Control system for electric motor car

Abstract

To provide a technique appropriately executing retreat travelling.SOLUTION: A vehicle control device can communicate with a logic circuit and a second processor without interposing a first processor, and also is structured so as to execute a retreat travelling mode making an electric motor car perform retreat travelling when abnormality occurs on the first processor. In the retreat travelling mode, the vehicle control device outputs a target torque for retreat travelling with respect to a first motor to the logic circuit and also outputs a target torque for the retreat travelling with respect to a second motor to the second processor. The logic circuit controls a first power control unit on the basis of the target torque for retreat travelling with respect to the first motor received from the vehicle control device. The second processor controls a second power control unit on the basis of the target torque for retreat travelling with respect to the second motor received from the vehicle control device.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The technology disclosed in this specification relates to a control system for an electric vehicle.

Background Art

[0002] Patent Document 1 discloses a control device for an electric vehicle including two motors. The control device includes two MG microcontrollers that control each of the two motors. Further, the control device includes an abnormality detection unit that detects an abnormality of the MG microcontroller. The abnormality detection unit is connected to an ASIC and outputs a signal indicating the abnormality to the ASIC when detecting an abnormality of the MG microcontroller. The ASIC has a function of causing the electric vehicle to perform a retreat running when an abnormality occurs in the microcontroller.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In the technology of Patent Document 1, when an electric vehicle performs a retreat running by the ASIC in response to an abnormality occurring in one of the MG microcontrollers, the other MG microcontroller in which no abnormality is detected is also reset at the same time. In this case, since the other MG microcontroller does not operate, the motor controlled by the other MG microcontroller is not driven. Further, in the motor, the motor functions as a generator when the electric vehicle performs a retreat running, and a back electromotive voltage is generated. If the battery voltage of the electric vehicle is not greater than this back electromotive voltage, the electric vehicle cannot run. That is, there is a possibility that the retreat running cannot be properly executed. The technology of Patent Document 1 does not consider the influence on the motor corresponding to the MG microcontroller in which such an abnormality is not detected. This specification provides a technology capable of properly executing a retreat running.

Means for Solving the Problems

[0005] This specification discloses a control system for an electric vehicle. The electric vehicle includes a first motor unit including at least one first motor, a second motor unit including at least one second motor, a first power control unit for adjusting the power supplied to the first motor of the first motor unit, and a second power control unit for adjusting the power supplied to the second motor of the second motor unit. The control system includes a vehicle control device that outputs target torques for the first motor and the second motor, and a motor control device configured to be communicable with the vehicle control device and control the first power control unit and the second power control unit based on the target torques output from the vehicle control device. The motor control device is configured to be communicable with the vehicle control device, and includes a first processor that controls the first power control unit based on the target torque for the first motor received from the vehicle control device, a second processor that controls the second power control unit based on the target torque for the second motor received from the vehicle control device via the first processor from the vehicle control device, and a logic circuit configured to be communicable with the first processor and the second processor and monitor the states of the first processor and the second processor. The vehicle control device is communicable with the logic circuit and the second processor without passing through the first processor, and is configured to execute an evacuation driving mode for causing the electric vehicle to perform evacuation driving when an abnormality occurs in the first processor. In the evacuation driving mode, the vehicle control device outputs a target torque for evacuation driving for the first motor to the logic circuit and outputs a target torque for evacuation driving for the second motor to the second processor. The logic circuit controls the first power control unit based on the target torque for evacuation driving for the first motor received from the vehicle control device, and the second processor controls the second power control unit based on the target torque for evacuation driving for the second motor received from the vehicle control device.

[0006] According to the above configuration, when an abnormality occurs in the first processor, the vehicle control device can communicate with the logic circuit and the second processor without going through the first processor. Therefore, when the vehicle control device executes the evacuation running mode, it can directly instruct the second processor to set the target torque for evacuation running for the second motor. As a result, the above-mentioned problem, that is, the counter electromotive voltage generated in the second motor during evacuation running can be canceled out. The evacuation running of the electric vehicle is appropriately executed.

