Control system for electric automobile

Abstract

The technology disclosed in the present specification provides a control system for an electric vehicle. A control system according to the present specification is provided with a power control device, a first control device, and a second control device, the second control device is provided with a processor and a logic circuit, the first control device outputs a second command value to the logic circuit when a retreat travel mode is executed, and the logic circuit has: a first circuit structure; a second circuit structure; a third circuit structure to which the drive signal converted by the first circuit structure and the drive signal for retreat travel converted by the second circuit structure are inputted, and which selectively outputs either the drive signal or the drive signal; and a fourth circuit structure into which the output provided by the third circuit structure and a cut-off command for the power control device are input, and which cuts off the output provided by the third circuit structure while the cut-off command is input.

Description

Technical Field

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

[0002] Japanese Patent Application Laid-Open No. 2020-062930 discloses an electric vehicle. The electric vehicle is a hybrid vehicle having a control system for controlling two motors. In addition, the electric vehicle in this specification refers to a vehicle in a broad sense having a driving motor for driving wheels. For example, electric vehicles include battery electric vehicles, fuel cell vehicles, plug-in hybrid vehicles, etc. in addition to hybrid vehicles. Summary of the invention

[0003] This type of control system is often composed of multiple control devices. For example, the control system may also include: a first control device that determines the target output (i.e., torque command value) of the motor; and a second control device that outputs an action command value to a power control device such as an inverter based on the torque command value from the first control device. In this case, the first control device and the second control device are configured to communicate with each other and control the motor while coordinating with each other.

[0004] In the above control system, when a fault occurs in the second control device, even if the first control device is healthy, the motor cannot be controlled. However, there are many cases where the fault that occurs in the second control device is a fault that occurs in a part of the second control device, and other structures of the second control device can still be used. In such a case, it is assumed that the motor is controlled by using other structures of the second control device that can be used to make the electric vehicle retreat.

[0005] In addition, in the above control system, in order to make the electric vehicle run safely, for example, a structure is envisioned in which a cut-off instruction for cutting off the action instruction to the power control device is output under a condition where the electric vehicle should not be run (for example, an abnormality in the sensor value, etc.). In the above control system, for example, a cut-off instruction is output from the first control device to the second control device. During the period when the cut-off instruction is output, even if the torque instruction value is output according to the user's instructions, the action of the power control device is still stopped because the action instruction value from the second control device is cut off. In order to make the electric vehicle run safely, it is important to properly cut off the action instruction value during the period when the cut-off instruction is input to the second control device.

[0006] Therefore, a structure is conceived in which a cut-off confirmation of whether to cut off the operation command value from the second control device is performed during the period when the cut-off command is output. In particular, a structure is conceived in which the cut-off confirmation is performed independently in the normal driving mode and the avoidance driving mode. In such a situation, when transferring from the normal driving mode to the avoidance driving mode, the cut-off confirmation can be performed at this timing. In this case, there is a possibility that the transfer from the normal driving mode to the avoidance driving mode may take a relatively long time. In this specification, a technique for smoothly transferring to the avoidance driving mode is provided.

[0007] This specification provides a control system for an electric vehicle. In the first mode, the control system includes: a power control device that adjusts the power supplied to the motor of the electric vehicle; a first control device that outputs a first command value representing the output that is the target of the motor; and a second control device that is configured to be able to communicate with the first control device and outputs a drive signal to the power control device according to the first command value output from the first control device. The second control device includes: a processor that is configured to be able to communicate with the first control device, processes the first command value output from the first control device with a program, and outputs an operation command value for the motor; and a logic circuit that has a first circuit configuration for converting the operation command value output from the processor into the drive signal. When the first control device executes the avoidance driving mode for causing the electric vehicle to perform avoidance driving, instead of the first command value, a second command value based on the avoidance driving mode is output to the logic circuit. The logic circuit further has: a second circuit configuration for converting the second command value output from the first control device into a drive signal for avoidance driving; a third circuit configuration that is input with the drive signal converted by the first circuit configuration and the drive signal for avoidance driving converted by the second circuit configuration, and alternatively outputs one of them; and a fourth circuit configuration that is input with the output provided by the third circuit configuration and a cut-off command for the power control device, and cuts off the output provided by the third circuit configuration during the period when the cut-off command is input.

