A permanent magnet synchronous motor fault diagnosis method, system, device and medium

Abstract

The application relates to a permanent magnet synchronous motor fault diagnosis method, system, device and medium. Whether an inter-phase short circuit fault occurs between an inverter and an isolation contactor, and between the isolation contactor and a permanent magnet synchronous motor is separately detected by controlling the isolation contactor to be opened and closed. A first diagnosis result of whether the inter-phase short circuit fault occurs between the inverter and the isolation contactor is obtained according to a first feedback current pulse obtained after a three-phase voltage pulse with a preset amplitude is sent and the preset amplitude. A second diagnosis result of whether the inter-phase short circuit fault occurs between the isolation contactor and the permanent magnet synchronous motor is obtained according to the first diagnosis result, the first feedback current pulse obtained after the three-phase voltage pulse with the preset amplitude is sent and the preset amplitude. The inter-phase short circuit fault can be accurately and quickly diagnosed, and the position of the inter-phase short circuit fault can be effectively determined, so that the risk of the inverter being burned out and the motor being damaged can be effectively reduced.

Description

Technical Field

[0001] This application belongs to the field of motor fault diagnosis technology, and in particular relates to a method, system, equipment and medium for fault diagnosis of permanent magnet synchronous motor. Background Technology

[0002] With the continuous development of permanent magnet synchronous motor technology, the application range of permanent magnet synchronous motors is becoming wider and wider, and the safety issues of permanent magnet synchronous motors are receiving more and more attention.

[0003] Permanent magnet synchronous motors (PMSMs) have a variety of faults, including bearing failures, inter-turn short circuits in the motor windings, phase-to-phase short circuits in the windings, grounding faults, and demagnetization of the permanent magnet rotor. Due to the effect of the rotor magnetic field, a back electromotive force is generated on the winding side. If a phase-to-phase short circuit occurs when the motor is running at speed, a huge asymmetrical two-phase or three-phase short-circuit current will be generated on the winding side. If this short-circuit current occurs for a long time, it will generate severe torque pulsation and vibration noise. In severe cases, it may cause the inverter connected to the motor to burn out and the motor to be damaged.

[0004] Therefore, how to diagnose whether a phase-to-phase short-circuit fault has occurred is a technical problem that urgently needs to be solved by those skilled in the art. Summary of the Invention

[0005] The purpose of this application is to provide a method, system, device, and medium for diagnosing faults in permanent magnet synchronous motors. The method, system, device, and medium for diagnosing faults in permanent magnet synchronous motors provided by this application can accurately and quickly diagnose whether a phase-to-phase short circuit fault has occurred, and can effectively determine the location of the phase-to-phase short circuit fault, thereby effectively reducing the risk of inverter burnout and motor damage. The technical solution provided in this application is as follows: A fault diagnosis method for a permanent magnet synchronous motor, wherein the permanent magnet synchronous motor is connected to an inverter via an isolation contactor, and a current sensor is installed between the isolation contactor and the inverter, the method comprising: If a fault is detected in the permanent magnet synchronous motor during vehicle operation, the permanent magnet synchronous motor will be stopped. Control the disconnecting contactor to disconnect; A three-phase voltage pulse of preset amplitude is sent to the switching transistor in the inverter, and the first feedback current pulse collected by the current sensor is obtained. Based on the amplitude of the first feedback current pulse and the preset amplitude, a first diagnostic result is obtained as to whether a phase-to-phase short circuit fault has occurred in the two-phase cable between the inverter and the isolation contactor. Control the closing of the isolation contactor; A three-phase voltage pulse of preset amplitude is sent to the switching transistor in the inverter, and a second feedback current pulse collected by the current sensor is obtained. Based on the first diagnostic result, the amplitude of the second feedback current pulse and the preset amplitude, a second diagnostic result is obtained to determine whether a phase-to-phase short circuit fault has occurred in the two-phase cable between the isolation contactor and the permanent magnet synchronous motor.

[0006] Optionally, the current sensor includes an A-phase current sensor and a B-phase current sensor. The A-phase current sensor is disposed on the A-phase cable between the isolation contactor and the inverter, and the B-phase current sensor is disposed on the B-phase cable between the isolation contactor and the inverter. The process involves sending a three-phase voltage pulse of a preset amplitude to the switching transistor in the inverter, acquiring a first feedback current pulse collected by the current sensor, and obtaining a first diagnostic result regarding whether a phase-to-phase short-circuit fault has occurred in the two-phase cable between the inverter and the isolation contactor based on the amplitude of the first feedback current pulse and the preset amplitude. This includes: A voltage pulse of a preset amplitude is sent to the switching transistors in the inverter so that the upper switching transistor of phase A in the inverter is forward-biased and the lower switching transistors of phases B and C are reverse-biased. The first A-phase feedback current pulse collected by the A-phase current sensor and the first B-phase feedback current pulse collected by the B-phase current sensor are obtained, wherein the first feedback current pulse includes the first A-phase feedback current pulse and the first B-phase feedback current pulse. If the amplitude of the first A-phase feedback current pulse and the amplitude of the first B-phase feedback current pulse are both less than or equal to a preset multiple of the preset amplitude, then it is determined that no phase-to-phase short circuit fault has occurred in the A-phase cable and the B-phase cable between the inverter and the isolation contactor. If the amplitude of the first A-phase feedback current pulse and the amplitude of the first B-phase feedback current pulse are both greater than a preset multiple of the preset amplitude, then it is determined that a phase-to-phase short circuit fault has occurred in the A-phase cable and the B-phase cable between the inverter and the isolation contactor. If the amplitude of the first A-phase feedback current pulse is greater than a preset multiple of the preset amplitude, and the amplitude of the first B-phase feedback current pulse is less than or equal to a preset multiple of the preset amplitude, then it is determined that a phase-to-phase short circuit fault has occurred in the A-phase cable and the C-phase cable between the inverter and the isolation contactor.

[0007] Optionally, the step of sending a three-phase voltage pulse of a preset amplitude to the switching transistor in the inverter, obtaining the first feedback current pulse collected by the current sensor, and obtaining a first diagnostic result of whether a phase-to-phase short circuit fault has occurred in the two-phase cable between the inverter and the isolation contactor based on the amplitude of the first feedback current pulse and the preset amplitude, further includes: A preset amplitude B-phase voltage pulse is sent to the switching transistors in the inverter so that the upper switching transistor of the B-phase in the inverter is forward-biased and the lower switching transistors of the A-phase and C-phase are reverse-biased. The second A-phase feedback current pulse collected by the A-phase current sensor and the second B-phase feedback current pulse collected by the B-phase current sensor are obtained, wherein the first feedback current pulse further includes the second A-phase feedback current pulse and the second B-phase feedback current pulse; If the amplitude of the second phase A feedback current pulse is less than or equal to a preset multiple of the preset amplitude, and the amplitude of the second phase B feedback current pulse is greater than a preset multiple of the preset amplitude, then it is determined that a phase-to-phase short circuit fault has occurred in the phase B cable and phase C cable between the inverter and the isolation contactor.

[0008] Optionally, the step of sending a three-phase voltage pulse of a preset amplitude to the switching transistor in the inverter, obtaining a first feedback current pulse collected by the current sensor, and obtaining a first diagnostic result of whether a phase-to-phase short-circuit fault has occurred in the two-phase cable between the inverter and the isolation contactor based on the amplitude of the first feedback current pulse and the preset amplitude, further includes: A C-phase voltage pulse of preset amplitude is sent to the switching transistors in the inverter so that the upper switching transistor of the C-phase in the inverter is forward-biased and the lower switching transistors of the A-phase and B-phase are reverse-biased. The third A-phase feedback current pulse collected by the A-phase current sensor and the third B-phase feedback current pulse collected by the B-phase current sensor are obtained, wherein the first feedback current pulse further includes the third A-phase feedback current pulse and the third B-phase feedback current pulse. If the amplitude of the third phase A feedback current pulse and the amplitude of the third phase B feedback current pulse are both less than or equal to a preset multiple of the preset amplitude, then it is determined that no phase-to-phase short circuit fault has occurred in the A-phase cable and C-phase cable, as well as the B-phase cable and C-phase cable between the inverter and the isolation contactor.

[0009] Optionally, the step of sending a three-phase voltage pulse of preset amplitude to the switching transistor in the inverter, acquiring the second feedback current pulse collected by the current sensor, and obtaining a second diagnostic result of whether a phase-to-phase short-circuit fault has occurred in the two-phase cable between the isolation contactor and the permanent magnet synchronous motor based on the first diagnostic result, the amplitude of the second feedback current pulse, and the preset amplitude, includes: A voltage pulse of a preset amplitude is sent to the switching transistors in the inverter so that the upper switching transistor of phase A in the inverter is forward-biased and the lower switching transistors of phases B and C are reverse-biased. The fourth A-phase feedback current pulse collected by the A-phase current sensor and the fourth B-phase feedback current pulse collected by the B-phase current sensor are obtained, wherein the second feedback current pulse includes the fourth A-phase feedback current pulse and the fourth B-phase feedback current pulse. If the amplitudes of the fourth A-phase feedback current pulse and the fourth B-phase feedback current pulse are both less than or equal to a preset multiple of the preset amplitude, it is determined that no phase-to-phase short circuit fault has occurred in the A-phase cable and the B-phase cable between the isolation contactor and the permanent magnet synchronous motor. If the first diagnostic result indicates that there is no phase-to-phase short circuit fault in the A-phase cable and B-phase cable between the inverter and the isolation contactor, and the amplitudes of the fourth A-phase feedback current pulse and the fourth B-phase feedback current pulse are both greater than a preset multiple of the preset amplitude, then it is determined that there is a phase-to-phase short circuit fault in the A-phase cable and B-phase cable between the isolation contactor and the permanent magnet synchronous motor. If the first diagnostic result indicates that no phase-to-phase short circuit fault has occurred in the A-phase cable and C-phase cable between the inverter and the isolation contactor, and the amplitude of the fourth A-phase feedback current pulse is greater than a preset multiple of the preset amplitude, and the amplitude of the fourth B-phase feedback current pulse is less than or equal to a preset multiple of the preset amplitude, then it is determined that a phase-to-phase short circuit fault has occurred in the A-phase cable and C-phase cable between the isolation contactor and the permanent magnet synchronous motor.

[0010] Optionally, the step of sending a three-phase voltage pulse of a preset amplitude to the switching transistor in the inverter, obtaining a second feedback current pulse collected by the current sensor, and obtaining a second diagnostic result of whether a phase-to-phase short-circuit fault has occurred in the two-phase cable between the isolation contactor and the permanent magnet synchronous motor based on the first diagnostic result, the amplitude of the second feedback current pulse, and the preset amplitude, further includes: A preset amplitude B-phase voltage pulse is sent to the switching transistors in the inverter so that the upper switching transistor of the B-phase in the inverter is forward-biased and the lower switching transistors of the A-phase and C-phase are reverse-biased. The fifth A-phase feedback current pulse collected by the A-phase current sensor and the fifth B-phase feedback current pulse collected by the B-phase current sensor are obtained, wherein the second feedback current pulse further includes the fifth A-phase feedback current pulse and the fifth B-phase feedback current pulse; If the first diagnostic result indicates that no phase-to-phase short circuit fault has occurred in the B-phase cable and C-phase cable between the inverter and the isolation contactor, and the amplitude of the fifth A-phase feedback current pulse is less than or equal to a preset multiple of the preset amplitude, and the amplitude of the fifth B-phase feedback current pulse is greater than a preset multiple of the preset amplitude, then it is determined that a phase-to-phase short circuit fault has occurred in the B-phase cable and C-phase cable between the isolation contactor and the permanent magnet synchronous motor.

[0011] Optionally, the step of sending a three-phase voltage pulse of a preset amplitude to the switching transistor in the inverter, obtaining a second feedback current pulse collected by the current sensor, and obtaining a second diagnostic result of whether a phase-to-phase short-circuit fault has occurred in the two-phase cable between the isolation contactor and the permanent magnet synchronous motor based on the first diagnostic result, the amplitude of the second feedback current pulse, and the preset amplitude, further includes: A C-phase voltage pulse of preset amplitude is sent to the switching transistors in the inverter so that the upper switching transistor of the C-phase in the inverter is forward-biased and the lower switching transistors of the A-phase and B-phase are reverse-biased. The sixth phase A feedback current pulse collected by the phase A current sensor and the sixth phase B feedback current pulse collected by the phase B current sensor are obtained, wherein the second feedback current pulse further includes the sixth phase A feedback current pulse and the sixth phase B feedback current pulse; If the amplitude of the sixth phase A feedback current pulse is less than or equal to a preset multiple of the preset amplitude, and the amplitude of the sixth phase B feedback current pulse is less than or equal to a preset multiple of the preset amplitude, then it is determined that no phase-to-phase short circuit fault has occurred in the A-phase cable and C-phase cable, as well as the B-phase cable and C-phase cable between the isolation contactor and the permanent magnet synchronous motor.

