JP2022044936A - Power control device of electric vehicle - Google Patents

Abstract

To provide a power control device of an electric vehicle that is provided with a power transmission passage through which output of a first motor and output of a second motor are transmitted to left and right wheels respectively of the vehicle and in which ratios of transmission of the output to the left and right wheels can be adjusted, which is configured to enable a running state thereof to be stably maintained when an abnormality occurs in either of the motors to cause functional defect.SOLUTION: A power control device 30 of an electric vehicle, which comprises a turning moment control device 11 and in which rotation speeds and magnitude of torque in respective elements of left and right wheels, of a left motor and of a right motor have a collinear relation in which the speeds and the magnitude are positioned on a straight line on a characteristics diagram representing the magnitude, comprises: a running state determining part 45 that determines whether the vehicle is turning, is running straight forward, is being driven or is being regenerated; a left motor defect detecting part 47; a right motor defect detecting part 49; and a defect-time control part 51 that adjusts motor torque of the motor which is normal when detecting functional defect of either of the motors so as to adjust a torque difference between the left and right wheels into a torque difference therebetween at which a running state in which the defect is not yet determined by the running state determining part can be maintained.SELECTED DRAWING: Figure 2

Description

The present disclosure relates to a power control device for an electric vehicle of an electric vehicle or a hybrid vehicle having a motor for driving a wheel.

Patent Document 1 is known regarding power control of left and right motors that drive a pair of left and right wheels of an electric vehicle, respectively. In Patent Document 1, the left and right motors are connected to each of the left and right wheels, and the power transmission paths to the left and right wheels are independent of each other. It has been shown that by appropriately controlling both the left and right motors, operations such as forward movement, backward movement, turning, and stopping are correctly executed.

Further, in Patent Document 1, one of a first inverter circuit that supplies AC power to one of the left and right first motors and a second inverter circuit that supplies AC power to the other left and right second motors. It has been shown that when an abnormality occurs, multiple switching elements of both inverter circuits are turned off at the same time.

Further, in Patent Document 1, after turning off a plurality of switching elements of both inverter circuits, the torque difference between the first motor and the second motor is monitored, and when the torque difference exceeds the permissible value, it is normal. It has been shown to operate an inverter circuit to reduce the torque difference.

Further, Patent Document 2 describes an energy transfer device including a planetary gear device that transfers energy between one of the left and right first motors and the left and right wheels, and between the other left and right second motors and the left and right wheels. In addition, an energy transfer path is shown in which the output of the first motor or the output of the second motor is transmitted to both the left and right wheels, and the transmission ratio is further adjusted. It is shown that the rotational speeds and transmission torques of the left and right wheels and the left and right motors have a collinear relationship in which they are located on a straight line.

Japanese Patent No. 6418196 Japanese Patent No. 4637136

However, in Patent Document 1, as described above, since the left and right motors are individually connected to each of the left and right wheels and are independent power transmission paths, the output of the first motor or the output of the second motor Is transmitted to both the left and right wheels, and the control of the motor when an abnormality occurs in one of the motors in the power transmission path in which the power transmission ratio to the left and right wheels is adjusted is not shown.

Further, Patent Document 2 discloses a power transmission path in which the output of the first motor or the output of the second motor is transmitted to both the left and right wheels, and the transmission ratio to the left and right wheels is adjusted. However, the control of the motor when an abnormality occurs in one of the motors and the motor function is lost is not shown.

Therefore, in any of the patent documents, an electric vehicle having a power transmission path such that the output of the first motor or the output of the second motor is transmitted to both the left and right wheels and the transmission ratio to the left and right wheels is adjusted. In, there is no disclosure about the power control of the other motor when an abnormality occurs in one motor and the motor function is lost, and in Patent Document 1 and Patent Document 2, from each motor to the left and right wheels. Since the power transmission path is different, it is difficult to apply the technique shown in Patent Document 1 to Patent Document 2.

Therefore, in view of the above problems, in at least one embodiment of the present invention, the output of the first motor and the output of the second motor are transmitted to the left and right wheels of the vehicle, respectively, and the transmission ratio to the left and right wheels can be adjusted. To provide a power control device for an electric vehicle having a power transmission path, which can stably maintain the running state of the vehicle when an abnormality occurs in one of the motors and a malfunction occurs. The purpose.

(1) It was invented to achieve the above-mentioned object, and in at least one embodiment of the present invention, the output of the first motor and the output of the second motor have differential mechanisms on the left and right wheels of the vehicle, respectively. A swivel moment control device for controlling the swivel moment by adjusting the share of torque between the left and right wheels by controlling the outputs of the first motor and the second motor is provided. A power control device for an electric vehicle having a co-wire relationship in which the magnitudes of rotation speed and torque in each element of the left and right wheels, the first motor, and the second motor are located in a straight line on a characteristic diagram showing the magnitudes. The traveling state determination unit for determining whether the electric vehicle is traveling straight or turning, and whether it is in the driving state or the regenerating state, and the first motor failure detection for detecting the functional failure of the first motor. The function of one of the motors is lost due to the unit, the second motor failure detection unit that detects the malfunction of the second motor, and the first motor failure detection unit and the second motor failure detection unit. When a failure is detected, the motor torque of the normal side motor is adjusted to adjust the torque difference between the left and right wheels that can maintain the driving state before the failure determined by the traveling state determination unit. It is characterized by having and.

According to such a configuration, when the function failure of either motor is detected by the first motor failure detection unit and the second motor failure detection unit, the motor torque of the normal side motor is adjusted. Since it is equipped with a failure control unit that adjusts to the torque difference between the left and right wheels that can maintain the driving state before the failure determined by the driving state determination unit, it is possible to maintain the driving state before the failure and the vehicle is running. The state can be maintained stably. Therefore, even when one of the motors fails, it is possible to maintain the function of turning moment control by the turning moment control device.

In addition, when a functional failure of one of the motors is detected, the motor torque of the normal side motor is adjusted to maintain the running state before the failure, so it is possible to respond quickly in the event of a failure. ..

(2) In some embodiments, when the failure control unit determines that the traveling state determination unit is in the driving state and the straight running state, the driving torque of the normal side motor is reduced to reduce the driving torque of the left and right wheels. The feature is that the wheel torque of the wheel mainly in charge of the collapsed motor is controlled to be zero.

According to such a configuration, when the electric vehicle is in the driving state and the straight running state, the failure control unit reduces the drive torque of the normal side motor, and the failure side motor is mainly in charge of the left and right wheels. Since the wheel torque of the wheels is controlled to be zero, it is possible to suppress an increase in the drag resistance of the wheels and maintain straight running.

(3) In some embodiments, when the failure control unit determines that the traveling state determination unit is in the driving state and the straight running state, the driving torque of the normal side motor is reduced, and the left and right wheels are reduced. It is characterized in that the difference in wheel torque is controlled to be smaller than the permissible value that can maintain straight running stability.

According to such a configuration, when the electric vehicle is in the driving state and the straight running state, the failure control unit reduces the driving torque of the normal side motor, and the difference between the wheel torques of the left and right wheels provides straight running stability. Since the control is performed so as to be smaller than the allowable value that can be maintained, the stability of the straight running state can be maintained even in the driving state and even after the failure of one of the motors.