[0008] According to the above structure, the logic circuit has: a third circuit configuration that is input with a drive signal transformed by the first circuit configuration and a drive signal for retreat driving transformed by the second circuit configuration, and selectively outputs one of them; and a fourth circuit configuration that is input with the output provided by the third circuit configuration and a cut-off instruction for the power control device, and cuts off the output provided by the third circuit configuration during the period when the cut-off instruction is input. That is, the fourth circuit configuration is provided commonly for the drive signal transformed by the first circuit configuration and the drive signal transformed by the second circuit configuration. Therefore, in the case of executing the retreat driving mode, it is possible to shift to the retreat driving mode without confirming the soundness of the fourth circuit configuration. That is, it is possible to smoothly shift to the retreat driving mode.

[0009] In the second mode, in the above first mode, the cut-off instruction may also be output from the first control device to the logic circuit.

[0010] In the third mode, in the above first or second mode, the first control device may output the first command value or the second command value to the second control device when the power supply of the electric vehicle is turned on, and output the cut-off instruction to the logic circuit, confirm that the output provided by the third circuit configuration is cut off, and thus perform the process of confirming the soundness of the fourth circuit configuration. According to the above structure, the first control device can pre-confirm the soundness of the fourth circuit configuration when the power supply of the electric vehicle is turned on.

[0011] In the fourth mode, in any one of the above first to third modes, the first control device may execute the retreat driving mode when detecting a failure of the processor.

[0012] In the fifth mode, in any one of the above first to fourth modes, the first control device may output the second command value to the logic circuit and output the cut-off instruction to the logic circuit when the power supply of the electric vehicle is turned on and a failure of the processor is detected, confirm that the output provided by the third circuit configuration is cut off, and thus perform the process of confirming the soundness of the fourth circuit configuration. According to the above structure, the first control device can pre-confirm the soundness of the fourth circuit configuration when the power supply of the electric vehicle is turned on. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Hereinafter, the features, advantages, and technical and industrial significance of the exemplary embodiments of the present invention will be described with reference to the drawings, in which the same reference numerals denote the same elements, and in which:

[0014] Figure 1 is a schematic diagram of the circuit structure of the control system.

[0015] Figure 2 It is a flowchart of the process executed by the upper ECU. Detailed implementation

[0016] (Circuit structure of control system 2; Figure 1 )

[0017] The control system 2 of this embodiment is mounted on an electric vehicle (such as a battery electric vehicle, a hybrid vehicle, a fuel cell vehicle, a plug-in hybrid vehicle, etc.) having a motor for driving wheels. As Figure 1 shown, the control system 2 includes an inverter 4, a motor 6, an upper ECU (abbreviation for Electronic Control Unit) 10, and a motor ECU 20.

[0018] The inverter 4 converts the DC power output from a battery (not shown) into three-phase AC power and supplies it to the motor 6. That is, the inverter 4 is a device that adjusts the power supplied to the motor 6. The electric vehicle can travel by driving the motor 6. In addition, the inverter 4 can also convert the regenerative power (three-phase AC power) of the motor 6 into DC power and supply it to the battery (not shown). Since the specific circuit structure of the inverter 4 is widely known, its detailed description is omitted.

[0019] The upper ECU 10 outputs a torque command value representing the target output of the motor 6, for example, based on the accelerator opening degree, etc. The motor ECU 20 is configured to be able to communicate with the upper ECU 10. The motor ECU 20 outputs a drive signal to the inverter 4 based on the torque command value output from the upper ECU 10. More specifically, when the upper ECU 10 executes the normal driving mode for normal driving of the electric vehicle, it outputs the torque command value for normal driving to the microcomputer 30 of the motor ECU 20. In addition, when the upper ECU 10 executes the avoidance driving mode for avoiding driving of the electric vehicle, it outputs the torque command value for avoidance driving to the ASIC 40 of the motor ECU 20. In addition, the upper ECU 10 is configured to be able to output a cut-off command for the inverter 4 to the ASIC 40.

[0020] The motor ECU 20 includes a microcomputer 30 and an ASIC (abbreviation for Application Specific Integrated Circuit). The microcomputer 30 is configured to be able to communicate with the upper ECU 10. The microcomputer 30 processes the torque command value for normal driving output from the upper ECU 10 by a program and outputs a current command value for the motor 6. The microcomputer 30 includes, for example, a CPU (abbreviation for Central Processing Unit), and can use this CPU to process the torque command value for normal driving output from the upper ECU 10 by a program.

[0021] The ASIC 40 is configured to be able to communicate with the upper ECU 10 and the microcomputer 30. In particular, the ASIC 40 is configured to be able to communicate with the upper ECU 10 without going through the microcomputer 30.