[0012] Optionally, the method further includes: If the first diagnostic result is that a phase-to-phase short circuit fault has occurred in the two-phase cable between the inverter and the isolation contactor, or if the second diagnostic result is that a phase-to-phase short circuit fault has occurred in the two-phase cable between the isolation contactor and the permanent magnet synchronous motor, then the upper switch tubes of each phase in the inverter are turned on and the lower switch tubes of each phase are turned off, or the upper switch tubes of each phase in the inverter are turned off and the lower switch tubes of each phase are turned on.

[0013] Optionally, the method further includes: Control the disconnecting contactor to disconnect; Control the upper-phase switching transistors of each phase in the inverter to be turned on and the lower-phase switching transistors of each phase to be turned off; Acquire the seventh phase A feedback current pulse collected by the phase A current sensor and the seventh phase B feedback current pulse collected by the phase B current sensor; If the amplitude of the seventh phase A feedback current pulse and the amplitude of the seventh phase B feedback current pulse are both zero, it is determined that neither the A-phase cable nor the B-phase cable between the inverter and the isolation contactor has a grounding fault. If the amplitude of the seventh phase A feedback current pulse is greater than zero and the amplitude of the seventh phase B feedback current pulse is zero, then it is determined that the A phase cable between the inverter and the isolation contactor has a grounding fault, and the B phase cable has not a grounding fault. If the amplitude of the seventh phase A feedback current pulse is equal to zero and the amplitude of the seventh phase B feedback current pulse is greater than zero, then it is determined that the A-phase cable between the inverter and the isolation contactor has not experienced a grounding fault, and the B-phase cable has experienced a grounding fault. If the amplitude of the seventh phase A feedback current pulse and the amplitude of the seventh phase B feedback current pulse are both greater than zero, then it is determined that both the A-phase cable and the B-phase cable between the inverter and the isolation contactor have a grounding fault.

[0014] Optionally, the method further includes: If it is determined that neither the A-phase cable nor the B-phase cable between the inverter and the isolation contactor has a grounding fault, then the isolation contactor is controlled to close. A positive voltage pulse is sent to the upper switching transistor in the inverter, and a negative voltage pulse is sent to the lower switching transistor in the inverter; The eighth phase A feedback current pulse collected by the phase A current sensor and the eighth phase B feedback current pulse collected by the phase B current sensor are obtained. If the amplitude of the eighth phase A feedback current pulse and the amplitude of the eighth phase B feedback current pulse are both zero, it is determined that neither the A-phase cable nor the B-phase cable between the isolation contactor and the permanent magnet synchronous motor has a grounding fault. If the amplitude of the eighth phase A feedback current pulse is greater than zero and the amplitude of the eighth phase B feedback current pulse is zero, then it is determined that the A-phase cable between the isolation contactor and the permanent magnet synchronous motor has a grounding fault, and the B-phase cable has not a grounding fault. If the amplitude of the eighth phase A feedback current pulse is equal to zero and the amplitude of the eighth phase B feedback current pulse is greater than zero, then it is determined that the A-phase cable between the isolation contactor and the permanent magnet synchronous motor has no grounding fault, and the B-phase cable has a grounding fault. If the amplitude of the eighth phase A feedback current pulse and the amplitude of the eighth phase B feedback current pulse are both greater than zero, then it is determined that both the A-phase cable and the B-phase cable between the isolation contactor and the permanent magnet synchronous motor have grounding faults.

[0015] This application also provides a fault diagnosis system for a permanent magnet synchronous motor, wherein the permanent magnet synchronous motor is connected to an inverter via an isolation contactor, and a current sensor is provided between the isolation contactor and the inverter. The system includes: The first control module is used to control the permanent magnet synchronous motor to stop when a fault is detected in the permanent magnet synchronous motor during the operation of the vehicle. The second control module is used to control the disconnection of the isolating contactor; The first diagnostic module is used to send a three-phase voltage pulse of preset amplitude to the switching transistor in the inverter, obtain the first feedback current pulse collected by the current sensor, and obtain a first diagnostic result of whether a phase-to-phase short circuit fault has occurred in the two-phase cable between the inverter and the isolation contactor based on the amplitude of the first feedback current pulse and the preset amplitude. The third control module is used to control the closing of the isolating contactor; The second diagnostic module is used to send a three-phase voltage pulse of preset amplitude to the switching transistor in the inverter, obtain the second feedback current pulse collected by the current sensor, and obtain a second diagnostic result of whether a phase-to-phase short circuit fault has occurred in the two-phase cable between the isolation contactor and the permanent magnet synchronous motor based on the first diagnostic result, the amplitude of the second feedback current pulse and the preset amplitude.

[0016] Optionally, the current sensor includes an A-phase current sensor and a B-phase current sensor. The A-phase current sensor is disposed on the A-phase cable between the isolation contactor and the inverter, and the B-phase current sensor is disposed on the B-phase cable between the isolation contactor and the inverter. When the first diagnostic module sends a three-phase voltage pulse of preset amplitude to the switching transistor in the inverter, acquires the first feedback current pulse collected by the current sensor, and obtains a first diagnostic result regarding whether a phase-to-phase short-circuit fault has occurred in the two-phase cable between the inverter and the isolation contactor based on the amplitude of the first feedback current pulse and the preset amplitude, it is specifically used for: A voltage pulse of a preset amplitude is sent to the switching transistors in the inverter so that the upper switching transistor of phase A in the inverter is forward-biased and the lower switching transistors of phases B and C are reverse-biased. The first A-phase feedback current pulse collected by the A-phase current sensor and the first B-phase feedback current pulse collected by the B-phase current sensor are obtained, wherein the first feedback current pulse includes the first A-phase feedback current pulse and the first B-phase feedback current pulse. If the amplitude of the first A-phase feedback current pulse and the amplitude of the first B-phase feedback current pulse are both less than or equal to a preset multiple of the preset amplitude, then it is determined that no phase-to-phase short circuit fault has occurred in the A-phase cable and the B-phase cable between the inverter and the isolation contactor. If the amplitude of the first A-phase feedback current pulse and the amplitude of the first B-phase feedback current pulse are both greater than a preset multiple of the preset amplitude, then it is determined that a phase-to-phase short circuit fault has occurred in the A-phase cable and the B-phase cable between the inverter and the isolation contactor. If the amplitude of the first A-phase feedback current pulse is greater than a preset multiple of the preset amplitude, and the amplitude of the first B-phase feedback current pulse is less than or equal to a preset multiple of the preset amplitude, then it is determined that a phase-to-phase short circuit fault has occurred in the A-phase cable and the C-phase cable between the inverter and the isolation contactor.

[0017] Optionally, when the first diagnostic module sends a three-phase voltage pulse of preset amplitude to the switching transistor in the inverter, acquires the first feedback current pulse collected by the current sensor, and obtains a first diagnostic result of whether a phase-to-phase short-circuit fault has occurred in the two-phase cable between the inverter and the isolation contactor based on the amplitude of the first feedback current pulse and the preset amplitude, it is further specifically used for: A preset amplitude B-phase voltage pulse is sent to the switching transistors in the inverter so that the upper switching transistor of the B-phase in the inverter is forward-biased and the lower switching transistors of the A-phase and C-phase are reverse-biased. The second A-phase feedback current pulse collected by the A-phase current sensor and the second B-phase feedback current pulse collected by the B-phase current sensor are obtained, wherein the first feedback current pulse further includes the second A-phase feedback current pulse and the second B-phase feedback current pulse; If the amplitude of the second phase A feedback current pulse is less than or equal to a preset multiple of the preset amplitude, and the amplitude of the second phase B feedback current pulse is greater than a preset multiple of the preset amplitude, then it is determined that a phase-to-phase short circuit fault has occurred in the phase B cable and phase C cable between the inverter and the isolation contactor.

[0018] Optionally, when the first diagnostic module sends a three-phase voltage pulse of preset amplitude to the switching transistor in the inverter, acquires the first feedback current pulse collected by the current sensor, and obtains a first diagnostic result of whether a phase-to-phase short-circuit fault has occurred in the two-phase cable between the inverter and the isolation contactor based on the amplitude of the first feedback current pulse and the preset amplitude, it is further specifically used for: A C-phase voltage pulse of preset amplitude is sent to the switching transistors in the inverter so that the upper switching transistor of the C-phase in the inverter is forward-biased and the lower switching transistors of the A-phase and B-phase are reverse-biased. The third A-phase feedback current pulse collected by the A-phase current sensor and the third B-phase feedback current pulse collected by the B-phase current sensor are obtained, wherein the first feedback current pulse further includes the third A-phase feedback current pulse and the third B-phase feedback current pulse. If the amplitude of the third phase A feedback current pulse and the amplitude of the third phase B feedback current pulse are both less than or equal to a preset multiple of the preset amplitude, then it is determined that no phase-to-phase short circuit fault has occurred in the A-phase cable and C-phase cable, as well as the B-phase cable and C-phase cable between the inverter and the isolation contactor.

[0019] Optionally, when the second diagnostic module sends a three-phase voltage pulse of preset amplitude to the switching transistors in the inverter, acquires the second feedback current pulse collected by the current sensor, and obtains a second diagnostic result regarding whether a phase-to-phase short-circuit fault has occurred in the two-phase cable between the isolation contactor and the permanent magnet synchronous motor based on the first diagnostic result, the amplitude of the second feedback current pulse, and the preset amplitude, it is specifically used for: A voltage pulse of a preset amplitude is sent to the switching transistors in the inverter so that the upper switching transistor of phase A in the inverter is forward-biased and the lower switching transistors of phases B and C are reverse-biased. The fourth A-phase feedback current pulse collected by the A-phase current sensor and the fourth B-phase feedback current pulse collected by the B-phase current sensor are obtained, wherein the second feedback current pulse includes the fourth A-phase feedback current pulse and the fourth B-phase feedback current pulse. If the amplitudes of the fourth A-phase feedback current pulse and the fourth B-phase feedback current pulse are both less than or equal to a preset multiple of the preset amplitude, it is determined that no phase-to-phase short circuit fault has occurred in the A-phase cable and the B-phase cable between the isolation contactor and the permanent magnet synchronous motor. If the first diagnostic result indicates that there is no phase-to-phase short circuit fault in the A-phase cable and B-phase cable between the inverter and the isolation contactor, and the amplitudes of the fourth A-phase feedback current pulse and the fourth B-phase feedback current pulse are both greater than a preset multiple of the preset amplitude, then it is determined that there is a phase-to-phase short circuit fault in the A-phase cable and B-phase cable between the isolation contactor and the permanent magnet synchronous motor. If the first diagnostic result indicates that no phase-to-phase short circuit fault has occurred in the A-phase cable and C-phase cable between the inverter and the isolation contactor, and the amplitude of the fourth A-phase feedback current pulse is greater than a preset multiple of the preset amplitude, and the amplitude of the fourth B-phase feedback current pulse is less than or equal to a preset multiple of the preset amplitude, then it is determined that a phase-to-phase short circuit fault has occurred in the A-phase cable and C-phase cable between the isolation contactor and the permanent magnet synchronous motor.

[0020] Optionally, when the second diagnostic module sends a three-phase voltage pulse of preset amplitude to the switching transistors in the inverter, acquires the second feedback current pulse collected by the current sensor, and obtains a second diagnostic result regarding whether a phase-to-phase short-circuit fault has occurred in the two-phase cable between the isolation contactor and the permanent magnet synchronous motor based on the first diagnostic result, the amplitude of the second feedback current pulse, and the preset amplitude, it is further specifically used for: A preset amplitude B-phase voltage pulse is sent to the switching transistors in the inverter so that the upper switching transistor of the B-phase in the inverter is forward-biased and the lower switching transistors of the A-phase and C-phase are reverse-biased. The fifth A-phase feedback current pulse collected by the A-phase current sensor and the fifth B-phase feedback current pulse collected by the B-phase current sensor are obtained, wherein the second feedback current pulse further includes the fifth A-phase feedback current pulse and the fifth B-phase feedback current pulse; If the first diagnostic result indicates that no phase-to-phase short circuit fault has occurred in the B-phase cable and C-phase cable between the inverter and the isolation contactor, and the amplitude of the fifth A-phase feedback current pulse is less than or equal to a preset multiple of the preset amplitude, and the amplitude of the fifth B-phase feedback current pulse is greater than a preset multiple of the preset amplitude, then it is determined that a phase-to-phase short circuit fault has occurred in the B-phase cable and C-phase cable between the isolation contactor and the permanent magnet synchronous motor.

