Interphase short circuit fault diagnosis method and device, system, equipment and storage medium

Abstract

The invention relates to the field of testing, and discloses an inter-phase short-circuit fault diagnosis method, device, system and equipment, and a storage medium. In the system, a frequency converter is connected with a motor through a three-phase line, and at least two phases of lines are respectively and correspondingly provided with a current sensor; the method comprises the following steps: determining the current change rate of each phase line based on the current signal of each current sensor under the condition of detecting that a power device of the frequency converter has a fault or the frequency converter outputs overcurrent, and detecting whether the current change rates of at least two phase lines in the current change rates of the phase lines are greater than a current change rate threshold value or not; performing inter-phase short-circuit fault diagnosis based on the current change rate detection result to obtain a diagnosis result; the diagnosis result is the position where there is no interphase short circuit fault or there is an interphase short circuit fault, and a fault protection strategy corresponding to the diagnosis result is determined for fault protection. The problem of low accuracy of inter-phase short-circuit fault diagnosis is solved, and the reliability and availability are improved by using a proper fault protection strategy.

Description

Technical Field

[0001] The present application relates to the field of testing, and in particular to a method and apparatus, system, equipment, and storage medium for diagnosing phase-to-phase short circuit faults. Background Art

[0002] Motors are a crucial component for energy conversion and power transmission in power systems such as rail transit vehicle traction systems and new materials industry equipment. Frequency converters convert input electrical energy into three-phase AC power and supply it to the motor. A phase-to-phase short circuit can compromise the safety of the power system in which the motor resides. Current methods for diagnosing phase-to-phase short circuit faults are prone to missed diagnoses and misdiagnoses. Missed diagnoses can result in the short-circuit voltage and torque ripple caused by phase-to-phase short circuits not being suppressed promptly, impacting power system safety. Misdiagnosis can lead to system overprotection, impacting system availability. Therefore, the low accuracy of phase-to-phase short circuit fault diagnosis is a critical issue that needs to be addressed urgently in the industry. Summary of the Invention

[0003] The purpose of this application is to at least provide a phase-to-phase short circuit fault diagnosis method and device, system, equipment, and storage medium, which can at least solve the problem of low accuracy in phase-to-phase short circuit fault diagnosis, and at least achieve the effect of improving the accuracy of phase-to-phase short circuit fault diagnosis and improving the reliability and availability of the power system in which the motor is located.

[0004] In a first aspect, the present application provides a phase-to-phase short circuit fault diagnosis method, which is applied to a phase-to-phase short circuit fault diagnosis system. The phase-to-phase short circuit fault diagnosis system includes: an inverter and a motor, the inverter is connected to the motor via a three-phase line, and at least two phases of the three-phase line are respectively provided with current sensors. The method includes: When a fault is detected in a power device of the inverter or an overcurrent is detected in the inverter output, a current change rate of each phase of the three-phase circuit is determined based on the current signal of each current sensor, and whether the current change rate of at least two phases of the current change rate of each phase is greater than a current change rate threshold, to obtain a current change rate detection result; Based on the current change rate detection result, a phase-to-phase short circuit fault diagnosis is performed to obtain a diagnosis result; wherein, the diagnosis result is the location where there is no phase-to-phase short circuit fault or there is a phase-to-phase short circuit fault, and the diagnosis result is used to determine the fault protection strategy corresponding to the diagnosis result to perform fault protection.

[0005] Optionally, each phase of the three-phase circuit has a first node, and the current sensor is arranged at the first node; the motor is a permanent magnet synchronous motor; The interphase short circuit fault diagnosis based on the current change rate detection result is performed to obtain a diagnosis result, including: When the inverter blocks pulses and stops working, if the current change rate detection result shows that the current change rate of at least two phase lines is greater than the current change rate threshold, it is determined that an interphase short circuit fault exists in the first position area, and the first position area includes the body of the motor and the area between the motor and the first node: If the current change rate detection result shows that there are no at least two phase lines whose current change rates are greater than the current change rate threshold, the sum of the instantaneous current values ​​and the effective current value of each phase line of the three-phase line are obtained based on the current signals of each current sensor, and based on the output current of the inverter, the sum of the instantaneous current values ​​of each phase line and the effective current value of each phase line, it is determined whether the inter-phase short-circuit current characteristics are currently met, and a first judgment result is obtained; wherein the inter-phase short-circuit current characteristics include: the inverter does not output current, the sum of the instantaneous current values ​​of each phase line is less than a first threshold, the maximum value of the effective current value of each phase line is greater than a second threshold, and the ratio of the minimum value to the maximum value of the effective current value of each phase line is less than a third threshold; If the first judgment result satisfies the phase-to-phase short-circuit current characteristic, it is determined that an interphase short-circuit fault exists in a second location area, where the second location area includes an area between the first node and the inverter; If the first judgment result is that the inter-phase short-circuit current characteristic is not satisfied, it is determined that there is no inter-phase short-circuit fault.

