Electric vehicle

Abstract

This electric vehicle equipped with an electric motor (2) for driving left and right wheels and a brake (9) for applying braking force to the left and right wheels comprises: a higher-level control device (10) for calculating a required torque (Tr) of the electric vehicle; an electric motor control device (11) for receiving the required torque (Tr) calculated by the higher-level control device (10) to control the electric motor (2) and performing a traction control for reducing the torque (Ti) of the electric motor (2) on the basis of the rotational acceleration (R) of the electric motor (2); and a brake control device (12) which, when detecting the slip of one of the left and right wheels, performs a slip suppression control for applying a braking force (F1) to one of the wheels by operating the brake (9). When receiving, from the brake control device (12), a signal indicating performing of the slip suppression control or non-performance after the performing of the slip suppression control, the electric motor control device (11) adjusts a torque amount (ΔT) that is reduced by the traction control in accordance with the received signal.

Description

Technical Field

[0001] The present invention relates to an electric vehicle that performs traction control to suppress slip when slip of left and right wheels is detected.

Background Art

[0002] Conventionally, in a vehicle that drives the left and right wheels with electric motors (electric motors, motors) and travels, when slip of the left and right wheels is detected, traction control for limiting the torque output from the electric motor so that the slip is suppressed, and traction control for applying a braking force to the slipping wheel are known to be performed.

[0003] For example, Patent Document 1 discloses performing traction control for limiting the torque output from the motor at a predetermined rate and brake traction control for outputting a braking force (brake torque) to the slipping wheel when slip of the drive wheel occurs. In Patent Document 1, the former traction control is performed by the main electronic control unit, and the latter brake traction control is performed by the electronic control unit for brakes. In the vehicle of Patent Document 1, when it is determined that there is an intervention of the latter brake traction control during the execution of the former traction control, the torque output from the motor is limited at a rate having a gradient smaller than the above-mentioned predetermined rate. Thereby, it is said that interference between the two types of traction control can be suppressed and the driving feeling when suppressing the generated slip can be made good.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] By the way, in recent years, a technology has been proposed in which a predetermined program is incorporated into a control device (MCU; Motor Control Unit) for controlling a motor. This MCU is provided separately from an electronic control unit (ECU; Electronic Control Unit) that integrally controls various devices mounted on a vehicle. By incorporating the above-described traction control program into the MCU, it becomes possible to control the vehicle by taking advantage of the high responsiveness of the motor. On the other hand, in such a vehicle, if the traction control implemented by the MCU and the traction control for applying the above-described braking force are individually implemented, the two types of control may interfere with each other, leading to a decrease in controllability and fluctuations in driving force.

[0006] The electric vehicle of the present case has been devised in view of such problems, and one of its purposes is to appropriately suppress slip while taking advantage of the high responsiveness of the motor (electric motor). Note that this is not the only purpose, and another purpose of the present case is to achieve an operational effect that is not obtained by the conventional technology and is derived from each configuration shown in the form for implementing the invention described later.

Means for Solving the Problems

[0007] (1) The electric vehicle of the vehicle disclosed herein is an electric vehicle including an electric motor that drives left and right wheels and a brake that applies a braking force to the left and right wheels, and includes a higher-level control device that calculates a required torque of the electric vehicle, and receives the required torque calculated by the higher-level control device to control the electric motor, and an electric motor control device that performs traction control to reduce the torque of the electric motor based on the rotational acceleration of the electric motor, and a brake control device that, when detecting slip of one of the left and right wheels, operates the brake to apply a braking force to the one wheel to perform slip suppression control. A battery management device that acquires the battery voltage of a battery that exchanges power with the electric motor The electric motor control device adjusts the amount of torque to be reduced by the traction control according to the received signal when receiving a signal indicating the implementation or non-implementation of the slip suppression control after the implementation from the brake control device. When the battery voltage received from the battery management device without going through the upper control device exceeds a predetermined upper limit voltage, the electric motor control device suppresses the amount of torque reduced by the traction control and calculates a supplementary braking force that compensates for the amount by which the amount of torque reduced by the traction control is suppressed, and transmits the calculated supplementary braking force to the brake control device. When the brake control device receives the supplementary braking force from the electric motor control device, the brake control device performs battery protection control in which the brake is operated to apply the supplementary braking force to both of the left and right wheels.

[0008] (2) Preferably, the braking control device determines whether or not to perform the slip suppression control based on the rotational speeds of the left and right wheels, and transmits the braking force applied to the one wheel together with the signal to the electric motor control device. In this case, the electric motor control device preferably corrects the torque amount based on the braking force received from the braking control device.

[0009] (3) Preferably, the electric motor control device calculates a corrected braking force to be applied to the one wheel based on the corrected torque amount and transmits it to the braking control device. In this case, the braking control device preferably applies the corrected braking force received from the electric motor control device to the one wheel.

[0011] ( 4 ) When the braking control device performs both the slip suppression control and the battery protection control, the electric motor control device preferably corrects the torque amount based on the braking force applied to the one wheel by the slip suppression control and the braking forces applied to both the left and right wheels by the battery protection control.

Advantages of the Invention

[0012] According to the disclosed vehicle, it is possible to appropriately suppress slip while taking advantage of the high responsiveness of the motor (electric motor).

Brief Description of the Drawings

[0013]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

[0014] An electric vehicle as an embodiment will be described with reference to the drawings. The embodiment described below is merely an example, and is not intended to exclude various modifications or application of techniques not specified in the following embodiment. Each configuration of the present embodiment can be modified in various ways without departing from the spirit of the embodiment. In addition, the configurations can be selected as necessary, or can be combined appropriately.

[0015] [1. Configuration] 1 is a schematic diagram showing the front of an electric vehicle 1 (hereinafter referred to as "vehicle 1") according to this embodiment. Vehicle 1 is equipped with an electric motor 2 (electric motor) that drives left and right wheels 6, and a brake 9 (brake) that brakes the left and right wheels 6. Vehicle 1 according to this embodiment further includes an engine 3 and a generator 4, and is capable of external charging. In other words, vehicle 1 is a plug-in hybrid vehicle (hybrid vehicle) that includes the electric motor 2 and the engine 3 as drive sources.

[0016] The electric motor 2 is an electric motor / generator that has both a function of driving the left and right wheels 6 with power from the battery 7 or power generated by the generator 4, and a function of charging the battery 7 with regenerative power generated by utilizing the inertial rotation of the left and right wheels 6. The battery 7 is, for example, a lithium-ion secondary battery or a nickel-metal hydride secondary battery, and is a secondary battery that can supply a high-voltage direct current of several hundred volts.

[0017] The engine 3 is an internal combustion engine such as a gasoline engine or a diesel engine, and drives the rotating shafts of the left and right wheels 6 by burning a mixture of fuel and air in the combustion chamber. The engine 3 can output a driving force for generating electricity in the generator 4 and a driving force for running the vehicle 1.