[0021] Optionally, when the second diagnostic module sends a three-phase voltage pulse of preset amplitude to the switching transistors in the inverter, acquires the second feedback current pulse collected by the current sensor, and obtains a second diagnostic result regarding whether a phase-to-phase short-circuit fault has occurred in the two-phase cable between the isolation contactor and the permanent magnet synchronous motor based on the first diagnostic result, the amplitude of the second feedback current pulse, and the preset amplitude, it is further specifically used for: A C-phase voltage pulse of preset amplitude is sent to the switching transistors in the inverter so that the upper switching transistor of the C-phase in the inverter is forward-biased and the lower switching transistors of the A-phase and B-phase are reverse-biased. The sixth phase A feedback current pulse collected by the phase A current sensor and the sixth phase B feedback current pulse collected by the phase B current sensor are obtained, wherein the second feedback current pulse further includes the sixth phase A feedback current pulse and the sixth phase B feedback current pulse; If the amplitude of the sixth phase A feedback current pulse is less than or equal to a preset multiple of the preset amplitude, and the amplitude of the sixth phase B feedback current pulse is less than or equal to a preset multiple of the preset amplitude, then it is determined that no phase-to-phase short circuit fault has occurred in the A-phase cable and C-phase cable, as well as the B-phase cable and C-phase cable between the isolation contactor and the permanent magnet synchronous motor.

[0022] Optionally, the system further includes: The protection module is configured to, if the first diagnostic result indicates a phase-to-phase short circuit fault in the two-phase cable between the inverter and the isolation contactor, or the second diagnostic result indicates a phase-to-phase short circuit fault in the two-phase cable between the isolation contactor and the permanent magnet synchronous motor, control the upper phase switching transistors of the inverter to be turned on and the lower phase switching transistors of the inverter to be turned off, or control the upper phase switching transistors of the inverter to be turned off and the lower phase switching transistors of the inverter to be turned on.

[0023] This application also provides a fault diagnosis device for a permanent magnet synchronous motor, including: a processor, a memory, and a communication bus; The communication bus is used to realize the connection and communication between the processor and the memory; The processor is used to execute the permanent magnet synchronous motor fault diagnosis processing program stored in the memory to implement the steps of the permanent magnet synchronous motor fault diagnosis method as described in any of the above.

[0024] This application also provides a readable storage medium storing computer-executable instructions, which, when loaded and executed by a processor, implement the steps of the permanent magnet synchronous motor fault diagnosis method as described in any of the above claims.

[0025] Compared with existing technologies, the permanent magnet synchronous motor fault diagnosis method, system, equipment, and medium provided in this application, by controlling the opening and closing of the isolating contactor, separately detects whether a phase-to-phase short circuit fault has occurred in the two-phase cable between the inverter and the isolating contactor, and whether a phase-to-phase short circuit fault has occurred in the two-phase cable between the isolating contactor and the permanent magnet synchronous motor. After the isolating contactor is opened, based on the relationship between the first feedback current pulse obtained after sending a three-phase voltage pulse of preset amplitude and the preset amplitude, a first diagnostic result of whether a phase-to-phase short circuit fault has occurred in the two-phase cable between the inverter and the isolating contactor can be obtained. After the isolating contactor is closed, based on the first diagnostic result, the relationship between the first feedback current pulse obtained after sending a three-phase voltage pulse of preset amplitude and the preset amplitude, a second diagnostic result of whether a phase-to-phase short circuit fault has occurred in the two-phase cable between the isolating contactor and the permanent magnet synchronous motor can be obtained. Thus, it can accurately and quickly diagnose whether a phase-to-phase short circuit fault has occurred, and effectively determine the location of the phase-to-phase short circuit fault, thereby effectively reducing the risk of inverter burnout and motor damage. Attached Figure Description

[0026] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0027] Figure 1 This is a flowchart of a fault diagnosis method for a permanent magnet synchronous motor disclosed in an embodiment of this application; Figure 2 This is a schematic diagram showing the connection relationship between the inverter, current sensor, isolation contactor and permanent magnet synchronous motor disclosed in the embodiments of this application. Figure 3 This is a schematic diagram illustrating a phase-to-phase short-circuit fault in the A-phase cable and B-phase cable between the inverter and the isolation contactor as disclosed in the embodiments of this application. Figure 4 This is a schematic diagram illustrating a phase-to-phase short-circuit fault in the A-phase cable and B-phase cable between the isolating contactor and the permanent magnet synchronous motor disclosed in this application embodiment; Figure 5 This is a structural block diagram of a permanent magnet synchronous motor fault diagnosis system disclosed in an embodiment of this application; Figure 6 This is a structural block diagram of a fault diagnosis device for a permanent magnet synchronous motor disclosed in an embodiment of this application. Detailed Implementation

[0028] To enable those skilled in the art to better understand the technical solutions in this application, the technical solutions in the embodiments of this application will be clearly and completely described below. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of the embodiments. Based on the embodiments in this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0029] It should be noted that when a component is referred to as being "fixed to" or "set on" another component, it can be directly on or indirectly set on the other component; when a component is referred to as being "connected to" another component, it can be directly connected to or indirectly connected to the other component.

[0030] It should be understood that the terms "length", "width", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this application.

[0031] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this application, "a plurality of" or "several" means two or more, unless otherwise explicitly specified.

[0032] It should be noted that the structures, proportions, sizes, etc., shown in the accompanying drawings of this specification are only for the purpose of assisting those skilled in the art in understanding and reading the content disclosed in the specification, and are not intended to limit the conditions under which this application can be implemented. Therefore, they have no substantial technical significance. Any modifications to the structure, changes in the proportions, or adjustments to the size should still fall within the scope of the technical content disclosed in this application, provided that they do not affect the effects and purposes that this application can produce.

[0033] like Figure 1 As shown, this application provides a method for diagnosing faults in a permanent magnet synchronous motor. Figure 2 As shown, the permanent magnet synchronous motor 100 is connected to the inverter 300 via an isolation contactor 200. A current sensor 400 is installed between the isolation contactor 200 and the inverter 300. The method includes: S11. If a fault is detected in the permanent magnet synchronous motor during vehicle operation, the permanent magnet synchronous motor will be stopped. In this embodiment, if the current value or the amplitude of the current pulse collected by the current sensor exceeds the preset current threshold during the operation of the vehicle, it can generally be considered that the permanent magnet synchronous motor has failed, and the permanent magnet synchronous motor will be stopped.

[0034] S12, Control the disconnecting contactor to disconnect; In this embodiment, by first controlling the disconnection of the isolation contactor, the system can detect whether a phase-to-phase short circuit fault has occurred in the two-phase cable between the inverter and the isolation contactor.

[0035] S13. Send a three-phase voltage pulse with a preset amplitude to the switching transistor in the inverter, obtain the first feedback current pulse collected by the current sensor, and obtain the first diagnostic result of whether a phase-to-phase short circuit fault has occurred in the two-phase cable between the inverter and the isolation contactor based on the amplitude of the first feedback current pulse and the preset amplitude. In this embodiment, the preset amplitude is a pre-set amplitude. Since the inverter generally only collects two-phase current, the current sensor can be a two-phase current sensor, that is, two current sensors that collect two-phase current respectively. Based on the relationship between the amplitude of the first feedback current pulse and the preset amplitude, specifically, it can be comparing the magnitude relationship between the amplitude of the first feedback current pulse and the preset amplitude, or comparing the magnitude relationship between the amplitude of the first feedback current pulse and a preset multiple of the preset amplitude, to obtain the first diagnostic result of whether a phase-to-phase short circuit fault has occurred in the two-phase cable between the inverter and the isolation contactor.

[0036] S14. Control the closing of the isolating contactor; In this embodiment, after obtaining the first diagnostic result of whether a phase-to-phase short circuit fault has occurred in the two-phase cable between the inverter and the isolation contactor, the isolation contactor is then closed to detect whether a phase-to-phase short circuit fault has occurred in the two-phase cable between the inverter and the isolation contactor.

[0037] S15. Send a three-phase voltage pulse with a preset amplitude to the switching transistor in the inverter, obtain the second feedback current pulse collected by the current sensor, and obtain the second diagnostic result of whether a phase-to-phase short circuit fault has occurred in the two-phase cable between the isolation contactor and the permanent magnet synchronous motor based on the first diagnostic result, the amplitude of the second feedback current pulse and the preset amplitude.

[0038] In this embodiment, a second diagnostic result can be obtained based on the relationship between the amplitude of the second feedback current pulse and the preset amplitude. Specifically, it can be based on comparing the magnitude relationship between the amplitude of the second feedback current pulse and the preset amplitude, or comparing the magnitude relationship between the amplitude of the second feedback current pulse and a preset multiple of the preset amplitude, to determine whether a phase-to-phase short circuit fault has occurred in the two-phase cable between the isolation contactor and the permanent magnet synchronous motor.

[0039] Compared with existing technologies, the permanent magnet synchronous motor fault diagnosis method, system, equipment, and medium provided in this application, by controlling the opening and closing of the isolating contactor, separately detects whether a phase-to-phase short circuit fault has occurred in the two-phase cable between the inverter and the isolating contactor, and whether a phase-to-phase short circuit fault has occurred in the two-phase cable between the isolating contactor and the permanent magnet synchronous motor. After the isolating contactor is opened, based on the relationship between the first feedback current pulse obtained after sending a three-phase voltage pulse of preset amplitude and the preset amplitude, a first diagnostic result of whether a phase-to-phase short circuit fault has occurred in the two-phase cable between the inverter and the isolating contactor can be obtained. After the isolating contactor is closed, based on the first diagnostic result, the relationship between the first feedback current pulse obtained after sending a three-phase voltage pulse of preset amplitude and the preset amplitude, a second diagnostic result of whether a phase-to-phase short circuit fault has occurred in the two-phase cable between the isolating contactor and the permanent magnet synchronous motor can be obtained. Thus, it can accurately and quickly diagnose whether a phase-to-phase short circuit fault has occurred, and effectively determine the location of the phase-to-phase short circuit fault, thereby effectively reducing the risk of inverter burnout and motor damage.

[0040] As one implementation method, in the embodiments of this application, such as Figure 2 As shown, the current sensor 400 includes an A-phase current sensor 410 and a B-phase current sensor 420. The A-phase current sensor 410 is disposed on the A-phase cable between the isolation contactor 200 and the inverter 300, and the B-phase current sensor 420 is disposed on the B-phase cable between the isolation contactor 200 and the inverter 300. Step S13 includes: S1311. Send a voltage pulse of A phase with a preset amplitude to the switching transistors in the inverter so that the upper switching transistor of A phase in the inverter is forward-biased and the lower switching transistors of B phase and C phase are reverse-biased. In this embodiment, as Figure 2 As shown, the inverter 300 includes an upper switch 310 of phase A, a lower switch 320 of phase A, an upper switch 330 of phase B, a lower switch 340 of phase B, an upper switch 350 of phase C, and a lower switch 360 of phase C. It sends a voltage pulse of phase A with a preset amplitude to the switches in the inverter 300, so that the upper switch 310 of phase A is forward-biased, the lower switch 340 of phase B and the lower switch 360 of phase C are reverse-biased, and the lower switch 320 of phase A, the upper switch 330 of phase B, and the upper switch 350 of phase C are disconnected.

[0041] S1312. Obtain the first A-phase feedback current pulse collected by the A-phase current sensor and the first B-phase feedback current pulse collected by the B-phase current sensor, wherein the first feedback current pulse includes the first A-phase feedback current pulse and the first B-phase feedback current pulse. S1313. If the amplitude of the first A-phase feedback current pulse and the amplitude of the first B-phase feedback current pulse are both less than or equal to a preset multiple of the preset amplitude, it is determined that no phase-to-phase short circuit fault has occurred in the A-phase cable and the B-phase cable between the inverter and the isolation contactor. In this embodiment, the preset multiple is a pre-set multiple, which can be 2 or other values ​​greater than 1. It can be set specifically as needed. If the amplitude of the first A-phase feedback current pulse and the amplitude of the first B-phase feedback current pulse are both less than or equal to the preset multiple of the preset amplitude, it means that when the upper switch of phase A is forward conducting and the lower switches of phases B and C are reverse conducting, no overcurrent occurs in the A-phase cable and the B-phase cable between the inverter and the isolation contactor. Therefore, it is determined that no phase-to-phase short circuit fault has occurred in the A-phase cable and the B-phase cable between the inverter and the isolation contactor.

