Vehicle control system

Abstract

To efficiently perform regenerative brake also when a temperature of a travel motor rises in a vehicle during charging limitation.SOLUTION: A vehicle control device includes: a travel battery which supplies power to a front motor and a rear motor; charging propriety detection means which detects a charging propriety state of the travel battery; temperature detection means which detects each of a temperature of the front motor and a temperature of the rear motor; and a control section which controls the front motor and the rear motor. The control section makes at least one of the front motor and the rear motor into a regenerative state and charges regenerative power in the travel battery when a vehicle is decelerating and the travel battery is in a chargeable state. When the vehicle is decelerating and the travel battery is in a charging impossible state, a value obtained by subtracting a first output limit threshold from the temperature of the front motor is compared with a value obtained by subtracting a second output limit threshold from the temperature of the rear motor. The motor on a side having a larger value is made into the regenerative state, the motor on a side having a smaller value is made into an electric discharge state, and regenerative power is consumed.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] This invention relates to a control device for electric vehicles. [Background technology]

[0002] Electric vehicles, equipped with a drive motor as the power source for propulsion, are becoming increasingly popular. In electric vehicles, when the accelerator is released while the vehicle is being driven by the drive motor, the drive motor's regenerative control generates regenerative torque equivalent to engine braking, thereby braking the vehicle. Furthermore, the regenerative power generated as a result of this regenerative braking is used to charge the vehicle's battery.

[0003] However, there may be limitations on the power that can be used to charge the traction battery. For example, if the State of Charge (SOC) exceeds a predetermined value set near the charging limit, or if the battery temperature falls outside the normal temperature range, charging will be limited to protect the battery. If the accelerator is released while charging is limited, the regenerative torque of the motor must be limited. This can lead to insufficient braking force in the vehicle, causing discomfort to the driver.

[0004] For example, in Patent Document 1, the driving force of a first and second drive motor arranged in series is transmitted to the left and right rear wheels via a differential gear mechanism. When the accelerator is released during charging restriction, one of the drive motors is regenerated, and the generated electricity drives the other drive motor. This ensures braking force for the vehicle during charging restriction.

[0005] Furthermore, for example, Patent Document 2 describes a system in which the front and rear wheels are each equipped with a drive motor. When the accelerator is released during charging restriction, the displacement of the front and rear suspensions of the vehicle is read, and the ground contact load of the front and rear wheels is determined from these displacements. The side with the larger ground contact load is set to the regenerative braking side, and the side with the smaller ground contact load is set to the power braking side, thereby improving braking performance. [Prior art documents] [Patent Documents]

[0006] [Patent Document 1] Japanese Patent Application Publication No. 7-99704 [Patent Document 2] Japanese Patent Publication No. 2017-38470 [Overview of the project] [Problems that the invention aims to solve]

[0007] Incidentally, the temperature of the traction motor may rise depending on the operating conditions. If the temperature of the traction motor rises excessively, it may not only fail to perform at its full potential, but continuing to operate it in that state could lead to equipment failure. Therefore, it is common practice to implement motor output limiting control when the temperature of the traction motor exceeds a predetermined threshold.

[0008] Conventional technology, when a vehicle is under charge restriction, regenerative braking is performed by regenerating power from one of the drive motors and consuming the regenerated power with the other drive motor to ensure braking force for regenerative braking. However, it is not disclosed how to ensure braking force for regenerative braking when the temperature of the drive motors rises.

[0009] Therefore, the objective of this invention is to efficiently perform regenerative braking even when the temperature of the traction motor rises in a vehicle under charging restrictions. [Means for solving the problem]