(4) In some embodiments, when the traveling state determination unit determines that the traveling state determination unit is in the driving state and the turning state, the failure control unit reduces the driving torque of the normal side motor to reduce the drive torque of the left and right wheels. It is characterized in that the difference in wheel torque is controlled so as to maintain the turning moment of the vehicle.

According to such a configuration, when the electric vehicle is in the driving state and the turning state, the failure control unit reduces the driving torque of the normal side motor, and the difference between the wheel torques of the left and right wheels is the turning moment of the vehicle. Since it is controlled to maintain the torque, the stability of the turning state can be maintained even after the failure of one of the motors.

(5) In some embodiments, when the collapsed side motor is a motor mainly responsible for driving the wheels on the inside of the turning, it is within a range larger than the drag torque generated by the collapsed side motor on the positive side. The present invention is characterized in that the drive torque of the normal side motor is reduced and controlled so that the turning moment is maintained.

According to such a configuration, when the failing side motor is a motor mainly responsible for driving the wheels on the inside of the turning, it is normal within a range larger than the drag torque generated by the failing side motor on the positive side. Since the drive torque of the side motor is reduced, the turning moment is properly maintained. That is, if the drive torque of the normal side motor is reduced to a range larger than the drag torque generated by the fallen side motor to the negative side, a moment in the opposite direction to that during turning is generated and an appropriate turning moment is obtained. Because it cannot be done.

(6) In some embodiments, when the failing side motor is a motor mainly responsible for driving the wheels on the outer side of turning, the normality is further negative than the drag torque generated by the falling side motor. It is characterized in that the drive torque of the side motor is reduced and controlled so that the turning moment is maintained.

According to such a configuration, when the fallen side motor is a motor mainly responsible for driving the wheels on the outer side of turning, the normal side motor is driven to the negative side further than the drag torque generated by the fallen side motor. Since the torque is reduced, the turning moment is properly maintained. That is, unless the drive torque of the normal side motor is lowered further to the negative side than the drag torque generated by the fallen side motor, a moment opposite to that during turning is generated and an appropriate turning moment cannot be obtained. Is.

(7) In some embodiments, when the failure control unit determines that the traveling state determination unit is in the regenerative state and the straight running state, the drag torque generated by the failure side motor is reached by the normal side motor. It is characterized in that the regenerative torque is reduced and the difference between the wheel torques of the left and right wheels is controlled so as to maintain straight-line stability.

According to such a configuration, when the electric vehicle is in the regenerative state and the straight running state, the failure control unit reduces the regenerative torque of the normal side motor to the drag torque generated by the failure side motor, and the left and right wheels. Since the difference in wheel torque is controlled so as to maintain the straight running stability, the stability in the straight running state can be maintained even in the regenerative state and even after the failure of one of the motors.

(8) In some embodiments, when the failure control unit determines that the traveling state determination unit is in the regenerative state and the turning state, the failing side motor mainly drives the wheels inside the turning. In the case of the motor in charge, the regenerative torque of the normal side motor is reduced to the drag torque generated by the failed side motor.

According to such a configuration, when the electric vehicle is in the regenerated state and the turning state, the failing control unit is a motor that is mainly in charge of driving the wheels inside the turning. If the torque of the normal side motor is increased to the positive side, the vehicle will be in an accelerated state, so the regenerative torque of the normal side motor will be reduced to the drag torque generated by the failed side motor, and the failed side motor will be generated. Control so that it is balanced with the drag torque. As a result, it is possible to prevent the vehicle behavior from becoming unstable in the regenerative state and the turning state.

(9) In some embodiments, when the failure control unit determines that the traveling state determination unit is in the regenerative state and the turning state, the failing side motor mainly drives the wheels on the outer side of the turning. In the case of the motor in charge, the regenerative torque of the normal side motor is reduced within a range larger than the drag torque generated by the collapsed side motor on the negative side, and the turning moment is controlled to be maintained. It is characterized by that.

According to such a configuration, when the electric vehicle is in the regenerative state and the turning state, the failure control unit is a motor that is mainly in charge of driving the wheels on the outside of the turning when the failure side motor is a motor. Since the regenerative torque of the normal side motor is reduced and controlled so that the turning moment is maintained within a range larger than the drag torque generated by the fallen side motor on the negative side, the vehicle is in the regenerative state and in the turning state. The turning state can be stably maintained without destabilizing the behavior.

(10) In some embodiments, the electric vehicle is a four-wheel drive vehicle including the turning moment control device provided on the rear wheel side and a front wheel side drive motor for further driving the front wheel side. And.

According to such a configuration, even if the electric vehicle is a four-wheel drive vehicle, when the malfunction of one of the first motor and the second motor is detected, the electric vehicle of the normal side motor is used. Since the motor torque of the above is adjusted to the torque difference between the left and right wheels that can maintain the running state, the running state before the failure can be maintained, and the running state of the vehicle can be stably maintained.

(11) In some embodiments, the co-wire relationship arranges the first motor, the left wheel, the right wheel, and the second motor in order on the horizontal axis at intervals of gear ratios of gears constituting each element. , The relationship is such that they are located on a straight line on the characteristic diagram showing the magnitude of rotation speed or torque on the vertical axis, and the failure control unit uses the co-wire relationship to determine the motor torque of the normal side motor. It is characterized by calculation and adjustment.

With such a configuration, the collinear relationship of the rotational speed or the torque in each element of the first motor, the left wheel, the right wheel, and the second motor becomes clear. Further, since the failure control unit calculates and adjusts the motor torque of the normal side motor using this collinear relationship, the normal side motor torque can be easily and quickly adjusted.

According to at least one embodiment of the present invention, the output of the first motor and the output of the second motor are transmitted to the left and right wheels of the vehicle, respectively, and further provided with a power transmission path in which the transmission ratio to the left and right wheels can be adjusted. In an electric vehicle, when an abnormality occurs in one of the motors and a functional failure occurs, the motor torque of the normal side motor is adjusted to adjust the torque difference between the left and right wheels that can maintain the running state before the failure. Therefore, when an abnormality occurs in one of the motors and a malfunction occurs, the running state of the vehicle can be stably maintained.