[0042] S1314. If the amplitude of the first A-phase feedback current pulse and the amplitude of the first B-phase feedback current pulse are both greater than a preset multiple of the preset amplitude, then it is determined that a phase-to-phase short circuit fault has occurred in the A-phase cable and the B-phase cable between the inverter and the isolation contactor. In this embodiment, the amplitudes of both the first A-phase feedback current pulse and the first B-phase feedback current pulse are greater than a preset multiple of the preset amplitude. This indicates that when the upper switch of phase A is forward-biased and the lower switches of phases B and C are reverse-biased, overcurrent occurs in both the A-phase cable and the B-phase cable between the inverter and the isolation contactor. Figure 3 As shown, a short-circuit current ΔI has occurred between phase A and phase B cables of inverter 300 and isolation contactor 200. Therefore, it is determined that a phase-to-phase short-circuit fault has occurred between phase A and phase B cables of inverter and isolation contactor.

[0043] S1315. If the amplitude of the first A-phase feedback current pulse is greater than a preset multiple of the preset amplitude, and the amplitude of the first B-phase feedback current pulse is less than or equal to a preset multiple of the preset amplitude, then it is determined that a phase-to-phase short circuit fault has occurred in the A-phase cable and the C-phase cable between the inverter and the isolation contactor.

[0044] In this embodiment, if the amplitude of the first A-phase feedback current pulse is greater than a preset multiple of the preset amplitude, and the amplitude of the first B-phase feedback current pulse is less than or equal to a preset multiple of the preset amplitude, it indicates that an overcurrent has occurred in the A-phase cable between the inverter and the isolation contactor when the upper switch of the A-phase is forward-biased and the lower switches of the B-phase and C-phase are reverse-biased. However, no overcurrent has occurred in the B-phase cable between the inverter and the isolation contactor. This indicates that an interphase short circuit has occurred in the A-phase cable and the C-phase cable between the inverter and the isolation contactor, resulting in an overcurrent in the A-phase cable between the inverter and the isolation contactor. Therefore, it is determined that an interphase short circuit fault has occurred in the A-phase cable and the C-phase cable between the inverter and the isolation contactor.

[0045] As one implementation method, in this embodiment of the application, step S13 further includes; S1321. Send a B-phase voltage pulse of preset amplitude to the switching transistors in the inverter so that the upper switching transistor of B-phase in the inverter is forward-biased and the lower switching transistors of A-phase and C-phase are reverse-biased. In this embodiment, a B-phase voltage pulse of preset amplitude is sent to the switching transistors in the inverter, so that the upper switching transistor of the B phase in the inverter is forward-biased, the lower switching transistors of the A and C phases are reverse-biased, and the lower switching transistor of the B phase, the upper switching transistor of the A phase, and the upper switching transistor of the C phase are disconnected.

[0046] S1322. Obtain the second A-phase feedback current pulse collected by the A-phase current sensor and the second B-phase feedback current pulse collected by the B-phase current sensor, wherein the first feedback current pulse also includes the second A-phase feedback current pulse and the second B-phase feedback current pulse. S1323. If the amplitude of the second phase A feedback current pulse is less than or equal to a preset multiple of the preset amplitude, and the amplitude of the second phase B feedback current pulse is greater than a preset multiple of the preset amplitude, then it is determined that a phase-to-phase short circuit fault has occurred in the phase B cable and phase C cable between the inverter and the isolation contactor.

[0047] In this embodiment, if the amplitude of the second phase A feedback current pulse is less than or equal to a preset multiple of the preset amplitude, and the amplitude of the second phase B feedback current pulse is greater than a preset multiple of the preset amplitude, it indicates that when the upper switch of phase B is forward-biased and the lower switches of phases A and C are reverse-biased, no overcurrent occurs in the phase A cable between the inverter and the isolation contactor. However, if an overcurrent occurs in the phase B cable between the inverter and the isolation contactor, it indicates that a phase-to-phase short circuit has occurred in the phase B cable and the phase C cable between the inverter and the isolation contactor, resulting in an overcurrent in the phase B cable between the inverter and the isolation contactor. Therefore, it is determined that a phase-to-phase short circuit fault has occurred in the phase B cable and the phase C cable between the inverter and the isolation contactor.

[0048] As one implementation method, in this embodiment of the application, step S13 further includes: S1331. Send a C-phase voltage pulse of preset amplitude to the switching transistors in the inverter so that the upper switching transistor of the C-phase in the inverter is forward-biased and the lower switching transistors of the A-phase and B-phase are reverse-biased. In this embodiment, a C-phase voltage pulse of preset amplitude is sent to the switching transistors in the inverter, so that the upper switching transistor of the C-phase in the inverter is forward-biased, the lower switching transistors of the A-phase and B-phase are reverse-biased, and the upper switching transistors of the A-phase, the upper switching transistors of the B-phase, and the lower switching transistors of the C-phase are disconnected.

[0049] S1332. Obtain the third A-phase feedback current pulse collected by the A-phase current sensor and the third B-phase feedback current pulse collected by the B-phase current sensor, wherein the first feedback current pulse also includes the third A-phase feedback current pulse and the third B-phase feedback current pulse. S1333. If the amplitude of the third phase A feedback current pulse and the amplitude of the third phase B feedback current pulse are both less than or equal to a preset multiple of the preset amplitude, then it is determined that no phase-to-phase short circuit fault has occurred in the A-phase cable and C-phase cable, as well as the B-phase cable and C-phase cable between the inverter and the isolation contactor.

[0050] In this embodiment, if the amplitude of the third phase A feedback current pulse and the amplitude of the third phase B feedback current pulse are both less than or equal to a preset multiple of the preset amplitude, it indicates that when the upper switch of phase C is forward-biased and the lower switches of phases A and B are reverse-biased, no overcurrent occurs in the phase A and phase B cables between the inverter and the isolation contactor. Therefore, it is determined that no phase-to-phase short circuit fault has occurred in the phase A and phase C cables, as well as the phase B and phase C cables between the inverter and the isolation contactor.

[0051] As one implementation method, in this embodiment of the application, step S15 includes: S1511. Send a voltage pulse of A phase with a preset amplitude to the switching transistors in the inverter so that the upper switching transistor of A phase in the inverter is forward-biased and the lower switching transistors of B phase and C phase are reverse-biased. In this embodiment, a voltage pulse of A phase with a preset amplitude is sent to the switching transistors in the inverter, so that the upper switching transistor of A phase in the inverter is forward-biased, the lower switching transistors of B phase and C phase are reverse-biased, and the lower switching transistor of A phase, the upper switching transistor of B phase, and the upper switching transistor of C phase are disconnected.

[0052] S1512. Obtain the fourth A-phase feedback current pulse collected by the A-phase current sensor and the fourth B-phase feedback current pulse collected by the B-phase current sensor, wherein the second feedback current pulse includes the fourth A-phase feedback current pulse and the fourth B-phase feedback current pulse. S1513. If the amplitudes of the fourth phase A feedback current pulse and the fourth phase B feedback current pulse are both less than or equal to a preset multiple of the preset amplitude, it is determined that no phase-to-phase short circuit fault has occurred in the A-phase cable and the B-phase cable between the isolation contactor and the permanent magnet synchronous motor. In this embodiment, if the amplitudes of the fourth phase A feedback current pulse and the fourth phase B feedback current pulse are both less than or equal to a preset multiple of the preset amplitude, it indicates that when the upper switch of phase A is forward-biased and the lower switches of phases B and C are reverse-biased, not only is there no overcurrent in the phase A and phase B cables between the inverter and the isolation contactor, but there is also no overcurrent in the phase A and phase B cables between the isolation contactor and the permanent magnet synchronous motor. Therefore, it is determined that no phase-to-phase short circuit fault has occurred in the phase A and phase B cables between the inverter and the isolation contactor.

[0053] S1514. If the first diagnostic result is that there is no phase-to-phase short circuit fault in the A-phase cable and B-phase cable between the inverter and the isolation contactor, and the amplitude of the fourth A-phase feedback current pulse and the fourth B-phase feedback current pulse are both greater than the preset multiple of the preset amplitude, then it is determined that there is a phase-to-phase short circuit fault in the A-phase cable and B-phase cable between the isolation contactor and the permanent magnet synchronous motor. In this embodiment, if the first diagnostic result indicates that there is no phase-to-phase short circuit fault in the A-phase cable and B-phase cable between the inverter and the isolation contactor, but the amplitudes of the fourth A-phase feedback current pulse and the fourth B-phase feedback current pulse are both greater than a preset multiple of the preset amplitude, it indicates that under the condition that the upper switch of phase A is forward-biased and the lower switches of phases B and C are reverse-biased, overcurrent has occurred in both the A-phase cable and B-phase cable between the isolation contactor and the permanent magnet synchronous motor. Figure 4 As shown, a short-circuit current ΔI has occurred between the A-phase cable and the B-phase cable of the isolating contactor 200 and the permanent magnet synchronous motor 100. Therefore, it is determined that a phase-to-phase short-circuit fault has occurred between the A-phase cable and the B-phase cable of the isolating contactor and the permanent magnet synchronous motor.

[0054] S1515. If the first diagnostic result is that there is no phase-to-phase short circuit fault in the A-phase cable and C-phase cable between the inverter and the isolation contactor, and the amplitude of the fourth A-phase feedback current pulse is greater than a preset multiple of the preset amplitude, and the amplitude of the fourth B-phase feedback current pulse is less than or equal to a preset multiple of the preset amplitude, then it is determined that there is a phase-to-phase short circuit fault in the A-phase cable and C-phase cable between the isolation contactor and the permanent magnet synchronous motor.

[0055] In this embodiment, if the first diagnostic result indicates that there is no phase-to-phase short circuit fault in the A-phase cable and C-phase cable between the inverter and the isolation contactor, but the amplitude of the fourth A-phase feedback current pulse is greater than a preset multiple of the preset amplitude, and the amplitude of the fourth B-phase feedback current pulse is less than or equal to a preset multiple of the preset amplitude, it indicates that an overcurrent has occurred in the A-phase cable between the isolation contactor and the permanent magnet synchronous motor when the upper switch of the A-phase is forward-biased and the lower switches of the B-phase and C-phase are reverse-biased. However, no overcurrent has occurred in the B-phase cable between the isolation contactor and the permanent magnet synchronous motor. This indicates that the overcurrent is caused by a phase-to-phase short circuit in the A-phase cable between the isolation contactor and the permanent magnet synchronous motor. Therefore, it is determined that a phase-to-phase short circuit fault has occurred in the A-phase cable and C-phase cable between the isolation contactor and the permanent magnet synchronous motor.

[0056] As one implementation method, in this embodiment of the application, step S15 further includes: S1521. Send a B-phase voltage pulse of preset amplitude to the switching transistors in the inverter so that the upper switching transistor of the B phase in the inverter is forward-biased and the lower switching transistors of the A and C phases are reverse-biased. In this embodiment, a B-phase voltage pulse of preset amplitude is sent to the switching transistors in the inverter, so that the upper switching transistor of the B phase in the inverter is forward-biased, the lower switching transistors of the A and C phases are reverse-biased, and the lower switching transistor of the B phase, the upper switching transistor of the A phase, and the upper switching transistor of the C phase are disconnected.

[0057] S1522. Obtain the fifth A-phase feedback current pulse collected by the A-phase current sensor and the fifth B-phase feedback current pulse collected by the B-phase current sensor, wherein the second feedback current pulse also includes the fifth A-phase feedback current pulse and the fifth B-phase feedback current pulse. S1523. If the first diagnostic result is that there is no phase-to-phase short circuit fault in the B-phase cable and C-phase cable between the inverter and the isolation contactor, and the amplitude of the fifth A-phase feedback current pulse is less than or equal to a preset multiple of the preset amplitude, and the amplitude of the fifth B-phase feedback current pulse is greater than a preset multiple of the preset amplitude, then it is determined that there is a phase-to-phase short circuit fault in the B-phase cable and C-phase cable between the isolation contactor and the permanent magnet synchronous motor.