[0022] The ASIC 40 has a circuit structure for controlling the motor 6. For example, in the ASIC 40, it includes a resolver digital converter, an analog-to-digital converter, a motor IP, etc., which are part or all of the hardware parts dedicated to motor control. More specifically, the ASIC 40 includes a first circuit structure 42, a second circuit structure 44, a third circuit structure 46, and a fourth circuit structure 48. In addition, although not shown in the figure, the ASIC 40 also has a circuit structure for detecting faults of the microcomputer 30.

[0023] The first circuit structure 42 is a circuit that receives the current command value output from the microcomputer 30 and converts this current command value into a drive signal. The second circuit structure 44 is a circuit that receives the torque command value for retreat driving output from the upper ECU 10 and converts this torque command value for retreat driving into a drive signal.

[0024] The third circuit structure 46 is a circuit that receives the drive signal converted by the first circuit structure 42 and the drive signal converted by the second circuit structure 44, and alternatively outputs one of them. For example, it is configured to input whether the microcomputer 30 is faulty from the circuit structure for detecting faults of the microcomputer 30 to the third circuit structure 46. When the microcomputer 30 is not faulty, it outputs the drive signal converted by the first circuit structure 42, and when the microcomputer 30 is faulty, it outputs the drive signal converted by the second circuit structure 44.

[0025] The fourth circuit structure 48 is configured to receive the output provided by the third circuit structure 46 and the output from the upper ECU 10, and cut off the output provided by the third circuit structure 46 during the period when a cut-off command is input. That is, during the period when a cut-off command is output from the upper ECU 10, the drive signal for the inverter 4 is not output, so the operation of the inverter 4 stops.

[0026] In addition, the upper ECU 10 is also configured to be able to detect a failure of the microcomputer 30. For example, the upper ECU 10 may also send a signal to the microcomputer 30 for each predetermined period, and detect a failure of the microcomputer 30 when no response to the signal is received.

[0027] As described above, in the control system 2 of the present embodiment, the upper ECU 10 and the motor ECU 20 (i.e., the microcomputer 30 and the ASIC 40) cooperate with each other while controlling the inverter 4. Specifically, first, the upper ECU 10 outputs a torque command value that is the target output of the motor 6 based on the accelerator opening degree and the like to the microcomputer 30. The microcomputer 30 processes the torque command value with a program and outputs a current command value for the motor 6 to the ASIC 40. The ASIC 40 converts the current command value into a drive signal.

[0028] In such a control system 2, a situation is envisioned in which a failure occurs in a part of the structure of the motor ECU 20 (specifically, the microcomputer 30). In such a situation, the torque command value output from the upper ECU 10 is not acquired by the microcomputer 30. Therefore, the ASIC 40 cannot acquire the current command value from the microcomputer 30 and thus cannot output a drive signal. That is, generally, when the microcomputer 30 fails in such a control system 2, the control system 2 cannot make the electric vehicle travel.

[0029] Therefore, in the control system 2 of the present embodiment, when the upper ECU 10 detects a failure of the microcomputer 30, it shifts to the retreat travel mode. In the retreat travel mode, the upper ECU 10 outputs a torque command value for retreat travel to the second circuit structure 44 of the ASIC 40 instead of outputting the torque command value to the microcomputer 30. In addition, as described above, when the ASIC 40 detects a failure of the microcomputer 30, the third circuit structure 46 cuts off the output provided by the second circuit structure 44. In this way, even when a failure of the microcomputer 30 is detected, the electric vehicle can be made to retreat and travel.

[0030] In particular, the ASIC 40 of the present embodiment has a fourth circuit structure 48 at the final stage of the ASIC 40. Moreover, the drive signal converted by the first circuit structure 42 and the drive signal converted by the second circuit structure 44 are alternatively input to the fourth circuit structure 48. That is, in the structure of the present embodiment, a cut-off command for the inverter 4 is provided commonly for the drive signal converted by the first circuit structure 42 (i.e., the drive signal for normal travel) and the drive signal converted by the second circuit structure 44 (i.e., the drive signal for retreat travel).

[0031] Here, a comparative example is envisioned in which a cut-off instruction for the inverter 4 is provided independently for the normal driving signal and the retreat driving signal. In this comparative example, first, when the electric vehicle starts (i.e., when the upper ECU 10 starts) without a failure of the microcomputer 30, a cut-off confirmation for the normal driving signal is executed. After that, when a failure of the microcomputer 30 is detected, a cut-off confirmation for the retreat driving signal is executed. Thus, in the comparative example, when shifting from the normal driving mode to the retreat driving mode, a cut-off confirmation for the retreat driving signal is executed. When this cut-off confirmation takes time, it is impossible to smoothly shift from the normal driving mode to the retreat driving mode. As a result, there is a possibility that the convenience of the user is reduced.

