Electric vehicle control device

Abstract

To stabilize behavior of an electric vehicle, in which four wheels are driven by motors, by suppressing an increase in driving force difference between left and right wheels even when a motor abnormality occurs during travel.SOLUTION: A control device for an electric vehicle provided with four motors that independently drive front, rear, left, and right wheels and independently control driving force of each of the four wheels. When an abnormality is detected in any of the motors while the electric vehicle is traveling, the control device determines whether traveling posture of the electric vehicle is in a predetermined unstable state, one that leads to unstable vehicle behavior, based on a differential value of a yaw rate of the electric vehicle. When determining that the traveling posture is in the unstable state, the control device executes shutdown control (all-wheel shutdown) to cut off power supply to all four motors (Step S3).SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present invention relates to a control device for an electric vehicle using a motor as a driving force source, and more particularly to a control device for an electric vehicle that drives four wheels, front, rear, left, and right, with independent motors respectively.

Background Art

[0002] Patent Document 1 describes a front and rear wheel drive vehicle (four-wheel drive electric vehicle) including a front motor for driving the front wheels and a rear motor for driving the rear wheels. In the electric vehicle described in this Patent Document 1, the mutual relationship of the thermal ratings of the front motor and the rear motor is set to a specific state (for example, a state where the thermal rating of the front motor is higher than the thermal rating of the rear motor). Further, when the operation of the rear motor is restricted (during drive operation restriction or regeneration operation restriction), the operation (drive operation or regeneration operation) of the front motor is increased. On the other hand, when the operation of the front motor is restricted, the operation of the rear motor is reduced in order to make the driving force distribution ratio between the front and rear wheels the target distribution ratio. Thereby, the balance of the driving force between the front and rear is maintained, and the running stability of the electric vehicle is ensured.

[0003] Note that Patent Document 2 describes a control device for an electric vehicle including a first motor (PM motor) for driving the left and right front wheels, a second motor (induction motor) for driving the left and right rear wheels, a first inverter for converting direct current to alternating current between the battery and the first motor, and a second inverter for converting direct current to alternating current between the battery and the second motor. In the control device for the electric vehicle described in this Patent Document 2, when an overvoltage of the first motor is detected and acceleration of the electric vehicle is required, the first inverter is controlled for operation, and the second inverter on the side of the second motor that does not use a permanent magnet is controlled to shut down. The shutdown control is a control for blocking (shutting down) the control signal from the control device to the first inverter or the second inverter and turning off each switching element.

Prior Art Documents

Patent Documents

[0004] [Patent Document 1] Japanese Patent Laid-Open No. 2001-112114 [Patent Document 2] Japanese Patent Laid-Open No. 2015-216725 [Summary of the Invention] [Problems to be Solved by the Invention]

[0005] In the electric vehicles described in the above Patent Document 1 and Patent Document 2, by controlling the front motor (first motor) and the rear motor (second motor) individually, the driving force of the front wheels and the driving force of the rear wheels can be controlled independently. Also, electric vehicles have been developed in which motors for vehicle drive (drive motors) are provided on all four wheels, front, rear, left, and right, and by controlling these four drive motors individually, it is possible to independently control the driving forces of all four wheels.

[0006] In such an electric vehicle that independently drives the front and rear wheels or all four wheels, when shutdown control as described in the above Patent Document 2 is performed during the running of the electric vehicle, the behavior of the electric vehicle is disturbed and the running stability is reduced. In particular, when the electric vehicle is turning at high speed and the above shutdown control is executed, the driving force difference between the left and right wheels becomes large, and in some situations, the electric vehicle may spin. When the above shutdown control is executed on the inverter of a synchronous motor (or PM motor) using a permanent magnet, a counter electromotive force of the motor is generated and the drag torque increases. That is, a braking force is generated. Therefore, when shutdown control is performed on either one of the left and right wheels, the driving force difference between those left and right wheels suddenly increases.

