric vehicle includes a detection means for detecting driving operations by the driver, and a control means for calculating the driver's requested torque and the torque difference applied to the left and right wheels when turning, and for calculating the left and right torque difference maintenance torque of the electric motor when the requested torque is generated while maintaining the torque difference, and for controlling the electric motor based on the torque difference maintenance torque. When the torque difference maintenance torque on the outer wheel side of the turning among the left and right torque difference maintenance torques exceeds the maximum output torque of the electric motor, the control means determines the priority between a requested torque mode that generates the requested torque and a torque difference mode that generates a torque difference according to the driving operations detected by the detection means. With such a driving force control device for an electric vehicle, it is possible to improve cornering performance while realizing the driver's requests.

JP 2016-13052 A

In a four-wheel drive electric vehicle, it is preferable to generate a desired drive torque difference between the left and right wheels of one of the front and rear wheels in order to control the yaw moment acting on the vehicle, while outputting the total drive torque required by the vehicle as a whole.

In view of the above circumstances, at least one embodiment of the present invention aims to provide a control device for a four-wheel drive electric vehicle that can output the total drive torque required by the vehicle as a whole while generating a desired drive torque difference between the left and right wheels of one of the front and rear wheels, even when the first motor and the second motor cannot output the drive torque required for one of the front and rear wheels.

A motor control device for a four-wheel drive electric vehicle according to at least one embodiment of the present invention is a control device for a four-wheel drive electric vehicle in which one of the front and rear wheels of the vehicle is driven by a first motor and a second motor different from the first motor, and the other of the front and rear wheels is driven by a drive source different from the first motor and the second motor, and includes a front-rear torque distribution calculation unit that calculates a drive torque required for the front and rear wheels from a total drive torque required by the vehicle, a left-right torque distribution calculation unit that calculates a drive torque required for the left and right wheels of one of the front and rear wheels from the drive torque calculated by the front-rear torque distribution calculation unit so that a desired drive torque difference is generated between the left and right wheels of one of the front and rear wheels in order to control the yaw moment acting on the vehicle, a motor torque calculation unit that calculates an output torque of the first motor and an output torque of the second motor based on the drive torque calculated by the left-right torque distribution calculation unit, and a control unit that controls the motor torque calculation unit. The motor control unit controls the first motor and the second motor so that the first motor outputs the output torque of the first motor calculated by the motor torque calculation unit, and the second motor outputs the output torque of the second motor calculated by the motor torque calculation unit; a motor torque determination unit determines whether the output torque of the first motor calculated by the motor torque calculation unit exceeds a first upper limit value determined based on the operating state and motor temperature of the first motor, and whether the output torque of the second motor calculated by the motor torque calculation unit exceeds a second upper limit value determined based on the operating state and motor temperature of the second motor; and a front-rear torque redistribution calculation unit recalculates the drive torque calculated by the front-rear torque distribution calculation unit to output the total drive torque when the motor torque determination unit determines that the output torque of the first motor exceeds the first upper limit value or the second upper limit value.

According to the above configuration, when the motor torque determination unit determines that the first upper limit value or the second upper limit value is exceeded, the front/rear torque reallocation calculation unit recalculates the drive torque calculated by the front/rear torque allocation calculation unit in order to output the total drive torque. As a result, even if the first motor and the second motor cannot output the drive torque required for one of the front/rear wheels, the total drive torque required by the vehicle can be output for the entire vehicle while generating the desired drive torque difference between the left and right wheels of one of the front/rear wheels.

In one embodiment of the present invention, when the motor torque determination unit determines that the first upper limit value or the second upper limit value is exceeded, the front/rear torque reallocation calculation unit recalculates the drive torque calculated by the front/rear torque reallocation calculation unit so that the desired drive torque difference occurs between the left and right wheels of one of the front and rear wheels within a range in which the output torque of the first motor is equal to or less than the first upper limit value and the output torque of the second motor is equal to or less than the second upper limit value.

According to the above configuration, the output torque of the first motor is equal to or less than the first upper limit value, and the output torque of the second motor is equal to or less than the second upper limit value, and a desired drive torque difference is generated between the left and right wheels of one of the front and rear wheels. As a result, even if the output torque of the first motor exceeds the first upper limit value or the output torque of the second motor exceeds the second upper limit value, a desired drive torque difference can be generated between the left and right wheels of one of the front and rear wheels.

In one embodiment of the present invention, a drive source torque determination unit is provided that determines whether the output torque of the drive source calculated based on the drive torque calculated by the front/rear torque distribution calculation unit exceeds a third upper limit value determined based on the operating state of the drive source and the temperature of the drive source, and when the drive source torque determination unit determines that the output torque exceeds the third upper limit value, the front/rear torque reallocation calculation unit recalculates the drive torque calculated by the front/rear torque distribution calculation unit so that the output torque of the drive source is equal to or less than the third upper limit value.

According to the above configuration, when the drive source torque determination unit determines that the third upper limit will be exceeded, the front/rear torque reallocation calculation unit recalculates the drive torque calculated by the front/rear torque reallocation calculation unit so that the output torque of the drive source is equal to or less than the third upper limit. This allows the total drive torque required by the vehicle to be output as a whole vehicle, even if the drive source cannot output the drive torque required for the other of the front and rear wheels.

In one embodiment of the present invention, a braking unit capable of braking either the left or right wheel of the front or rear wheels independently is provided, and when the motor torque determination unit determines that the desired drive torque difference cannot be generated between the left or right wheel of the front or rear wheels using only the first motor and the second motor, the braking unit is caused to apply the brakes so as to increase the braking force of the wheel of the front or rear wheels for which the required drive torque is smaller.