[0010] In order to solve the above problems, the present invention includes a front motor that supplies driving force to the front wheels of a vehicle, a rear motor that supplies driving force to the rear wheels of the vehicle, a traveling battery that supplies electric power to the front motor and the rear motor, chargeability detection means for detecting the chargeable state of the traveling battery, temperature detection means for detecting the temperature of the front motor and the temperature of the rear motor respectively, and a control unit for controlling the front motor and the rear motor. The control unit performs output limit control of the front motor when the temperature of the front motor becomes equal to or higher than a first output limit threshold value, and performs output limit control of the rear motor when the temperature of the rear motor becomes equal to or higher than a second output limit threshold value. When the vehicle is decelerating and the traveling battery is in a chargeable state, the control unit sets at least one of the front motor and the rear motor in a regenerative state and charges the traveling battery with regenerative power. When the vehicle is decelerating and the traveling battery is in a non-chargeable state, the control unit compares the value obtained by subtracting the first output limit threshold value from the temperature of the front motor and the value obtained by subtracting the second output limit threshold value from the temperature of the rear motor, sets the motor on the side with the larger value in a regenerative state, sets the motor on the side with the smaller value in a discharging state, and performs regenerative power consumption control to consume the regenerative power of the motor on the side with the larger value (Configuration 1).

[0011] In Configuration 1, when the vehicle is decelerating and the traveling battery is in a non-chargeable state, and when output limit control of the front motor and the rear motor is being performed, the control unit can adopt a configuration that uses the regenerative braking force of the motor on the side with the larger value and the braking force by the friction brake (Configuration 2).

[0012] In Configuration 1, the discharge state includes power running control for applying rotational torque to the motor on the discharge state side so as not to increase the rotation of the wheels accompanying deceleration of the vehicle, and non-power running control for supplying power so as to cancel the induced electromotive force generated in the motor on the discharge state side by the rotation of the wheels accompanying deceleration of the vehicle. When the required deceleration of the vehicle is less than a predetermined value, non-power running control is adopted, and when the required deceleration of the vehicle is greater than or equal to the predetermined value, power running control may be adopted (Configuration 3).

[0013] In each of the above aspects, when the vehicle is traveling on an uphill slope steeper than a predetermined gradient, the front motor is set in the regeneration state and the rear motor is set in the discharge state, and when the vehicle is traveling on a downhill slope steeper than a predetermined gradient, the front motor is set in the discharge state and the rear motor is set in the regeneration state (Configuration 4).

Advantages of the Invention

[0014] This invention can efficiently perform regenerative braking even when the temperature of the driving motor rises in a vehicle during charging restriction.

Brief Description of the Drawings

[0015] [Figure 1] It is a schematic diagram of a vehicle showing an embodiment of this invention. [Figure 2] It is a graph showing an example of control. [Figure 3] It is a chart showing an example of control. [Figure 4] It is a schematic diagram showing an example of control on a slope.

Embodiments for Carrying Out the Invention

[0016] [[ID=3,6]]A vehicle 1 equipped with a control device for a vehicle according to this invention is a four-wheel drive vehicle including an electric front motor 12 (driving motor) for supplying driving force to the front wheels 2 and an electric rear motor 13 (driving motor) for supplying driving force to the rear wheels 3, as shown in FIG. 1.

[0017] The front motor 12 is powered by the traction battery 11 via an inverter and drives the drive shaft of the front wheel 2 via a reduction gear. The rear motor 13 is also powered by the traction battery 11 via an inverter and drives the drive shaft of the rear wheel 3 via a reduction gear. The front motor 12 and the rear motor 13 each have a rotor that rotates integrally with the rotation shaft and a stator fixed to the casing on the outer circumference of the rotor, and are configured so that the rotation shaft rotates around the axis together with the rotor when power is supplied. The inverter has the function of converting the DC current supplied from the traction battery 11 into AC current, and the rotation speed of the front motor 12 and the rear motor 13 can be adjusted by controlling the inverter. This makes it possible to independently control the driving force of the front wheel 2 and the rear wheel 3.

[0018] Furthermore, the front motor 12 is equipped with a temperature detection means for detecting the temperature of the front motor 12, and the rear motor 13 is equipped with a temperature detection means for detecting the temperature of the rear motor 13. The temperature detection means for the front motor 12 and the rear motor 13 are composed of temperature sensors or the like. The part that measures the temperature can be, for example, the stator.