[0007] The present invention has been conceived by focusing on the above technical problems, and is directed to an electric vehicle in which four wheels on the front, rear, left, and right are independently driven by motors. Even when an abnormality occurs in a motor during traveling, by appropriately executing shutdown control, an increase in the driving force difference between the left and right wheels is suppressed, and a control device for an electric vehicle capable of stabilizing vehicle behavior is provided.

Means for Solving the Problems

[0008] In order to achieve the above object, the present invention includes a first motor and a second motor that independently drive the left and right front wheels, and a third motor and a fourth motor that independently drive the left and right rear wheels, and is a control device for an electric vehicle that independently controls the driving forces of the four wheels on the front, rear, left, and right. The controller includes a controller that controls each of the motors and executes shutdown control for cutting off the supply of power to at least one of the motors. During traveling of the electric vehicle, the controller determines the presence or absence of an abnormality in each of the motors. When it is determined that an abnormality has occurred in any one of the motors, based on the yaw rate of the electric vehicle, it is determined whether the traveling posture of the electric vehicle is a predetermined unstable state in which the behavior of the electric vehicle becomes unstable. When it is determined that the traveling posture is the unstable state, shutdown control is executed for all of the motors corresponding to the four wheels respectively.

[0009] In addition, the controller in the present invention may be configured to execute the shutdown control for all of the motors when it is determined that an abnormality has occurred in at least one of the motors (the first motor and the second motor) corresponding to the left and right front wheels respectively, and it is determined that an abnormality has occurred in at least one of the motors (the third motor and the fourth motor) corresponding to the left and right rear wheels respectively.

[0010] Further, when the controller in the present invention determines that the abnormality has occurred in the motor corresponding to at least one of the left and right front wheels, it may be configured to execute the shutdown control on the motors corresponding to both the left and right front wheels (including normal ones).

[0011] And, when the controller in the present invention determines that the abnormality has occurred in the motor corresponding to at least one of the left and right rear wheels, it may be configured to execute the shutdown control on the motors corresponding to both the left and right rear wheels (including normal ones).

Advantages of the Invention

[0012] The vehicle to be controlled in this invention is an electric vehicle that uses a motor as a driving force source, and in particular, is a four-wheel drive electric vehicle in which the four wheels on the front, rear, left, and right are each driven by an independent motor. With such a four-wheel drive electric vehicle as the control target, in the control device for the electric vehicle of this invention, for example, when an output abnormality of the motor occurs, in order to deal with the abnormality, shutdown control for cutting off the power supply to the motor is executed. And, when the control device for the electric vehicle of this invention determines that the running posture of the electric vehicle is in an unstable state when an abnormality of the motor occurs, shutdown control is executed for all of the motors of all four wheels. For example, when the electric vehicle is turning at a high vehicle speed and is in an unstable state where spin or skidding of the electric vehicle may occur, if shutdown control is executed for the motor that drives either one of the left and right wheels, drag torque (braking torque) due to the counter electromotive force of the motor is generated, and the driving force difference between the left and right of the electric vehicle increases. As a result, the occurrence of spin of the electric vehicle is promoted. Therefore, the control device for the electric vehicle of this invention evaluates the running posture of the electric vehicle at that time when an abnormality of the motor occurs during the running of the electric vehicle. For example, when the yaw rate (or the differential value of the yaw rate) of the electric vehicle is greater than a predetermined threshold value determined in advance for judging an unstable state, it is determined that the running posture of the electric vehicle is in an unstable state. In short, in the control device for the electric vehicle of this invention, when an abnormality of the motor occurs during the running of the electric vehicle, giving top priority to stabilizing the running posture and behavior of the electric vehicle, when the electric vehicle is in an unstable state, shutdown control is executed for all of the motors corresponding to each of the four wheels, including normal motors. Therefore, even when an abnormality occurs in any one of the motors during the running of the electric vehicle, it is possible to avoid or suppress an increase in the driving force difference between the left and right, and to stabilize the running posture or behavior of the electric vehicle.