According to the above configuration, when the motor torque determination unit determines that the desired drive torque difference cannot be generated between the left and right wheels of one of the front and rear wheels using only the first motor and the second motor, the brake unit applies the brakes so as to increase the braking force of the wheel of the left and right wheels of the front and rear wheels that requires a smaller drive torque. As a result, even when the desired drive torque difference cannot be generated between the left and right wheels of the front and rear wheels using only the first motor and the second motor, the braking force of the wheel of the left and right wheels of the front and rear wheels that requires a smaller drive torque can be increased, thereby generating the desired torque difference between the left and right wheels of the front and rear wheels.

In one embodiment of the present invention, the front/rear torque redistribution calculation unit halts recalculation of the drive torque calculated by the front/rear torque redistribution calculation unit when the motor temperature of the first motor is equal to or lower than a preset first temperature and the motor temperature of the second motor is equal to or lower than a preset second temperature even if the motor torque determination unit determines that the first upper limit value or the second upper limit value will be exceeded.

According to the above configuration, even if the output torque of the first motor exceeds the first upper limit value or the output of the second motor exceeds the second upper limit value, if the motor temperature of the first motor is equal to or lower than the preset first temperature and the motor temperature of the second motor is equal to or lower than the preset second temperature, the front/rear torque reallocation calculation unit stops recalculating the drive torque calculated by the front/rear torque reallocation calculation unit. As a result, even if the output torque of the first motor exceeds the first upper limit value or the output of the second motor exceeds the second upper limit value, if the motor temperature of the first motor is equal to or lower than the preset first temperature and the motor temperature of the second motor is equal to or lower than the preset second temperature, the total drive torque required by the vehicle can be output while generating a desired drive torque difference between the left and right wheels of one of the front and rear wheels.

According to at least one embodiment of the present invention, even if the first motor and the second motor cannot output the drive torque required for one of the front or rear wheels, the total drive torque required by the vehicle can be output for the entire vehicle while generating the desired drive torque difference between the left and right wheels of one of the front or rear wheels.

1 is a diagram illustrating a schematic configuration of an electric vehicle equipped with a control device for a four-wheel drive electric vehicle according to an embodiment of the present invention. 1 is a block diagram showing an outline of a control configuration of a control device for a four-wheel drive electric vehicle according to an embodiment of the present invention; 4 is a flowchart showing control operations of a control device for a four-wheel drive electric vehicle according to an embodiment of the present invention. 1 is a block diagram showing an outline of a control configuration of a control device for a four-wheel drive electric vehicle according to an embodiment of the present invention; 4 is a flowchart showing control operations of a control device for a four-wheel drive electric vehicle according to an embodiment of the present invention. 1 is a block diagram showing an outline of a control configuration of a control device for a four-wheel drive electric vehicle according to an embodiment of the present invention; 4 is a flowchart showing control operations of a control device for a four-wheel drive electric vehicle according to an embodiment of the present invention. 4 is a flowchart showing control operations of a control device for a four-wheel drive electric vehicle according to an embodiment of the present invention.

Below, several embodiments of the present invention will be described with reference to the attached drawings. However, the dimensions, materials, shapes, relative positions, etc. of the components described as the embodiments or shown in the drawings are not intended to limit the scope of the present invention and are merely illustrative examples.

As shown in FIG. 1, a control device 1 according to some embodiments of the present invention is mounted on an electric vehicle such as an electric vehicle (EV), a hybrid vehicle (HV), or a plug-in hybrid vehicle (PHV, PHEV) that uses electricity charged in a drive battery 110 as a power source. In a vehicle 100 on which a control device 1 according to some embodiments of the present invention is mounted, one of the front and rear wheels of the vehicle 100 is driven by a first motor and a second motor different from the first motor, and the other of the front and rear wheels is driven by a drive source different from the first motor and the second motor.

In a vehicle 100 equipped with a control device 1 according to one embodiment of the present invention, for example, the rear wheels 102 of the vehicle 100 are driven by a first motor 141 (hereinafter referred to as the "first rear wheel motor 141") and a second motor 142 (hereinafter referred to as the "second rear wheel motor 142") different from the first rear wheel motor 141, and the front wheels 101 are driven by a third motor 131 (hereinafter referred to as the "front wheel motor 131") different from the first rear wheel motor 141 and the second rear wheel motor 142.

In addition, a vehicle 100 equipped with a control device 1 according to some embodiments of the present invention can be controlled to generate a desired drive torque difference between the left and right wheels of one of the front and rear wheels 101, 102 in order to control the yaw moment acting on the vehicle 100.

A vehicle 100 equipped with a control device 1 according to one embodiment of the present invention can be controlled to generate a desired drive torque difference between the left and right rear wheels 102, for example, to control the yaw moment acting on the vehicle 100.

In the vehicle 100 according to one embodiment of the present invention, a transaxle 132 is provided between the front wheels 101 and the front wheel motor 131, and the power supplied from the front wheel motor 131 to the front wheels 101 is decelerated in the transaxle 132 and distributed to the front wheels 101. In the vehicle 100 according to one embodiment of the present invention, for example, a power distribution device 143 is provided between the rear wheels 102 and the first rear wheel motor 141 and the second rear wheel motor 142, and power is distributed from the first rear wheel motor 141 to the rear wheels 102 (left wheel 102L and right wheel 102R), and power is distributed from the second rear wheel motor 142 to the rear wheels 102 (left wheel 102L and right wheel 102R).