[0032] In contrast, in the structure of the present embodiment, a cut-off instruction for the inverter 4 is provided commonly for the normal driving signal and the retreat driving signal. Therefore, when the electric vehicle starts (i.e., when the upper ECU 10 starts), if a cut-off confirmation is executed to confirm the soundness of the fourth circuit configuration 48, the electric vehicle can travel properly regardless of whether it is in the normal driving mode or the retreat driving mode. In particular, when shifting from the normal driving mode to the retreat driving mode, it is not necessary to execute the cut-off confirmation again, so it is possible to smoothly shift to the retreat driving mode. Therefore, the convenience of the user is improved.

[0033] (Processing of the upper ECU 10; Figure 2 )

[0034] Next, with reference to Figure 2 , the processing executed by the upper ECU 10 will be described. Triggered by the turning on of the switch of the electric vehicle and the turning on of the switch of the upper ECU 10, the processing of Figure 2 starts.

[0035] The upper ECU 10 determines in S10 of Figure 2 whether the microcomputer 30 has failed. For example, as described above, the upper ECU 10 sends a signal to the microcomputer 30, and if a response to this signal is received, it is determined that the microcomputer 30 has not failed (in S10, "No"), and the process proceeds to S20. On the other hand, the upper ECU 10 sends a signal to the microcomputer 30, and if a response to this signal is not received, it is determined that the microcomputer 30 has failed (in S10, "Yes"), and the process proceeds to S30.

[0036] In S20, the upper ECU 10 performs a cut-off confirmation to verify whether the fourth circuit structure 48 of the ASIC 40 is sound (i.e., whether it can appropriately cut off the output of the third circuit structure 46 according to the cut-off instruction from the upper ECU 10). Specifically, the upper ECU 10 first outputs a torque command value for normal driving to the microcomputer 30 and outputs a cut-off instruction to the fourth circuit structure 48. At the stage of S20, the microcomputer 30 is not faulty (in S10, "No"), so the microcomputer 30 uses the torque command value obtained by program processing and outputs a current command value to the first circuit structure 42 of the ASIC 40. The first circuit structure 42 converts the obtained current command value into a drive signal and outputs it to the third circuit structure 46. In addition, at the stage of S10, the microcomputer 30 is not faulty, so the third circuit structure 46 outputs the drive signal converted by the first circuit structure 42. Therefore, the drive signal converted by the first circuit structure 42 and the cut-off instruction are input to the fourth circuit structure 48.

[0037] As described above, the fourth circuit structure 48 cuts off the output provided by the third circuit structure 46 during the period when the cut-off instruction is input. Therefore, if the fourth circuit structure 48 is sound, the output of the third circuit structure 46 (i.e., the drive signal for normal driving) is cut off. The upper ECU 10 confirms that the drive signal for normal driving is cut off. In addition, assuming that an abnormality occurs in the fourth circuit structure 48, although the cut-off instruction is input from the upper ECU 10, it may not be possible to cut off the drive signal for normal driving. In this case, although not shown in the figure, the upper ECU 10 can also determine that the electric vehicle cannot travel and turn off the switch of the electric vehicle.

[0038] In addition, in this embodiment, the upper ECU 10 only outputs a torque command value for normal driving, but in addition or alternatively, it can also output a torque command value for emergency driving to the second circuit structure 44 of the ASIC 40.

[0039] In S30, the upper ECU 10 performs a cut-off confirmation. Specifically, the upper ECU 10 first outputs a torque command value for emergency driving to the second circuit structure 44 of the ASIC 40 and outputs a cut-off instruction to the fourth circuit structure 48. The second circuit structure 44 converts the obtained torque command value into a drive signal for emergency driving and outputs it to the third circuit structure 46. In addition, at the stage of S30, the microcomputer 30 is faulty, so the third circuit structure 46 outputs the drive signal for emergency driving converted by the second circuit structure 44. Therefore, the drive signal for emergency driving converted by the second circuit structure 44 and the cut-off instruction are input to the fourth circuit structure 48. Except that the output of the third circuit structure 46 is the drive signal for emergency driving converted by the second circuit structure 44, the subsequent processing is the same as that of S20.