[0018] The generator 4 is a generator that generates electricity using the driving force of the engine 3. The three components of the electric motor 2, the engine 3, and the generator 4 are connected via a transaxle 5. Inside the transaxle 5, for example, a transmission gear, a clutch device, etc. are incorporated.

[0019] The electric motor 2, the engine 3, and the generator 4 are used selectively or in combination according to the driving state of the vehicle 1. For example, at the start or during low-speed driving, only the electric motor 2 with a large torque in the low rotation range is used (EV mode). On the other hand, when the charge rate of the battery 7 decreases or during accelerating driving, while running with the driving force of the electric motor 2 (motor torque), power generation by the generator 4 with the driving force of the engine 3 is carried out (series mode). Also, during high-speed driving with good engine efficiency, the driving force of the engine 3 is mainly used, and the driving force of the electric motor 2 is used assistively (parallel mode, ENG mode). These modes are appropriately selected and implemented by the upper control device 10 described later.

[0020] The brake 9 is, for example, a hydraulic disc brake that brakes the left and right wheels 6 based on the operation amount BP of the brake pedal described later. Note that the brake 9 is not limited to this as long as it is a device capable of braking the left and right wheels 6, and it may be an electric brake. The brake 9 is configured to be able to apply different magnitudes of braking forces (brake torques) to the left wheel 6L on the left side of the vehicle and the right wheel 6R on the right side of the vehicle.

[0021] In the vehicle 1, a plurality of ControlA device is provided. Specifically, as shown in FIG. 2, in the vehicle 1, there are provided a host control device 10 (Electronic Control Unit, hereinafter also referred to as "ECU10") for integrally controlling various in-vehicle devices, a motor control device 11 (Motor Control Unit, hereinafter also referred to as "MCU11") for controlling the motor 2, a hydraulic unit 12 (Hydraulic Unit, brake control device, hereinafter also referred to as "H / U12") for controlling the brake 9, and a battery management device 13 (Battery Management Unit, hereinafter also referred to as "BMU13") for managing the state of the battery 7.

[0022] Each of the control devices 10 to 13 is an electronic control device (computer) incorporating a processor (central processing unit), a memory (main memory), a storage device (storage), an interface, etc. The content of the control implemented by each of the control devices 10 to 13 is recorded and stored in the memory as firmware or an application program, and when the program is executed, the content of the program is expanded in the memory space and executed by the processor.

[0023] In addition to the engine 3 and the generator 4, an accelerator opening sensor 21, a brake sensor 22, etc. are connected to the ECU10. The accelerator opening sensor 21 detects an accelerator opening AP corresponding to the depression amount of the accelerator pedal. The brake sensor 22 detects an operation amount BP of the brake pedal. In addition to the motor 2, a resolver 23 is connected to the MCU11. The resolver 23 detects the rotational speed of the output shaft 2s of the motor 2 (see FIG. 1) (hereinafter referred to as "motor rotational speed Nm"). Note that instead of the resolver 23, the motor rotational speed Nm may be detected by a hall sensor or an encoder. Further, the MCU11 may include an inverter (not shown) for converting direct current and alternating current, or the MCU11 and the inverter may be provided separately.

[0024] In addition to the brake 9, a left wheel speed sensor 24L attached to the left wheel 6L and a right wheel speed sensor 24R attached to the right wheel 6R are connected to the H / U12. The left wheel speed sensor 24L detects the rotational speed of the left wheel 6L (hereinafter referred to as "left wheel rotational speed Nwl"). The right wheel speed sensor 24R detects the rotational speed of the right wheel 6R (hereinafter referred to as "right wheel rotational speed Nwr"). A hydraulic pressure sensor 25 for detecting the hydraulic pressure of the brake 9 may be connected to the H / U12. A voltage sensor 26 for detecting the battery voltage V of the battery 7 is connected to the BMU13.

[0025] Each of the control devices 10 to 13 is connected to be communicable with each other via a CAN (Controller Area Network) bus 14. Further, the MCU11 and the H / U12 are connected to be communicable with each other via a first bus 15. The MCU11 and the BMU13 are connected so that the MCU11 can receive information transmitted from the BMU13 via a second bus 16.

[0026] Note that the first bus 15 and the second bus 16 may be included in the above-mentioned CAN bus 14, or may be configured as a communication network independent of the CAN bus 14. Also, a plurality of CAN buses may be used for connecting the control devices 10 to 13. For example, a CAN bus for connecting the ECU10 and a control device of the drive system (for example, the MCU11), and a CAN bus for connecting the ECU10 and a control device of the braking system (for example, the H / U12) may be provided respectively.

[0027] [2. Control Configuration] Hereinafter, the control configuration implemented by each of the control devices 10 to 13 will be described. The ECU10 integrally controls various devices based on information received from the control devices 11 to 13 and information obtained from the engine 3, the generator 4, and the sensors 21, 22 connected to the ECU10. For example, based on the above information, the ECU10 sets a mode according to the driving state of the vehicle 1, and controls the electric motor 2, the engine 3, and the generator 4 to realize driving in the set mode.

[0028] Taking the case where ECU10 selects the series mode as an example for detailed description, when ECU10 selects the series mode, ECU10 calculates the required torque Tr to be output by the motor 2 based on the driving state of the vehicle 1, and indirectly controls the motor 2 by transmitting the calculated required torque Tr to the MCU11 via the CAN bus 14. Further, ECU10 receives from the MCU11 the torque instruction value Ti (described later) that the MCU11 instructs the motor 2 via the CAN bus 14, and controls the engine 3 and the generator 4 so that the generated power P corresponding to the received torque instruction value Ti is output.

[0029] Also, ECU10 calculates the required braking torque to be applied to the left and right wheels 6 based on the operation amount BP of the brake pedal and other information, and indirectly controls the brake 9 by transmitting the calculated required braking torque to the H / U12 via the CAN bus 14. Note that the calculation methods of the required torque Tr and the required braking torque are not particularly limited. For example, they are calculated based on information such as the accelerator opening AP, vehicle speed (left and right wheel rotation speeds Nwl, Nwr and vehicle body speed), operation amount BP of the brake pedal, steering angle, battery voltage V, and the like.

[0030] The MCU11 receives the required torque Tr calculated by the ECU10 and controls the motor 2 to output the received required torque Tr. Specifically, the MCU11 calculates a torque instruction value Ti based on the required torque Tr, and controls the motor 2 by instructing this to the motor 2 (or the inverter if the inverter is separately provided from the MCU11). The MCU11 transmits the information it manages, calculates, and acquires (for example, the torque instruction value Ti, the motor rotation speed Nm detected by the resolver 23, the motor temperature and the inverter temperature, etc.) to the ECU10 via the CAN bus 14.