Brief Description of the Drawings

[0007]

Figure 1

Figure 2

Embodiments for Carrying Out the Invention

[0008] (Configuration of Control System 2; Fig. 1) The control system 2 of this embodiment is mounted on an electric vehicle (for example, an electric car, a hybrid car, a plug-in hybrid car, a fuel cell car, etc.) having a running motor for driving the vehicle. In particular, the control system 2 of this embodiment is mounted on a four-wheel drive electric vehicle. As shown in Fig. 1(a), the control system 2 includes a host ECU (abbreviation for Electronic Control Unit) 10, an MG ECU 20, two inverters 32, 34, and two motor units 42, 44. The motor unit 42 includes two running motors 42a, 42b for driving the front wheels of the electric vehicle. The motor unit 44 includes a motor 44a for driving the rear wheels of the electric vehicle.

[0009] The upper ECU 10 outputs a target torque indicating the target output of each of the motors 42a, 42b, and 44a, for example, based on the accelerator opening degree or the like. The MG ECU 20 is configured to be communicable with the upper ECU 10. The MG ECU 20 controls the inverters 32 and 34 based on the target torque output from the upper ECU 10. Specifically, the MG ECU 20 outputs a drive signal (for example, a PWM signal) to the inverters 32 and 34 based on the target torque.

[0010] The MG ECU 20 includes an ASIC (abbreviation for Application Specific Integrated Circuit) 22, a front-wheel drive microcomputer (hereinafter referred to as Fr microcomputer) 24, and a rear-wheel drive microcomputer (hereinafter referred to as Rr microcomputer) 26. The ASIC 22 is configured to be communicable with the Fr microcomputer 24 and the Rr microcomputer 26. The ASIC 22 monitors the states of the Fr microcomputer 24 and the Rr microcomputer 26. That is, the ASIC 22 has a circuit structure 22a for monitoring the state of the Fr microcomputer 24 and a circuit structure 22b for monitoring the state of the Rr microcomputer 26. Further, the ASIC 22 has some or all of the functions of a hardware part specialized for motor control (for example, a resolver digital converter, an analog-to-digital converter, a motor control IP, etc.).

[0011] The Fr microcomputer 24 is configured to be communicable with the upper ECU 10. The Fr microcomputer 24 receives the target torque for the motors 42a and 42b from the upper ECU 10. The Fr microcomputer 24 controls the front-wheel drive inverter (hereinafter referred to as Fr inverter) 32 based on the target torque received from the upper ECU 10. Specifically, the Fr microcomputer 24 includes, for example, a CPU, and the CPU can convert the target torque into a drive signal. Then, the Fr microcomputer 24 outputs the drive signal to the Fr inverter 32.

[0012] The Rr microcomputer 26 is configured to be communicable with the Fr microcomputer 24. The Rr microcomputer 26 receives, via the Fr microcomputer 24, a target torque for the motor 44a from the upper ECU 10. The Rr microcomputer 26 controls a rear-wheel drive inverter (hereinafter referred to as the Rr inverter) 34 based on the target torque received from the upper ECU 10 via the Fr microcomputer 24. Specifically, the Rr microcomputer 26 includes, for example, a CPU, and the CPU can convert the target torque into a drive signal. Then, the Rr microcomputer 26 outputs the drive signal to the Rr inverter 34.

[0013] The inverters 32 and 34 convert the DC power output from a battery (not shown) into three-phase AC power and supply it to the motor units 42 and 44, respectively. That is, the Fr inverter 32 adjusts the power supplied to the motors 42a and 42b. The Rr inverter 34 adjusts the power supplied to the motor 44a. Each of the inverters 32 and 34 can also convert the regenerative power (three-phase AC power) of the corresponding motors 42a, 42b, and 44a into DC power and supply it to a battery (not shown). Since the specific circuit configurations of the inverters 32 and 34 are well known, detailed descriptions thereof are omitted.