The front wheel motor 131, the first rear wheel motor 141, and the second rear wheel motor 142 are, for example, AC motors, and inverters 133, 145, and 146 are provided between the front wheel motor 131 and the drive battery 110, between the first rear wheel motor 141 and the drive battery 110, and between the second rear wheel motor 142 and the drive battery 110, respectively. The inverters 133, 145, and 146 convert the DC power charged in the drive battery 110 into AC power, and can output the output torque of the front wheel motor 131, the first rear wheel motor 141, and the second rear wheel motor 142 as desired.

The vehicle 100 is equipped with a vehicle control device 2 and multiple motor control devices 135, 147, and 148. The vehicle control device 2 (hereinafter referred to as "EV-ECU 2") is a higher-level control device that performs overall control of the vehicle 100, and the multiple motor control devices 135, 147, and 148 are lower-level control devices that control the motors 131, 141, and 142 based on commands from the EV-ECU 2.

The EV-ECU2 is made up of a processor (not shown) that is made up of an arithmetic unit, registers that store instructions and information, peripheral circuits, etc., memories (not shown) such as ROM (Read Only Memory) and RAM (Random Access Memory), as well as an input/output interface (not shown).

The EV-ECU 2 receives information such as steering information (e.g., steering angle), vehicle speed information (e.g., wheel speed), accelerator pedal information (e.g., amount of depression), and brake pedal information (e.g., amount of depression).

The multiple motor control devices 135, 147, 148, like the EV-ECU 2, are composed of a processor (not shown) consisting of an arithmetic unit, registers for storing instructions and information, peripheral circuits, etc., memories (not shown) such as ROM (Read Only Memory) and RAM (Random Access Memory), as well as an input/output interface (not shown).

The multiple motor control devices 135, 147, 148 include a motor control device 135 that controls the front wheel motor 131, a motor control device 147 that controls the first rear wheel motor 141, and a motor control device 148 that controls the second rear wheel motor 142. Commands from the EV-ECU 2 are input to each of the motor control devices 135, 147, 148, and information from each of the motor control devices 135, 147, 148 is output to the EV-ECU 2.

As shown in FIG. 2, the control device 1 according to some embodiments of the present invention includes a front/rear torque distribution calculation unit 21, a left/right torque distribution calculation unit 22, a motor torque calculation unit 23, a motor control unit 24, a motor torque determination unit 25, and a front/rear torque redistribution calculation unit 26.

The front/rear torque distribution calculation unit 21 in some embodiments of the present invention is a part that calculates the drive torque required for the front and rear wheels 101, 102 from the total drive torque required by the vehicle.

The front/rear torque distribution calculation unit 21 according to one embodiment of the present invention is provided in, for example, the EV-ECU 2. As described above, the front/rear torque distribution calculation unit 21 calculates the drive torque required for the front and rear wheels 101, 102 from the total drive torque required by the vehicle 100, but the total drive torque required by the vehicle 100 is calculated based on the driving conditions of the vehicle 100 and the operation of the driver. The driving conditions are obtained, for example, from vehicle speed information, and the driver's operation is obtained, for example, from the operation of the accelerator pedal or the brake pedal. The drive torque required for the front and rear wheels is the drive torque required for the front wheels 101 and the drive torque required for the rear wheels 102, and the total drive torque required by the vehicle 100 is distributed. The drive torque required for the front wheels 101 and the drive torque required for the rear wheels 102 calculated by the front/rear torque distribution calculation unit 21 are calculated based on the driving conditions of the vehicle 100 and the operation of the driver, but may be calculated based on a predetermined distribution. The drive torque calculated by the front/rear torque distribution calculation unit 21 may be a distribution amount relative to the total drive torque required by the vehicle 100, or may be a distribution ratio relative to the total drive torque required by the vehicle 100. In this way, the front/rear torque distribution calculation unit 21 calculates the drive torque required for the front wheels 101 and the drive torque required for the rear wheels 102.

The left/right torque distribution calculation unit 22 according to some embodiments of the present invention is a part that calculates the driving torque required for one of the left and right wheels of the front and rear wheels 101, 102 from the driving torque calculated by the front/rear torque distribution calculation unit 21 so that a desired driving torque difference is generated between the left and right wheels of one of the front and rear wheels 101, 102 in order to control the yaw moment acting on the vehicle 100.

The left/right torque distribution calculation unit 22 according to one embodiment of the present invention is provided in, for example, the EV-ECU 2. The left/right torque distribution calculation unit 22 calculates the drive torque required for the left and right wheels 102L, 102R of the rear wheels 102 from the drive torque required for the rear wheels 102 calculated by the front/rear torque distribution calculation unit 21 so that a desired torque difference occurs between the left and right wheels 102 in order to control the yaw moment on the vehicle 100. The desired torque difference is calculated based on, for example, steering information (e.g., steering angle), vehicle speed information (e.g., wheel speed), accelerator pedal information, brake pedal information, etc. (e.g., yaw rate, drive torque, brake pressure). As a result, the left/right torque distribution calculation unit 22 calculates the drive torque required for the left wheel 102L of the rear wheels 102 and the drive torque required for the right wheel 102R of the rear wheels 102.

In some embodiments of the present invention, the motor torque calculation unit 23 is a part that calculates the output torque of the first motor and the output torque of the second motor based on the drive torque calculated by the left/right torque distribution calculation unit 22.