[0031] Also, when the MCU11 detects (judges) that at least one of the left and right wheels 6 is slipping, it performs traction control to reduce the torque output from the electric motor 2 to a value lower than the required torque Tr. Whether the left and right wheels 6 are slipping is determined based on, for example, the rotational acceleration R which is the change rate of the motor rotational speed Nm. Specifically, the MCU11 calculates the rotational acceleration R based on the motor rotational speed Nm detected by the resolver 23, and when the calculated rotational acceleration R is equal to or greater than a predetermined rotational acceleration R1, it determines that the left and right wheels 6 are slipping. The predetermined rotational acceleration R1 is preset, for example, as a value greater than the maximum value of the rotational acceleration R obtained when the vehicle 1 is traveling without the left and right wheels 6 spinning.

[0032] As the implementation of traction control, the MCU11 calculates the torque amount ΔT to be subtracted from the required torque Tr, calculates a value obtained by subtracting the torque amount ΔT from the required torque Tr as the torque instruction value Ti, and controls the electric motor 2 by sending the torque instruction value Ti to the inverter. Since the electric motor 2 outputs a motor torque corresponding to the torque instruction value Ti from the MCU11, the torque instruction value Ti can also be referred to as the motor torque.

[0033] During the implementation of traction control, when a predetermined end condition is satisfied, the MCU 11 terminates the traction control. The predetermined end conditions include that the slip has been eliminated, or the required torque Tr has changed (for example, the changed required torque Tr has become smaller than the torque command value Ti). Further, the predetermined end conditions may include that the torque reduction amount, that is, the torque amount ΔT has become equal to or less than a certain value. For example, when the calculated torque amount ΔT becomes a value lower than the accuracy of the control torque, in other words, a value that should be recognized as 0, the MCU 11 may determine that it is not a problem to terminate the traction control and may terminate the traction control. The MCU 11 may terminate the traction control when the state where the torque amount ΔT has become equal to or less than a certain value continues for a certain time or more. Further, the predetermined end conditions may include that the accelerator opening degree AP has become equal to or less than a predetermined value. The predetermined value is set to a value that can be determined, for example, that the driver has no clear intention (request) to start or accelerate. Further, the predetermined end conditions may include conditions based on parameters such as the motor rotation speed Nm, the rotational acceleration R, the vehicle speed (the left and right wheel rotation speeds Nwl, Nwr and the vehicle body speed), the motor torque, etc., and switch operations by the driver.

[0034] The H / U 12 receives the required braking torque calculated by the ECU 10 and controls the brake 9 so as to output the received required braking torque. Further, the H / U 12 transmits information (for example, the left wheel rotation speed Nwl, the right wheel rotation speed Nwr, the hydraulic pressure, etc.) that it manages, calculates, and acquires to the ECU 10 via the CAN bus 14.

[0035] Further, when the H / U 12 detects the slip of one of the left wheel 6L and the right wheel 6R (single-wheel slip), the H / U 12 performs slip suppression control for applying a braking force (hereinafter referred to as "first braking force F1") to the slipping wheel (left wheel 6L or right wheel 6R).

[0036] The necessity of slip suppression control is determined based on the left wheel rotation speed Nwl and the right wheel rotation speed Nwr. Specifically, when either one of the left wheel rotation speed Nwl and the right wheel rotation speed Nwr is extremely larger than the other, H / U12 detects (judges) single-wheel slip and performs slip suppression control. More specifically, when the left wheel rotation speed Nwl is extremely larger than the right wheel rotation speed Nwr, H / U12 judges that the left wheel 6L is slipping and controls the brake 9 to apply the first braking force F1 to the left wheel 6L. Conversely, when the right wheel rotation speed Nwr is extremely larger than the left wheel rotation speed Nwl, H / U12 judges that the right wheel 6R is slipping and controls the brake 9 to apply the first braking force F1 to the right wheel 6R.

[0037] When starting slip suppression control, H / U12 begins to transmit a first signal (a signal, for example, flag information) indicating the implementation of slip suppression control to the MCU11 via the first bus 15 and continues to transmit during the implementation of slip suppression control. In addition, the H / U12 of this embodiment transmits the braking force applied to one of the slipping wheels (the left wheel 6L or the right wheel 6R) to the MCU11 together with the first signal. Here, the braking force applied to one of the slipping wheels may be the first braking force F1 (the target value of the braking force set by H / U12 during the implementation of slip suppression control or the instruction value of the braking force actually sent to the brake 9), or when a hydraulic pressure sensor 25 is connected to H / U12, it may be the detected hydraulic pressure (that is, the measured value of the braking force actually applied to one of the wheels).

[0038] When a predetermined suppression control end condition is satisfied during the execution of the slip suppression control described above, H / U12 terminates the slip suppression control, stops transmitting the first signal, and discontinues the control. The predetermined suppression control end condition may include the elimination of single-wheel slip (for example, the rotational speeds Nwl and Nwr of one of the slipping wheels becoming equal to the rotational speeds Nwl and Nwr of the other wheel). Further, the predetermined suppression control end condition may include the traction control torque reduction amount, that is, the torque amount ΔT becoming equal to or less than a certain value, or the state where the torque amount ΔT is equal to or less than a certain value continuing for a certain period of time. In this case, H / U12 may be configured to receive the torque amount ΔT from MCU11. MCU11 may terminate the slip suppression control when the calculated first braking force F1 becomes a value lower than the accuracy of the control torque, in other words, a value that should be recognized as 0, or when this state has elapsed for a certain period or more. Additionally, the predetermined suppression control end condition may include the accelerator opening AP becoming equal to or less than a predetermined value. The predetermined value is set to a value that can be determined, for example, as a value indicating that the driver has no clear intention (request) to start or accelerate, similar to the traction control end condition. Further, conditions based on parameters such as the motor rotational speed Nm, rotational acceleration R, vehicle speed (left and right wheel rotational speeds Nwl, Nwr and vehicle body speed), motor torque, etc., or switch operations by the driver may be included.

[0039] Immediately after terminating the slip suppression control, H / U12 gradually reduces the first braking force F1 applied to the slipping wheel (left wheel 6L or right wheel 6R) to 0. Further, when terminating the slip suppression control, H / U12 starts transmitting a second signal (signal, for example, flag information) indicating the non-execution of the slip suppression control to MCU11 via the first bus 15. At this time, H / U12 may transmit the first braking force F1 that is gradually reduced to MCU11. Note that H / U12 continues transmitting the second signal until the traction control is terminated or until the slip suppression control is restarted.

[0040] The BMU13 is a unit that monitors the state of the battery 7 (such as the charge state and temperature state), acquires the battery voltage V detected by the voltage sensor 26, and transmits the acquired battery voltage V to the ECU10 via the CAN bus 14. Further, the BMU13 calculates the state of charge (hereinafter also referred to as "SOC") of the battery 7 from the battery voltage V, and transmits the calculated SOC to the ECU10 via the CAN bus 14. The BMU13 of the present embodiment also transmits the battery voltage V to the MCU11 via the second bus 16.