[0014] Further, FIG. 1(b) shows a situation where an abnormality has occurred in the Fr microcomputer 24. As shown in FIG. 1(b), the upper ECU 10 is configured to be communicable with the ASIC 22 and the Rr microcomputer 26 without going through the Fr microcomputer 24. When the Fr microcomputer monitoring circuit structure 22a of the ASIC 22 detects an abnormality in the Fr microcomputer 24, it outputs a notification indicating the abnormality of the Fr microcomputer 24 to the upper ECU 10. As a result, the upper ECU 10 executes an evacuation driving mode in which the electric vehicle is driven in evacuation.

[0015] In the evacuation driving mode, the upper ECU 10 outputs, for example, based on the accelerator opening degree or the like, a target torque for evacuation driving for the motors 42a and 42b to the ASIC 22, and outputs a target torque for evacuation driving for the motor 44a to the Rr microcomputer 26.

[0016] The ASIC 22 controls the Fr inverter 32 based on the target torque for the retreat travel received from the upper ECU 10 for the motors 42a and 42b. Specifically, the ASIC 22 has a circuit structure (i.e., the fail-safe logic for the retreat travel control) that converts the target torque for the retreat travel into a drive signal for the retreat travel. Then, the ASIC 22 outputs the drive signal for the retreat travel to the Fr inverter 32.

[0017] The Rr microcomputer 26 controls the Rr inverter 34 based on the target torque for the retreat travel received from the upper ECU 10 for the motor 44a. Specifically, the Rr microcomputer 26 can convert, by the CPU, the target torque for the retreat travel into a drive signal for the retreat travel. Then, the Rr microcomputer 26 outputs the drive signal for the retreat travel to the Rr inverter 34.

[0018] In this way, in the control system 2 of this embodiment, even when an abnormality occurs in the Fr microcomputer 24, each of the motors 42a, 42b, and 44a can be driven to make the electric vehicle perform a retreat travel.

[0019] Here, referring to FIG. 2, the conventional control system 102 will be described. In the conventional control system 102, as shown in FIG. 2, instead of the ASIC 122, the Fr microcomputer 124 monitors the state of the Rr microcomputer 126. That is, the Fr microcomputer 124 includes a unit 124a that executes a process for monitoring the state of the Rr microcomputer 126. In such a situation, as shown in FIG. 2(b), when an abnormality occurs in the Fr microcomputer 124, the Fr microcomputer 124 cannot monitor the state of the Rr microcomputer 126. Therefore, even if an abnormality occurs in the Rr microcomputer 126 in such a situation, the Fr microcomputer 124 cannot detect the abnormality. For this reason, in the conventional control system 102, when an abnormality occurs in the Fr microcomputer 124, the Rr microcomputer 126 that has no abnormality is also configured to stop operating.

[0020] In the conventional control system 102, when the circuit structure 122a for monitoring the Fr microcomputer of the ASIC 122 detects an abnormality in the Fr microcomputer 124, it outputs a notification indicating the abnormality of the Fr microcomputer 124 to the upper ECU 110. As a result, the upper ECU 110 executes an evacuation driving mode in which the electric vehicle performs evacuation driving.

[0021] In the evacuation driving mode, the upper ECU 110 outputs a target torque for evacuation driving for the motors 142a and 142b to the ASIC 122 based on, for example, the accelerator opening degree or the like. The ASIC 122 controls the Fr inverter 132 based on the target torque for evacuation driving for the motors 142a and 142b received from the upper ECU 110. Specifically, the ASIC 122 has, for example, a circuit structure that converts the target torque for evacuation driving into a driving signal for evacuation driving. Then, the ASIC 122 outputs the driving signal for evacuation driving to the Fr inverter 132.

[0022] Also, in the conventional control system 102, in the evacuation driving mode, no driving signal is output to the Rr inverter 134. That is, in the evacuation driving mode, the motor 144a is not driven. Therefore, in the evacuation driving mode, the electric vehicle travels by driving the motors 142a and 142b for operating the front wheels.