It is an overall block diagram of the electric vehicle to which the power control device which concerns on one Embodiment of this invention is applied. It is a block diagram of a power control device. It is a control flowchart of the whole of the control unit at the time of failure. Of the control flowcharts of FIG. 3, it is a flowchart of a subroutine for driving straight-ahead control. Of the control flowcharts of FIG. 3, it is a flowchart of a subroutine for driving and turning control. Of the control flowcharts of FIG. 3, it is a flowchart of a subroutine for regenerative straight-ahead control. Of the control flowcharts of FIG. 3, it is a flowchart of a subroutine for regenerative turning control. It is an output characteristic figure which shows the collinear relationship of the drive torque in each element of a left motor, a left wheel, a right wheel, and a right motor in the control at the time of driving straight-ahead, and shows the normal state in a straight-ahead state. FIG. 8 is an output characteristic diagram showing a collinear relationship of drive torques of each element when the right motor fails in the drive straight-ahead state of FIG. 8A. FIG. 8 is an output characteristic diagram showing a collinear relationship of drive torque of each element under the control of the failure control unit with respect to the failure of FIG. 8B. FIG. 8 is an output characteristic diagram showing control when straight-line stability becomes a problem due to the control of FIG. 8C and showing the collinear relationship of the drive torque of each element. It is an output characteristic figure which shows the collinear relationship of the drive torque in each element of a left motor, a left wheel, a right wheel, and a right motor in the drive turn control, and shows the normal state of a right turn state. FIG. 9 is an output characteristic diagram showing a collinear relationship of drive torques of each element when the right motor (turn inner motor) fails in the drive right turn state of FIG. 9A. FIG. 9 is an output characteristic diagram showing a collinear relationship of drive torque of each element under the control of the failure control unit with respect to the failure of FIG. 9B. FIG. 9 is an output characteristic diagram showing a collinear relationship of drive torques of each element when the left motor (turning outer motor) fails in the drive right turn state of FIG. 9A. FIG. 9 is an output characteristic diagram showing a collinear relationship of drive torque of each element under the control of the failure control unit with respect to the failure of FIG. 9D. FIG. 8A is an output characteristic diagram showing the collinear relationship of the regenerative torque in each element of the left motor, the left wheel, the right wheel, and the right motor in the regenerative straight-ahead control, and shows the normal state in the straight-ahead state. It is a diagram corresponding to FIG. 8B, and is an output characteristic diagram showing the collinear relationship of the regenerative torque of each element when the right motor fails in the regenerative straight traveling state of FIG. 10A. FIG. 10B is an output characteristic diagram showing a collinear relationship of regenerative torque of each element under the control of the failure control unit with respect to the failure of FIG. 10B. 9A is a diagram corresponding to FIG. 9A, which is an output characteristic diagram showing a collinear relationship of regenerative torque in each element of the left motor, the left wheel, the right wheel, and the right motor in the regenerative turning control, and shows the normal state of the right turning state. .. 9B is a diagram corresponding to FIG. 9B, which is an output characteristic diagram showing a collinear relationship of regenerative torque of each element when the right motor (turning inner motor) fails in the regenerative right turning state of FIG. 11A. It is a diagram corresponding to FIG. 9C, and is an output characteristic diagram showing a collinear relationship of regenerative torque of each element under the control of the failure control unit with respect to the failure of FIG. 11B. 9D is a corresponding diagram, and is an output characteristic diagram showing a collinear relationship of regenerative torque of each element when the left motor (turning outer motor) fails in the regenerative right turning state of FIG. 11A. 9E is a correspondence diagram, which is an output characteristic diagram showing a collinear relationship of regenerative torque of each element under the control of the failure control unit with respect to the failure of FIG. 11D. It is a collinear diagram which shows a comparative example, and shows the state which shuts down a left motor on a normal side when a right motor fails when going straight. It is a skeleton diagram which shows the power transmission path of a turning moment control device. It is a collinear diagram which shows the collinear relationship of the rotation speed in each element of the left motor, the left wheel, the right wheel, and the right motor by the power transmission path shown in FIG. It is an overall block diagram of another embodiment of the electric vehicle to which a power control device is applied.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. However, the relative arrangement of the components described as the embodiment or shown in the drawings is not intended to limit the scope of the present invention to these, and is merely an explanatory example.

FIG. 1 shows an overall configuration block diagram of an electric vehicle to which the power control device according to the embodiment of the present invention is applied. The vehicle 1 is an electric vehicle having a motor for driving wheels or an electric vehicle of a hybrid vehicle, and is an electric vehicle in which the left and right wheels 3 and 5 on the rear wheel side are driven by a pair of left and right motors 7 and 9.

The vehicle 1 is equipped with a turning moment control device 11 having an AYC (active yaw control) function. The turning moment control device 11 is interposed between the left axle 13 connected to the left wheel 3 and the right axle 15 connected to the right wheel 5.

The AYC function is a function that adjusts the magnitude of the yaw moment (turning moment) by independently controlling the share of drive torque between the left and right wheels 3 and 5, and stabilizes the posture of the vehicle 1 in the yaw direction. .. The turning moment control device 11 of the present embodiment has not only the AYC function but also the function of transmitting the driving force to the left and right wheels 3 and 5 to drive the vehicle 1 and the left and right wheels 3 and 5 generated when the vehicle 1 turns. It also has a function to absorb the difference in rotation speed.

As shown in FIGS. 1 and 13, the turning moment control device 11 includes a pair of left and right motors 7 and 9, one of which is a left motor (first) that transmits driving force to the left wheel 3 mainly via the left axle 13. 1 motor) 7 and the other is a right motor (second motor) 9 that mainly transmits a driving force to the right wheel 5 via the right axle 15. Both the left motor 7 and the right motor 9 are motor generators (MGs) having both a function as a motor and a function as a generator.

Further, the turning moment control device 11 has a gear meshing path (gear train) for transmitting drive torque from the left motor 7 and the right motor 9 to the left axle 13 and the right axle 15, and also has the left axle 13 and the right axle 15. It comprises a power transmission path 19 having a differential mechanism (DIFF) 17 capable of moving drive torque between the two.

FIG. 13 is a skeleton diagram showing an example of the configuration of the turning moment control device 11, and shows a power transmission path 19. The output shafts of the left motor 7 and the right motor 9 are connected to the differential gear Zd via a reduction gear train consisting of an input gear Zi, a counter gear Zc, and an updoya Zo, respectively. The differential gear Zd on the left motor 7 side is connected to the I / P sun gear Zs1 of the planetary gear mechanism constituting the differential mechanism 17, and the differential gear Zd on the right motor 9 side is the annulus of the planetary gear mechanism constituting the differential mechanism 17. It is connected to the gear Zr1.

The pinion gear large Zp1 of the planetary gear and the pinion gear small Zp2 juxtaposed with the pinion gear large Zp1 are in common carrier C, which are meshed and interposed between the annulus gear Zr1 and the I / P sun gear Zs1 of the planetary gear mechanism. It is freely rotatably supported, and the rotation center axis 21 of the carrier C is connected to the right axle 15. Further, the rotation center shaft 23 of the O / P sun gear Zs2 that meshes with the inside of the pinion gear small Zp2 is connected to the left axle 13. The torque difference amplification type torque vectoring device is configured by the power transmission path 19 shown in the skeleton diagram of FIG.

In the power transmission path 19 configured as described above, the rotation speeds of the left motor 7, the left wheel 3, the right wheel 5, and the right motor 9 are on the same straight line as shown in the collinear diagram shown in FIG. It has a collinear relationship that is located. In the collinear diagram shown in FIG. 14, the left motor 7, the left wheel 3, the right wheel 5, and the right motor 9 are arranged in order on the horizontal axis at intervals of the gear ratios of the gears constituting each element, and each on the vertical axis. It represents the rotation speed. The configuration of the power transmission path 19 shown in the skeleton diagram of FIG. 13 is an example, and as shown in the collinear diagram of FIG. 14, the rotation speeds of the left motor 7, the left wheel 3, the right wheel 5, and the right motor 9 are set. Any structure may be used as long as it has a collinear relationship located on the same straight line.