[0041] [3. Control Configuration Related to Traction Control] As described above, each of the traction control for suppressing the slip of the left and right wheels 6 and the slip suppression control for suppressing the single-wheel slip is implemented by the MCU11 and the H / U12, respectively. At this time, if the traction control and the slip suppression control are implemented independently, the two types of controls may interfere with each other, leading to a decrease in controllability and fluctuations in driving force. Therefore, in the vehicle 1 of the present embodiment, when both types of controls are implemented (overlapped), the MCU11 adjusts the control amount (torque amount ΔT) to be reduced by the traction control. Further, in the vehicle 1 of the present embodiment, even when the slip suppression control being implemented becomes non-implemented, the MCU11 adjusts the control amount to suppress a decrease in controllability and fluctuations in driving force.

[0042] Specifically described. When the MCU11 of the present embodiment receives the first signal from the H / U12 during the implementation of the traction control, it implements the first control to adjust so as to suppress the torque amount ΔT to be reduced by the traction control. That is, when the first control is implemented, the reduction amount of the motor torque becomes smaller compared to during the traction control when the first control is not implemented. The torque amount ΔT is suppressed, for example, by subtracting a predetermined amount (hereinafter referred to as "first predetermined amount X") from the torque amount (hereinafter referred to as "base torque amount ΔTb") calculated during the implementation of the traction control.

[0043] As a result, during the execution of the first control, the torque command value Ti (the value obtained by subtracting the torque amount ΔT from the required torque Tr) sent from the MCU 11 to the electric motor 2 increases by the amount by which the first predetermined amount X is reduced, compared to during traction control in which the first control is not executed (before the torque amount ΔT is suppressed). Therefore, excessive torque suppression of the left and right wheels 6 due to the overlap of traction control and slip suppression control is prevented. Note that the base torque amount ΔTb is a variable value calculated based on the degree of slip of the left and right wheels 6 (that is, the rotational acceleration R), and is calculated each time traction control starts.

[0044] Also, the MCU 11 of the present embodiment receives the first braking force F1 together with the first signal, and corrects the torque amount ΔT based on the first braking force F1. For example, the larger the first braking force F1, the smaller the MCU 11 makes the torque amount ΔT. That is, in the above example, the first predetermined amount X is a variable value set according to the first braking force F1, and is set to a larger value as the first braking force F1 increases. As a result, during the execution of the first control, the torque command value Ti sent from the MCU 11 to the electric motor 2 becomes larger as the first braking force F1 is larger, compared to during traction control in which the first control is not executed (before the torque amount ΔT is suppressed). Therefore, when the first braking force F1 is received, excessive torque suppression of the left and right wheels 6 is more reliably prevented.

[0045] Furthermore, when the MCU 11 receives a second signal indicating the end (non-execution) of slip suppression control from the H / U 12, the MCU 11 executes a second control to adjust to increase the torque amount ΔT suppressed by the first control. That is, when the slip suppression control by the H / U 12 changes from execution to non-execution, the MCU 11 executes a second control to adjust to restore the suppressed torque amount ΔT.

[0046] The MCU 11 increases the torque amount ΔT by adding a predetermined amount (hereinafter referred to as "second predetermined amount X'") to the torque amount ΔT ( = ΔTb - X) suppressed by the first control, for example. As a result, during the execution of the second control, the torque command value Ti (the value obtained by subtracting the torque amount ΔT from the required torque Tr) sent from the MCU 11 to the electric motor 2 decreases by the amount obtained by adding the second predetermined amount X' compared to during the execution of the first control (when the torque amount ΔT is suppressed).

[0047] Also, when implementing the second control, the MCU 11 of the present embodiment receives the first braking force F1 that is gradually reduced and corrects the torque amount ΔT based on the first braking force F1. For example, the MCU 11 increases the torque amount ΔT as the first braking force F1 gradually decreases. That is, in the above example, the second predetermined amount X' is a variable value set according to the first braking force F1 that is gradually reduced, and is set to a value close to the first predetermined amount X as the first braking force F1 gradually decreases. Thereby, after the end of the first control, the slip-up of the left and right wheels 6 due to the release of the first braking force F1 applied to one wheel is suppressed.

[0048] In the above description, for the sake of convenience of explanation, the contents of the first control and the second control have been described separately, but the first control and the second control are common in that the MCU 11 adjusts the control amount. Also, the first signal and the second signal are common in that they are signals indicating the execution or non-execution (execution state) of the slip suppression control. Therefore, these first control and second control may be regarded as one control, and the first signal and the second signal may be regarded as the same signal.

[0049] When the MCU 11 of the present embodiment further determines that the battery voltage V received from the BMU 13 exceeds a predetermined upper limit voltage Vmax during the execution of the traction control, it performs a third control to suppress the torque amount ΔT reduced by the traction control. The upper limit threshold Vmax is set in advance to a value equal to or slightly smaller than the allowable upper limit voltage of the battery 7, for example.

[0050] Here, the case where the battery voltage V exceeds the upper limit voltage Vmax will be described in detail. As described above, when the ECU 10 selects the series mode, it sets the generated power P according to the torque command value Ti (motor torque). For this reason, when traction control is started and the torque command value Ti is suppressed, the engine 3 and the generator 4 are controlled so that the generated power P decreases. However, since the response speed of the motor 2 is faster than that of the engine 3 and the generator 4, the motor torque output by the motor 2 decreases before the generated power P can be reduced. As a result, the power that was not consumed by the motor 2 moves from the motor 2 to the battery 7, causing the battery voltage V to rise and potentially exceed the upper limit voltage Vmax. The reason why the response speed of the motor 2 is faster includes, in addition to the communication lag caused by passing through the CAN bus 14, the fact that the engine 3 and the generator 4 are controlled via the ECU 10.

[0051] Therefore, when the battery voltage V exceeds the upper limit voltage Vmax, the MCU 11 of the present embodiment suppresses the torque amount ΔT to be reduced by traction control. That is, when the third control is implemented, the reduction amount of the motor torque is smaller compared to during traction control when the third control is not implemented. The torque amount ΔT is suppressed, for example, by subtracting a predetermined amount (hereinafter referred to as "third predetermined amount Y") from the base torque amount ΔTb. As a result, the torque command value Ti sent from the MCU 11 to the motor 2 during the implementation of the third control increases by the amount obtained by subtracting the third predetermined amount Y compared to during traction control without implementing the third control (before the torque amount ΔT is suppressed). For this reason, the power consumed by the motor 2 is increased (secured), suppressing the rise of the battery voltage V.

[0052] Also, when performing the third control, the MCU11 calculates a supplementary braking force that compensates for the amount by which the torque amount ΔT is suppressed, in other words, a supplementary braking force corresponding to the third predetermined amount Y (hereinafter referred to as "second braking force F2"), and transmits the calculated second braking force F2 to the H / U12 via the first bus 15. When the H / U12 receives the second braking force F2, it performs battery protection control to apply the second braking force F2 to both the left wheel 6L and the right wheel 6R. As a result, since the motor torque corresponding to the amount by which the torque amount ΔT is suppressed by the third control is offset by the second braking force F2, the stability of the vehicle 1 is maintained.