[0019] The traction battery 11 is composed of a secondary battery such as a lithium-ion battery and includes a battery module composed of multiple battery cells arranged in parallel. The traction battery 11 is equipped with a charge state detection means for detecting the charge state of the traction battery 11 and a battery temperature detection means for detecting the temperature state of the traction battery 11. The charge state information detected by the charge state detection means includes the ratio of the remaining capacity to the full capacity of the secondary battery that can store power (remaining capacity / full capacity), and this charge state information will be referred to as State of Charge (SOC) below. The battery temperature detection means is also composed of a temperature sensor or the like. The vehicle 1 is equipped with a charger that charges the traction battery 11 using an external power source.

[0020] The front motor 12, rear motor 13, traction battery 11, and other components are controlled by a control unit 10 of the electronic control unit installed in this vehicle 1. The electronic control unit includes a central processing unit (CPU), input / output devices, and memory devices (ROM, RAM, non-volatile RAM, etc.). The drive of the front wheels 2 and rear wheels 3 by the front motor 12 and rear motor 13, and the supply of regenerative power from the front motor 12 and rear motor 13 to the traction battery 11 are controlled by the control unit 10. Temperature information from temperature detection means for the front motor 12 and rear motor 13, charge status information from charge status detection means, battery temperature information from battery temperature detection means, and other information from various sensors installed in this vehicle 1 are transmitted to the control unit 10.

[0021] Furthermore, the control unit 10 is connected to an accelerator pedal position sensor, which detects the amount the driver depresses the accelerator pedal, i.e., the accelerator pedal position. The accelerator pedal position information is transmitted to the control unit 10 and used for controlling the inverter and other components.

[0022] Furthermore, when the accelerator pedal is pressed to zero, i.e., the accelerator is released, the control unit 10 sets a negative vehicle request output and controls the front motor 12 and rear motor 13 to achieve that negative vehicle request output. At this time, both the front motor 12 and rear motor 13 generate a negative regenerative torque through regenerative control, and charge the traction battery 11 with the electricity generated by this regenerative control (regenerative power).

[0023] Furthermore, the control unit 10 recognizes the traction battery 11 as being in a non-charging state if the State of Charge (SOC) of the traction battery 11 is above a predetermined value near the charging limit (for example, 95% of the charging limit), or if the battery temperature is outside the normal operating temperature range (for example, below 45°C). When a non-charging state is recognized, a charging restriction is implemented to limit the charging power supplied to the traction battery 11 in order to protect the battery. If a charging state is recognized, charging is permitted as usual. In other words, the charging state detection means and the battery temperature detection means function as charging feasibility detection means for detecting whether the traction battery 11 can be charged or not. Note that a non-charging state is not limited to a state where no charging power can be supplied to the traction battery 11 at all, but also includes a state in which the charging power is limited compared to when the traction battery 11 is in a normal state (a charging state, i.e., not a non-charging state).

[0024] Here, each of the front motor 12 and the rear motor 13 is set with a threshold that restricts some of its functions if the temperature of each motor exceeds a certain temperature outside its normal operating temperature range. Specifically, when the temperature of the front motor 12 exceeds the first output limit threshold S1 (for example, S1 = 100°C), control is performed to limit the output of the front motor 12 to below a predetermined output (output limit control). Similarly, when the temperature of the rear motor 13 exceeds the second output limit threshold S2 (for example, S2 = 110°C), control is performed to limit the output of the rear motor 13 to below a predetermined output (output limit control). In this case, it is also possible to set the permitted output to zero.

[0025] Furthermore, a first temperature threshold R1 (for example, R1 = 80°C), which is lower than the first output limit threshold S1, and a second temperature threshold R2 (for example, R2 = 90°C), which is lower than the second output limit threshold S2, are set for each of the front motor 12 and the rear motor 13. When the temperature of the front motor 12 is equal to or greater than the first temperature threshold R1, it can be determined that the temperature of the front motor 12 is approaching the first output limit threshold S1. Similarly, when the temperature of the rear motor 13 is equal to or greater than the second temperature threshold R2, it can be determined that the temperature of the rear motor 13 is approaching the second output limit threshold S2. Note that the difference between the first output limit threshold S1 and the first temperature threshold R1 is the same as the difference between the second output limit threshold S2 and the second temperature threshold R2.