[0006] Optionally, the interphase short circuit fault diagnosis system further includes an isolation contactor, which is arranged between the first node and the inverter; The determining that an interphase short circuit fault exists in the second location area includes: Disconnecting the isolation contactor, and determining whether the interphase short-circuit current characteristic is currently satisfied based on the output current of the inverter, the sum of the instantaneous current values ​​of each phase line, and the effective current value of each phase line, to obtain a second determination result; If the second judgment result satisfies the phase-to-phase short-circuit current characteristic, it is determined that an interphase short-circuit fault exists in a third location area, where the third location area includes the line between the isolation contactor and the first node and the contact of the isolation contactor close to the first node; If the second judgment result is that the inter-phase short-circuit current characteristic is not satisfied, it is determined that an inter-phase short-circuit fault exists in a fourth position area, where the fourth position area includes the line between the isolation contactor and the inverter and the contact of the isolation contactor close to the inverter; The second location area includes the third location area and the fourth location area.

[0007] Optionally, the interphase short circuit fault diagnosis system further includes an isolation contactor, which is arranged between the first node and the motor; The determining that an interphase short circuit fault exists in the first location area includes: Disconnecting the isolation contactor and starting the frequency converter to output a test pulse; When the frequency converter outputs the test pulse, determine whether the power device still fails or the frequency converter outputs overcurrent, and whether the current change rate of at least two-phase lines is greater than the current change rate threshold; if so, determine that an interphase short circuit fault exists in the fifth position area, and the fifth position area includes the line between the isolation contactor and the first node and the contact of the isolation contactor close to the first node; otherwise, determine that an interphase short circuit fault exists in the sixth position area, and the sixth position area includes the line between the isolation contactor and the motor, the contact of the isolation contactor close to the motor, and the body of the motor; The first location area includes the fifth location area and the sixth location area.

[0008] Optionally, the third threshold is a fixed threshold or is determined based on the current rotation speed of the motor.

[0009] Optionally, each phase of the three-phase circuit has a first node, and the current sensor is arranged at the first node; two or three voltage sensors are provided on the three-phase circuit for detecting voltage signals between different phases, and each phase of the three-phase circuit has a second node located between the first node and the inverter, and the voltage sensor is arranged at the second node; the motor is a permanent magnet synchronous motor; The interphase short circuit fault diagnosis based on the current change rate detection result is performed to obtain a diagnosis result, including: When the inverter blocks pulses and stops working, if the current change rate detection result shows that the current change rate of at least two phase lines is greater than the current change rate threshold, it is determined that an interphase short circuit fault exists in the first position area, and the first position area includes the body of the motor and the area between the motor and the first node: If the current change rate detection result shows that there is no current change rate greater than the current change rate threshold in at least two-phase lines, the voltage value between each two-phase lines of the three-phase line is obtained based on the voltage signal of each voltage sensor, and based on the voltage value between each two-phase lines of the three-phase line, it is determined whether there is an inter-phase short circuit fault in the second position area, and the second position area includes the area between the first node and the inverter.

[0010] Optionally, the inter-phase short circuit fault diagnosis system further includes an isolation contactor, which is arranged between the first node and the second node; The determining whether there is an interphase short circuit fault in the second location area based on the voltage value between each two phases of the three-phase line includes: Based on the voltage values ​​between each two phases of the three-phase circuit, determining whether at least one interphase short-circuit voltage characteristic exists, and obtaining a third judgment result; wherein the interphase short-circuit voltage characteristic includes: when the inverter is in an operating state, the voltage value drops from a normal value to below a voltage threshold; after the inverter is started from a stopped state, the voltage value remains zero continuously and the current sensors of the corresponding two phases have overcurrents; If the third judgment result is no, determining that there is no interphase short circuit fault in the second position area; If the third judgment result is yes, disconnect the isolation contactor and start the frequency converter to output a test pulse; when the frequency converter outputs the test pulse, determine whether at least one of the phase-to-phase short-circuit voltage characteristics still exists, and obtain a fourth judgment result; If the fourth judgment result is no, it is determined that an interphase short circuit fault exists in a third position area, where the third position area includes a line between the isolation contactor and the first node and a contact of the isolation contactor close to the first node; If the fourth judgment result is yes, it is determined that an interphase short circuit fault exists in a fourth position area, and the fourth position area includes the line between the isolation contactor and the inverter and the contact of the isolation contactor close to the inverter; The second location area includes the third location area and the fourth location area.