[0053] Furthermore, when performing the third control, the MCU11 may transmit a third signal indicating that the third control is being performed to the ECU10 via the CAN bus 14. When the ECU10 receives the third signal, it may control the engine 3 and the generator 4 to suppress the generated power P. As a result, since the battery voltage V further decreases, the safety of the battery 7 is more guaranteed.

[0054] Summarizing the control configuration regarding the above traction control, the first control, the second control, and the third control are all performed by the MCU11 during the implementation of the traction control. Also, both the slip suppression control and the battery protection control are performed by the H / U12. The first control and the second control are controls that are performed according to the implementation or non-implementation of the slip suppression control, and both are not performed simultaneously. On the other hand, the third control is a control that is performed according to the battery voltage V regardless of the implementation or non-implementation of the slip suppression control, and can be performed simultaneously with each of the first control and the second control. Also, the battery protection control is performed according to the implementation of the third control.

[0055] [4. Flowchart] FIG. 3 is a flowchart for explaining the traction control performed by the MCU 11. This flowchart is executed at a predetermined calculation cycle when the MCU 11 receives the required torque Tr. Note that the flag f for identifying whether the traction control in the flowchart of FIG. 3 is being executed has an initial value of 0 (traction control not being executed).

[0056] In step S1, it is determined whether the flag f is 0. As described above, since the value of the flag f is 0 in the initial state, the process proceeds to step S2, and it is determined whether the left and right wheels 6 are slipping (rotational acceleration R ≧ predetermined rotational acceleration R1). In step S2, if it is determined that neither of the left and right wheels 6 is slipping, it is considered that traction control is unnecessary, and the process proceeds to step S15, where the required torque Tr received from the ECU 10 is set as the torque instruction value Ti, and in the subsequent step S16, the torque instruction value Ti is sent to the electric motor 2 to control the electric motor 2, and this flow returns.

[0057] In the subsequent calculation cycles, if it is determined in step S2 that the left and right wheels 6 are slipping, the process proceeds to step S3, where the flag f is set to the value 1 indicating that the traction control is being executed, and then in step S4, the torque amount ΔT (base torque amount ΔTb) to be reduced by the traction control is calculated. Thereafter, in steps S5, S7, and S9, it is determined whether each of the first control, the second control, and the third control is necessary.

[0058] That is, in step S5, it is determined whether the first signal is received. In step S7, it is determined whether the second signal is received. In step S9, it is determined whether the battery voltage V exceeds the upper limit voltage Vmax. Here, if it is determined in step S5 that the first signal is not received, and since the first control is not implemented in step S7, it is determined that the second signal is not received, and further, if it is determined in step S9 that the battery voltage V does not exceed the upper limit voltage Vmax (that is, when it is determined that all of steps S5, S8, and S9 do not hold), none of the first control, the second control, and the third control are implemented, and the process proceeds to step S13.

[0059] In step S13, it is determined whether the above-described end condition of the traction control is satisfied. If it is determined in step S13 that the end condition is satisfied, then in step S14, the flag f is set to 0 and the process proceeds to step S15. On the other hand, if it is determined in step S13 that the end condition is not satisfied, the flag f remains as it is (remains 1), and the process proceeds to step S15. Thereafter, the control process of the motor 2 (steps S15 and S16) is implemented, and this flow returns. Note that in this case, the torque command value Ti set in step S15 is set to a value obtained by subtracting the base torque amount ΔTb from the required torque Tr.

[0060] On the other hand, if it is determined in step S5 that the first signal is received, the process proceeds to step S6, and the torque amount ΔT is adjusted to be suppressed (first control). At this time, the torque amount ΔT is corrected according to the first braking force F1 received from H / U12. The torque amount ΔT is suppressed, for example, to a value obtained by subtracting the first predetermined amount X from the base torque amount ΔTb (ΔT = ΔTb - X). Thereafter, the process proceeds to step S9, and it is determined whether the battery voltage V exceeds the upper limit voltage Vmax.

[0061] And when it is determined in step S9 that the battery voltage V does not exceed the upper limit voltage Vmax (the third control is not performed), the flag processing based on the success or failure of the end condition (steps S13 and S14) and the control processing of the motor 2 (steps S15 and S16) are sequentially performed, and this flow returns. Note that in this case, the torque command value Ti set in step S15 is set to a value obtained by subtracting the torque amount ΔT (=ΔTb - X) suppressed (adjusted) by the first control from the required torque Tr.

[0062] On the other hand, when it is determined in step S9 that the battery voltage V exceeds the upper limit voltage Vmax, the process proceeds to step S10, and the torque amount ΔT is further suppressed (third control). At this time, the torque amount ΔT is suppressed (corrected) to a value obtained by further subtracting a third predetermined amount Y from a value obtained by subtracting a first predetermined amount X from the base torque amount ΔTb (ΔT = ΔTb - X - Y). In the subsequent step S11, the second braking force F2 is calculated, and in step S12, the second braking force F2 is transmitted to H / U12, and the process proceeds to step S13. Then, the flag processing based on the success or failure of the end condition (steps S13 and S14) and the control processing of the motor 2 (steps S15 and S16) are sequentially performed, and this flow returns. Note that in this case, the torque command value Ti set in step S15 is set to a value obtained by subtracting the torque amount ΔT (=ΔTb - X - Y) suppressed (adjusted) by the first control and the third control from the required torque Tr.

[0063] If the end condition is not satisfied in step S13 of the foregoing flow, in the subsequent operation cycles, since the flag f is 1, the process proceeds to step S5. Here, in step S5, if it is determined that the first signal has not been received, the process proceeds to step S7, and it is determined whether the second signal has been received. As described above, when the slip suppression control by H / U12 is changed from being implemented to not being implemented, a second signal is transmitted from H / U12 to MCU11. Therefore, step S7 is satisfied, and the process proceeds to step S8. In the subsequent step S8, the torque amount ΔT is adjusted to increase (second control). That is, the torque amount ΔT is increased to a value obtained by adding a second predetermined amount X′ to the value of the torque amount suppressed by the first control (ΔT = ΔTb - X) [ΔT = (ΔTb - X) + X′].

[0064] Thereafter, the processes based on the necessity of the third control (steps S9 to S12), the process of the flag f based on whether the end condition is satisfied (steps S13 and S14), and the control process of the electric motor 2 (steps S15 and S16) are sequentially performed, and this flow returns. In this case, the torque command value Ti set in step S15 is set to a value obtained by subtracting the torque amount ΔT [= (ΔTb - X) + X′] adjusted in step S8 from the required torque Tr when proceeding through the No route of step S9. Further, when proceeding through the Yes route of step S9, the torque amount ΔT [= (ΔTb - X) + X′ - Y] obtained by further adjusting the torque amount ΔT [= (ΔTb - X) + X′] adjusted in step S8 by the third control is subtracted from the required torque Tr, and the resulting value is set as the torque command value Ti.