[0026] Here, since the front motor 12 and the rear motor 13 are composed of motors of different types (output, model, etc.), the first output limit threshold S1 and the second output limit threshold S2, and the first temperature threshold R1 and the second temperature threshold R2 are set to different values. However, if the front motor 12 and the rear motor 13 are motors of the same type (output, model, etc.), then the first output limit threshold S1 and the second output limit threshold S2, and the first temperature threshold R1 and the second temperature threshold R2 may be the same value.

[0027] This information, including the first output limit threshold S1, the second output limit threshold S2, the first temperature threshold R1, and the second temperature threshold R2, is stored in the control unit 10.

[0028] The following explanation of the control process will be based on the example of a case where the traction battery 11 is in a non-rechargeable state (an operating state with charging limitations), and this non-rechargeable state is determined by the fact that the State of Charge (SOC) of the traction battery 11 is above a predetermined value.

[0029] When an accelerator-off operation is performed while the vehicle is running in a non-chargeable state, regenerative control is performed on either the front motor 12 or the rear motor 13, and the regenerative power generated by the regeneration is consumed by driving the other motor (positive-side output) so as to act on the vehicle 1 as a braking force. Hereinafter, the motor during regenerative control is referred to as the regenerative-side motor or the motor on the regenerative-state side, and the motor during drive control is referred to as the discharge-side motor or the motor on the discharge-state side. These controls are hereinafter referred to as regenerative power consumption control.

[0030] Here, in a state where the front motor 12 and the rear motor 13 are less than the output limit threshold value S (the first output limit threshold value S1 and the second output limit threshold value S2), the temperature T of the front motor 12 12 is determined as to whether it has become equal to or higher than the first temperature threshold value R1, and the temperature T of the rear motor 13 13 is determined as to whether it has become equal to or higher than the second temperature threshold value R2. Then, the motor on the side that has become equal to or higher than the temperature threshold value R (the first temperature threshold value R1 and the second temperature threshold value R2) is set to the regenerative state, and the motor on the side less than the temperature threshold value R is set to the discharge state.

[0031] For example, when the temperature T of the front motor 12 12 has become equal to or higher than the first temperature threshold value R1 and the temperature T of the rear motor 13 13 is less than the second temperature threshold value R2, the front motor 12 is set to the regenerative state and the rear motor 13 is set to the discharge state. That is, when the temperature T of the front motor 12 12 has become equal to or higher than the first temperature threshold value R1 and the temperature T of the rear motor 13 13 is less than the second temperature threshold value R2, when comparing the value U 12 (U F (U F = T 12 - S1) obtained by subtracting the first output limit threshold value S1 from the temperature T of the front motor 12 and the value U 13 (U R (U R = T 13 (U FThis value will be larger. By putting the motor with the larger value (closer to the output limit threshold) into a regenerative state, the temperature of the motor with the larger value (closer to the output limit threshold) will rise, preventing it from exceeding the output limit threshold. This is based on the fact that the temperature of a motor in a discharge state rises more easily than that of a motor in a regenerative state. Note that the value U F and value U R When comparing the magnitudes of two values, the decision should be based not only on the absolute value of the value, but also on its sign (positive or negative).

[0032] Furthermore, if the front motor 12 and the rear motor 13 are both above the first temperature threshold R1 and the second temperature threshold R2, or if the front motor 12 and the rear motor 13 are both below the first temperature threshold R1 and the second temperature threshold R2, then either one (for example, the front motor 12) may be uniformly designated as the regenerative motor and the other (for example, the rear motor 13) as the discharge motor, or the regenerative motor and the discharge motor may be determined based on other operating conditions described later. Also, the first temperature threshold R1 and the second temperature threshold R2 may not be set, and simply a value U may be used. F and value U R Alternatively, the motor with the larger value may be put into a regenerative state, and the motor with the smaller value may be put into a discharge state.