[0013] Therefore, according to the control device for an electric vehicle of the present invention, even when an abnormality occurs in a motor during traveling of an electric vehicle in which four wheels on the front, rear, left, and right are independently driven by motors, appropriate shutdown control is executed to suppress an increase in the driving force difference between the left and right wheels and stabilize the vehicle behavior. That is, the traveling stability of the electric vehicle can be improved.

Brief Description of the Drawings

[0014]

Figure 1

Figure 2

Embodiments for Carrying Out the Invention

[0015] Embodiments of the present invention will be described with reference to the drawings. Note that the embodiments shown below are merely examples when the present invention is embodied and do not limit the present invention.

[0016] The vehicle to be controlled in the embodiment of the present invention is a four-wheel drive electric vehicle equipped with motors as driving power sources and capable of independently driving four wheels on the front, rear, left, and right. And the electric vehicle to be controlled in the present invention is equipped with four motors (first motor 1, second motor 2, third motor 3, and fourth motor 4) capable of independently controlling the driving torques of the four wheels on the front, rear, left, and right.

[0017] An electric vehicle (hereinafter, referred to as vehicle) Ve shown in FIG. 1 includes a first motor (MG1) 1, a second motor (MG2) 2, a third motor (MG3) 3, and a fourth motor (MG4) 4 as driving power sources. And the vehicle Ve includes a detection unit 5 and a controller (ECU) 6 for executing various controls.

[0018] Each of the motors 1, 2, 3, and 4 is, for example, constituted by a permanent magnet type synchronous motor (PM motor). Each of the motors 1, 2, 3, and 4 has at least a function as a prime mover that is driven by being supplied with power to output torque. Further, each of the motors 1, 2, 3, and 4 may function as a generator that generates electric power by being driven by receiving torque from the outside. That is, each of the motors 1, 2, 3, and 4 may be a so-called motor - generator having both a function as a prime mover and a function as a generator. A battery (not shown) is connected to each of the motors 1, 2, 3, and 4 via an inverter (not shown). Therefore, the electric power stored in the battery can be supplied to each of the motors 1, 2, 3, and 4, and each of the motors 1, 2, 3, and 4 can be made to function as a prime mover to output driving torque. Also, each of the motors 1, 2, 3, and 4 can be driven by the torque transmitted from the wheels 11, 12, 13, and 14 described later, and at that time, each of the motors 1, 2, 3, and 4 can be made to function as a generator to charge the battery with the generated electric power.

[0019] Note that each of the motors 1, 2, 3, and 4 can also be constituted by, for example, an induction motor that does not use a permanent magnet. However, in the embodiment of this invention, by controlling each of the motors 1, 2, 3, and 4 constituted by the above - described permanent magnet type synchronous motor (PM motor), the operational effects of the control device of the electric vehicle in the embodiment of this invention become more remarkable.

[0020] The first motor 1 drives the left front wheel 11. For example, the first motor 1 and the front wheel 11 are connected so as to be capable of power transmission via a predetermined transmission mechanism such as a reduction gear (not shown). Alternatively, as a so - called "in - wheel motor", the first motor 1 may be disposed inside a wheel (not shown) of the front wheel 11, and the first motor 1 and the front wheel 11 may be directly connected.

[0021] The second motor 2 drives the right front wheel 12. For example, the second motor 2 and the front wheel 12 are connected so as to be able to transmit power through a predetermined transmission mechanism such as a reduction gear (not shown). Alternatively, as a so-called "in-wheel motor", the second motor 2 may be disposed inside a wheel (not shown) of the front wheel 12, and the second motor 2 and the front wheel 12 may be directly connected.