[0065] In addition, in the determination of the necessity of the first control, the second control, and the third control in steps S5, S7, and S9, when it is determined that only step S9 is satisfied, the processes related to the third control are performed in steps S10 to S12, and the processes of the flag f based on the satisfaction or non-satisfaction of the end condition (steps S13 and S14) and the control process of the electric motor 2 (steps S15 and S16) are sequentially performed, and this flow returns. In this case, the torque command value Ti set in step S15 is set to a value obtained by subtracting the torque amount ΔT (=ΔTb - Y) suppressed (adjusted) by the third control from the required torque Tr.

[0066] [5. Timing Chart] Referring to FIGS. 4 to 7, the operation of the vehicle 1 of the present embodiment will be described. The horizontal axis of each timing chart is time. FIG. 4 is a timing chart illustrating a case where neither the above-described first control nor the third control is performed, and FIG. 5 is a timing chart illustrating a case where only the above-described third control is performed. Further, FIG. 6 is a timing chart illustrating a case where only the above-described first control is performed, and FIG. 7 is a timing chart illustrating a case where both the above-described first control and the third control are performed.

[0067] In FIGS. 4 to 7, it is assumed that the torque command value Ti increases as the accelerator opening AP starts to increase at time t1, and a blow-up (rotation acceleration R ≧ predetermined rotation acceleration R1) of the motor rotation speed Nm is detected at time t2. In both FIGS. 4 and 5, it is assumed that the vehicle 1 accelerates or starts on a road surface where both of the left and right wheels 6 are likely to slip (for example, on ice), and in both FIGS. 6 and 7, it is assumed that the vehicle 1 accelerates or starts on a road surface where one of the left and right wheels 6 (for example, the right wheel 6R) is likely to slip (split μ road). Further, in FIGS. 4 and 6, the battery input power of the battery 7 is high [for example, when the SOC is relatively low (for example, less than 50%) and the battery temperature is appropriate], and in FIGS. 5 and 7, the battery input power of the battery 7 is low [for example, when the SOC is relatively high (for example, close to 100%) or when the battery temperature is higher or lower than the appropriate temperature].

[0068] First, with reference to the time chart of FIG. 4, the operation of the vehicle 1 according to the present embodiment will be described. At time t2, upon detecting a rise in the motor speed Nm, the MCU 11 starts traction control to reduce the motor torque (torque command value Ti). As a result, the torque command value Ti becomes a value lower than the required torque Tr transmitted from the ECU 10 [Ti = Tr - ΔT (= ΔTb)], so that slip (spin) of the left and right wheels 6 is suppressed. Therefore, skidding of the vehicle 1 is prevented and stable acceleration or start is achieved. In the time chart of FIG. 4, since both the left wheel 6L and the right wheel 6R slip, the above-described first control is not performed, and the braking forces of the left wheel 6L and the right wheel 6R are always 0.

[0069] Also, when the ECU 10 receives that the traction control has started at time t2, the ECU 10 controls the engine 3 and the generator 4 so as to obtain the generated power P corresponding to the torque command value Ti. As a result, the generated power P gradually decreases until it becomes the generated power P corresponding to the torque command value Ti from time t2. The battery voltage V rises due to power transfer of the portion not consumed by the motor 2 until the generated power P corresponding to the torque command value Ti is obtained from time t2. This power transfer occurs because the motor 2 has a faster response speed than the engine 3 and the generator 4 as described above. However, when the battery acceptance power of the battery 7 is high, the fluctuation of the battery voltage V due to the power transfer is small, so the battery voltage V changes within a range lower than the upper limit voltage Vmax. Therefore, the safety of the battery 7 is ensured.

[0070] On the other hand, as shown in the time chart of FIG. 5, when the battery input power of the battery 7 is low, the margin of the battery voltage fluctuation due to the power transfer is small. Therefore, the battery voltage V rapidly rises from time t2 and exceeds the upper limit voltage Vmax at time t3. Along with this, in the MCU 11, third control for suppressing the torque amount ΔT is implemented. Therefore, since the torque command value Ti becomes a higher value [Ti = Tr - ΔT (= ΔTb - Y)] than when the third control is not implemented (the two-dot chain line of the torque command value in FIG. 5), the power consumed by the electric motor 2 increases. As a result, the rise of the battery voltage V after time t3 is suppressed.

[0071] Also, at time t3, when H / U 12 receives the second braking force F2 calculated by the MCU 11, battery protection control for applying the second braking force F2 to both the left wheel 6L and the right wheel 6R is implemented. As a result, the second braking force F2 is applied to the left wheel 6L and the right wheel 6R, and the motor torque (torque command value Ti) increased by the amount by which the torque amount ΔT is suppressed is canceled out by the second braking force F2, so that the stability of the vehicle 1 is maintained.

[0072] When the ECU 10 receives a third signal from the MCU 11 indicating that the third control has started at time t3, the ECU 10 controls the engine 3 and the generator 4 so as to suppress the power generation power P more than when the third control is not implemented (the two-dot chain line of the power generation power in FIG. 5). As a result, the battery voltage V applied to the battery 7 becomes even smaller after time t3 and turns to a decrease, and the battery 7 is appropriately protected.

[0073] Next, with reference to the time chart of FIG. 6, the operation of vehicle 1 when the first control is performed will be described. In the time chart of FIG. 6, similar to the time chart of FIG. 4, traction control for reducing the motor torque (torque command value Ti) by MCU11 is started at time t2. However, in the example of the time chart of FIG. 6, since only the right wheel 6R slips, the motor speed Nm becomes smaller than when both the left and right wheels 6 slip (the dashed-dotted line of the motor speed in FIG. 6). Accordingly, the torque amount ΔT (base torque amount ΔTb) becomes a smaller value than when both the left and right wheels 6 slip. Therefore, the torque command value Ti becomes larger than when both the left and right wheels 6 slip (the dashed-dotted line of the torque command value in FIG. 6).

[0074] Also, in the time chart of FIG. 6, at time t2, along with H / U12 detecting single-wheel slip (Nwr≫Nwl), slip suppression control for applying the first braking force F1 to the slipping wheel (right wheel 6R) is performed. As a result, the first braking force F1 is applied to the right wheel 6R, and the first control is performed by MCU11 that has received the first signal from H / U12. By performing the first control, the torque command Ti becomes a higher value [Ti = Tr - ΔT (= ΔTb - X)] than when the first control is not performed (the two-dot chain line of the torque command value in FIG. 6). Thereby, even when traction control and slip suppression control overlap, excessive torque suppression of the left and right wheels 6 is prevented.

[0075] Also, when ECU10 receives that traction control has started at time t2, ECU10 controls engine 3 and generator 4 so as to obtain the generated power P corresponding to the torque command value Ti. As a result, the generated power P gradually decreases from time t2 until it becomes the generated power P corresponding to the torque command value Ti. During this period, the battery voltage V rises due to the power transfer of the portion not consumed by the motor 2, but when the battery acceptance power of battery 7 is high, the margin for battery voltage fluctuations due to power transfer is large, so it fluctuates within a range lower than the upper limit voltage Vmax.