The motor torque calculation unit 23 according to one embodiment of the present invention is provided in, for example, the EV-ECU 2. The motor torque calculation unit 23 calculates the output torque of the first rear wheel motor 141 based on the drive torque required for the left wheel 102L of the rear wheels 102 calculated by the left/right torque distribution calculation unit 22, and calculates the output torque of the second rear wheel motor 142 based on the drive torque required for the right wheel 102R of the rear wheels 102. In this way, the motor torque calculation unit 23 calculates the output torque of the first rear wheel motor 141 and the output torque of the second rear wheel motor 142.

The motor control unit 24 according to some embodiments of the present invention is a part that controls the first motor and the second motor so that the first motor outputs the output torque of the first motor calculated by the motor torque calculation unit 23, and the second motor outputs the output torque of the second motor calculated by the motor torque calculation unit 23.

The motor control unit 24 according to one embodiment of the present invention is provided, for example, in a motor control device 147 (hereinafter referred to as "RMCU(R) 147") that controls the first rear wheel motor 141 and a motor control device 148 (hereinafter referred to as "RMCU(L) 148") that controls the second rear wheel motor 142.

The motor control unit 24 provided in the RMCU(R) 147 controls the first rear wheel motor 141 so that the first rear wheel motor 141 outputs the output torque of the first rear wheel motor 141 calculated by the motor torque calculation unit 23. The motor control unit 24 controls the inverter 145 provided between the drive battery 110 and the first rear wheel motor 141 so that the first rear wheel motor 141 outputs the output torque of the first rear wheel motor 141 calculated by the motor torque calculation unit 23, for example. In addition, the motor control unit 24 provided in the RMCU(R) 147 directly or indirectly acquires the operating state and motor temperature of the first rear wheel motor 141, manages this information (operating temperature and motor temperature of the first rear wheel motor 141) and shares it with the EV-ECU 2 (outputs it to the EV-ECU 2). The operating condition of the first rear wheel motor 141 is, for example, the magnitude of the load, and the motor temperature of the first rear wheel motor 141 is, for example, the motor coil temperature, the cooling oil temperature, or the motor housing temperature.

The motor control unit 24 provided in the RMCU (L) 148 controls the second rear wheel motor 142 so that the second rear wheel motor 142 outputs the output torque of the second rear wheel motor 142 calculated by the motor torque calculation unit 23. The motor control unit 24 controls the inverter 146 provided between the drive battery 110 and the second rear wheel motor 142 so that the second rear wheel motor 142 outputs the output torque of the second rear wheel motor 142 calculated by the motor torque calculation unit 23, for example. In addition, the motor control unit 24 provided in the RMCU (L) 148 directly or indirectly acquires the operating state, motor temperature, and torque difference (difference between the output torque of the first motor and the output torque of the second motor) of the second rear wheel motor 142, manages this information (operating state, motor temperature, and torque difference of the second motor) and shares it with the EV-ECU 2 (outputs it to the EV-ECU 2). The operating condition of the second rear wheel motor 142 is, for example, the magnitude of the load, and the motor temperature of the second rear wheel motor 142 is, for example, the motor coil temperature, the cooling oil temperature, or the motor housing temperature.

The motor torque determination unit 25 in some embodiments of the present invention is a part that determines whether the output torque of the first motor calculated by the motor torque calculation unit 23 exceeds a first upper limit value determined based on the operating state and motor temperature of the first motor, and whether the output torque of the second motor calculated by the motor torque calculation unit 23 exceeds a second upper limit value determined based on the operating state and motor temperature of the second motor.

The motor torque determination unit 25 according to one embodiment of the present invention is provided in, for example, the EV-ECU 2. The motor torque determination unit 25 determines whether the output torque of the first rear wheel motor 141 calculated by the motor torque calculation unit 23 exceeds a first upper limit value determined based on the operating state and motor temperature of the first rear wheel motor 141, and whether the output torque of the second rear wheel motor 142 calculated by the motor torque calculation unit 23 exceeds a second upper limit value determined based on the operating state and motor temperature of the second rear wheel motor 142. As a result, the motor torque determination unit 25 determines whether the first rear wheel motor 141 can output the output torque of the first rear wheel motor 141 calculated by the motor torque calculation unit 23, and whether the second rear wheel motor 142 can output the output torque of the second rear wheel motor 142 calculated by the motor torque calculation unit 23.

In some embodiments of the present invention, the front/rear torque redistribution calculation unit 26 is a part that recalculates the drive torque calculated by the front/rear torque distribution calculation unit 21 in order to output the total drive torque when the motor torque determination unit 25 determines that the first upper limit value or the second upper limit value is exceeded.

The front/rear torque reallocation calculation unit 26 according to one embodiment of the present invention is provided in, for example, the EV-ECU 2. When the motor torque determination unit 25 determines that the first upper limit value or the second upper limit value will be exceeded, the front/rear torque reallocation calculation unit 26 recalculates the drive torque required for the front wheels 101 and the drive torque required for the rear wheels 102 calculated by the front/rear torque reallocation calculation unit 21 so that the output torque of the first rear wheel motor 141 is equal to or lower than the first upper limit value and the output torque of the second rear wheel motor 142 is equal to or lower than the second upper limit value.

As shown in FIG. 3, in the control device 1 according to one embodiment of the present invention, the front/rear torque distribution calculation unit 21 calculates the total drive torque required by the vehicle 100 based on the driving conditions of the vehicle 100 and the driver's operation, and calculates the drive torque required for the front wheels 101 and the drive torque required for the rear wheels 102 from the total drive torque based on the driving conditions of the vehicle 100 and the driver's operation (step S11).