[0040] In S40, the host ECU 10 starts the control in the normal running mode. That is, the host ECU 10 starts the process of outputting the torque command value to the microcomputer 30 according to the instruction from the user such as the accelerator opening. The process of S42 is the same as the process of S10.

[0041] In S50 , the host ECU 10 starts control in the evacuation travel mode. Specifically, the host ECU 10 starts processing to output a torque command value for evacuation travel to the second circuit structure 44 of the ASIC 40 based on an instruction from the user such as the accelerator opening.

[0042] As described above, according to the structure of this embodiment, when the upper ECU 10 starts the electric vehicle (i.e., when the upper ECU 10 starts), if the disconnection confirmation is performed to confirm the soundness of the fourth circuit structure 48, the electric vehicle can be properly driven regardless of the normal driving mode or the evacuation driving mode. Therefore, when the normal driving mode is shifted to the evacuation driving mode, the disconnection confirmation does not need to be performed again, so the evacuation driving mode can be smoothly shifted. As a result, the convenience of the user is improved.

[0043] The host ECU 10 and the motor ECU 20 are examples of the “first control device” and the “second control device” of the present technology, respectively. The microcomputer 30 and the ASIC 40 are examples of the “processor” and the “logic circuit” of the present technology, respectively. The inverter 4 is an example of the “power control device” of the present technology. The torque command value output from the host ECU 10 to the microcomputer 30 and the torque command value output from the host ECU 10 to the ASIC 40 are examples of the “first command value” and the “second command value” of the present technology, respectively. The current command value output from the microcomputer 30 to the ASIC 40 is an example of the “action command value” of the present technology.

[0044] A variation of the above embodiment is described. The upper ECU 10 can omit the processing of S10 and S30. In this case, the upper ECU 10 can also output at least one of the torque command value for normal driving or the torque command value for retreat driving and the cut-off command in S20 when the switch of the electric vehicle is turned on, thereby executing the cut-off confirmation.

[0045] The above describes in detail the specific examples of the technology disclosed in this specification, but these are only examples and do not limit the claims. The technology recorded in the claims includes examples obtained by various deformations and changes of the specific examples illustrated above. The technical elements described in this specification or the drawings play a technical usefulness alone or through various combinations, and are not limited to the combinations recorded in the claims at the time of application. In addition, the technology illustrated in this specification or the drawings can achieve multiple purposes at the same time, and has technical usefulness by achieving one of the purposes.

Claims

1. A control system for an electric vehicle, comprising: A power control device that adjusts the power supplied to the motor of the electric vehicle; A first control device that outputs a first command value representing the output that is the target of the motor; and A second control device configured to be able to communicate with the first control device and output a drive signal to the power control device according to the first command value output from the first control device, The second control device includes: A processor configured to be able to communicate with the first control device, process the first instruction value output from the first control device using a program, and output an operation instruction value for the motor; And A logic circuit having a first circuit configuration that transforms the operation command value output from the processor into the drive signal, When the first control device executes an avoidance driving mode for causing the electric vehicle to perform avoidance driving, instead of the first command value, it outputs a second command value based on the avoidance driving mode to the logic circuit, The logic circuit further has: A second circuit configuration that transforms the second command value output from the first control device into a drive signal for avoidance driving; A third circuit configuration that is input with the drive signal transformed by the first circuit configuration and the drive signal for avoidance driving transformed by the second circuit configuration, and selectively outputs one of them; And A fourth circuit configuration that is input with the output provided by the third circuit configuration and a cut-off command for the power control device, and cuts off the output provided by the third circuit configuration during the period when the cut-off command is input.

2. The control system according to claim 1, wherein: The cut-off command is output from the first control device to the logic circuit.

3. The control system according to claim 1, wherein: When the power of the electric vehicle is turned on, the first control device outputs the first command value or the second command value to the second control device, and outputs the cut-off command to the logic circuit, and confirms that the output provided by the third circuit configuration is cut off, thereby performing a process of confirming the soundness of the fourth circuit configuration.

4. The control system according to claim 1, wherein: When the first control device detects a failure of the processor, it executes the avoidance driving mode.

5. The control system according to claim 1, wherein: When the power of the electric vehicle is turned on and the first control device detects a failure of the processor, it outputs the second command value to the logic circuit, and outputs the cut-off command to the logic circuit, and confirms that the output provided by the third circuit configuration is cut off, thereby performing a process of confirming the soundness of the fourth circuit configuration.

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