[0023] As described above, in the evacuation driving mode, since the motor 144a is not driven, the rear wheels are not driven. However, as the front wheels are driven, the rear wheels roll. When the rear wheels roll, the motor 144a operates as a generator, and a back electromotive voltage is generated in the motor 144a. The magnitude of this back electromotive voltage is given by the product of the rotational speed of the motor 144a and the magnetic flux of the magnet of the motor 144a. For this reason, the electric vehicle can only travel with a vehicle speed limit (that is, the magnitude of the battery voltage must be greater than the magnitude of the back electromotive voltage). Therefore, in the conventional control system 102, depending on the magnitude of the battery voltage or the like, there is a possibility that the evacuation driving may not be properly executed.

[0024] On the other hand, according to the control system 2 of this embodiment, even when an abnormality occurs in the Fr microcomputer 24, the Rr microcomputer 26 does not stop operating. For this reason, even when an abnormality occurs in the Fr microcomputer 24, the motor 44a is driven. Therefore, by driving the motor 44a, the above-described back electromotive voltage can be canceled. For this reason, even when an abnormality occurs in the Fr microcomputer 24, the evacuation running of the electric vehicle is appropriately executed.

[0025] The upper ECU 10 and the MG ECU 20 respectively correspond to examples of the "vehicle control device" and the "motor control device" of the present technology. The ASIC 22, the Fr microcomputer 24, and the Rr microcomputer 26 respectively correspond to examples of the "logic circuit", the "first processor", and the "second processor" of the present technology. The Fr inverter 32 and the Rr inverter 34 respectively correspond to examples of the "first power control unit" and the "second power control unit" of the present technology. The motor units 42 and 44 respectively correspond to examples of the "first motor unit" and the "second motor unit" of the present technology. The motors 42a and 42b correspond to an example of the "first motor" of the present technology. The motor 44a corresponds to an example of the "second motor" of the present technology.

[0026] As described above, specific examples of the technology disclosed in this specification have been described in detail, but these are merely examples and do not limit the scope of the claims. The technology described in the claims includes various modifications and changes of the specific examples illustrated above. The technical elements described in this specification or the drawings exhibit technical utility alone or in various combinations, and are not limited to the combinations described in the claims at the time of filing. Also, the technology illustrated in this specification or the drawings can achieve a plurality of purposes simultaneously, and achieving one of those purposes itself has technical utility.

Description of Reference Numerals

[0027] 2: Control system, 10: Host ECU, 20: MG ECU, 22: ASIC, 24: Front microcomputer, 26: Rear microcomputer, 32: Front inverter, 34: Rear inverter, 42, 44: Motor unit, 42a, 42b, 44a: Motor

Claims

[Claim 1] 1. A control system for an electric vehicle, comprising: The electric vehicle includes: a first motor unit including at least one first motor; a second motor unit including at least one second motor; a first power control unit that adjusts power supplied to the first motor of the first motor unit; a second power control unit that adjusts power supplied to the second motor of the second motor unit; Equipped with The control system includes: a vehicle control device that outputs a target torque for the first motor and the second motor; a motor control device configured to be able to communicate with the vehicle control device and configured to control the first power control unit and the second power control unit based on the target torque output from the vehicle control device; Equipped with The motor control device includes: a first processor configured to be able to communicate with the vehicle control device and configured to control the first power control unit based on the target torque for the first motor received from the vehicle control device; a second processor configured to be able to communicate with the first processor and configured to control the second power control unit based on the target torque for the second motor received from the vehicle control device via the first processor; a logic circuit configured to be able to communicate with the first processor and the second processor, the logic circuit monitoring states of the first processor and the second processor; Equipped with the vehicle control device is configured to be able to communicate with the logic circuit and the second processor without going through the first processor, and to execute an evacuation travel mode in which the electric vehicle is caused to travel in an evacuation manner when an abnormality occurs in the first processor; In the evacuation travel mode, the vehicle control device outputs a target torque for evacuation running for the first motor to the logic circuit, and outputs a target torque for evacuation running for the second motor to the second processor; the logic circuit controls the first power control unit based on the target torque for the evacuation traveling for the first motor received from the vehicle control device; The second processor controls the second power control unit based on the target torque for the evacuation traveling for the second motor received from the vehicle control device. Control system.

Images