Next, in the control device 1 according to one embodiment of the present invention, the left/right torque distribution calculation unit 22 calculates the driving torque required for the left wheel 102L and the right wheel 102R of the rear wheels 102 from the driving torque of the rear wheels 102 calculated by the front/rear torque distribution calculation unit 21 so that a desired driving torque difference is generated between the left and right wheels 102 to control the yaw moment acting on the vehicle 100 (step S12).

For example, the left/right torque distribution calculation unit 22 calculates the desired drive torque difference based on steering information, vehicle speed information, accelerator pedal information, brake pedal information, etc. (step S121). Then, based on the drive torque required for the rear wheels 102 and the desired drive torque difference, the left wheel 102L and the right wheel 102R of the rear wheels 102 are calculated (step S122).

Next, in the control device 1 according to one embodiment of the present invention, the motor torque calculation unit 23 calculates the output torque of the first rear wheel motor 141 and the output torque of the second rear wheel motor 142 based on the drive torque required for the left wheel 102L of the rear wheels 102 and the drive torque required for the right wheel 102R of the rear wheels 102 calculated by the left/right torque distribution calculation unit 22 (step S13).

Next, in the control device 1 according to one embodiment of the present invention, the motor torque determination unit 25 determines whether the output torque of the first rear wheel motor 141 calculated by the motor torque calculation unit 23 exceeds a first upper limit value determined based on the operating state and motor temperature of the first rear wheel motor 141, and whether the output torque of the second rear wheel motor 142 calculated by the motor torque calculation unit 23 exceeds a second upper limit value determined based on the operating state and motor temperature of the second rear wheel motor 142 (step S14).

Next, in the control device 1 according to one embodiment of the present invention, when the motor torque determination unit 25 determines that the torque is equal to or less than the first upper limit value and equal to or less than the second upper limit value, the motor control unit 24 provided in the RMCU(R) 147 controls the first rear wheel motor 141 to output the output torque of the first rear wheel motor 141 calculated by the motor torque calculation unit 23, and the motor control unit 24 provided in the RMCU(L) 148 controls the second rear wheel motor 142 to output the output torque of the second rear wheel motor 142 calculated by the motor torque calculation unit 23 (step S15).

Next, in the control device according to one embodiment of the present invention, when the motor torque determination unit 25 determines that the first upper limit value or the second upper limit value is exceeded, the front/rear torque reallocation calculation unit 26 recalculates the drive torque required for the front wheels 101 and the drive torque required for the rear wheels 102 calculated by the front/rear torque allocation calculation unit 21 in order to output the total drive torque required by the vehicle 100 (step S16). As a result, the drive torque required for the front wheels 101 increases, and the drive torque required for the rear wheels 102 decreases.

According to the control device 1 according to one embodiment of the present invention described above, when the motor torque determination unit 25 determines that the first upper limit value or the second upper limit value is exceeded, the front/rear torque reallocation calculation unit 26 recalculates the drive torque required for the front wheels 101 and the drive torque required for the rear wheels 102 calculated by the front/rear torque allocation calculation unit 21 in order to output the total drive torque. As a result, the drive torque required for the front wheels 101 increases and the drive torque required for the rear wheels 102 decreases. Then, when the motor torque determination unit 25 determines that the drive torque is equal to or less than the first upper limit value and the second upper limit value, the motor control unit 24 provided in the RMCU (R) 147 controls the first rear wheel motor 141 to output the output torque of the first rear wheel motor 141 calculated by the motor torque calculation unit 23, and the motor control unit 24 provided in the RMCU (L) 148 controls the second rear wheel motor 142 to output the output torque of the second rear wheel motor 142 calculated by the motor torque calculation unit 23. As a result, even if the first motor and the second motor cannot output the drive torque required for one of the front and rear wheels, the total drive torque required by the vehicle 100 can be output for the entire vehicle while creating a desired drive torque difference between the left and right wheels of one of the front and rear wheels.

In the control device 1 according to some embodiments of the present invention, when the motor torque determination unit 25 determines that the first upper limit value or the second upper limit value is exceeded, the front/rear torque redistribution calculation unit 26 recalculates the drive torque calculated by the front/rear torque distribution calculation unit 21 so that a desired drive torque difference occurs between the left and right wheels of one of the front and rear wheels within a range in which the output torque of the first motor is equal to or less than the first upper limit value and the output torque of the second motor is equal to or less than the second upper limit value.

In the control device 1 according to one embodiment of the present invention, when the motor torque determination unit 25 determines that the first upper limit value or the second upper limit value will be exceeded, the front/rear torque reallocation calculation unit 26 recalculates the drive torque required for the front wheels 101 and the drive torque required for the rear wheels 102 calculated by the front/rear torque allocation calculation unit 21 so that a desired drive torque difference occurs between the left and right rear wheels 102 within a range in which the output torque of the first rear wheel motor 141 is equal to or less than the first upper limit value and the output torque of the second rear wheel motor 142 is equal to or less than the second upper limit value.

According to the control device 1 according to one embodiment of the present invention described above, the output torque of the first rear wheel motor 141 is equal to or less than the first upper limit value, and the output torque of the second rear wheel motor 142 is equal to or less than the second upper limit value, and a desired drive torque difference is generated between the left and right rear wheels 102. As a result, even if the output torque of the first rear wheel motor 141 exceeds the first upper limit value, or the output torque of the second rear wheel motor 142 exceeds the second upper limit value, a desired drive torque difference can be generated between the left and right rear wheels 102.

As shown in FIG. 4, the control device 1 according to some embodiments of the present invention further includes a drive source control unit 27 and a drive source torque determination unit 28.

The drive source control unit 27 according to some embodiments of the present invention is a part that calculates the output torque of the drive source based on the drive torque calculated by the front/rear torque distribution calculation unit 21, and controls the drive source so that the drive source outputs the output torque.