[0058] In this embodiment, if the first diagnostic result indicates that there is no phase-to-phase short circuit fault in the B-phase cable and C-phase cable between the inverter and the isolation contactor, but the amplitude of the fifth A-phase feedback current pulse is less than or equal to a preset multiple of the preset amplitude, and the amplitude of the fifth B-phase feedback current pulse is greater than a preset multiple of the preset amplitude, it means that when the upper switch of phase A is forward-biased and the lower switches of phases B and C are reverse-biased, no overcurrent occurs in the A-phase cable between the isolation contactor and the permanent magnet synchronous motor, but an overcurrent occurs in the B-phase cable between the isolation contactor and the permanent magnet synchronous motor. This indicates that the overcurrent occurs in the B-phase cable between the isolation contactor and the permanent magnet synchronous motor due to a phase-to-phase short circuit in the B-phase cable between the isolation contactor and the permanent magnet synchronous motor. Therefore, it is determined that a phase-to-phase short circuit fault has occurred in the B-phase cable and C-phase cable between the isolation contactor and the permanent magnet synchronous motor.

[0059] As one implementation method, in this embodiment of the application, step S15 further includes: S1531. Send a C-phase voltage pulse of preset amplitude to the switching transistors in the inverter so that the upper switching transistor of the C-phase in the inverter is forward-biased and the lower switching transistors of the A-phase and B-phase are reverse-biased. In this embodiment, a C-phase voltage pulse of preset amplitude is sent to the switching transistors in the inverter, so that the upper switching transistor of the C-phase in the inverter is forward-biased, the lower switching transistors of the A-phase and B-phase are reverse-biased, and the upper switching transistors of the A-phase, the upper switching transistors of the B-phase, and the lower switching transistors of the C-phase are disconnected.

[0060] S1532. Obtain the sixth A-phase feedback current pulse collected by the A-phase current sensor and the sixth B-phase feedback current pulse collected by the B-phase current sensor, wherein the second feedback current pulse also includes the sixth A-phase feedback current pulse and the sixth B-phase feedback current pulse. S1533. If the amplitude of the sixth phase A feedback current pulse is less than or equal to a preset multiple of the preset amplitude, and the amplitude of the sixth phase B feedback current pulse is less than or equal to a preset multiple of the preset amplitude, then it is determined that no phase-to-phase short circuit fault has occurred in the A-phase cable and C-phase cable, as well as the B-phase cable and C-phase cable between the isolating contactor and the permanent magnet synchronous motor.

[0061] In this embodiment, if the amplitude of the sixth phase A feedback current pulse is less than or equal to a preset multiple of the preset amplitude, and the amplitude of the sixth phase B feedback current pulse is less than or equal to a preset multiple of the preset amplitude, it indicates that when the upper switch of phase C in the inverter is forward-biased and the lower switches of phases A and B are reverse-biased, not only is there no overcurrent in the phase A and phase C cables, as well as the phase B and phase C cables between the inverter and the isolation contactor, but also no overcurrent in the phase A and phase C cables, as well as the phase B and phase C cables between the isolation contactor and the permanent magnet synchronous motor. Therefore, it is determined that no phase-to-phase short circuit fault has occurred in the phase A and phase C cables, as well as the phase B and phase C cables between the isolation contactor and the permanent magnet synchronous motor.

[0062] As one implementation method, in this embodiment of the application, the method further includes: S16. If the first diagnostic result is a phase-to-phase short circuit fault in the two-phase cable between the inverter and the isolation contactor, or the second diagnostic result is a phase-to-phase short circuit fault in the two-phase cable between the isolation contactor and the permanent magnet synchronous motor, then control the upper switch tubes of each phase in the inverter to be turned on and the lower switch tubes of each phase to be turned off, or control the upper switch tubes of each phase in the inverter to be turned off and the lower switch tubes of each phase to be turned on.

[0063] In this embodiment, if the first diagnostic result is a phase-to-phase short circuit fault in the two-phase cable between the inverter and the isolation contactor, or the second diagnostic result is a phase-to-phase short circuit fault in the two-phase cable between the isolation contactor and the permanent magnet synchronous motor, that is, after the phase-to-phase short circuit is diagnosed, since the vehicle is in the starting state, if active safety control is not performed, it will damage the overall vehicle design. By controlling the upper phase switching transistors in the inverter to be turned on and the lower phase switching transistors to be turned off, or by controlling the upper phase switching transistors in the inverter to be turned off and the lower phase switching transistors to be turned on, active three-phase winding short circuit is performed. By utilizing the low on-resistance and voltage drop characteristics of the power devices, the current of the short-circuit loop is diverted to the inverter to reduce the risk of damage to the overall vehicle design.

[0064] As one implementation method, in this embodiment of the application, the method further includes: S21, Control the disconnecting contactor to disconnect; S22, control the upper switch transistors of each phase in the inverter to be turned on and the lower switch transistors of each phase to be turned off; S23. Obtain the seventh phase A feedback current pulse collected by the phase A current sensor and the seventh phase B feedback current pulse collected by the phase B current sensor. S24. If the amplitude of the feedback current pulse of the seventh phase A and the amplitude of the feedback current pulse of the seventh phase B are both zero, then it is determined that neither the A-phase cable nor the B-phase cable between the inverter and the isolation contactor has a grounding fault. In this embodiment, if the amplitude of the seventh phase A feedback current pulse and the amplitude of the seventh phase B feedback current pulse are both zero, it indicates that there is no current in the A-phase cable and the B-phase cable between the inverter and the isolation contactor. Therefore, it is determined that there is no grounding fault in the A-phase cable and the B-phase cable between the inverter and the isolation contactor.

[0065] S25. If the amplitude of the feedback current pulse of the seventh phase A is greater than zero and the amplitude of the feedback current pulse of the seventh phase B is zero, then it is determined that the A-phase cable between the inverter and the isolation contactor has a grounding fault, and the B-phase cable has not a grounding fault. In this embodiment, if the amplitude of the seventh phase A feedback current pulse is greater than zero and the amplitude of the seventh phase B feedback current pulse is zero, it indicates that there is current in the A-phase cable between the inverter and the isolation contactor, but there is no current in the B-phase cable between the inverter and the isolation contactor. Therefore, it is determined that the A-phase cable between the inverter and the isolation contactor has a grounding fault, and the B-phase cable between the inverter and the isolation contactor has not a grounding fault.

[0066] S26. If the amplitude of the feedback current pulse of the seventh phase A is equal to zero and the amplitude of the feedback current pulse of the seventh phase B is greater than zero, then it is determined that the A-phase cable between the inverter and the isolation contactor has not been grounded, and the B-phase cable has been grounded. In this embodiment, if the amplitude of the seventh phase A feedback current pulse is equal to zero and the amplitude of the seventh phase B feedback current pulse is greater than zero, it indicates that there is no current in the A-phase cable between the inverter and the isolation contactor, but there is current in the B-phase cable between the inverter and the isolation contactor. Therefore, it is determined that the A-phase cable between the inverter and the isolation contactor has not experienced a grounding fault, and the B-phase cable between the inverter and the isolation contactor has experienced a grounding fault.

[0067] S27. If the amplitude of the feedback current pulse of the seventh phase A and the amplitude of the feedback current pulse of the seventh phase B are both greater than zero, then it is determined that both the A-phase cable and the B-phase cable between the inverter and the isolation contactor have grounding faults.

[0068] In this embodiment, if the amplitude of the seventh phase A feedback current pulse and the amplitude of the seventh phase B feedback current pulse are both greater than zero, it indicates that there is current in both the A-phase cable and the B-phase cable between the inverter and the isolation contactor. Therefore, it is determined that both the A-phase cable and the B-phase cable between the inverter and the isolation contactor have experienced grounding faults.

[0069] As one implementation method, in this embodiment of the application, the method further includes: S31. If it is determined that neither the A-phase cable nor the B-phase cable between the inverter and the isolation contactor has a grounding fault, then control the isolation contactor to close. S32. Send a positive voltage pulse to the upper switching transistor in the inverter and send a negative voltage pulse to the lower switching transistor in the inverter. S33. Obtain the eighth phase A feedback current pulse collected by the phase A current sensor and the eighth phase B feedback current pulse collected by the phase B current sensor. S34. If the amplitude of the feedback current pulse of the eighth phase A and the amplitude of the feedback current pulse of the eighth phase B are both zero, then it is determined that neither the A-phase cable nor the B-phase cable between the isolation contactor and the permanent magnet synchronous motor has a grounding fault. In this embodiment, if the amplitude of the eighth phase A feedback current pulse and the amplitude of the eighth phase A feedback current pulse are both zero, it indicates that there is no current in the A-phase cable and the B-phase cable between the isolating contactor and the permanent magnet synchronous motor. Therefore, it is determined that there is no grounding fault in the A-phase cable and the B-phase cable between the isolating contactor and the permanent magnet synchronous motor.

[0070] S35. If the amplitude of the feedback current pulse of the eighth phase A is greater than zero and the amplitude of the feedback current pulse of the eighth phase B is zero, then it is determined that the A-phase cable between the isolation contactor and the permanent magnet synchronous motor has a grounding fault, and the B-phase cable has not a grounding fault. In this embodiment, if the amplitude of the eighth phase A feedback current pulse is greater than zero and the amplitude of the eighth phase B feedback current pulse is zero, it indicates that there is current in the A-phase cable between the isolating contactor and the permanent magnet synchronous motor, but there is no current in the B-phase cable between the isolating contactor and the permanent magnet synchronous motor. Since it has been determined that neither the A-phase cable nor the B-phase cable between the inverter and the isolating contactor has a grounding fault, it indicates that the current in the A-phase cable between the isolating contactor and the permanent magnet synchronous motor is due to a grounding fault in the A-phase cable. Therefore, it is determined that the A-phase cable between the isolating contactor and the permanent magnet synchronous motor has a grounding fault, and the B-phase cable has not a grounding fault.

[0071] S36. If the amplitude of the feedback current pulse of the eighth phase A is equal to zero and the amplitude of the feedback current pulse of the eighth phase B is greater than zero, then it is determined that the A-phase cable between the isolation contactor and the permanent magnet synchronous motor has not been grounded, and the B-phase cable has been grounded. In this embodiment, if the amplitude of the eighth phase A feedback current pulse is zero and the amplitude of the eighth phase B feedback current pulse is greater than zero, it indicates that there is no current in the A-phase cable between the isolating contactor and the permanent magnet synchronous motor, but there is current in the B-phase cable between the isolating contactor and the permanent magnet synchronous motor. Since it has been determined that neither the A-phase cable nor the B-phase cable between the inverter and the isolating contactor has a grounding fault, it indicates that the B-phase cable between the isolating contactor and the permanent magnet synchronous motor has a grounding fault, which causes the current in the B-phase cable between the isolating contactor and the permanent magnet synchronous motor. Therefore, it is determined that the A-phase cable between the isolating contactor and the permanent magnet synchronous motor has no grounding fault, and the B-phase cable has a grounding fault.

[0072] S37. If the amplitude of the feedback current pulse of the eighth phase A and the amplitude of the feedback current pulse of the eighth phase B are both greater than zero, then it is determined that both the A-phase cable and the B-phase cable between the isolation contactor and the permanent magnet synchronous motor have grounding faults.

[0073] In this embodiment, if the amplitudes of the eighth phase A feedback current pulse and the eighth phase B feedback current pulse are both greater than zero, it indicates that there is current in both phase A and phase B cables between the isolation contactor and the permanent magnet synchronous motor. Since it has been determined that there is no grounding fault in either phase A or phase B cables between the inverter and the isolation contactor, it indicates that the presence of current in phase A and phase B cables between the isolation contactor and the permanent magnet synchronous motor is due to a grounding fault. Therefore, it is determined that there is a grounding fault in both phase A and phase B cables between the isolation contactor and the permanent magnet synchronous motor.

[0074] In this embodiment of the application, when the upper or lower switch tube of phase C reports a protection fault, i.e., a tube fault, it can be assumed that the phase C cable may have a grounding fault.

[0075] In this embodiment of the application, since the three-phase short-circuit current of a normal motor is completely symmetrical, the current imbalance can be calculated based on the A-phase current sensor and the B-phase current sensor respectively collected after the three-phase short circuit. Then, based on the approximate range of the short-circuit impedance estimated by the current imbalance, it can be analyzed whether there is a short circuit phenomenon such as discharge short circuit between devices or foreign object connection.