Further, FIG. 14 is a common line diagram in which the rotational speeds of the left motor 7, the left wheel 3, the right wheel 5, and the right motor 9 are located on the same straight line connecting the left and right motors as described above. When the motor torque TLm is output by the left motor 7 and the motor torque TRm is output by the right motor 9, the left wheel torque TL is output from the left wheel 3 and the right wheel torque TR is output from the right wheel 5 due to the torque balance and the like. Indicates that is output. The case where the torque difference between the left and right wheels is amplified with respect to the torque difference between the left and right motors is shown (conceptually shown as the length of the arrow in FIG. 14).

Further, when the motor torque TLm of the left motor 7 and the motor torque TRm of the right motor 9 are output, the relationship between the left wheel torque TL transmitted to the left wheel 3 and the right wheel torque TR transmitted to the right wheel 5 is shown in FIG. 8A. -It has a collinear relationship located on the same straight line as shown in the output characteristic diagram shown in FIG. In the output characteristic diagrams shown in FIGS. 8A to 12, the left motor 7, the left wheel 3, the right wheel 5, and the right motor 9 are arranged in order on the horizontal axis at intervals of the gear ratios of the gears constituting each element, and are vertically arranged. Each drive torque is shown on the shaft. The horizontal axes of FIGS. 8A to 12 are schematically shown at equal intervals. Further, the torque on the vertical axis means the positive torque, that is, the driving torque above zero, and the negative torque, that is, the regenerative torque below. The torque output from the left and right motors 7 and 9 to the power transmission path 19 is defined as the positive torque, and the torque output from the left and right axles 13 and 15 to the left and right wheels 3 and 5 is defined as the positive torque.

The operating states of the left motor 7 and the right motor 9 are controlled by the left inverter (INV) 25 and the right inverter 27. The left inverter 25 and the right inverter 27 are converters (DC-AC inverters) that convert DC power supplied from the battery (BATT) 29 into AC power and supply it to the left motor 7 and the right motor 9, respectively. Each of the inverters 25 and 27 has a built-in three-phase bridge circuit including a plurality of switching elements. AC power is generated by intermittently switching the connection state of each switching element. Further, by controlling the switching frequency and the output voltage, the output (driving torque) and the rotation speed of each of the motors 7 and 9 are adjusted. The operating states of the left motor 7, the right motor 9, the left inverter 25, and the right inverter 27 are controlled by the motor ECU (motor control device) (power control device) 30.

As shown in FIG. 2, the motor ECU 30 has a signal from the accelerator opening sensor 31 that detects the opening degree of the accelerator pedal operated by the driver, and a signal from the vehicle speed sensor 33 that detects the vehicle speed, via the interface. A signal from the steering angle sensor 35 that detects the steering angle of the steering operated by the driver is input.

Further, in order to calculate the drive torque and regenerative torque output by the left and right motors 7 and 9, and to detect the operating state of each motor, the left motor current sensor 37 and the right motor current sensor 39 that detect each motor current The signal from is input.

Further, signals from the left inverter abnormality detecting means 41 and the right inverter abnormality detecting means 43 for detecting the abnormalities of the left and right inverters 25 and 27 are input. The left inverter abnormality detecting means 41 and the right inverter abnormality detecting means 43 may cause such a state because the motor function is lost when, for example, an overcurrent or a short circuit occurs in the switching element constituting the inverter. To detect. In the present embodiment, the left inverter abnormality detecting means 41 and the right inverter abnormality detecting means 43 are provided inside the inverters 25 and 27, but may be provided inside the motor control device 29.

Further, as shown in FIG. 2, the motor ECU (power control device) 30 is provided with a traveling state determination unit 45 for determining whether the vehicle 1 is traveling straight or turning, and whether it is in a driving state or a regenerative state. ing. The driving state is a state in which the driver depresses the accelerator pedal to accelerate or travel at a predetermined constant speed, and the regenerative state is a state in which the driver depresses the accelerator pedal to decelerate the vehicle 1. .. The traveling state determination unit 45 determines the traveling state based on signals from various sensors such as an accelerator opening degree sensor 31, a vehicle speed sensor 33, a steering angle sensor 35, and a torque sensor (not shown) of each motor.

Further, the motor ECU 30 has a left motor failure detection unit (first motor failure detection unit) 47 for detecting the functional failure of the left motor 7 and a right motor failure detection for detecting the functional failure of the right motor 9. A unit (second motor failure detection unit) 49 is provided. Each of these motor failure detection units 47 and 49 is based on the signals from the left inverter abnormality detecting means 41 and the right inverter abnormality detecting means 43, and the signals from the left motor current sensor 37 and the right motor current sensor 39, respectively. It is determined whether the motors 7 and 9 are in a failed state.

Further, when the motor ECU 30 detects the malfunction of one of the motors by the left motor failure detection unit 47 and the right motor failure detection unit 49, the motor torque of the normal side motor is adjusted. A failure control unit 51 that adjusts to a torque difference between the left and right wheels 3 and 5 that can maintain the travel state before the failure determined by the travel state determination unit 45 is provided. Then, if the left motor 7 is normal, the failure control unit 51 outputs the left motor instruction torque 53 to the left motor 7, and if the right motor 9 is normal, the right motor instruction torque 55 is output to the right motor 9. Output.

As described above, according to one embodiment, when the left motor failure detection unit 47 and the right motor failure detection unit 49 detect the malfunction of either motor, the motor torque of the normal side motor is increased. Since the failure control unit 51 is provided to adjust and adjust the torque difference between the left and right wheels 3 and 5 capable of maintaining the running state before the failure determined by the running state determination unit 45, the running state before the failure is provided. Can be maintained, and the running state of the vehicle can be stably maintained. Therefore, even when one of the motors fails, it is possible to maintain the function of turning moment control by the turning moment control device.

In addition, when a functional failure of one of the motors is detected, the motor torque of the normal side motor is adjusted to maintain the running state before the failure, so it is possible to respond quickly in the event of a failure. .. For example, as shown in Patent Document 1, the normal side motor is also controlled to be shirted down at the same time as one of the motors fails (for example, the control at the time of straight running shown in the comparative example of FIG. 12), and then the first By monitoring the torque difference between the motor and the second motor, when the torque difference exceeds the permissible value, it is possible to respond more quickly than the control that operates the normal inverter circuit to reduce the torque difference. Become.

Further, in the output characteristic diagram (FIGS. 8A to 11E) in which the left motor 7, the left wheel 3, the right wheel 5, and the right motor 9 are arranged in order on the horizontal axis and the torque of each element is shown on the vertical axis, the left motor 7 is arranged. When the motor torque TLm of the right motor 9 and the motor torque TRm of the right motor 9 are output, the relationship between the left wheel torque TL transmitted to the left wheel 3 and the right wheel torque TR transmitted to the right wheel 5 is a co-wire located on the same straight line. Have a relationship. Therefore, as will be described in the control flowchart described later, the failure control unit 51 can easily and quickly calculate and adjust the motor torque of the normal side motor using this collinear relationship. It becomes possible to adjust the motor torque of.

Next, the control flowchart of the failure control unit 51 will be described with reference to FIGS. 3 to 7. FIG. 3 is an overall flowchart, FIG. 4 is a flowchart of a straight-ahead control subroutine in a driving state, FIG. 5 is a flowchart of a turning control subroutine in a driving state, and FIG. 6 is a regenerative state. It is a flowchart of the subroutine of straight-ahead control in the above, and FIG. 7 is a flowchart of a subroutine of turn-around control in a regenerative state.