[0033] In this regenerative power consumption control, the regenerating motor converts kinetic energy (see symbol b in Figure 2) into electrical (regenerative) energy for the purpose of regenerative braking. The discharging motor, on the other hand, performs drive control to consume electrical (regenerative) energy (see symbol c in Figure 2).

[0034] In this case, the discharge-side motor can consume regenerative energy within a range of rotational torque (generated torque) that does not exceed the inertial rotational speed corresponding to the speed of vehicle 1. Generated torque that does not exceed the inertial rotational speed is rotational torque within a range that does not accelerate the rotational speed of the stator. Here, a gear shift mechanism may be provided to broaden the range of generated torque that does not exceed the inertial rotational speed. That is, by lowering the gear shift stage of the gear shift mechanism of the discharge-side motor, the generated torque that does not exceed the inertial rotational speed of the discharge-side motor may be increased, thereby increasing the amount of regenerative energy consumed. Alternatively, the motor characteristic point may be changed to broaden the range of generated torque that does not exceed the inertial rotational speed. Changing the motor characteristic point includes changes in motor efficiency using boost / buck voltage by a converter that converts regenerative power from AC to DC. Changing the motor characteristic point also includes changes in motor efficiency using phase / current control by an inverter that converts the power of the traction battery 11 from DC to AC. In terms of motor efficiency changes, it is also possible to increase energy consumption by deliberately performing inefficient power operation.

[0035] The drive control in the discharge-side motor includes non-powering control, which consumes power by supplying power to the discharge-side motor to counteract the induced electromotive force generated by the rotation transmitted from the front wheels 2 or rear wheels 3, and powering control, which consumes power by supplying power to the discharge-side motor to apply rotational torque to an extent that does not exceed the inertial rotational speed. Non-powering control is a "0 Nm (zero Newton) control" that consumes regenerative energy, which is neither powering control nor regenerative control.

[0036] In non-powered control, only power equivalent to the induced electromotive force at the current vehicle speed (rotation speed of the rotor due to wheel rotation) can be consumed for 0 Nm control. On the other hand, in powered control, the motor on the discharge side is rotated, allowing for higher power consumption. Also, in non-powered control, no torque is generated in the motor on the discharge side, resulting in stable deceleration. On the other hand, in powered control, torque is generated in the motor on the discharge side, and the upper limit of this torque is set to the point where no torque is output to the wheels. Therefore, as vehicle 1 decelerates, the upper limit of the torque changes, making the control complex and making it difficult to stabilize the deceleration. For this reason, non-powered control is used when the required deceleration (required braking force) of vehicle 1 is below a predetermined value, and powered control is used when the required deceleration (required braking force) exceeds a predetermined value. The required deceleration (required braking force) is a braking force equivalent to engine braking, set according to the vehicle speed, etc. The required deceleration (required braking force) may be manually set, for example, by operating the paddle shifters.

[0037] In both non-powered and powered control, the upper limit of power consumption by the discharge-side motor increases in proportion to the motor's rotational speed. Therefore, one way to increase the upper limit of power consumption by the discharge-side motor is to increase the rotational speed using a speed change mechanism. Alternatively, the power consumption of the discharge-side motor at the same rotational speed can also be increased by increasing the voltage supplied to the discharge-side motor using a voltage booster converter. In this embodiment, in regenerative power consumption control, the control unit 10 increases the power consumption of the discharge-side motor using the above method.

[0038] Regenerative power consumption control can be applied in patterns 1 to 12 in Figure 3. Patterns 1 and 2 are applied when the temperature T of the front motor 12 is... 12 and the temperature T of the rear motor 13 13 However, since all of these are within the normal operating temperature range, in this case, the motor closer to the corresponding temperature threshold R may be determined as the regenerative motor and the motor further away as the discharge motor, or the regenerative motor and discharge motor may be determined based on other operating conditions described later. Also, patterns 3 to 6 are based on the temperature T of the front motor 12.12 and the temperature T of the rear motor 13 13 If at least one of them is above the temperature threshold R (close to the output limiting threshold S), then in patterns 7 to 12, the temperature T of the front motor 12 12 and the temperature T of the rear motor 13 13 This is regenerative power consumption control performed when at least one of the following is within the scope of application of output limit control (output limit threshold S or higher).