[0022] The third motor 3 drives the left rear wheel 13. For example, the third motor 3 and the rear wheel 13 are connected so as to be able to transmit power through a predetermined transmission mechanism such as a reduction gear (not shown). Alternatively, as a so-called "in-wheel motor", the third motor 3 may be disposed inside a wheel (not shown) of the rear wheel 13, and the third motor 3 and the rear wheel 13 may be directly connected.

[0023] The fourth motor 4 drives the right rear wheel 14. For example, the fourth motor 4 and the rear wheel 14 are connected so as to be able to transmit power through a predetermined transmission mechanism such as a reduction gear (not shown). Alternatively, as a so-called "in-wheel motor", the fourth motor 4 may be disposed inside a wheel (not shown) of the rear wheel 14, and the fourth motor 4 and the rear wheel 14 may be directly connected.

[0024] The detection unit 5 is a device or apparatus for acquiring various data and information necessary when controlling the vehicle Ve. For example, the detection unit 5 includes a power supply unit, a microcomputer, sensors, an input / output interface, and the like. In particular, the detection unit 5 in the embodiment of the present invention detects the running state of the vehicle Ve and the operating states of the motors 1, 2, 3, 4 for driving the vehicle, respectively. At the same time, during the running of the vehicle Ve, the detection unit 5 detects various data for determining the presence or absence of abnormalities in the motors 1, 2, 3, 4, for determining whether the running posture of the vehicle Ve is in an unstable state, and for executing shutdown control for the motors 1, 2, 3, 4.

[0025] Specifically, the detection unit 5 includes, for example, wheel speed sensors 5a that respectively detect the rotational speeds of the wheels 11, 12, 13, 14, motor rotation speed sensors (or resolvers) 5b that respectively detect the rotational speeds of the motors 1, 2, 3, 4, motor torque sensors 5c that respectively detect the torques of the motors 1, 2, 3, 4, current sensors 5d that respectively detect the current values of the motors 1, 2, 3, 4, an acceleration sensor 5e that detects the acceleration of the vehicle Ve, and a yaw rate sensor 5f that detects the yaw rate of the vehicle Ve. In addition, the detection unit 5 includes, for example, motor temperature sensors (not shown) that respectively detect the temperatures of the motors 1, 2, 3, 4, a SOC sensor (not shown) that detects the state of charge (SOC) of a battery (not shown), a battery temperature sensor (not shown) that detects the temperature of the battery, and an oil temperature sensor (not shown) that detects the temperature of the oil that cools the motors 1, 2, 3, 4. The detection unit 5 is electrically connected to a controller 6 described later, and outputs an electrical signal corresponding to the detection values or calculated values of the various sensors, devices, and apparatuses as described above to the controller 6 as detection data.

[0026] The controller 6 is an electronic control device mainly composed of, for example, a microcomputer. The controller 6 in the embodiment of the present invention controls the vehicle Ve, and in particular, controls each of the motors 1, 2, 3, 4 for vehicle driving and an inverter (not shown) to execute the shutdown control in the embodiment of the present invention. The shutdown control is, for example, a control for cutting off (shutting down) the control signal from the controller 6 to the inverter and turning off each switching element (not shown) to cut off (shut down) the power supply to each of the motors 1, 2, 3, 4. Various data detected or calculated by the above-described detection unit 5 are input to the controller 6. The controller 6 performs calculations using the input various data and the data and calculation formulas stored in advance. Then, the controller 6 outputs the calculation result as a control command signal, and as described above, is mainly configured to control each of the motors 1, 2, 3, 4 for vehicle driving, the inverter, and execute the shutdown control in the embodiment of the present invention. In FIG. 1, an example in which one controller 6 is provided is shown, but a plurality of controllers 6 may be provided for each device or equipment to be controlled, or for each control content.

[0027] As described above, the control device of the electric vehicle in the embodiment of the present invention is configured for the purpose of appropriately executing the shutdown control and stabilizing the behavior of the vehicle Ve even when an abnormality occurs in each of the motors 1, 2, 3, 4 during traveling. For this purpose, an example of the control executed by the controller 6 is shown in the flowchart of FIG. 2.