First, in FIG. 3, in step S1, various sensor information such as an accelerator opening sensor 31, a vehicle speed sensor 33, a steering angle sensor 35, and a torque sensor (not shown) of each motor are acquired. In step S2, it is determined whether the traveling state is the driving state of the vehicle 1 (when the accelerator is ON) or the regenerative state (when the accelerator is OFF when the accelerator is regenerated) based on the information.

When the drive state is determined in step S2, it is further determined in step S3 whether the vehicle is traveling straight or turning based on various sensor information. If it is determined that the vehicle is in a straight-ahead state, the subroutine control of the drive straight-ahead control in step S4 is executed, and if it is determined that the vehicle is in a turning state, the subroutine control of the drive-turning control in step S5 is executed.

On the other hand, when the regenerative state is determined in step S2, it is further determined in step S6 whether the vehicle is traveling straight or turning based on various sensor information. If it is determined to be in the straight-ahead state, the subroutine control for the regenerative straight-ahead control in step S7 is executed, and if it is determined to be in the turning state, the subroutine control for the regenerative turning-time control in step S8 is executed.

As described above, the traveling state determination unit 45 determines whether the vehicle (electric vehicle) 1 is traveling straight or turning, and whether it is in the driving state or the regenerative state. Control, drive turning control, regenerative straight-ahead control, and regenerative turning control are executed by subroutine control, so the motor torque of the normal motor when a malfunction of one of the motors is detected can be adjusted quickly and reliably. Is executed.

(Driving straight-ahead control), the driving straight-ahead control shown in the flowchart of FIG. 4 will be described. When it starts, it is determined in step S11 whether the one-sided motor has failed. If the one-sided motor has not failed, NO is determined and the process proceeds to step S12 to perform normal control. This normal control is a case where the left and right motors 7 and 9 are normal, and the vehicle 1 is driven straight in response to the driver's request for driving operation. FIG. 8A shows an output characteristic diagram showing the collinear relationship of the drive torque in each element of the left motor 7, the left wheel 3, the right wheel 5, and the right motor 9 when the left and right motors 7 and 9 are normal in the straight running state.

If the one-sided motor has a failure, it is determined to be Yes in step S11, and the process proceeds to step S13. In step S13, the drag torque (minus torque) generated by the failed motor is calculated. Since this drag torque differs depending on the motor rotation speed at the time of the failure and the battery voltage applied to the motor, it is calculated based on the state at the time of the failure. FIG. 8B shows the collinear relationship of the drive torques in each element of the left motor 7, the left wheel 3, the right wheel 5, and the right motor 9 when the right motor 9 fails in the straight running state, and shows the collapsed right motor. 9 indicates the state of the drag torque.

In the next step S14, the torque of the normal side motor (left motor 7) is calculated so that the drive torque of the wheel on the collapsed side (right wheel 5) becomes zero. That is, as shown in the output characteristic diagram of FIG. 8C, the drive torque of the left motor 7 which is the normal side motor is set so that the drive torque of the right wheel 5 of the wheel on the collapsed side becomes zero (black circle portion of part A in FIG. 8C). Lower. The amount to be lowered and the drive torque of the left motor 7 after being lowered can be calculated based on the collinear relationship.

In the next step S15, it is determined whether or not there is a problem in straight running based on the drive torque of the normal side motor (left motor 7) calculated in step S14. That is, as shown in FIG. 8C, even if the drive torque of the left motor 7 is reduced so that the drive torque of the right wheel 5 becomes zero, the torque difference between the left wheel 3 and the right wheel 5 maintains the straight running stability. It is determined whether or not the vehicle can be lowered to a preset allowable value or less. If it can be lowered to the allowable value or less, it is determined that there is no problem and the process proceeds to step S16. In step S16, the drive torque value of the normal side motor (left motor 7) calculated in step S14 is set to the normal side motor (left). It is output to the motor 7) as the left motor indicated torque 53.

On the other hand, if it is determined in step S15 that the drive torque of the normal side motor (left motor 7) calculated in step S14 has a problem in running while maintaining straight-line stability, the process proceeds to step S17. In step S17, the drive torque value of the normal side motor (left motor 7) is calculated so as to be within a range that does not cause a problem in straight running. That is, as shown in FIG. 8D, the normal side motor (the normal side motor) so that the torque difference between the left wheel 3 and the right wheel 5 is equal to or less than the allowable value set in advance by tests and calculations so that the vehicle can travel while maintaining straight-line stability. The drive torque of the left motor 7) is further reduced (black circle in part B of FIG. 8D).

When the drive torque of the normal side motor (left motor 7) is further reduced, the right wheel 5 is lowered to the torque on the minor side, so that the torque difference between the left wheel 3 and the right wheel 5 can be reduced to an allowable value or less. Then, in step S18, the drive torque value of the normal side motor (left motor 7) calculated in step S17 is output to the normal side motor (left motor 7) as the left motor instruction torque 53.

According to the drive straight-ahead control shown in the flowchart of FIG. 4, the drive torque of the normal side motor (left motor 7) is reduced (adjusted) as in step S14, and the right wheel 5 on one side of the left and right wheels 5 Since the drive torque of the right wheel 5 is controlled to be zero, it is possible to suppress an increase in the drag resistance of the right wheel 5 and maintain straight running. For example, when the vehicle 1 is a four-wheel drive vehicle and the power control device of the present embodiment is provided on the rear wheel side, the increase in the drag resistance of the right wheel 5 can be suppressed, thereby driving the front wheel side. It is possible to suppress the increase in power work. Further, when the vehicle 1 is a two-wheel drive vehicle, the difference in drive torque between the left wheel 3 and the right wheel 5 when the one-sided motor fails can be reduced, and the vehicle can be stably decelerated to maintain straight running.

Further, even if the drive torque of the normal side motor (left motor 7) is reduced (adjusted) and controlled so that the drive torque of the right wheel 5 becomes zero as in steps S15 and S17, the left wheel 3 and the right If the drive torque difference from the wheel 5 is not smaller than the allowable value that can maintain straight-line stability, the drive torque of the normal side motor (left motor 7) is further reduced to reduce the drive torque of the right wheel 5 to the negative torque region. By reducing the torque to, the difference in drive torque between the left and right wheels 3 and 5 can be controlled to be smaller than the allowable value for straight-line stability, and the stability in the straight-line state can be maintained even after the failure of one of the motors. ..

(Drive turn control), drive turn control shown in the flowchart of FIG. 5 will be described. When it starts, it is determined in step S21 whether the one-sided motor has failed. If no failure has occurred in the one-sided motor, NO is determined and the process proceeds to step S22 to perform normal control. This normal control is a case where the left and right motors 7 and 9 are normal, and controls are performed to stabilize the posture of the vehicle 1 in the turning direction in response to the driver's request for driving operation. FIG. 9A shows an output characteristic diagram showing the collinear relationship of the drive torque in each element of the left motor 7, the left wheel 3, the right wheel 5, and the right motor 9 when the right turn is normal.