[0039] In patterns 3-12, the temperature T of the front motor 12 is 12 and the temperature T of the rear motor 13 13 The system monitors the temperature and controls the switching between the regenerative and discharge motors. Specifically, in patterns 3-4 and 7-8, the motor whose temperature exceeds the temperature threshold R becomes the regenerative motor, and the motor whose temperature is below the temperature threshold R becomes the discharge motor. The temperature T of the front motor 12 12 and the temperature T of the rear motor 13 13 If both of these conditions exceed their respective temperature thresholds R, the motor closer to the corresponding output limit threshold S may be determined as the regenerative motor and the motor further away as the discharge motor, or the regenerative motor and the discharge motor may be determined based on other operating conditions described later.

[0040] Regarding the high and low temperature conditions shown in Figure 3, F <Rとは、U F R This indicates that... Furthermore, in the temperature status column, "Caution" indicates that the motor temperature is above the corresponding temperature threshold R, and "Exceeded" indicates that the motor temperature is above the corresponding output limit threshold S. "Caution (Low)" and "Caution (High)" indicate which motor's temperature is higher (closer to the output limit threshold) in the Caution state. "Exceeded (Low)" and "Exceeded (High)" indicate which motor's temperature is higher (greater than the output limit threshold) in the Exceeded state.

[0041] ​In this embodiment, as shown in Figure 3, when the temperature state of the front motor 12 and the rear motor 13 is the same (normal, caution, and excessive), the motor with the higher temperature (the motor with the higher temperature relative to the output limit threshold) is designated as the regenerative motor.

[0042] However, in patterns 7-12, the temperature T of the front motor 12 12 and the temperature T of the rear motor 13 13 At least one of the two thresholds is equal to or greater than the first usage limit threshold S1 or the second usage limit threshold S2, and is within the scope of application of output limit control. In this case, the regenerative motor is controlled to a regenerative limit state (regenerative limit control) that suppresses the regenerative output more than normal (when within the normal operating temperature range (normal range)). Accordingly, the discharge output of the discharge motor is also reduced (discharge limit control). Note that regenerative limit control may also set the allowed regenerative power output to zero. In this case, the output of the discharge limit control is also set to zero.

[0043] When performing control that involves regenerative braking and discharge limiting states, as shown in patterns 7 to 12, the regenerative braking force is insufficient, so friction brakes are used to compensate for this deficiency. Friction brakes exert braking force through friction by pressing brake pads against brake discs using hydraulic pressure. The braking force from the friction brakes is controlled by the control unit 10 according to the difference between the required deceleration (required braking force) and the regenerative braking force.

[0044] In this embodiment, the regenerative motor and the discharge motor are determined by considering other driving conditions of the vehicle 1. Specifically, the regenerative motor and the discharge motor are determined according to the road surface gradient. For example, if the road surface gradient is uphill (gradient α is steeper than a predetermined gradient), the front motor 12 is set to the regenerative state and the rear motor 13 is set to the discharge state (powering state). Also, if the road surface gradient is downhill (gradient β is steeper than a predetermined gradient), the front motor 12 is set to the discharge state (powering state) and the rear motor 13 is set to the regenerative state. That is, as shown on the left side of Figure 4, when the road surface gradient is uphill, the discharge power from the rear motor 13, which is under greater load, can be increased, and therefore the regenerative braking force from the front motor 12 can also be increased. Similarly, as shown on the right side of Figure 4, when the road surface gradient is downhill, the front motor 12, which is under greater load, is set to the discharge state. Furthermore, as shown in the center of Figure 4, on flat ground (with a small road surface gradient), the load is placed more on the front motor 12 due to nose dive caused by deceleration. Therefore, the front motor 12 may be in a discharge state, or the motor on the regenerative side and the motor on the discharge side may be determined by considering the temperature state.