[0028] The control shown in the flowchart of FIG. 2 is executed during the traveling of the vehicle Ve as shown in step S0. In addition, when the possibility that the traveling posture of the vehicle Ve described later becomes unstable increases, when the vehicle speed is equal to or higher than a predetermined vehicle speed, when the vehicle Ve is turning, and when the rotational speed difference between the left and right wheels (wheel 11 and wheel 12, or wheel 13 and wheel 14) is equal to or higher than a predetermined value, the control shown in the flowchart of FIG. 2 may be executed.

[0029] In step S1, it is determined whether there is any abnormality in each of the motors 1, 2, 3, and 4. For example, based on the detected value of the current sensor 5d or the like, it is determined whether an output abnormality (MG output abnormality) has occurred in each of the motors 1, 2, 3, and 4.

[0030] If it is determined as “No” in this step S1 because no abnormality has occurred in any of the motors 1, 2, 3, and 4, the routine shown in this flowchart of FIG. 2 is terminated once without executing the control of each subsequent step.

[0031] On the other hand, if it is determined as “Yes” in step S1 because an abnormality has occurred in at least one of the motors 1 (or 2, 3, 4), the process proceeds to step S2.

[0032] In step S2, it is determined whether the running attitude of the vehicle Ve is in a predetermined unstable state (or unstable region). The unstable state in this case is, for example, a state (or running region) in which the behavior of the vehicle Ve becomes unstable such that the vehicle Ve may spin or skid, and is predetermined based on the results of running experiments or simulations using the actual machine. Specifically, in the example shown in this flowchart of FIG. 2, it is determined whether the differential value (dYR / dt) of the yaw rate of the vehicle Ve is greater than a predetermined threshold value α. When the differential value dYR / dt of the yaw rate, that is, the change speed of the yaw rate, is greater than the threshold value α, it is determined that the running attitude of the vehicle Ve is in an unstable state.

[0033] If it is determined as “Yes” in this step S2 because the differential value dYR / dt of the yaw rate is greater than the threshold value α, that is, the running attitude of the vehicle Ve is in an unstable state, the process proceeds to step S3.

[0034] In step S3, shutdown control (all-wheel shutdown) is executed for all motors 1, 2, 3, and 4 corresponding to the four wheels 11, 12, 13, and 14 respectively. In this case, the vehicle Ve is in an unstable state, and there is a risk of spin, skidding, etc. Therefore, with the top priority being to stabilize the running posture and behavior of the vehicle Ve, shutdown control is executed for all motors 1, 2, 3, and 4 of the four wheels 11, 12, 13, and 14 (including those that are normal without any abnormalities). Thus, for example, when the vehicle Ve is turning at high speed and the running posture of the vehicle Ve is in an unstable state, even if an abnormality occurs in at least one of the motors 1 (or 2, 3, 4), it is possible to avoid or suppress an increase in the difference in driving force between the left and right, and stabilize the running posture or behavior of the vehicle Ve.

[0035] When the above "all-wheel shutdown" is executed in this step S3, the routine shown in the flowchart of FIG. 2 is terminated once.

[0036] On the other hand, when the differential value dYR / dt of the yaw rate is equal to or less than the threshold value α, that is, when it is determined as "No" in the above step S2 because the running posture of the vehicle Ve is not in an unstable state, the process proceeds to step S4.

[0037] In step S4, it is determined whether an abnormality has occurred in both the motors 1 and 2 on the front-wheel 11, 12 side and the motors 3 and 4 on the rear-wheel 13, 14 side. That is, it is determined whether an abnormality has occurred in at least one of the motors 1 and 2 corresponding to the front wheels 11 and 12 respectively, and at least one of the motors 3 and 4 corresponding to the rear wheels 13 and 14 respectively.