If the one-sided motor has failed in step S21, it is determined to be Yes and the process proceeds to step S23. In step S23, the defective motor is determined. That is, it is determined whether the defective motor is a motor mainly responsible for driving the wheels on the outer side of the turn or a motor mainly responsible for driving the wheels on the inner side of the turn. If the motor mainly in charge of driving the wheels on the inner side of the turn fails, the process proceeds to step S24, and if the motor mainly in charge of the wheels on the outer side of the turn fails, the process proceeds to step S27.

In step S24, the drag torque (minus torque) generated by the failed motor is calculated. As already described in step S13 in the case of going straight, the drag torque differs depending on the motor rotation speed at the time of the failure and the battery voltage applied to the motor, so that the drag torque is based on the state at the time of the failure. It is calculated.

FIG. 9B shows the collinear drive torque in each element of the left motor 7, the left wheel 3, the right wheel 5, and the right motor 9 when the right motor 9 in charge of the right wheel 5 inside the turn fails during a right turn. The relationship is shown, and a state in which a drag torque is generated in the failed right motor 9 is shown.

In the next step S25, the drive torque of the normal side motor (left motor 7) for generating the required turning moment is calculated with respect to the drag torque generated by the collapsed side motor (right motor 9).

That is, as shown in FIG. 9C, the left motor 7 is driven so as to maintain the same inclination as the inclination of the collinear line K1 in the normal state shown in FIG. 9A with respect to the drag torque generated by the failed right motor 9. Reduce the torque. That is, the amount of decrease in the drive torque of the left motor 7 is the amount by which the drive torque of the failed right motor 9 is reduced. The amount to be lowered and the drive torque of the left motor 7 after being lowered can be calculated based on the collinear relationship.

The control of lowering the drive torque of the left motor 7 so as to maintain the same inclination as the inclination of the collinear line K1 in the normal state is an example, and is based on the detection value of the yaw rate sensor in the normal state by using another yaw rate sensor. The turning moment may be maintained or feedback control may be performed so as to stabilize the vehicle behavior so as to reduce the drive torque of the left motor 7.

In the next step S26, the torque value of the normal side motor (left motor 7) calculated in step S25 is output to the normal side motor (left motor 7) as the left motor instruction torque 53.

On the other hand, if it is determined in step S23 that the motor having the defect is the motor mainly in charge of the wheels on the outer side of the turn, the process proceeds to step S27, and in step S27, the motor rotation when the motor fails as in step S24. The drag torque generated by the failed motor is calculated based on the number and the state of the battery voltage applied to the motor. In the output characteristic diagram of FIG. 9D, the drive torque in each element of the left motor 7, the left wheel 3, the right wheel 5, and the right motor 9 when the left motor 7 in charge of the left wheel 3 on the outer side of the turn fails during a right turn. Shows the collinear relationship of. The state in which the drag torque is generated in the left motor 7 that has fallen is shown.

In the next step S28, the drive torque of the normal side motor (right motor 9) for generating the required turning moment is calculated with respect to the drag torque generated by the collapsed side motor (left motor 7).

That is, as shown in FIG. 9E, the right motor 9 is driven so as to maintain the same inclination as the inclination of the collinear line K1 in the normal state shown in FIG. 9A with respect to the drag torque generated by the failed left motor 7. Reduce the torque. That is, the amount of decrease in the drive torque of the right motor 9 is the amount by which the drive torque of the left motor 7 that has failed is reduced. The amount to be lowered and the drive torque of the right motor 9 after being lowered can be calculated based on the collinear relationship.

The control of lowering the drive torque of the left motor 7 so as to maintain the same inclination as the inclination of the collinear line K1 in the normal state is an example, and is based on the detection value of the yaw rate sensor in the normal state by using another yaw rate sensor. The turning moment may be maintained or feedback control may be performed so as to stabilize the vehicle behavior so as to reduce the drive torque of the left motor 7.

In the next step S29, it is determined whether the torque value calculated in step S28 exceeds the limit of the normal side motor (right motor 9). That is, as shown in FIG. 9E, since the torque value of the right motor 9 on the normal side is a negative torque, it is determined whether or not the limit value for generating a large negative torque, that is, the limit value of the regenerative power generation capacity is exceeded. Since the limit value of the regenerative capacity is changed depending on the state of charge of the battery, the limit value of step S29 is changed depending on the state of charge of the battery. In this way, the limit values of the motor capacity and the battery capacity are not exceeded.

If it is determined in step S29 that the torque is within the limit, the process proceeds to step S30, and in step S30, the torque value calculated in step S28 is output to the normal side motor (right motor 9) as the right motor instruction torque 55. do.

If it is determined in step S29 that the limit value is exceeded, the process proceeds to step S31, and in step S31, the torque limit value is output to the normal side motor (right motor 9) as the right motor indicated torque 55.

According to the drive turning control shown in the flowchart of FIG. 5, the drive torque of the normal side motor is reduced (adjusted) as in steps S24 to S31, and the difference in wheel torque between the left and right wheels 3 and 5 is one side. Since the control is performed so as to maintain the turning moment of the vehicle 1 before the failure of the motor, the stability of the turning state can be maintained even after the failure of one of the motors.

When the fallen side motor is the right motor 9 mainly responsible for driving the wheels on the inner side of the turn as in steps S24 to S26, the drive torque of the normal side motor (left motor 7) is applied to the fallen side motor (the fallen side motor (2). The right motor 9) is reduced within a range on the positive side of the drag torque generated (within the range M of the region M in FIG. 9C), and is controlled so that the turning moment is maintained.

That is, if the drive torque of the normal side motor (left motor 7) is lowered to the negative side from the drag torque generated by the failure side motor (right motor 9) (from the range of the region M in FIG. 9C to the negative side). (If it is lowered), a moment in the opposite direction is generated and an appropriate turning moment cannot be obtained. Therefore, it is controlled so that an appropriate turning moment can be obtained by preventing the occurrence of such a problem.

Further, when the fallen side motor is the left motor 7 mainly responsible for driving the left wheel on the outer side of the turn as in steps S27 to S31, the drive torque of the normal side motor (right motor 9) is lost. The drag torque generated by the motor (left motor 7) is further reduced to the negative side (up to the range N of the region N in FIG. 9E), and the turning moment is controlled to be maintained.

That is, if the motor torque of the normal side motor (right motor 9) is on the positive side of the drag torque generated by the fallen side motor (left motor 7) (if it is on the positive side of the range N of the region N in FIG. 9E), Since a moment in the opposite direction is generated and an appropriate turning moment cannot be obtained, the control is performed so that an appropriate turning moment can be obtained by preventing the occurrence of such a problem.

It should be noted that in the straight-ahead control and the turning control in the drive state described in the flowcharts of FIGS. 4 and 5 above, reducing the drive torque of the normal side motor is shown in the output characteristic diagrams of FIGS. 8A to 9E. In addition, it has substantially the same meaning as increasing the regenerative torque of the normal side motor. Therefore, the control for reducing the drive torque of the normal side motor is also the control for increasing the regenerative torque of the normal side motor.

(Regenerative straight-ahead control) Next, the regenerative straight-ahead control shown in the flowchart of FIG. 6 will be described. When it starts, it is determined in step S41 whether the one-sided motor has failed. If no failure has occurred in the one-sided motor, NO is determined and the process proceeds to step S42 to perform normal control. This normal control is a case where the left and right motors 7 and 9 are normal, and the vehicle 1 is driven straight in response to the driver's request for driving operation. FIG. 10A shows an output characteristic diagram showing the collinear relationship of the regenerative torque in each element of the left motor 7, the left wheel 3, the right wheel 5, and the right motor 9 when the left and right motors 7 and 9 are normal in the straight running state.