[0011] Optionally, the interphase short circuit fault diagnosis system further includes an isolation contactor, which is arranged between the first node and the motor; The determining that an interphase short circuit fault exists in the first location area includes: Disconnecting the isolation contactor and starting the frequency converter to output a test pulse; When the frequency converter outputs the test pulse, determine whether the power device still fails or the frequency converter outputs overcurrent, and whether the current change rate of at least two-phase lines is greater than the current change rate threshold; if so, determine that an interphase short circuit fault exists in the fifth position area, and the fifth position area includes the line between the isolation contactor and the first node and the contact of the isolation contactor close to the first node; otherwise, determine that an interphase short circuit fault exists in the sixth position area, and the sixth position area includes the line between the isolation contactor and the motor, the contact of the isolation contactor close to the motor, and the body of the motor; The first location area includes the fifth location area and the sixth location area.

[0012] Optionally, the interphase short circuit fault diagnosis system further includes an isolation contactor, which is arranged between the first node and the motor; The determining whether there is an interphase short circuit fault in the second location area based on the voltage value between each two phases of the three-phase line includes: Disconnecting the isolation contactor and starting the frequency converter to output a test pulse; When the inverter outputs the test pulse, based on the voltage value between each two phases of the three-phase circuit, it is determined whether at least one interphase short-circuit voltage characteristic occurs; wherein the interphase short-circuit voltage characteristic includes: when the inverter is in an operating state, the voltage value drops from a normal value to below a voltage threshold; after the inverter is started from a stopped state, the voltage value remains zero and the current sensors of the corresponding two phase circuits have overcurrent; If so, determining that an interphase short circuit fault exists in the second location area; If not, it is determined that there is no interphase short circuit fault in the second location area.

[0013] Optionally, after the interphase short circuit fault diagnosis is performed based on the current change rate detection result and the diagnosis result is obtained, the method further includes: If the diagnosis result indicates that an interphase short circuit fault exists in the first position area, an active three-phase short circuit mode is executed for fault protection, wherein the active three-phase short circuit mode is a mode in which the three-phase upper bridge arm or the three-phase lower bridge arm of the inverter are all turned on, so that the three-phase winding of the motor forms a loop through the inverter to achieve demagnetization and braking; When the diagnosis result indicates that an interphase short circuit fault exists in the third position area, closing the isolation contactor and executing the active three-phase short circuit mode for fault protection; When the diagnosis result indicates that an interphase short circuit fault exists in the fourth position area, maintaining the disconnected state of the isolation contactor for fault protection; When the diagnosis result shows that there is no interphase short circuit fault, fault protection is performed using a protection strategy when the power device fails or the inverter outputs an overcurrent.

[0014] Optionally, after the interphase short circuit fault diagnosis is performed based on the current change rate detection result and the diagnosis result is obtained, the method further includes: If the diagnosis result indicates that an interphase short circuit fault exists in the sixth position area, the isolation contactor is closed to execute an active three-phase short circuit mode for fault protection, wherein the active three-phase short circuit mode is a mode in which the three-phase upper bridge arm or the three-phase lower bridge arm of the inverter are all turned on, so that the three-phase winding of the motor forms a loop through the inverter to achieve demagnetization and braking; When the diagnosis result indicates that an interphase short circuit fault exists in the fifth position area, maintaining the disconnected state of the isolation contactor for fault protection; If the diagnosis result indicates that an interphase short circuit fault exists in the second position area, disconnecting the isolation contactor for fault protection; When the diagnosis result shows that there is no interphase short circuit fault, fault protection is performed using a protection strategy when the power device fails or the inverter outputs an overcurrent.