[0045] This gradient-based control is based on the temperature T of the front motor 12. 12 and the temperature T of the rear motor 13 13 It may be given higher priority, for example, the temperature T of the front motor 12. 12 Furthermore, it may be applied only in operating regions where the temperature conditions of the rear motor 13 are favorable, for example, in patterns 1 and 2 of Figure 3, or in addition to those cases, when the temperature conditions of the front motor 12 and the rear motor 13 are similar, i.e., in patterns 5 to 6 and patterns 11 to 12 of Figure 3. In this embodiment, the temperature T of the front motor 12 12 and the temperature T of the rear motor 13 13 Prioritizing control based on the gradient, gradient-based control is performed when the temperature state of the front motor 12 and the rear motor 13 are similar. That is, gradient-based control is performed in patterns 1-2, 5-6, and 11-12 of Figure 3, and in other patterns the temperature T of the front motor 12 is used.12 and the temperature T of the rear motor 13 13 Control is performed based on this. For example, when on an uphill slope and in state 3 of pattern 3, the front motor 12 is set to discharge state and the rear motor 13 is set to regenerative state.

[0046] In the above embodiment, the charge state of the traction battery 11 was determined to be either rechargeable or unrechargeable based on the State of Charge (SOC) of the traction battery 11. However, instead of this, or in addition, the charge state may be determined based on the battery temperature.

[0047] In the above embodiment, the configuration of the present invention was described using an electric vehicle as an example, in which the vehicle 1 does not have an engine as a power source for driving, but is equipped only with a driving motor. However, the present invention is not limited to this embodiment, and can be applied to vehicles equipped with driving motors on at least the front wheels 2 and the rear wheels 3, for example, hybrid vehicles that use both an engine and a driving motor, and in particular hybrid vehicles called strong hybrid systems that have the function of driving using only a driving motor as a power source. [Explanation of symbols]

[0048] 1 vehicle 2 Front wheels 3 Rear wheels 10 Control Unit 11. Battery for driving 12 Front Motor 13 Rear Motor

Claims

1. The vehicle comprises a front motor that supplies driving force to the front wheels of the vehicle, a rear motor that supplies driving force to the rear wheels of the vehicle, a traction battery that supplies power to the front motor and the rear motor, a charging capability detection means for detecting whether the traction battery can be charged, a temperature detection means for detecting the temperature of the front motor and the rear motor, respectively, and a control unit that controls the front motor and the rear motor. The control unit performs output limit control of the front motor when the temperature of the front motor exceeds a first output limit threshold, and performs output limit control of the rear motor when the temperature of the rear motor exceeds a second output limit threshold. The control unit, when the vehicle is decelerating and the traction battery is in a rechargeable state, puts at least one of the front motor and the rear motor into a regenerative state and charges the traction battery with regenerative power; when the vehicle is decelerating and the traction battery is in a non-rechargeable state, compares the value obtained by subtracting the first output limit threshold from the temperature of the front motor and the value obtained by subtracting the second output limit threshold from the temperature of the rear motor, puts the motor with the larger value into a regenerative state, and puts the motor with the smaller value into a discharge state, thereby consuming the regenerative power of the motor with the larger value, in a regenerative power consumption control.

2. The vehicle control device according to claim 1, wherein when the vehicle is decelerating and the traction battery is in a non-charging state, the control unit uses the regenerative braking force and friction brake braking force of the motor with the larger value when output limiting control is performed on the front motor and the rear motor.

3. The vehicle control device according to claim 1, wherein the discharge state includes power control, which applies rotational torque to the motor on the discharge state side so as not to increase the rotation of the wheels due to the deceleration of the vehicle, and non-power control, which supplies power to cancel out the induced electromotive force generated in the motor on the discharge state side due to the rotation of the wheels due to the deceleration of the vehicle, wherein non-power control is performed when the required deceleration of the vehicle is less than a predetermined value, and power control is performed when the required deceleration of the vehicle is greater than or equal to a predetermined value.

4. A vehicle control device according to any one of claims 1 to 3, wherein when the vehicle is traveling uphill, the front motor is set to the regenerative state and the rear motor is set to the discharge state, and when the vehicle is traveling downhill, the front motor is set to the discharge state and the rear motor is set to the regenerative state.

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