[0076] like Figure 5 As shown in the figure, this application embodiment also provides a fault diagnosis system for a permanent magnet synchronous motor. The permanent magnet synchronous motor is connected to an inverter via an isolation contactor, and a current sensor is installed between the isolation contactor and the inverter. The system includes: The first control module 201 is used to control the permanent magnet synchronous motor to stop when a fault is detected in the permanent magnet synchronous motor during the operation of the vehicle. The second control module 202 is used to control the disconnection of the isolating contactor; The first diagnostic module 203 is used to send a three-phase voltage pulse of preset amplitude to the switching transistor in the inverter, obtain the first feedback current pulse collected by the current sensor, and obtain the first diagnostic result of whether a phase-to-phase short circuit fault has occurred in the two-phase cable between the inverter and the isolation contactor based on the amplitude of the first feedback current pulse and the preset amplitude. The third control module 204 is used to control the closing of the isolating contactor; The second diagnostic module 205 is used to send a three-phase voltage pulse of preset amplitude to the switching transistor in the inverter, obtain the second feedback current pulse collected by the current sensor, and obtain a second diagnostic result of whether a phase-to-phase short circuit fault has occurred in the two-phase cable between the isolation contactor and the permanent magnet synchronous motor based on the first diagnostic result, the amplitude of the second feedback current pulse and the preset amplitude.

[0077] In one implementation embodiment, the current sensor includes an A-phase current sensor and a B-phase current sensor. The A-phase current sensor is installed on the A-phase cable between the isolation contactor and the inverter, and the B-phase current sensor is installed on the B-phase cable between the isolation contactor and the inverter. When the first diagnostic module sends a three-phase voltage pulse of preset amplitude to the switching transistor in the inverter, acquires the first feedback current pulse collected by the current sensor, and obtains a first diagnostic result regarding whether a phase-to-phase short-circuit fault has occurred in the two-phase cable between the inverter and the isolation contactor based on the amplitude of the first feedback current pulse and the preset amplitude, it is specifically used for: Send a voltage pulse of A phase with a preset amplitude to the switching transistors in the inverter so that the upper switching transistor of A phase in the inverter is forward-biased and the lower switching transistors of B phase and C phase are reverse-biased. The first A-phase feedback current pulse collected by the A-phase current sensor and the first B-phase feedback current pulse collected by the B-phase current sensor are obtained, wherein the first feedback current pulse includes the first A-phase feedback current pulse and the first B-phase feedback current pulse. If the amplitude of the first A-phase feedback current pulse and the amplitude of the first B-phase feedback current pulse are both less than or equal to a preset multiple of the preset amplitude, it is determined that no phase-to-phase short circuit fault has occurred in the A-phase cable and the B-phase cable between the inverter and the isolation contactor. If the amplitude of the first A-phase feedback current pulse and the amplitude of the first B-phase feedback current pulse are both greater than a preset multiple of the preset amplitude, then it is determined that a phase-to-phase short circuit fault has occurred in the A-phase cable and the B-phase cable between the inverter and the isolation contactor. If the amplitude of the first phase A feedback current pulse is greater than a preset multiple of the preset amplitude, and the amplitude of the first phase B feedback current pulse is less than or equal to a preset multiple of the preset amplitude, then it is determined that a phase-to-phase short circuit fault has occurred in the phase A cable and phase C cable between the inverter and the isolation contactor.

[0078] As one implementation method, in this embodiment of the application, when the first diagnostic module sends a three-phase voltage pulse of preset amplitude to the switching transistor in the inverter, obtains the first feedback current pulse collected by the current sensor, and obtains the first diagnostic result of whether a phase-to-phase short circuit fault has occurred in the two-phase cable between the inverter and the isolation contactor based on the amplitude of the first feedback current pulse and the preset amplitude, it is further specifically used for: Send a B-phase voltage pulse of preset amplitude to the switching transistors in the inverter so that the upper switching transistor of the B phase in the inverter is forward-biased and the lower switching transistors of the A and C phases are reverse-biased. The second A-phase feedback current pulse collected by the A-phase current sensor and the second B-phase feedback current pulse collected by the B-phase current sensor are obtained. The first feedback current pulse also includes the second A-phase feedback current pulse and the second B-phase feedback current pulse. If the amplitude of the second phase A feedback current pulse is less than or equal to a preset multiple of the preset amplitude, and the amplitude of the second phase B feedback current pulse is greater than a preset multiple of the preset amplitude, then it is determined that a phase-to-phase short circuit fault has occurred in the phase B cable and phase C cable between the inverter and the isolation contactor.

[0079] As one implementation method, in this embodiment of the application, when the first diagnostic module sends a three-phase voltage pulse of preset amplitude to the switching transistor in the inverter, obtains the first feedback current pulse collected by the current sensor, and obtains the first diagnostic result of whether a phase-to-phase short circuit fault has occurred in the two-phase cable between the inverter and the isolation contactor based on the amplitude of the first feedback current pulse and the preset amplitude, it is further specifically used for: Send a C-phase voltage pulse of preset amplitude to the switching transistors in the inverter so that the upper switching transistor of the C-phase in the inverter is forward-biased and the lower switching transistors of the A-phase and B-phase are reverse-biased. The third A-phase feedback current pulse collected by the A-phase current sensor and the third B-phase feedback current pulse collected by the B-phase current sensor are obtained. The first feedback current pulse also includes the third A-phase feedback current pulse and the third B-phase feedback current pulse. If the amplitude of the third phase A feedback current pulse and the amplitude of the third phase B feedback current pulse are both less than or equal to a preset multiple of the preset amplitude, then it is determined that no phase-to-phase short circuit fault has occurred in the A-phase cable and C-phase cable, as well as the B-phase cable and C-phase cable between the inverter and the isolation contactor.

[0080] As one implementation method, in this embodiment of the application, when the second diagnostic module sends a three-phase voltage pulse of preset amplitude to the switching transistor in the inverter, acquires the second feedback current pulse collected by the current sensor, and obtains a second diagnostic result of whether a phase-to-phase short circuit fault has occurred in the two-phase cable between the isolation contactor and the permanent magnet synchronous motor based on the first diagnostic result, the amplitude of the second feedback current pulse, and the preset amplitude, it is specifically used for: Send a voltage pulse of A phase with a preset amplitude to the switching transistors in the inverter so that the upper switching transistor of A phase in the inverter is forward-biased and the lower switching transistors of B phase and C phase are reverse-biased. The fourth phase A feedback current pulse collected by the phase A current sensor and the fourth phase B feedback current pulse collected by the phase B current sensor are obtained, wherein the second feedback current pulse includes the fourth phase A feedback current pulse and the fourth phase B feedback current pulse. If the amplitudes of the fourth phase A feedback current pulse and the fourth phase B feedback current pulse are both less than or equal to a preset multiple of the preset amplitude, it is determined that no phase-to-phase short circuit fault has occurred in the A-phase cable and the B-phase cable between the isolation contactor and the permanent magnet synchronous motor. If the first diagnostic result is that there is no phase-to-phase short circuit fault in the A-phase cable and B-phase cable between the inverter and the isolation contactor, and the amplitude of the fourth A-phase feedback current pulse and the fourth B-phase feedback current pulse are both greater than the preset multiple of the preset amplitude, then it is determined that there is a phase-to-phase short circuit fault in the A-phase cable and B-phase cable between the isolation contactor and the permanent magnet synchronous motor. If the first diagnostic result indicates that there is no phase-to-phase short circuit fault in the A-phase cable and C-phase cable between the inverter and the isolation contactor, and the amplitude of the fourth A-phase feedback current pulse is greater than a preset multiple of the preset amplitude, and the amplitude of the fourth B-phase feedback current pulse is less than or equal to a preset multiple of the preset amplitude, then it is determined that there is a phase-to-phase short circuit fault in the A-phase cable and C-phase cable between the isolation contactor and the permanent magnet synchronous motor.

[0081] As one implementation method, in this embodiment of the application, when the second diagnostic module sends a three-phase voltage pulse of preset amplitude to the switching transistor in the inverter, acquires the second feedback current pulse collected by the current sensor, and obtains a second diagnostic result of whether a phase-to-phase short circuit fault has occurred in the two-phase cable between the isolation contactor and the permanent magnet synchronous motor based on the first diagnostic result, the amplitude of the second feedback current pulse, and the preset amplitude, it is further specifically used for: Send a B-phase voltage pulse of preset amplitude to the switching transistors in the inverter so that the upper switching transistor of the B phase in the inverter is forward-biased and the lower switching transistors of the A and C phases are reverse-biased. The fifth phase A feedback current pulse collected by the phase A current sensor and the fifth phase B feedback current pulse collected by the phase B current sensor are obtained. The second feedback current pulse also includes the fifth phase A feedback current pulse and the fifth phase B feedback current pulse. If the first diagnostic result indicates that there is no phase-to-phase short circuit fault in the B-phase cable and C-phase cable between the inverter and the isolation contactor, and the amplitude of the fifth A-phase feedback current pulse is less than or equal to a preset multiple of the preset amplitude, and the amplitude of the fifth B-phase feedback current pulse is greater than a preset multiple of the preset amplitude, then it is determined that there is a phase-to-phase short circuit fault in the B-phase cable and C-phase cable between the isolation contactor and the permanent magnet synchronous motor.

[0082] As one implementation method, in this embodiment of the application, when the second diagnostic module sends a three-phase voltage pulse of preset amplitude to the switching transistor in the inverter, acquires the second feedback current pulse collected by the current sensor, and obtains a second diagnostic result of whether a phase-to-phase short circuit fault has occurred in the two-phase cable between the isolation contactor and the permanent magnet synchronous motor based on the first diagnostic result, the amplitude of the second feedback current pulse, and the preset amplitude, it is further specifically used for: Send a C-phase voltage pulse of preset amplitude to the switching transistors in the inverter so that the upper switching transistor of the C-phase in the inverter is forward-biased and the lower switching transistors of the A-phase and B-phase are reverse-biased. The sixth phase A feedback current pulse collected by the phase A current sensor and the sixth phase B feedback current pulse collected by the phase B current sensor are obtained. The second feedback current pulse also includes the sixth phase A feedback current pulse and the sixth phase B feedback current pulse. If the amplitude of the sixth phase A feedback current pulse is less than or equal to a preset multiple of the preset amplitude, and the amplitude of the sixth phase B feedback current pulse is less than or equal to a preset multiple of the preset amplitude, then it is determined that no phase-to-phase short circuit fault has occurred in the A-phase cable and C-phase cable, as well as the B-phase cable and C-phase cable between the isolating contactor and the permanent magnet synchronous motor.

[0083] As one implementation method, in this embodiment of the application, the system further includes: The protection module is used to control the upper phase switching transistors of each phase in the inverter to be turned on and the lower phase switching transistors of each phase to be turned off, or to control the upper phase switching transistors of each phase to be turned off and the lower phase switching transistors of each phase to be turned on, if the first diagnostic result is that a phase-to-phase short circuit fault occurs in the two-phase cable between the inverter and the isolation contactor, or the second diagnostic result is that a phase-to-phase short circuit fault occurs in the two-phase cable between the isolation contactor and the permanent magnet synchronous motor.

[0084] like Figure 6 As shown in the figure, this application embodiment also provides a fault diagnosis device for a permanent magnet synchronous motor, including: a processor 301, a memory 302 and a communication bus 303; Communication bus 303 is used to realize the connection and communication between processor 301 and memory 302; The processor 301 is used to execute the permanent magnet synchronous motor fault diagnosis processing program stored in the memory 302 to implement the steps of any of the permanent magnet synchronous motor fault diagnosis methods described above.

[0085] This application also provides a readable storage medium storing computer-executable instructions, which, when loaded and executed by a processor, implement the steps of any of the above-described methods for diagnosing faults in a permanent magnet synchronous motor.

[0086] It should be understood that the use of terms such as "system," "device," "unit," and / or "module" in this application is merely one method of distinguishing different components, elements, parts, sections, or assemblies at different levels. However, if other terms can achieve the same purpose, they may be replaced by other expressions.

[0087] The embodiments in this specification are described in a progressive manner, with each embodiment focusing on the related aspects. For any differences between the embodiments, or for the same or similar parts between the embodiments, please refer to each other.

[0088] The above description of the disclosed embodiments enables those skilled in the art to make or use this application. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of this application. Therefore, this application is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method for diagnosing faults in a permanent magnet synchronous motor, characterized in that, The permanent magnet synchronous motor is connected to the inverter via an isolation contactor, and a current sensor is installed between the isolation contactor and the inverter. The method includes: If a fault is detected in the permanent magnet synchronous motor during vehicle operation, the permanent magnet synchronous motor will be stopped. Control the disconnecting contactor to disconnect; A three-phase voltage pulse of preset amplitude is sent to the switching transistor in the inverter, and the first feedback current pulse collected by the current sensor is obtained. Based on the amplitude of the first feedback current pulse and the preset amplitude, a first diagnostic result is obtained as to whether a phase-to-phase short circuit fault has occurred in the two-phase cable between the inverter and the isolation contactor. Control the closing of the isolation contactor; A three-phase voltage pulse of preset amplitude is sent to the switching transistor in the inverter, and a second feedback current pulse collected by the current sensor is obtained. Based on the first diagnostic result, the amplitude of the second feedback current pulse and the preset amplitude, a second diagnostic result is obtained to determine whether a phase-to-phase short circuit fault has occurred in the two-phase cable between the isolation contactor and the permanent magnet synchronous motor.