The drive source control unit 27 according to one embodiment of the present invention is provided, for example, in a motor control device 135 (hereinafter referred to as "FMCU 135") that controls the front wheel motor 131. The drive source control unit 27 calculates the output torque of the front wheel motor 131 based on the drive torque required for the front wheels 101 calculated by the front/rear torque distribution calculation unit 21, and controls the front wheel motor 131 so that the front wheel motor 131 outputs the output torque. The drive source control unit 27 controls the inverter 133 provided between the drive battery 110 and the front wheel motor 131 so that the front wheel motor 131 outputs the output torque of the front wheel motor 131 calculated by the drive source control unit 27, for example. In addition, the drive source control unit 27 directly or indirectly acquires the operating state and motor temperature of the front wheel motor 131, manages this information (operating temperature and motor temperature of the front wheel motor 131) and shares it with the EV-ECU 2 (outputs it to the EV-ECU 2). The operating condition of the front wheel motor 131 is, for example, the magnitude of the load, and the motor temperature of the front wheel motor 131 is, for example, the temperature of the motor coil, the temperature of the cooling oil, or the temperature of the motor housing.

The drive source torque determination unit 28 according to some embodiments of the present invention is a part that determines whether the output torque of the drive source calculated based on the drive torque calculated by the front/rear torque distribution calculation unit 21 exceeds a third upper limit value that is determined based on the operating state of the drive source and the temperature of the drive source.

The drive source torque determination unit 28 according to one embodiment of the present invention is provided in, for example, the EV-ECU 2. The drive source torque determination unit 28 determines whether the output torque of the front wheel motor 131 calculated based on the drive torque required for the front wheels 101 calculated by the front/rear torque distribution calculation unit 21 exceeds a third upper limit value determined based on the operating state and motor temperature of the front wheel motor 131. As a result, the drive source torque determination unit 28 determines whether the front wheel motor 131 can output the drive torque required for the front wheels 101 calculated by the front/rear torque distribution calculation unit 21.

In the control device 1 according to some embodiments of the present invention, when the drive source torque determination unit 28 determines that the third upper limit will be exceeded, the front/rear torque reallocation calculation unit 26 recalculates the drive torque calculated by the front/rear torque reallocation calculation unit 21 so that the output torque of the drive source is equal to or less than the third upper limit.

In the control device 1 according to one embodiment of the present invention, when the drive source torque determination unit 28 determines that the third upper limit is exceeded, the front/rear torque redistribution calculation unit 26 recalculates the drive torque calculated by the front/rear torque distribution calculation unit 21 so that the output torque of the front wheel motor 131 is equal to or less than the third upper limit.

As shown in FIG. 5, in the control device 1 according to one embodiment of the present invention described above, when the motor torque determination unit 25 determines that the torque is equal to or less than the first upper limit and equal to or less than the second upper limit, the drive source torque determination unit 28 determines whether the output torque of the front wheel motor 131 calculated based on the drive torque required for the front wheels 101 calculated by the front/rear torque distribution calculation unit 21 exceeds a third upper limit determined based on the operating state and motor temperature of the front wheel motor 131 (step S21).

Next, in the control device 1 according to one embodiment of the present invention, if the drive source torque determination unit 28 determines that the torque is equal to or less than the third upper limit (step S21: No), the drive source control unit 27 controls the front wheel motor 131 to output the output torque of the front wheel motor 131 calculated based on the drive torque required for the front wheels 101 calculated by the front/rear torque distribution calculation unit 21 (step S22).

Next, in the control device 1 according to one embodiment of the present invention, when the drive source torque determination unit 28 determines that the third upper limit will be exceeded, the front/rear torque reallocation calculation unit 26 recalculates the drive torque required for the front wheels 101 and the drive torque required for the rear wheels 102 calculated by the front/rear torque allocation calculation unit 21 in order to output the total drive torque required by the vehicle 100 (step S23). As a result, the drive torque required for the front wheels 101 decreases, and the drive torque required for the rear wheels 102 increases.

According to the control device 1 according to one embodiment of the present invention described above, when the drive source torque determination unit 28 determines that the third upper limit will be exceeded, the front/rear torque reallocation calculation unit 26 recalculates the drive torque calculated by the front/rear torque reallocation calculation unit 21 so that the output torque of the front wheel motor 131 is equal to or less than the third upper limit. As a result, even if the front wheel motor 131 cannot output the drive torque required for the front wheels 101, the total drive torque required by the vehicle 100 can be output for the entire vehicle.

As shown in FIG. 6, a vehicle 100 according to some embodiments of the present invention includes a brake unit 160. The brake unit 160 can brake either the left or right wheel of the front or rear wheels 101, 102 individually.

The brake unit 160 according to one embodiment of the present invention is capable of braking each of the left and right rear wheels 102 individually. The brake unit 160 (hereinafter referred to as "ASC unit 160") includes a hydraulic unit 161 and a control device 162 (hereinafter referred to as "ASC-ECU 162"), and the ASC-ECU 162 controls the hydraulic unit 161, thereby enabling braking of one or more wheels.

In the control device 1 according to some embodiments of the present invention, when the motor torque determination unit 25 determines that the desired drive torque difference cannot be generated between the left and right wheels of the front and rear wheels 101, 102 using only the first motor and the second motor, the brake unit 160 is caused to apply braking force to the wheel of the front and rear wheels 101, 102 for which the required drive torque is smaller, so as to increase the braking force.