[0015] In a second aspect, the present application provides a phase-to-phase short circuit fault diagnosis device, which is applied to a phase-to-phase short circuit fault diagnosis system. The phase-to-phase short circuit fault diagnosis system includes: an inverter and a motor, the inverter is connected to the motor via a three-phase line, and at least two phases of the three-phase line are respectively provided with current sensors. The device includes: a change rate detection module, configured to, upon detecting a fault in a power device of the inverter or an overcurrent in the inverter output, determine a current change rate of each phase of the three-phase circuit based on the current signal of each current sensor, and detect whether the current change rate of at least two phases of the current change rates of each phase is greater than a current change rate threshold, thereby obtaining a current change rate detection result; A short-circuit diagnostic module is used to diagnose an interphase short-circuit fault based on the current change rate detection result to obtain a diagnostic result; wherein, the diagnostic result is the location where there is no interphase short-circuit fault or the presence of an interphase short-circuit fault, and the diagnostic result is used to determine the fault protection strategy corresponding to the diagnostic result to perform fault protection.

[0016] In a third aspect, the present application provides a phase-to-phase short circuit fault diagnosis system, comprising: Motor; A frequency converter, the frequency converter being connected to the motor via a three-phase circuit, and current sensors being respectively provided on at least two phases of the three-phase circuit; A control device, wherein the control device is used to execute any one of the above-mentioned inter-phase short circuit fault diagnosis methods.

[0017] Optionally, each phase of the three-phase circuit has a first node, and the current sensor is provided at the first node; The interphase short circuit fault diagnosis system further includes an isolation contactor, which is arranged between the first node and the inverter or between the first node and the motor; The motor is a permanent magnet synchronous motor.

[0018] Optionally, each phase of the three-phase circuit has a first node, and the current sensor is arranged at the first node; two or three voltage sensors are arranged on the three-phase circuit for detecting voltage signals between different phases, and each phase of the three-phase circuit has a second node located between the first node and the inverter, and the voltage sensor is arranged at the second node; The interphase short circuit fault diagnosis system further includes an isolation contactor, which is arranged between the first node and the second node or between the first node and the motor; The motor is a permanent magnet synchronous motor.

[0019] In a fourth aspect, the present application provides an electronic device, comprising: at least one processor; and, a memory communicatively connected to the at least one processor; wherein, The memory stores instructions that can be executed by the at least one processor. The instructions are executed by the at least one processor to enable the at least one processor to perform any one of the above inter-phase short circuit fault diagnosis methods.

[0020] In a fifth aspect, the present application provides a computer-readable storage medium storing a computer program, which, when executed by a processor, implements any of the above-described methods for diagnosing interphase short circuit faults.

[0021] Compared with the prior art, the present invention has the following beneficial effects: In the method of the present application, when the power device of the inverter fails or the inverter outputs overcurrent, the fault may be caused by a phase-to-phase short circuit, or it may not be caused by a phase-to-phase short circuit. In order to avoid missed detection of phase-to-phase short circuits and untimely detection, when the power device of the inverter fails or the inverter outputs overcurrent, the current change rate of the three-phase line is further detected. If the short-circuit current passes through the current sensor, the current change rate of the current signal detected by the current sensor will be very large. Therefore, the current change rate can be detected in combination with the current signal detected by the current sensor, and the current change rate of each phase of the three-phase line is determined based on the current signal of each current sensor, and it is detected whether there are at least two phases with large current change rates in the current change rates of each phase. Based on the current change rate threshold, a current change rate detection result is obtained. Combined with the current change rate detection result, an accurate phase-to-phase short circuit fault diagnosis can be performed to obtain a diagnosis result. The diagnosis result is the location of the phase-to-phase short circuit fault or the location of the phase-to-phase short circuit fault. In this way, missed detection and false detection are avoided, and the location of the phase-to-phase short circuit can be obtained when a phase-to-phase short circuit fault occurs, and the location of the phase-to-phase short circuit fault is located, thereby improving the accuracy of the phase-to-phase short circuit fault diagnosis. The fault protection strategy corresponding to the diagnostic result is used for fault protection, so that the corresponding fault protection strategy is used for appropriate fault protection for phase-to-phase short circuits with no phase-to-phase short circuit fault and phase-to-phase short circuits at different locations, thereby avoiding overprotection, reducing the impact of the fault, and improving the reliability and availability of the power system where the motor is located.

[0022] It can be understood that the beneficial effects of the second to fifth aspects mentioned above can be found in the relevant description of the first aspect mentioned above, and will not be repeated here. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] One or more embodiments are exemplarily described by the figures in the corresponding drawings, and these exemplified descriptions do not constitute limitations on the embodiments.