[0038] If an abnormality occurs in both the motors 1 and 2 on the front wheel side 11, 12 and the motors 3 and 4 on the rear wheel side 13, 14, and it is determined as "Yes" in this step S4, the process proceeds to step S3, and the same control as before is executed. In this case, on both the front wheel side 11, 12 and the rear wheel side 13, 14, due to an abnormality occurring in any one of the motors 1 (or 2, 3, 4), the behavior of the vehicle Ve is likely to become unstable. Therefore, in step S2 above, when it is determined that the running posture of the vehicle Ve is in a predetermined unstable state, shutdown control (all-wheel shutdown) is executed for all the motors 1, 2, 3, 4 corresponding to the four wheels 11, 12, 13, 14 respectively. Therefore, also in this case, it is possible to avoid or suppress an increase in the difference in driving force between the left and right, and stabilize the running posture or behavior of the vehicle Ve.

[0039] And when the above "all-wheel shutdown" is executed in step S3, the routine shown in the flowchart of FIG. 2 is temporarily terminated.

[0040] On the other hand, if it is determined as "No" in step S4 because no abnormality has occurred in both the motors 1 and 2 on the front wheel side 11, 12 and the motors 3 and 4 on the rear wheel side 13, 14, the process proceeds to step S5.

[0041] In step S5, it is determined whether an abnormality has occurred in the motors 1 and 2 on the front wheel side 11, 12. That is, it is determined whether an abnormality has occurred in at least one of the motors 1 and 2 corresponding to the front wheels 11 and 12 respectively.

[0042] If it is determined as "Yes" in this step S5 because an abnormality has occurred in the motors 1 and 2 on the front wheel side 11, 12, the process proceeds to step S6.

[0043] In step S6, shutdown control (front-wheel shutdown) is executed for both the left and right motors 1 and 2 corresponding to the front wheels 11 and 12 respectively. In this case, either both of the motors 1 and 2 corresponding to both the left and right front wheels 11 and 12, or the motor 1 (or 2) corresponding to either the left or right front wheel 11 (or 12) is in an abnormal state. If an abnormality occurs in either the motor 1 (or 2) corresponding to either the left or right front wheel 11 (or 12), and shutdown control is performed only on the motor 1 (or 2) in which the abnormality has occurred, the difference in driving force between the left and right will increase, and the running posture or behavior of the vehicle Ve will be disrupted. Therefore, in the embodiment of this invention, when an abnormality occurs in at least either of the left and right motors 1 and 2 corresponding to the front wheels 11 and 12 respectively, shutdown control is executed for both of these left and right motors 1 and 2, including those that are normal and have no abnormalities. Therefore, even when an abnormality occurs in at least either of the motors 1 and 2 on the front-wheel 11, 12 side, an increase in the difference in driving force between the left and right can be avoided or suppressed, and the running posture or behavior of the vehicle Ve can be stabilized.

[0044] When the above “front-wheel shutdown” is executed in this step S6, the routine shown in the flowchart of FIG. 2 is terminated once.

[0045] On the other hand, if it is determined in step S5 that “No” because none of the motors 1 and 2 on the front-wheel 11, 12 side are abnormal, that is, both of the motors 1 and 2 on the front-wheel 11, 12 side are normal, but an abnormality has occurred in at least either of the motors 3 and 4 on the rear-wheel 13, 14 side, the process proceeds to step S7.