2. The fault diagnosis method according to claim 1, characterized in that, The current sensor includes an A-phase current sensor and a B-phase current sensor. The A-phase current sensor is installed on the A-phase cable between the isolation contactor and the inverter, and the B-phase current sensor is installed on the B-phase cable between the isolation contactor and the inverter. A three-phase voltage pulse of preset amplitude is sent to the switching transistor in the inverter to obtain the first feedback current pulse collected by the current sensor. Based on the amplitude of the first feedback current pulse and the preset amplitude, a first diagnostic result is obtained regarding whether a phase-to-phase short-circuit fault has occurred in the two-phase cable between the inverter and the isolation contactor, including: A voltage pulse of a preset amplitude is sent to the switching transistors in the inverter so that the upper switching transistor of phase A in the inverter is forward-biased and the lower switching transistors of phases B and C are reverse-biased. The first A-phase feedback current pulse collected by the A-phase current sensor and the first B-phase feedback current pulse collected by the B-phase current sensor are obtained, wherein the first feedback current pulse includes the first A-phase feedback current pulse and the first B-phase feedback current pulse. If the amplitude of the first A-phase feedback current pulse and the amplitude of the first B-phase feedback current pulse are both less than or equal to a preset multiple of the preset amplitude, then it is determined that no phase-to-phase short circuit fault has occurred in the A-phase cable and the B-phase cable between the inverter and the isolation contactor. If the amplitude of the first A-phase feedback current pulse and the amplitude of the first B-phase feedback current pulse are both greater than a preset multiple of the preset amplitude, then it is determined that a phase-to-phase short circuit fault has occurred in the A-phase cable and the B-phase cable between the inverter and the isolation contactor. If the amplitude of the first A-phase feedback current pulse is greater than a preset multiple of the preset amplitude, and the amplitude of the first B-phase feedback current pulse is less than or equal to a preset multiple of the preset amplitude, then it is determined that a phase-to-phase short circuit fault has occurred in the A-phase cable and the C-phase cable between the inverter and the isolation contactor.

3. The fault diagnosis method according to claim 2, characterized in that, The step of sending a three-phase voltage pulse of a preset amplitude to the switching transistor in the inverter, obtaining the first feedback current pulse collected by the current sensor, and obtaining a first diagnostic result of whether a phase-to-phase short circuit fault has occurred in the two-phase cable between the inverter and the isolation contactor based on the amplitude of the first feedback current pulse and the preset amplitude, also includes: A preset amplitude B-phase voltage pulse is sent to the switching transistors in the inverter so that the upper switching transistor of the B-phase in the inverter is forward-biased and the lower switching transistors of the A-phase and C-phase are reverse-biased. The second A-phase feedback current pulse collected by the A-phase current sensor and the second B-phase feedback current pulse collected by the B-phase current sensor are obtained, wherein the first feedback current pulse further includes the second A-phase feedback current pulse and the second B-phase feedback current pulse; If the amplitude of the second phase A feedback current pulse is less than or equal to a preset multiple of the preset amplitude, and the amplitude of the second phase B feedback current pulse is greater than a preset multiple of the preset amplitude, then it is determined that a phase-to-phase short circuit fault has occurred in the phase B cable and phase C cable between the inverter and the isolation contactor.

4. The fault diagnosis method according to claim 3, characterized in that, The process of sending a three-phase voltage pulse of a preset amplitude to the switching transistors in the inverter, acquiring a first feedback current pulse collected by the current sensor, and obtaining a first diagnostic result of whether a phase-to-phase short-circuit fault has occurred in the two-phase cable between the inverter and the isolation contactor based on the amplitude of the first feedback current pulse and the preset amplitude, further includes: A C-phase voltage pulse of preset amplitude is sent to the switching transistors in the inverter so that the upper switching transistor of the C-phase in the inverter is forward-biased and the lower switching transistors of the A-phase and B-phase are reverse-biased. The third A-phase feedback current pulse collected by the A-phase current sensor and the third B-phase feedback current pulse collected by the B-phase current sensor are obtained, wherein the first feedback current pulse further includes the third A-phase feedback current pulse and the third B-phase feedback current pulse. If the amplitude of the third phase A feedback current pulse and the amplitude of the third phase B feedback current pulse are both less than or equal to a preset multiple of the preset amplitude, then it is determined that no phase-to-phase short circuit fault has occurred in the A-phase cable and C-phase cable, as well as the B-phase cable and C-phase cable between the inverter and the isolation contactor.

5. The fault diagnosis method according to claim 4, characterized in that, The process involves sending a three-phase voltage pulse of preset amplitude to the switching transistors in the inverter, acquiring a second feedback current pulse collected by the current sensor, and obtaining a second diagnostic result regarding whether a phase-to-phase short-circuit fault has occurred in the two-phase cable between the isolation contactor and the permanent magnet synchronous motor based on the first diagnostic result, the amplitude of the second feedback current pulse, and the preset amplitude. This includes: A voltage pulse of a preset amplitude is sent to the switching transistors in the inverter so that the upper switching transistor of phase A in the inverter is forward-biased and the lower switching transistors of phases B and C are reverse-biased. The fourth A-phase feedback current pulse collected by the A-phase current sensor and the fourth B-phase feedback current pulse collected by the B-phase current sensor are obtained, wherein the second feedback current pulse includes the fourth A-phase feedback current pulse and the fourth B-phase feedback current pulse. If the amplitudes of the fourth A-phase feedback current pulse and the fourth B-phase feedback current pulse are both less than or equal to a preset multiple of the preset amplitude, it is determined that no phase-to-phase short circuit fault has occurred in the A-phase cable and the B-phase cable between the isolation contactor and the permanent magnet synchronous motor. If the first diagnostic result indicates that there is no phase-to-phase short circuit fault in the A-phase cable and B-phase cable between the inverter and the isolation contactor, and the amplitudes of the fourth A-phase feedback current pulse and the fourth B-phase feedback current pulse are both greater than a preset multiple of the preset amplitude, then it is determined that there is a phase-to-phase short circuit fault in the A-phase cable and B-phase cable between the isolation contactor and the permanent magnet synchronous motor. If the first diagnostic result indicates that no phase-to-phase short circuit fault has occurred in the A-phase cable and C-phase cable between the inverter and the isolation contactor, and the amplitude of the fourth A-phase feedback current pulse is greater than a preset multiple of the preset amplitude, and the amplitude of the fourth B-phase feedback current pulse is less than or equal to a preset multiple of the preset amplitude, then it is determined that a phase-to-phase short circuit fault has occurred in the A-phase cable and C-phase cable between the isolation contactor and the permanent magnet synchronous motor.

6. The fault diagnosis method according to claim 5, characterized in that, The process of sending a three-phase voltage pulse of a preset amplitude to the switching transistors in the inverter, acquiring a second feedback current pulse collected by the current sensor, and obtaining a second diagnostic result of whether a phase-to-phase short-circuit fault has occurred in the two-phase cable between the isolation contactor and the permanent magnet synchronous motor based on the first diagnostic result, the amplitude of the second feedback current pulse, and the preset amplitude, further includes: A preset amplitude B-phase voltage pulse is sent to the switching transistors in the inverter so that the upper switching transistor of the B-phase in the inverter is forward-biased and the lower switching transistors of the A-phase and C-phase are reverse-biased. The fifth A-phase feedback current pulse collected by the A-phase current sensor and the fifth B-phase feedback current pulse collected by the B-phase current sensor are obtained, wherein the second feedback current pulse further includes the fifth A-phase feedback current pulse and the fifth B-phase feedback current pulse; If the first diagnostic result indicates that no phase-to-phase short circuit fault has occurred in the B-phase cable and C-phase cable between the inverter and the isolation contactor, and the amplitude of the fifth A-phase feedback current pulse is less than or equal to a preset multiple of the preset amplitude, and the amplitude of the fifth B-phase feedback current pulse is greater than a preset multiple of the preset amplitude, then it is determined that a phase-to-phase short circuit fault has occurred in the B-phase cable and C-phase cable between the isolation contactor and the permanent magnet synchronous motor.

7. The fault diagnosis method according to claim 6, characterized in that, The process of sending a three-phase voltage pulse of a preset amplitude to the switching transistors in the inverter, acquiring a second feedback current pulse collected by the current sensor, and obtaining a second diagnostic result of whether a phase-to-phase short-circuit fault has occurred in the two-phase cable between the isolation contactor and the permanent magnet synchronous motor based on the first diagnostic result, the amplitude of the second feedback current pulse, and the preset amplitude, further includes: A C-phase voltage pulse of preset amplitude is sent to the switching transistors in the inverter so that the upper switching transistor of the C-phase in the inverter is forward-biased and the lower switching transistors of the A-phase and B-phase are reverse-biased. The sixth phase A feedback current pulse collected by the phase A current sensor and the sixth phase B feedback current pulse collected by the phase B current sensor are obtained, wherein the second feedback current pulse further includes the sixth phase A feedback current pulse and the sixth phase B feedback current pulse; If the amplitude of the sixth phase A feedback current pulse is less than or equal to a preset multiple of the preset amplitude, and the amplitude of the sixth phase B feedback current pulse is less than or equal to a preset multiple of the preset amplitude, then it is determined that no phase-to-phase short circuit fault has occurred in the A-phase cable and C-phase cable, as well as the B-phase cable and C-phase cable between the isolation contactor and the permanent magnet synchronous motor.

8. The fault diagnosis method according to any one of claims 1 to 7, characterized in that, The method further includes: If the first diagnostic result is that a phase-to-phase short circuit fault has occurred in the two-phase cable between the inverter and the isolation contactor, or if the second diagnostic result is that a phase-to-phase short circuit fault has occurred in the two-phase cable between the isolation contactor and the permanent magnet synchronous motor, then the upper switch tubes of each phase in the inverter are turned on and the lower switch tubes of each phase are turned off, or the upper switch tubes of each phase in the inverter are turned off and the lower switch tubes of each phase are turned on.

9. The fault diagnosis method according to claim 2, characterized in that, The method further includes: Control the disconnecting contactor to disconnect; Control the upper-phase switching transistors of each phase in the inverter to be turned on and the lower-phase switching transistors of each phase to be turned off; Acquire the seventh phase A feedback current pulse collected by the phase A current sensor and the seventh phase B feedback current pulse collected by the phase B current sensor; If the amplitude of the seventh phase A feedback current pulse and the amplitude of the seventh phase B feedback current pulse are both zero, it is determined that neither the A-phase cable nor the B-phase cable between the inverter and the isolation contactor has a grounding fault. If the amplitude of the seventh phase A feedback current pulse is greater than zero and the amplitude of the seventh phase B feedback current pulse is zero, then it is determined that the A phase cable between the inverter and the isolation contactor has a grounding fault, and the B phase cable has not a grounding fault. If the amplitude of the seventh phase A feedback current pulse is equal to zero and the amplitude of the seventh phase B feedback current pulse is greater than zero, then it is determined that the A-phase cable between the inverter and the isolation contactor has not experienced a grounding fault, and the B-phase cable has experienced a grounding fault. If the amplitude of the seventh phase A feedback current pulse and the amplitude of the seventh phase B feedback current pulse are both greater than zero, then it is determined that both the A-phase cable and the B-phase cable between the inverter and the isolation contactor have a grounding fault.

10. The fault diagnosis method according to claim 9, characterized in that, The method further includes: If it is determined that neither the A-phase cable nor the B-phase cable between the inverter and the isolation contactor has a grounding fault, then the isolation contactor is controlled to close. A positive voltage pulse is sent to the upper switching transistor in the inverter, and a negative voltage pulse is sent to the lower switching transistor in the inverter; The eighth phase A feedback current pulse collected by the phase A current sensor and the eighth phase B feedback current pulse collected by the phase B current sensor are obtained. If the amplitude of the eighth phase A feedback current pulse and the amplitude of the eighth phase B feedback current pulse are both zero, it is determined that neither the A-phase cable nor the B-phase cable between the isolation contactor and the permanent magnet synchronous motor has a grounding fault. If the amplitude of the eighth phase A feedback current pulse is greater than zero and the amplitude of the eighth phase B feedback current pulse is zero, then it is determined that the A-phase cable between the isolation contactor and the permanent magnet synchronous motor has a grounding fault, and the B-phase cable has not a grounding fault. If the amplitude of the eighth phase A feedback current pulse is equal to zero and the amplitude of the eighth phase B feedback current pulse is greater than zero, then it is determined that the A-phase cable between the isolation contactor and the permanent magnet synchronous motor has no grounding fault, and the B-phase cable has a grounding fault. If the amplitude of the eighth phase A feedback current pulse and the amplitude of the eighth phase B feedback current pulse are both greater than zero, then it is determined that both the A-phase cable and the B-phase cable between the isolation contactor and the permanent magnet synchronous motor have grounding faults.