[0024] Figure 1 This is an example of an application scenario of a phase-to-phase short circuit fault diagnosis system provided by an embodiment of the present application. Figure 1 ; Figure 2 This is a flow chart of a phase-to-phase short circuit fault diagnosis method provided by an embodiment of the present application. Figure 1 ; Figure 3 This is an example of an application scenario of a phase-to-phase short circuit fault diagnosis system provided by an embodiment of the present application. Figure 2 ; Figure 4 This is another example of the current change rate provided by the present application. Figure 1 ; Figure 5 This is another example of the current change rate provided by the present application. Figure 2 ; Figure 6 This is an example of an application scenario of a phase-to-phase short circuit fault diagnosis system provided by an embodiment of the present application. Figure 3 ; Figure 7 This is another embodiment of the present application providing a schematic diagram of the interphase short circuit fault location. Figure 1 ; Figure 8 This is a schematic diagram of the operation of the active three-phase short-circuit mode provided by another embodiment of the present application; Figure 9 This is a flow chart of a phase-to-phase short circuit fault diagnosis method provided by an embodiment of the present application. Figure 2 ; Figure 10 This is another embodiment of the present application providing a schematic diagram of the interphase short circuit fault location. Figure 2 ; Figure 11 This is a flow chart of a phase-to-phase short circuit fault diagnosis method provided by an embodiment of the present application. Figure 3 ; Figure 12 This is another embodiment of the present application providing a schematic diagram of the interphase short circuit fault location. Figure 3 ; Figure 13 This is a flow chart of a phase-to-phase short circuit fault diagnosis method provided by an embodiment of the present application. Figure 4 ; Figure 14 This is another embodiment of the present application providing a schematic diagram of the interphase short circuit fault location. Figure 4 ; Figure 15 This is a flow chart of a phase-to-phase short circuit fault diagnosis method provided by an embodiment of the present application. Figure 5 ; Figure 16 This is a schematic diagram of a phase short circuit fault diagnosis device provided by another embodiment of the present application. Figure 1 ; Figure 17 This is a schematic diagram of a phase short circuit fault diagnosis device provided by another embodiment of the present application. Figure 2 ; Figure 18 It is a structural diagram of an electronic device provided by another embodiment of the present application. DETAILED DESCRIPTION

[0025] In order to make the purpose, technical solutions and advantages of the embodiments of the present application clearer, each embodiment of the present application will be described in detail below with reference to the accompanying drawings. However, it will be understood by those skilled in the art that in each embodiment of the present application, many technical details are proposed to enable the reader to better understand the present application. However, even without these technical details and various changes and modifications based on the following embodiments, the technical solutions claimed in the present application can be implemented. The division of the following embodiments is for convenience of description and should not constitute any limitation on the specific implementation of the present application. The various embodiments can be combined and referenced with each other under the premise of no contradiction.

[0026] See also Figure 1 、 Figure 2 and Figure 3 This embodiment provides a phase-to-phase short circuit fault diagnosis method, which is applied to a phase-to-phase short circuit fault diagnosis system. The phase-to-phase short circuit fault diagnosis system includes: an inverter 104 and a motor M. The inverter 104 is connected to the motor M via a three-phase line. Current sensors 108 are respectively provided on at least two phases of the three-phase line. The phase-to-phase short circuit fault diagnosis method includes: Step S201: When it is detected that the power device of the inverter fails or the inverter output is overcurrent, the current change rate of each phase line of the three-phase line is determined based on the current signal of each current sensor, and it is detected whether the current change rate of at least two phase lines in the current change rate of each phase line is greater than the current change rate threshold, and the current change rate detection result is obtained.

[0027] Illustratively, the motor of this embodiment may be a traction motor in a traction system of a rail transit vehicle, and may also be a motor in a power system of other equipment, such as a motor in a power system of equipment in the new materials industry.

[0028] Figure 1 The traction motor of a traction system is used as an example. The traction system may include a four-quadrant rectifier 102, a DC circuit 103, a frequency converter 104, an isolation contactor 105, and a motor M, which are connected in sequence. The four-quadrant rectifier 102 draws power from the overhead catenary 101 via a transformer T and a pantograph. Transformer T is also grounded via a grounding device 107. The four-quadrant rectifier 102 converts the input electrical energy into DC power and supplies it to the DC circuit 103. The DC circuit 103 supplies the DC power to the frequency converter 104. The frequency converter 104 converts the input DC power into AC power and supplies it to the motor M via the isolation contactor 105.

[0029] In addition, the traction system further includes a chopper circuit 106 for maintaining the DC bus voltage.