[0046] In step S7, shutdown control (rear wheel shutdown) is executed for both the left and right motors 3 and 4 corresponding to the rear wheels 13 and 14 respectively. In this case, an abnormality has occurred in both of the motors 3 and 4 corresponding to both the left and right rear wheels 13 and 14, or in the motor 3 (or 4) corresponding to either the left or right rear wheel 13 (or 14). If an abnormality occurs in the motor 3 (or 4) corresponding to either the left or right rear wheel 13 (or 14), and shutdown control is performed only on the motor 3 (or 4) in which the abnormality has occurred, the difference in driving force between the left and right will increase, and the running posture or behavior of the vehicle Ve will be disrupted. Therefore, in the embodiment of this invention, when an abnormality occurs in at least either of the left and right motors 3 and 4 corresponding to the rear wheels 13 and 14, shutdown control is executed for both of those left and right motors 3 and 4, including the normal ones in which no abnormality has occurred. Therefore, even when an abnormality occurs in at least either of the motors 3 and 4 on the rear wheel 13, 14 side, it is possible to avoid or suppress an increase in the difference in driving force between the left and right, and stabilize the running posture or behavior of the vehicle Ve.

[0047] When the above-described "rear wheel shutdown" is executed in this step S7, the routine shown in the flowchart of FIG. 2 is terminated once.

[0048] As described above, in the control device for an electric vehicle according to the embodiment of the present invention, a four-wheel drive vehicle Ve in which the four wheels 11, 12, 13, and 14 on the front, rear, left, and right are driven by independent motors 1, 2, 3, and 4 respectively is the control target. When an output abnormality occurs in at least one of the motors 1 (or 2, 3, 4), shutdown control for cutting off the power supply to the motor 1 (or 2, 3, 4) is executed to cope with the abnormality. And, when determining that the running posture of the vehicle Ve is in an unstable state when performing such shutdown control, the control device for an electric vehicle according to the embodiment of the present invention gives top priority to stabilizing the running posture and behavior of the vehicle Ve, and executes shutdown control on all the motors 1, 2, 3, 4 corresponding to the four wheels 11, 12, 13, 14 respectively, including the normal ones. Therefore, as described above, even when an abnormality occurs in at least one of the motors 1, 2, 3, 4 during the running of the vehicle Ve, an increase in the driving force difference between the left and right wheels can be avoided or suppressed.

[0049] Therefore, according to the control device for an electric vehicle according to the embodiment of the present invention, for an electric vehicle Ve in which the four wheels 11, 12, 13, 14 on the front, rear, left, and right are independently driven by the motors 1, 2, 3, 4, even when an abnormality occurs in at least one of the motors 1, 2, 3, 4 during running, by appropriately executing shutdown control, an increase in the driving force difference between the left and right wheels can be suppressed, and the vehicle behavior can be stabilized. That is, the running stability of the electric vehicle Ve can be improved.

Explanation of Signs

[0050] 1 First motor (driving power source) 2 Second motor (driving power source) 3 Third motor (driving power source) 4 Fourth motor (driving power source) 5 Detection unit 5a Wheel speed sensor of (detection unit) 5b Motor rotation speed sensor (or resolver) of (detection unit) 5c Motor torque sensor of (detection unit) 5d Current sensor (of the detection unit) 5e Acceleration sensor (of the detection unit) 5f Yaw rate sensor (of the detection unit) 6 Controller (ECU) 11 Front wheel (left side) 12 Front wheel (right side) 13 Rear wheel (left side) 14 Rear wheel (right side) Ve Vehicle (electric vehicle)

Claims

【Claim 1】 A control device for an electric vehicle, comprising a first motor and a second motor that drive the left and right front wheels respectively, and a third motor and a fourth motor that drive the left and right rear wheels respectively, and independently controlling the driving forces of the four wheels on the front, rear, left, and right sides, comprising a controller that controls each of the motors and executes a shutdown control for cutting off the supply of power to at least one of the motors, wherein the controller, during running of the electric vehicle, determines the presence or absence of abnormalities in each of the motors, when it is determined that an abnormality has occurred in any one of the motors, based on the yaw rate of the electric vehicle, determines whether the running posture of the electric vehicle is in a predetermined unstable state in which the behavior of the electric vehicle becomes unstable, and when it is determined that the running posture is in the unstable state, executes the shutdown control for all of the motors, characterized in that it is a control device for an electric vehicle.

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