[0076] On the other hand, as shown in the time chart of FIG. 7, since the battery input power of the battery 7 is low and the margin for battery voltage fluctuations associated with power transfer is small, when the battery voltage V exceeds the upper limit voltage Vmax at time t3, in the MCU 11, in addition to the first control being executed, a third control for suppressing the torque amount ΔT is executed. Therefore, the torque command value Ti becomes a higher value [Ti = Tr - ΔT (= ΔTb - X - Y)] than when the third control is not executed during the execution of the first control (the two-dot chain line of the torque command value in FIG. 5). As a result, the power consumed by the electric motor 2 increases, and the rise in the battery voltage V is suppressed.

[0077] Also, at time t3, when the H / U 12 receives the second braking force F2, in addition to the slip suppression control being executed, a battery protection control for applying the second braking force F2 to both the left wheel 6L and the right wheel 6R is executed. As a result, the second braking force F2 is applied to the left wheel 6L and the right wheel 6R. More specifically, the second braking force F2 is applied to the left wheel 6L, and a braking force corresponding to the sum of the first braking force F1 and the second braking force F2 is applied to the right wheel 6R. As a result, the motor torque (torque command value Ti) increased by the amount by which the torque amount ΔT is suppressed in the third control is offset by the second braking force F2, so the stability of the vehicle 1 is maintained.

[0078] In the time chart of FIG. 7, when the ECU 10 receives a third signal indicating that the third control has started at time t3 from the MCU 11, the engine 3 and the generator 4 are controlled so as to suppress the power generation power P more than when the third control is not executed during the execution of the first control (the two-dot chain line of the power generation power in FIG. 7). As a result, the battery voltage V applied to the battery 7 becomes even smaller after time t3, and the battery 7 is appropriately protected.

[0079] Also, although not shown in the figures, when a predetermined suppression control end condition is satisfied after time t2 in the time charts of FIGS. 6 and 7 and the slip suppression control by H / U12 is no longer implemented, the MCU11 that has received the second signal from H / U12 performs the second control. By performing the second control, the torque command value Ti becomes a lower value [e.g., Ti = Tr - ΔT (= ΔTb - X + X')] than when the first control is performed by an amount obtained by adding the second predetermined amount X' to the suppressed torque amount. As a result, after the end of the first control, the slip-up of the left and right wheels 6 due to the release of the first braking force F1 applied to one wheel by the slip suppression control is suppressed.

[0080] [6. Effects] (1) According to the vehicle 1 described above, when the MCU11 receives the first signal indicating that the slip suppression control is being performed from the H / U12, it adjusts to suppress the torque amount ΔT to be reduced by the traction control. As a result, when both the traction control performed by the MUC11 and the slip suppression control performed by the H / U12 are implemented, excessive torque suppression for suppressing the slip of the left and right wheels 6 due to control duplication can be prevented without interfering with each other.

[0081] Also, when the MCU11 receives the second signal indicating the non-implementation of the slip suppression control after the implementation of the slip suppression control by the H / U12, it adjusts to increase the suppressed torque amount ΔT. As a result, the slip-up of the left and right wheels 6 due to the release of the first braking force F1 can be suppressed. Therefore, according to the vehicle 1 described above, by adjusting the torque amount ΔT to be reduced by the traction control according to the first signal or the second signal received from the H / U12, the slip of the left and right wheels 6 can be appropriately suppressed, and the acceleration or starting stability of the vehicle 1 can be enhanced.

[0082] In addition, since the MCU 11 directly receives the first signal and the second signal from the H / U 12 without going through the ECU 10, communication lag can be reduced, and the responsiveness of control can be enhanced. Therefore, according to the vehicle 1 described above, while taking advantage of the high responsiveness of the electric motor 2, the slip of the left and right wheels 6 can be appropriately suppressed.

[0083] Furthermore, in the above-described embodiment, the MCU 11 and the H / U 12 are communicably connected to each other by a first bus 15 provided separately from the CAN bus 14. Thereby, regardless of the communication situation in the CAN bus 14, the MCU 11 can immediately receive the first signal and the second signal from the H / U 12, so that the responsiveness of control can be further enhanced.

[0084] (2) The H / U 12 determines whether or not to perform slip suppression control based on the left wheel rotation speed Nwl and the right wheel rotation speed Nwr. Thus, the necessity of performing slip suppression control is determined in the H / U 12. In other words, since the determination of the necessity of performing slip suppression control is carried out without going through the ECU 10, the responsiveness of control can be further enhanced.

[0085] Furthermore, the MCU 11 corrects the torque amount ΔT based on the first braking force F1 received from the H / U 12. Specifically, when the MCU 11 receives the first signal, the correction is made such that the larger the first braking force F1, the more the torque amount ΔT to be reduced by traction control is suppressed. Thereby, excessive suppression or under-suppression of single-wheel slip can be prevented, so that single-wheel slip can be appropriately suppressed. Also, when the MCU 11 receives the second signal (at the end of slip suppression control), the correction is made such that the torque amount ΔT gradually increases as the first braking force F1 is gradually reduced. Thereby, excessive slip suppression or slip-up during the reduction of the first braking force F1 can be suppressed, and the stability of acceleration or start of the vehicle 1 can be enhanced.

[0086] (3) Also, when the battery voltage V received from the BMU13 exceeds a predetermined upper limit voltage Vmax, the MCU11 suppresses the torque amount ΔT. As a result, since the power consumed by the electric motor 2 is increased (secured) compared to before the torque amount ΔT is suppressed, an increase in the battery voltage V can be suppressed. Further, since the MCU11 directly receives the battery voltage V from the BMU13 without going through the ECU10, communication lag can be reduced and the responsiveness of control can be enhanced. In particular, in the above-described embodiment, the MCU11 and the BMU13 are communicably connected by a second bus 16 different from the CAN bus 14. For this reason, regardless of the communication situation in the CAN bus 14, the MCU11 can immediately receive the battery voltage V from the BMU13, so that the responsiveness of control can be further enhanced.

[0087] Furthermore, when the battery voltage V exceeds the upper limit voltage Vmax, the MCU11 calculates a second braking force F2 that compensates for the amount by which the torque amount ΔT is suppressed and transmits it to the H / U12. Also, when the H / U12 receives the second braking force F2 from the MCU11, it operates the brake 9 and performs battery protection control to apply the second braking force F2 to both of the left and right wheels 6. As a result, since the motor torque corresponding to the amount by which the torque amount ΔT is suppressed is offset by the second braking force F2, the stability of the vehicle 1 is maintained.

[0088] (4) Also, when both the slip suppression control and the battery protection control by the H / U12 are performed, the torque amount ΔT is corrected to a value obtained by subtracting a third predetermined amount Y corresponding to the second braking force F2 from a value obtained by subtracting a first predetermined amount X set according to the first braking force F1 from the base torque amount ΔTb (ΔT = ΔTb - X - Y). In other words, when the H / U12 performs both the slip suppression control and the battery protection control, the MCU11 corrects the torque amount ΔT based on both the first braking force F1 and the second braking force F2. Therefore, both suppression of single-wheel slip and protection of the battery 7 can be achieved.