If the one-sided motor has a failure, it is determined to be Yes in step S41, and the process proceeds to step S43. In step S43, the drag torque (minus torque) generated by the failed motor is calculated. Since this drag torque differs depending on the motor rotation speed at the time of the failure and the battery voltage applied to the motor, it is calculated based on the state at the time of the failure.

FIG. 10B shows the collinear relationship of the regenerative torque in each element of the left motor 7, the left wheel 3, the right wheel 5, and the right motor 9 when the right motor 9 fails in the straight running state, and the failed right motor. 9 indicates the state of the drag torque.

In the next step S44, a regenerative torque (regenerative torque equivalent to the drag torque) that is commensurate with the drag torque of the collapsed side motor (right motor) 9 is calculated. Then, in the next step S45, the calculated regenerative torque value is instructed to the normal side motor (left motor) 7, and the regenerative torque of the left motor 7 is reduced to the drag torque of the right motor 9.

FIG. 10C shows a state in which the regenerative torque of the left motor 7 is reduced to a regenerative torque that is commensurate with the drag torque of the right motor 9. The amount to be lowered and the drive torque of the left motor 7 after being lowered can be calculated based on the collinear relationship.

According to the regenerative straight-ahead control shown in the flowchart of FIG. 6 above, the regenerative torque of the normal left motor 7 is reduced (adjusted) to the drag torque generated by the failed right motor 9, and the left wheel 3 and the right wheel 5 are used. Since the difference in wheel torque is controlled so as to maintain the straight running stability, the stability in the straight running state can be maintained even in the regenerative state and even after the failure of one of the motors.

(Regenerative turning control) Next, the regenerative turning control shown in the flowchart of FIG. 7 will be described. When it starts, it is determined in step S51 whether the one-sided motor has failed. If no failure has occurred in the one-sided motor, NO is determined and the process proceeds to step S52 to perform normal control. This normal control is a case where the left and right motors 7 and 9 are normal, and controls are performed to stabilize the posture of the vehicle 1 in the turning direction in response to the driver's request for driving operation.

FIG. 11A shows an output characteristic diagram showing the collinear relationship of the regenerative torque in each element of the left motor 7, the left wheel 3, the right wheel 5, and the right motor 9 when the right turn is normal.

If the one-sided motor has failed in step S51, it is determined to be Yes and the process proceeds to step S53. In step S53, the defective motor is determined. That is, it is determined whether the defective motor is a motor mainly responsible for driving the wheels on the outer side of the turn or a motor mainly responsible for driving the wheels on the inner side of the turn. If the motor mainly in charge of driving the wheels on the inner side of the turn fails, the process proceeds to step S54, and if the motor mainly in charge of the wheels on the outer side of the turn fails, the process proceeds to step S58.

In step S54, the drag torque (minus torque) generated by the failed motor is calculated. As already described in step S43 in the case of regenerative straight travel, the drag torque differs depending on the motor rotation speed at the time of the failure and the battery voltage applied to the motor, and thus is based on the state at the time of the failure. Is calculated to.

FIG. 11B shows the collinear torque of the regenerative torque in each element of the left motor 7, the left wheel 3, the right wheel 5, and the right motor 9 when the right motor 9 in charge of the right wheel 5 inside the turn fails during a right turn. The relationship is shown, and a state in which a drag torque is generated in the failed right motor 9 is shown.

In the next step S55, a negative torque that is balanced with the drag torque generated by the collapsed side motor (right motor 9), that is, equivalent to the drag torque, is calculated as the regenerative torque value of the normal side motor (left motor 7). do. Then, in the next step S56, the calculated regenerative torque value is instructed to the left motor 7. Further, in step S57, the torque value is gradually reduced to the indicated torque value.

As shown in FIG. 11C, the regenerative torque of the normal left motor 7 is reduced until the regenerative torque is commensurate with the drag torque generated by the failed right motor 9, so that the vehicle behavior becomes unstable. It can be suppressed. Further, at the time of this decrease, the vehicle behavior can be moderately stabilized because the decrease is not abrupt such as shutdown but a gradual decrease.

In FIG. 11C, if the torque of the left motor 7 is brought to the positive side so as to maintain the same inclination as the inclination of the collinear line K2 at the normal time, the left motor 7 will be in the drive (acceleration) state. Therefore, it is not suitable for controlling the regenerative state.

On the other hand, if it is determined in step S53 that the motor having the defect is the motor mainly in charge of the wheels on the outer side of the turn, the process proceeds to step S58, and in step S58, the motor rotation when the motor fails as in step S54. The drag torque generated by the failed motor is calculated based on the number and the state of the battery voltage applied to the motor.

In the output characteristic diagram of FIG. 11D, the regenerative torque in each element of the left motor 7, the left wheel 3, the right wheel 5, and the right motor 9 when the left motor 7 in charge of the left wheel 3 on the outer side of the turn fails during a right turn. Shows the collinear relationship of. The state in which the drag torque is generated in the left motor 7 that has fallen is shown.

In the next step S59, the regenerative torque of the normal side motor (right motor 9) for generating the required turning moment is calculated with respect to the drag torque generated by the collapsed side motor (left motor 7).

That is, as shown in FIG. 11E, the regenerative torque is reduced in a range larger than the drag torque generated by the failed left motor 7 on the negative side (within the range R of the region R in FIG. 11E) to reduce the drag torque with respect to the drag torque. The slope equivalent to the slope of the collinear line K2 in the normal state shown in FIG. 11A is maintained. That is, the amount of reduction in the regenerative torque of the right motor 9 is the amount by which the regenerative torque of the left motor 7 that has failed is reduced. The amount to be lowered and the regenerative torque of the right motor 9 after being lowered can be calculated based on the collinear relationship.

It should be noted that the control of lowering the regenerative torque of the right motor 9 so as to maintain the same inclination as the inclination of the collinear line K2 in the normal state is an example, and the detection value of the yaw rate sensor in the normal state is obtained by using the yaw rate sensor as another example. Based on this, the turning moment may be maintained or feedback control may be performed so that the vehicle behavior is stable so as to reduce the regenerative torque of the right motor 9.

In the next step S60, the torque value of the normal side motor (left motor 7) calculated in step S59 is output as the left motor instruction torque 53.

According to the regenerative turning control shown in the flowchart of FIG. 7, when the fallen side motor is the right motor 9 mainly responsible for driving the wheels inside the turning as in steps S54 to S57, it is normal. If the torque of the left motor 7 on the side is increased to the positive side, the vehicle will be in an accelerated state, so the motor torque of the left motor 7 will be regenerated torque that balances the drag torque generated by the right motor 9 on the failed side. It is lowered (adjusted) to the extent that the vehicle behavior becomes unstable. Furthermore, since it is not a sudden decrease like shutdown but a gradual decrease, the vehicle behavior can be moderately stabilized.