In the control device 1 according to one embodiment of the present invention, when the motor torque determination unit 25 determines that the desired drive torque difference cannot be generated between the left and right rear wheels 102 using only the first rear wheel motor 141 and the second rear wheel motor 142, the ASC-ECU 162 controls the hydraulic unit 161 to increase the braking force of the wheel that is the smaller of the left and right rear wheels 102L, 102R.

As shown in FIG. 7, in the vehicle 100 according to one embodiment of the present invention, when the motor torque determination unit 25 determines that the first upper limit value or the second upper limit value is exceeded (step S14: No), it is determined whether the desired drive torque difference between the left and right rear wheels 102 can be generated by the first rear wheel motor 141 and the second rear wheel motor 142 alone (step S31).

When the motor torque determination unit 25 determines that the desired drive torque difference can be generated (step S31: Yes), the motor control unit 24 provided in the RMCU (R) 147 controls the first rear wheel motor 141 to output the output torque of the first rear wheel motor 141 calculated by the motor torque calculation unit 23, and the motor control unit 24 provided in the RMCU (L) 148 controls the second rear wheel motor 142 to output the output torque of the second rear wheel motor 142 calculated by the motor torque calculation unit 23 (step S15).

On the other hand, if the motor torque determination unit 25 determines that the desired drive torque difference cannot be generated (step S31: No), the ASC-ECU 162 controls the hydraulic unit 161 so as to increase the braking force of the one of the left and right rear wheels 102 for which the required drive torque is smaller (step S32). As a result, the required drive torque of the one of the left and right rear wheels 102 is smaller, and the desired torque difference is generated between the left and right rear wheels 102.

According to the vehicle 100 according to one embodiment of the present invention described above, even if the first rear wheel motor 141 and the second rear wheel motor 142 alone are unable to generate the desired drive torque difference between the left and right rear wheels 102, the desired drive torque difference can be generated between the left and right rear wheels 102 by increasing the braking force of one of the left and right rear wheels 102L, 102R that requires a smaller drive torque.

In the control device 1 according to some embodiments of the present invention, the front/rear torque redistribution calculation unit 26 stops recalculating the drive torque calculated by the front/rear torque distribution calculation unit 21 when the motor temperature of the first motor is equal to or lower than a preset first temperature and the motor temperature of the second motor is equal to or lower than a preset second temperature, even if the motor torque determination unit 25 determines that the first upper limit value or the second upper limit value will be exceeded.

In the control device 1 according to one embodiment of the present invention, the front/rear torque redistribution calculation unit 26 stops recalculating the drive torque calculated by the front/rear torque distribution calculation unit 21 when the motor temperature of the first rear wheel motor 141 is equal to or lower than a preset first temperature and the motor temperature of the second rear wheel motor 142 is equal to or lower than a preset second temperature, even if the motor torque determination unit 25 determines that the first upper limit value or the second upper limit value will be exceeded.

As shown in FIG. 8, in the control device 1 according to one embodiment of the present invention, when the motor torque determination unit 25 determines that the first upper limit value or the second upper limit value is exceeded (step S14: Yes), it is determined whether the motor temperature of the first rear wheel motor 141 exceeds the first temperature and whether the motor temperature of the second rear wheel motor 142 exceeds the second temperature (step S41).

If it is determined that the motor temperature of the first rear wheel motor 141 exceeds the first temperature or that the motor temperature of the second rear wheel motor 142 exceeds the second temperature (step S41: Yes), the recalculation of the drive torque calculated by the front/rear torque distribution calculation unit 21 is stopped (step S42).

On the other hand, if it is determined that the motor temperature of the first rear wheel motor 141 is equal to or lower than the first temperature and the motor temperature of the second rear wheel motor 142 is equal to or lower than the second temperature (step S41: No), the drive torque required for the front wheels 101 and the drive torque required for the rear wheels 102 calculated by the front/rear torque distribution calculation unit 21 are recalculated so that a desired drive torque difference occurs between the left and right rear wheels 102 within a range in which the output torque of the first rear wheel motor 141 is equal to or lower than the first upper limit value and the output torque of the second rear wheel motor 142 is equal to or lower than the second upper limit value.

According to the control device 1 according to one embodiment of the present invention described above, even if the output torque of the first rear wheel motor 141 exceeds the first upper limit value or the output of the second rear wheel motor 142 exceeds the second upper limit value, if the motor temperature of the first rear wheel motor 141 is equal to or lower than the first temperature and the motor temperature of the second rear wheel motor 142 is equal to or lower than the second temperature, the total drive torque required by the vehicle 100 can be output while creating a desired drive torque difference between the left and right rear wheels 102.

The present invention is not limited to the above-described embodiments, but also includes variations of the above-described embodiments and appropriate combinations of these embodiments.

For example, in the embodiment described above, an example was described in which the front wheels 101 are driven by the front wheel motor 131, but the front wheels 101 may be driven by an engine, or by a motor and an engine. When the front wheels 101 are driven by a motor and an engine, the motor serves as the driving source when traveling only with the power stored in the driving battery 110, and the motor serves as the driving source when traveling with the power stored in the driving battery 110 while charging the driving battery 110 with the engine. Also, when traveling with the engine and the motor, the engine and the motor serve as the driving sources.