11. A fault diagnosis system for a permanent magnet synchronous motor, characterized in that, The permanent magnet synchronous motor is connected to the inverter via an isolation contactor, and a current sensor is installed between the isolation contactor and the inverter. The system includes: The first control module is used to control the permanent magnet synchronous motor to stop when a fault is detected in the permanent magnet synchronous motor during the operation of the vehicle. The second control module is used to control the disconnection of the isolating contactor; The first diagnostic module is used to send a three-phase voltage pulse of preset amplitude to the switching transistor in the inverter, obtain the first feedback current pulse collected by the current sensor, and obtain a first diagnostic result of whether a phase-to-phase short circuit fault has occurred in the two-phase cable between the inverter and the isolation contactor based on the amplitude of the first feedback current pulse and the preset amplitude. The third control module is used to control the closing of the isolating contactor; The second diagnostic module is used to send a three-phase voltage pulse of preset amplitude to the switching transistor in the inverter, obtain the second feedback current pulse collected by the current sensor, and obtain a second diagnostic result of whether a phase-to-phase short circuit fault has occurred in the two-phase cable between the isolation contactor and the permanent magnet synchronous motor based on the first diagnostic result, the amplitude of the second feedback current pulse and the preset amplitude.

12. The fault diagnosis system according to claim 11, characterized in that, The current sensor includes an A-phase current sensor and a B-phase current sensor. The A-phase current sensor is installed on the A-phase cable between the isolation contactor and the inverter, and the B-phase current sensor is installed on the B-phase cable between the isolation contactor and the inverter. When the first diagnostic module sends a three-phase voltage pulse of preset amplitude to the switching transistors in the inverter, acquires the first feedback current pulse collected by the current sensor, and obtains a first diagnostic result regarding whether a phase-to-phase short-circuit fault has occurred in the two-phase cable between the inverter and the isolation contactor based on the amplitude of the first feedback current pulse and the preset amplitude, it is specifically used for: A voltage pulse of a preset amplitude is sent to the switching transistors in the inverter so that the upper switching transistor of phase A in the inverter is forward-biased and the lower switching transistors of phases B and C are reverse-biased. The first A-phase feedback current pulse collected by the A-phase current sensor and the first B-phase feedback current pulse collected by the B-phase current sensor are obtained, wherein the first feedback current pulse includes the first A-phase feedback current pulse and the first B-phase feedback current pulse. If the amplitude of the first A-phase feedback current pulse and the amplitude of the first B-phase feedback current pulse are both less than or equal to a preset multiple of the preset amplitude, then it is determined that no phase-to-phase short circuit fault has occurred in the A-phase cable and the B-phase cable between the inverter and the isolation contactor. If the amplitude of the first A-phase feedback current pulse and the amplitude of the first B-phase feedback current pulse are both greater than a preset multiple of the preset amplitude, then it is determined that a phase-to-phase short circuit fault has occurred in the A-phase cable and the B-phase cable between the inverter and the isolation contactor. If the amplitude of the first A-phase feedback current pulse is greater than a preset multiple of the preset amplitude, and the amplitude of the first B-phase feedback current pulse is less than or equal to a preset multiple of the preset amplitude, then it is determined that a phase-to-phase short circuit fault has occurred in the A-phase cable and the C-phase cable between the inverter and the isolation contactor.

13. The fault diagnosis system according to claim 12, characterized in that, When the first diagnostic module sends a three-phase voltage pulse of preset amplitude to the switching transistors in the inverter, acquires the first feedback current pulse collected by the current sensor, and obtains a first diagnostic result of whether a phase-to-phase short-circuit fault has occurred in the two-phase cable between the inverter and the isolation contactor based on the amplitude of the first feedback current pulse and the preset amplitude, it is also specifically used for: A preset amplitude B-phase voltage pulse is sent to the switching transistors in the inverter so that the upper switching transistor of the B-phase in the inverter is forward-biased and the lower switching transistors of the A-phase and C-phase are reverse-biased. The second A-phase feedback current pulse collected by the A-phase current sensor and the second B-phase feedback current pulse collected by the B-phase current sensor are obtained, wherein the first feedback current pulse further includes the second A-phase feedback current pulse and the second B-phase feedback current pulse; If the amplitude of the second phase A feedback current pulse is less than or equal to a preset multiple of the preset amplitude, and the amplitude of the second phase B feedback current pulse is greater than a preset multiple of the preset amplitude, then it is determined that a phase-to-phase short circuit fault has occurred in the phase B cable and phase C cable between the inverter and the isolation contactor.

14. The fault diagnosis system according to claim 13, characterized in that, When the first diagnostic module sends a three-phase voltage pulse of preset amplitude to the switching transistors in the inverter, acquires the first feedback current pulse collected by the current sensor, and obtains a first diagnostic result of whether a phase-to-phase short-circuit fault has occurred in the two-phase cable between the inverter and the isolation contactor based on the amplitude of the first feedback current pulse and the preset amplitude, it is also specifically used for: A C-phase voltage pulse of preset amplitude is sent to the switching transistors in the inverter so that the upper switching transistor of the C-phase in the inverter is forward-biased and the lower switching transistors of the A-phase and B-phase are reverse-biased. The third A-phase feedback current pulse collected by the A-phase current sensor and the third B-phase feedback current pulse collected by the B-phase current sensor are obtained, wherein the first feedback current pulse further includes the third A-phase feedback current pulse and the third B-phase feedback current pulse. If the amplitude of the third phase A feedback current pulse and the amplitude of the third phase B feedback current pulse are both less than or equal to a preset multiple of the preset amplitude, then it is determined that no phase-to-phase short circuit fault has occurred in the A-phase cable and C-phase cable, as well as the B-phase cable and C-phase cable between the inverter and the isolation contactor.

15. The fault diagnosis system according to claim 14, characterized in that, When the second diagnostic module sends a three-phase voltage pulse of preset amplitude to the switching transistors in the inverter, acquires the second feedback current pulse collected by the current sensor, and obtains a second diagnostic result regarding whether a phase-to-phase short-circuit fault has occurred in the two-phase cable between the isolation contactor and the permanent magnet synchronous motor based on the first diagnostic result, the amplitude of the second feedback current pulse, and the preset amplitude, it is specifically used for: A voltage pulse of a preset amplitude is sent to the switching transistors in the inverter so that the upper switching transistor of phase A in the inverter is forward-biased and the lower switching transistors of phases B and C are reverse-biased. The fourth A-phase feedback current pulse collected by the A-phase current sensor and the fourth B-phase feedback current pulse collected by the B-phase current sensor are obtained, wherein the second feedback current pulse includes the fourth A-phase feedback current pulse and the fourth B-phase feedback current pulse. If the amplitudes of the fourth A-phase feedback current pulse and the fourth B-phase feedback current pulse are both less than or equal to a preset multiple of the preset amplitude, it is determined that no phase-to-phase short circuit fault has occurred in the A-phase cable and the B-phase cable between the isolation contactor and the permanent magnet synchronous motor. If the first diagnostic result indicates that there is no phase-to-phase short circuit fault in the A-phase cable and B-phase cable between the inverter and the isolation contactor, and the amplitudes of the fourth A-phase feedback current pulse and the fourth B-phase feedback current pulse are both greater than a preset multiple of the preset amplitude, then it is determined that there is a phase-to-phase short circuit fault in the A-phase cable and B-phase cable between the isolation contactor and the permanent magnet synchronous motor. If the first diagnostic result indicates that no phase-to-phase short circuit fault has occurred in the A-phase cable and C-phase cable between the inverter and the isolation contactor, and the amplitude of the fourth A-phase feedback current pulse is greater than a preset multiple of the preset amplitude, and the amplitude of the fourth B-phase feedback current pulse is less than or equal to a preset multiple of the preset amplitude, then it is determined that a phase-to-phase short circuit fault has occurred in the A-phase cable and C-phase cable between the isolation contactor and the permanent magnet synchronous motor.

16. The fault diagnosis system according to claim 15, characterized in that, When the second diagnostic module sends a three-phase voltage pulse of preset amplitude to the switching transistors in the inverter, acquires the second feedback current pulse collected by the current sensor, and obtains a second diagnostic result regarding whether a phase-to-phase short-circuit fault has occurred in the two-phase cable between the isolation contactor and the permanent magnet synchronous motor based on the first diagnostic result, the amplitude of the second feedback current pulse, and the preset amplitude, it is also specifically used for: A preset amplitude B-phase voltage pulse is sent to the switching transistors in the inverter so that the upper switching transistor of the B-phase in the inverter is forward-biased and the lower switching transistors of the A-phase and C-phase are reverse-biased. The fifth A-phase feedback current pulse collected by the A-phase current sensor and the fifth B-phase feedback current pulse collected by the B-phase current sensor are obtained, wherein the second feedback current pulse further includes the fifth A-phase feedback current pulse and the fifth B-phase feedback current pulse; If the first diagnostic result indicates that no phase-to-phase short circuit fault has occurred in the B-phase cable and C-phase cable between the inverter and the isolation contactor, and the amplitude of the fifth A-phase feedback current pulse is less than or equal to a preset multiple of the preset amplitude, and the amplitude of the fifth B-phase feedback current pulse is greater than a preset multiple of the preset amplitude, then it is determined that a phase-to-phase short circuit fault has occurred in the B-phase cable and C-phase cable between the isolation contactor and the permanent magnet synchronous motor.

17. The fault diagnosis system according to claim 16, characterized in that, When the second diagnostic module sends a three-phase voltage pulse of preset amplitude to the switching transistors in the inverter, acquires the second feedback current pulse collected by the current sensor, and obtains a second diagnostic result regarding whether a phase-to-phase short-circuit fault has occurred in the two-phase cable between the isolation contactor and the permanent magnet synchronous motor based on the first diagnostic result, the amplitude of the second feedback current pulse, and the preset amplitude, it is also specifically used for: A C-phase voltage pulse of preset amplitude is sent to the switching transistors in the inverter so that the upper switching transistor of the C-phase in the inverter is forward-biased and the lower switching transistors of the A-phase and B-phase are reverse-biased. The sixth phase A feedback current pulse collected by the phase A current sensor and the sixth phase B feedback current pulse collected by the phase B current sensor are obtained, wherein the second feedback current pulse further includes the sixth phase A feedback current pulse and the sixth phase B feedback current pulse; If the amplitude of the sixth phase A feedback current pulse is less than or equal to a preset multiple of the preset amplitude, and the amplitude of the sixth phase B feedback current pulse is less than or equal to a preset multiple of the preset amplitude, then it is determined that no phase-to-phase short circuit fault has occurred in the A-phase cable and C-phase cable, as well as the B-phase cable and C-phase cable between the isolation contactor and the permanent magnet synchronous motor.

18. The fault diagnosis system according to claim 17, characterized in that, The system also includes: The protection module is configured to, if the first diagnostic result indicates a phase-to-phase short circuit fault in the two-phase cable between the inverter and the isolation contactor, or the second diagnostic result indicates a phase-to-phase short circuit fault in the two-phase cable between the isolation contactor and the permanent magnet synchronous motor, control the upper phase switching transistors of the inverter to be turned on and the lower phase switching transistors of the inverter to be turned off, or control the upper phase switching transistors of the inverter to be turned off and the lower phase switching transistors of the inverter to be turned on.

19. A fault diagnosis device for a permanent magnet synchronous motor, characterized in that, include: Processor, memory, and communication bus; The communication bus is used to realize the connection and communication between the processor and the memory; The processor is used to execute the permanent magnet synchronous motor fault diagnosis processing program stored in the memory to implement the steps of the permanent magnet synchronous motor fault diagnosis method as described in any one of claims 1-10.

20. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores computer-executable instructions, which, when loaded and executed by a processor, implement the steps of the permanent magnet synchronous motor fault diagnosis method as described in any one of claims 1 to 10.

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