[0089] [7. Modification Example] The configuration of the vehicle 1 and the control implemented in the vehicle 1 are just examples. As the first control, the MCU 11 not only corrects the torque amount ΔT based on the first braking force F1, but also calculates a corrected braking force F3 to be applied to one of the slipping wheels (left wheel 6L or right wheel 6R) based on the corrected torque amount ΔT, and may transmit the calculated corrected braking force F3 to the H / U 12. At this time, as the implementation of the slip suppression control, the H / U 12 may control the brake 9 so as to apply the corrected braking force F3 received from the MCU 11 to one of the slipping wheels instead of the first braking force F1. In this way, by configuring the traction control implemented by the MCU 11 to be feedback to the slip suppression control implemented by the H / U 12 as well, it is possible to more appropriately suppress the single-wheel slip. Similarly, as the second control, the MCU 11 may calculate a corrected braking force F3 to be applied to one of the slipping wheels (left wheel 6L or right wheel 6R) based on the torque amount ΔT corrected based on the first braking force F1, and transmit the calculated corrected braking force F3 to the H / U 12.

[0090] In addition to implementing the slip suppression control, the H / U 12 may also implement a two-wheel slip suppression control that applies braking forces to both of the left and right wheels 6 when both the left and right wheels 6 are slipping (two-wheel slip). As the two-wheel slip suppression control, for example, after the MCU 11 calculates a torque amount ΔT for reducing the motor torque when detecting the slip of the vehicle 1 (after step S4 in the flowchart of FIG. 3), it may calculate an auxiliary braking force required for the H / U 12 to suppress the slip, and transmit the calculated auxiliary braking force to the H / U 12. Then, when receiving this auxiliary braking force, the H / U 12 may apply the auxiliary braking force to both of the left and right wheels 6. Note that this auxiliary braking force may be calculated as the upper and lower limit values of the braking force.

[0091] The definition of "implementation or non-implementation of the slip suppression control" described in the claims is not limited to the above. For example, "implementation of the slip suppression control" may include the period from the time when the suppression control end condition is satisfied until the first braking force F1 applied to the slipping wheel (left wheel 6L or right wheel 6R) is gradually reduced to 0. In this case, H / U12 may continue to transmit the second signal indicating non-implementation of the slip suppression control from the time when the first braking force F1 becomes 0 until the time when the traction control ends or the slip suppression control is restarted. The control for adjusting the torque amount ΔT during the implementation of the slip suppression control is not limited to the first control for adjusting the torque amount ΔT to be suppressed, and the control for adjusting the torque amount ΔT to be increased may also be implemented. Further, the control for adjusting the torque amount ΔT during the non-implementation of the slip suppression control is not limited to the second control for adjusting the torque amount ΔT to be increased, and the control for adjusting the torque amount ΔT to be suppressed may also be implemented.

[0092] The electric vehicle may be a so-called EV vehicle that does not include the engine 3 and the generator 4. Further, the electric vehicle may be a so-called four-wheel drive vehicle including a front-side electric motor that drives the left and right wheels (front wheels) on the front side of the vehicle and a rear-side electric motor that drives the left and right wheels (rear wheels) on the rear side of the vehicle. In the case of a four-wheel drive vehicle, the electric vehicle may separately have an MCU that controls the front-side electric motor and an MCU that controls the rear-side electric motor. The above traction control and the first control and the second control implemented during the traction control may be separately implemented for each of the front-side electric motor and the rear-side electric motor.

[0093] Further, the brake 9 may be one that brakes the left and right wheels 6 on the front side and the left and right wheels on the rear side of the vehicle 1. Further, the electric vehicle may separately be provided with a front-side brake that brakes the front wheels and a rear-side brake that brakes the rear wheels. In this case, the electric vehicle may separately have an H / U that controls the front-side brake and an H / U that controls the rear-side brake. At this time, the above slip suppression control and battery protection control may be separately implemented for each of the front-side brake and the rear-side brake. Note that the brake control device is not limited to H / U, and various brake control devices are applicable.

Explanation of Symbols

[0094] 1 Vehicle (Electric Vehicle) 2 Electric Motor 6 Left and Right Wheels 6L Left Wheel 6R Right Wheel 7 Battery 9 Brake 10 Upper Control Device (ECU) 11 Electric Motor Control Device (MCU) 12 Brake Control Device (H / U) 13 Battery Management Device (BMU) F1 First Braking Force F2 Second Braking Force (Auxiliary Braking Force) F3 Correction Braking Force Nm Motor Rotation Speed Nwl Left Wheel Rotation Speed Nwr Right Wheel Rotation Speed R Rotational Acceleration Ti Torque Instruction Value (Torque of Electric Motor) Tr Required Torque V Battery Voltage Vmax Upper Limit Voltage ΔT Torque Amount

Claims

1. An electric vehicle comprising an electric motor that drives left and right wheels and a brake that applies braking force to the left and right wheels, a host control device that calculates a required torque of the electric vehicle, an electric motor control device that receives the required torque calculated by the host control device, controls the electric motor, and performs traction control to reduce the torque of the electric motor based on the rotational acceleration of the electric motor, a brake control device that, when detecting slip of one of the left and right wheels, operates the brake to apply braking force to the one wheel and performs slip suppression control, and a battery management device that acquires a battery voltage of a battery that exchanges power with the electric motor, wherein when the electric motor control device receives a signal indicating implementation or non-implementation of the slip suppression control after implementation from the brake control device, the electric motor control device adjusts an amount of torque to be reduced by the traction control according to the received signal, wherein when the battery voltage received by the electric motor control device from the battery management device without passing through the host control device exceeds a predetermined upper limit voltage, the electric motor control device suppresses an amount of torque to be reduced by the traction control and calculates a supplementary braking force to compensate for the suppressed amount of torque to be reduced by the traction control, and transmits the supplementary braking force to the brake control device, and wherein when the brake control device receives the supplementary braking force from the electric motor control device, the brake control device operates the brake to apply the supplementary braking force to both of the left and right wheels and performs battery protection control. An electric vehicle characterized by the above.

2. The brake control device determines necessity of implementing the slip suppression control based on rotational speeds of the left and right wheels, and transmits the braking force applied to the one wheel together with the signal to the electric motor control device, and the electric motor control device corrects the amount of torque based on the braking force received from the brake control device. The electric vehicle according to claim 1, characterized by the above.

3. The electric motor control device calculates a corrected braking force to be applied to the one wheel based on the corrected amount of torque, and transmits the corrected braking force to the brake control device, and the brake control device applies the corrected braking force received from the electric motor control device to the one wheel. The electric vehicle according to claim 2, characterized by the above.

4. When the braking control device performs both the slip suppression control and the battery protection control, the electric motor control device corrects the torque amount based on the braking force applied to one of the wheels by the slip suppression control and the braking forces applied to both of the left and right wheels by the battery protection control. The electric vehicle according to any one of claims 1 to 3, characterized by the above.

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