1. Control device (control device for four-wheel drive electric vehicle)
2. Vehicle control device (EV-ECU)
21 Front/rear torque distribution calculation unit 22 Left/right torque distribution calculation unit 23 Motor torque calculation unit 24 Motor control unit 25 Motor torque determination unit 26 Front/rear torque reallocation calculation unit 27 Driving source control unit 28 Driving source torque determination unit 100 Electric vehicle 101 Front wheel 102 Rear wheel 102L Left wheel 102R Right wheel 110 Driving battery 131 Front wheel motor 132 Transaxle 133 Inverter 135 Motor control unit (FMCU)
141: First rear wheel motor 142: Second rear wheel motor 143: Power distribution device 145: Inverter 146: Inverter 147: Motor control device (RMCU(R))
148 Motor control device (RMCU(L))
160 Braking unit (ASC unit)
161 Hydraulic unit 162 ASC-ECU

Claims (4)

A control device for a four-wheel drive electric vehicle in which one of front and rear wheels of a vehicle is driven by a first motor and a second motor different from the first motor, and the other of the front and rear wheels is driven by a drive source different from the first motor and the second motor,
a front/rear torque distribution calculation unit that calculates a drive torque required for the front and rear wheels from a total drive torque required by the vehicle;
a left/right torque distribution calculation unit that calculates a drive torque required for one of the front and rear wheels from the drive torque calculated by the front/rear torque distribution calculation unit so that a desired drive torque difference is generated between the left and right wheels of one of the front and rear wheels in order to control a yaw moment acting on the vehicle;
a motor torque calculation unit that calculates an output torque of the first motor and an output torque of the second motor based on the drive torque calculated by the left/right torque distribution calculation unit;
a motor control unit that controls the first motor and the second motor so that the first motor outputs the output torque of the first motor calculated by the motor torque calculation unit, and the second motor outputs the output torque of the second motor calculated by the motor torque calculation unit;
a motor torque determination unit that determines whether or not the output torque of the first motor calculated by the motor torque calculation unit exceeds a first upper limit value that is determined based on an operating state and a motor temperature of the first motor, and whether or not the output torque of the second motor calculated by the motor torque calculation unit exceeds a second upper limit value that is determined based on an operating state and a motor temperature of the second motor;
a front/rear torque redistribution calculation unit that recalculates the drive torque calculated by the front/rear torque distribution calculation unit so as to output the total drive torque when the motor torque determination unit determines that the first upper limit value or the second upper limit value is exceeded ;
A braking unit capable of braking either the left or right wheels of the front or rear wheels independently;
Equipped with
A control device for a four-wheel drive electric vehicle that, when it is determined by the motor torque determination unit that the desired drive torque difference cannot be generated between the left and right wheels of one of the front and rear wheels using only the first motor and the second motor, causes the brake unit to apply braking so as to increase the braking force of one of the front and rear wheels for which a smaller drive torque is required . A control device for a four-wheel drive electric vehicle in which one of front and rear wheels of a vehicle is driven by a first motor and a second motor different from the first motor, and the other of the front and rear wheels is driven by a drive source different from the first motor and the second motor,
a front/rear torque distribution calculation unit that calculates a drive torque required for the front and rear wheels from a total drive torque required by the vehicle;
a left/right torque distribution calculation unit that calculates a drive torque required for one of the front and rear wheels from the drive torque calculated by the front/rear torque distribution calculation unit so that a desired drive torque difference is generated between the left and right wheels of one of the front and rear wheels in order to control a yaw moment acting on the vehicle;
a motor torque calculation unit that calculates an output torque of the first motor and an output torque of the second motor based on the drive torque calculated by the left/right torque distribution calculation unit;
a motor control unit that controls the first motor and the second motor so that the first motor outputs the output torque of the first motor calculated by the motor torque calculation unit, and the second motor outputs the output torque of the second motor calculated by the motor torque calculation unit;
a motor torque determination unit that determines whether or not the output torque of the first motor calculated by the motor torque calculation unit exceeds a first upper limit value that is determined based on an operating state and a motor temperature of the first motor, and whether or not the output torque of the second motor calculated by the motor torque calculation unit exceeds a second upper limit value that is determined based on an operating state and a motor temperature of the second motor;
a front/rear torque distribution calculation unit that recalculates the drive torque calculated by the front/rear torque distribution calculation unit so as to output the total drive torque when the motor torque determination unit determines that the first upper limit value or the second upper limit value is exceeded ,
A control device for a four-wheel drive electric vehicle, wherein the front-rear torque reallocation calculation unit stops recalculating the drive torque calculated by the front-rear torque reallocation calculation unit when the motor temperature of the first motor is equal to or lower than a predetermined first temperature and the motor temperature of the second motor is equal to or lower than a predetermined second temperature even if the motor torque determination unit determines that the first upper limit value or the second upper limit value will be exceeded . 3. The control device for a four-wheel drive electric vehicle according to claim 1 or 2, wherein, when the motor torque determination unit determines that the first upper limit value or the second upper limit value will be exceeded, the front/rear torque reallocation calculation unit recalculates the drive torque calculated by the front/rear torque reallocation calculation unit so that the desired drive torque difference occurs between the left and right wheels of one of the front and rear wheels within a range in which the output torque of the first motor is equal to or less than the first upper limit value and the output torque of the second motor is equal to or less than the second upper limit value. a drive source torque determination unit that determines whether or not an output torque of the drive source calculated based on the drive torque calculated by the front/rear torque distribution calculation unit exceeds a third upper limit value that is determined based on an operating state of the drive source and a temperature of the drive source,
The front/rear torque redistribution calculation unit
4. The control device for a four-wheel drive electric vehicle according to claim 1, wherein, when the drive source torque determination unit determines that the output torque of the drive source will exceed the third upper limit value, the drive torque calculated by the front/rear torque distribution calculation unit is recalculated so that the output torque of the drive source is equal to or less than the third upper limit value .

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