Further, when the failure side motor is the left motor 7 mainly responsible for driving the left wheel on the outer side of the turn as in steps S58 to S60, the torque of the right motor 9 on the normal side is applied to the left side of the failure side. By lowering (adjusting) within a range larger than the drag torque generated by the motor 7 to the negative side, the turning moment is controlled to be maintained, so that the vehicle behavior becomes unstable in the regenerative state and the turning state. The turning state can be maintained stably without any problem.

That is, when the torque of the right motor 9 on the normal side is increased to the positive side from the drag torque generated by the left motor 7 on the failed side (when it is on the positive side from the range R of the region R in FIG. 17E), the moment in the opposite direction Is generated and an appropriate turning moment cannot be obtained. Therefore, it is controlled so that an appropriate turning moment can be obtained by preventing the occurrence of such a problem.

It should be noted that in the straight-ahead control and the turning control in the regenerative state described in the flowcharts of FIGS. 6 and 7 above, reducing the regeneration torque of the normal side motor is shown in the output characteristic diagrams of FIGS. 10A to 11E. In addition, it has substantially the same meaning as increasing the drive torque of the normal side motor. Therefore, the control for reducing the regeneration torque of the normal side motor is also the control for increasing the drive torque of the normal side motor.

The vehicle 1 of the embodiment described above may be a four-wheel drive vehicle including a front wheel side drive motor 62 that further drives the front wheel side, as in the vehicle 60 shown in FIG. 15, and the electric vehicle is a four-wheel drive vehicle. Even if it is a two-wheel drive vehicle, when it detects that one of the left motor 7 and the right motor 9 has lost its function, the motor torque of the normal side motor is adjusted to drive the vehicle. Since the torque difference between the left and right wheels 3 and 5 that can maintain the state is adjusted, the running state before the failure can be maintained, and the running state of the vehicle can be stably maintained.

According to at least one embodiment of the present invention, the output of the first motor and the output of the second motor are transmitted to the left and right wheels of the vehicle, respectively, and further provided with a power transmission path in which the transmission ratio to the left and right wheels can be adjusted. In an electric vehicle, when an abnormality occurs in one of the motors and a functional failure occurs, the motor torque of the normal side motor can be adjusted to stably maintain the running state before the failure. Suitable for use in power control devices for electric vehicles.

1,60 vehicles (electric vehicles)
3 Left wheel 5 Right wheel 7 Left motor (1st motor)
9 Right motor (second motor)
11 Turning moment control device 13 Left axle 15 Right axle 17 Differential mechanism 19 Power transmission path 25 Left inverter 27 Right inverter 29 Battery 30 Motor ECU (power control device)
31 Accelerator opening sensor 33 Vehicle speed sensor 35 Steering angle sensor 37 Left motor current sensor 39 Right motor current sensor 41 Left inverter abnormality detection means 43 Right inverter abnormality detection means 45 Driving state determination unit 47 Left motor failure detection unit (first motor) Failure detection unit)
49 Right motor failure detection unit (second motor failure detection unit)
51 Failure control unit

Claims (11)

The output of the first motor and the output of the second motor can be transmitted to the left and right wheels of the vehicle via a differential mechanism, respectively, and by controlling the outputs of the first motor and the second motor, the left and right wheels A swivel moment control device for controlling the swivel moment by adjusting the torque sharing ratio in the above is provided, and the magnitude of the rotational speed and torque in each element of the left and right wheels, the first motor, and the second motor is the magnitude. It is a power control device of an electric vehicle having a common line relationship located on a straight line on the characteristic diagram showing the above.
A traveling state determination unit that determines whether the electric vehicle is traveling straight or turning, and whether it is in a driving state or a regenerative state.
The first motor failure detection unit that detects the functional failure of the first motor, and
The second motor failure detection unit that detects the functional failure of the second motor, and
When the function failure of either motor is detected by the first motor failure detection unit and the second motor failure detection unit, the motor torque of the normal side motor is adjusted to determine the running state. The control unit at the time of failure that adjusts to the torque difference between the left and right wheels that can maintain the running state before the failure determined by
A power control device for an electric vehicle, characterized by being equipped with. When the traveling state determination unit determines that the driving state determination unit is in the driving state and the straight running state, the failure control unit reduces the drive torque of the normal side motor, and the failure side motor is mainly in charge of the left and right wheels. The power control device for an electric vehicle according to claim 1, wherein the wheel torque of the wheels is controlled to be zero. When the traveling state determination unit determines that the driving state determination unit is in the driving state and the straight running state, the failure control unit reduces the driving torque of the normal side motor, and the difference between the wheel torques of the left and right wheels maintains the straight running stability. The power control device for an electric vehicle according to claim 1, wherein the power control device is controlled so as to be smaller than a possible allowable value. When the traveling state determination unit determines that the driving state determination unit is in the driving state and the turning state, the failure control unit reduces the driving torque of the normal side motor, and the difference between the wheel torques of the left and right wheels determines the turning moment of the vehicle. The power control device for an electric vehicle according to claim 1, wherein the power control device is controlled so as to be maintained. When the fallen side motor is a motor mainly responsible for driving the wheels on the inner side of the turn, the drive torque of the normal side motor is within a range larger to the positive side than the drag torque generated by the fallen side motor. The power control device for an electric vehicle according to claim 4, wherein the reduction is performed and the turning moment is controlled so as to be maintained. When the fallen side motor is a motor mainly responsible for driving the wheels on the outer side of turning, the drive torque of the normal side motor is reduced to the negative side of the drag torque generated by the fallen side motor. The power control device for an electric vehicle according to claim 4, wherein the turning moment is controlled so as to be maintained. When the traveling state determination unit determines that the traveling state determination unit is in the regenerative state and the straight running state, the failure control unit reduces the regenerative torque of the normal side motor to the drag torque generated by the failure side motor, and reduces the regenerative torque of the left and right wheels. The power control device for an electric vehicle according to claim 1, wherein the difference in wheel torque is controlled so as to maintain straight-line stability. When the failure control unit determines that the traveling state determination unit is in the regenerative state and the turning state, the failure-side motor is a motor that is mainly in charge of driving the wheels inside the turning. The power control device for an electric vehicle according to claim 1, wherein the regenerative torque of the normal side motor is reduced to the drag torque generated by the fallen side motor. When the failure control unit determines that the traveling state determination unit is in the regenerative state and the turning state, the failure-side motor is a motor that is mainly in charge of driving the wheels on the outer side of the turning. The first aspect of claim 1, wherein the regenerative torque of the normal side motor is reduced and controlled so that the turning moment is maintained within a range larger than the drag torque generated by the fallen side motor on the negative side. Power control device for electric vehicles. One of claims 1 to 9, wherein the electric vehicle is a four-wheel drive vehicle including the turning moment control device provided on the rear wheel side and a front wheel side drive motor for further driving the front wheel side. The power control device for an electric vehicle according to item 1. In the co-wire relationship, the first motor, the left wheel, the right wheel, and the second motor are arranged in order on the horizontal axis at intervals of the gear ratios of the gears constituting each element, and the vertical axis represents the magnitude of rotational speed or torque. It is a relationship that is located on a straight line on the characteristic diagram showing the above, and is characterized in that the failure control unit calculates and adjusts the motor torque of the normal side motor using the co-wire relationship. The power control device for an electric vehicle according to claim 1.

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