[0030] The frequency converter 104 is an inverter, which can convert the input direct current into alternating current by using variable voltage and variable frequency (VVVF) technology.

[0031] Here, the isolation contactor 105 is used to isolate the inverter 104 from the motor M when the traction system is abnormal.

[0032] The current sensor 108 may be provided between the isolation contactor 105 and the frequency converter 104 , or between the isolation contactor 105 and the motor M.

[0033] like Figure 3 As shown, in the traction converter of the traction system, the frequency converter 104 is connected to the three-phase U, V, and W terminals of the motor M via a three-phase line. Current sensors 108 are provided on at least two phases of the three-phase line. In other words, three or two current sensors 108 can be provided, and the current sensors 108 on each phase constitute a current sensor system. Figure 3 In the figure, a current sensor 108 is provided on each of the three-phase lines, and the current sensor 108 is provided between the isolation contactor 105 and the motor M.

[0034] The interphase short circuit fault diagnosis system may further include a control device 109, which can execute the interphase short circuit fault diagnosis method of this embodiment. The control device 109 can receive current signals from the current sensors 108 on each phase line, send DO instructions (e.g., close instructions and open instructions) to the isolation contactor 105 to control the opening and closing of the isolation contactor 105, and send pulse width modulation (PWM) pulse signals to the inverter 104 to control the operation of the inverter 104, so that the inverter 104 outputs current.

[0035] The control device 109 may be an additional control device or an existing vehicle-mounted control device, such as a transmission control device.

[0036] The inverter 104 has a power device fault detection function that can detect whether a power device has failed. When a power device fault is detected, a power device fault signal is issued. The control device can determine that a power device fault has been detected in the inverter upon detecting the power device fault signal. For example, the power device fault can be an overcurrent fault in the power device. The inverter's driver board has a corresponding driver-level overcurrent protection function for the power device. When the power device overcurrent occurs, a power device overcurrent fault signal (e.g., a high-level signal or a low-level signal) is issued and overcurrent protection is performed.

[0037] Exemplarily, the frequency converter 104 includes three-phase bridge arms connected in parallel, each phase bridge arm includes an upper bridge arm and a lower bridge arm, and both the upper bridge arm and the lower bridge arm include a switch tube. Figure 3 The inverter 104 includes a first switching transistor V1, a second switching transistor V2, a third switching transistor V3, a fourth switching transistor V4, a fifth switching transistor V5, and a sixth switching transistor V6. The first switching transistor V1, the third switching transistor V3, and the fifth switching transistor V5 are respectively located in the upper bridge arm of each phase, and the second switching transistor V2, the fourth switching transistor V4, and the sixth switching transistor V6 are respectively located in the lower bridge arm of each phase.

[0038] Exemplarily, the method for detecting output overcurrent of the inverter 104 includes: An instantaneous current value of each phase of the three-phase line is obtained based on the current signal from each current sensor 108, and the instantaneous current value of each phase is compared with a fourth threshold value. When the instantaneous current value of any phase line is greater than the fourth threshold value, it is determined that the inverter 104 outputs an overcurrent. The fourth threshold value can be set according to actual needs and is not specifically limited here.

[0039] Obtaining the instantaneous current value of each phase of the three-phase line based on the current signal of each current sensor 108 may specifically include: when all three phase lines are provided with current sensors 108, obtaining the instantaneous current value of each phase line based on the current signal of the current sensor 108 of each phase line. When two phase lines are provided with current sensors 108, obtaining the instantaneous current value of the two phase lines based on the current signals of the current sensors 108 of the two phase lines, and obtaining the instantaneous current value of the other phase line based on the instantaneous current values ​​of the two phase lines based on the rule that the sum of the instantaneous current values ​​of the three phase lines is zero.

[0040] When a fault is detected in the power device of the inverter 104 or an overcurrent is output by the inverter 104, the current change rate of each phase of the three-phase line is determined based on the current signal of each current sensor 108. Specifically, the current instantaneous value of each phase line can be obtained based on the current signal of each current sensor 108. For each phase line, the current change rate di / dt is obtained based on the ratio of the difference between the current instantaneous value of the current and the instantaneous value of the current at the previous moment and the time change.

[0041] When the current change rate di / dt is greater than the current change rate threshold K0, it indicates that the current change rate is too large and there may be a phase short circuit. The specific value of K0 can be obtained through a real phase short circuit simulation test. The specific value of K0 is greater than the current change rate when an abnormality such as control abnormality or motor grounding causes overcurrent. This is because when an abnormality such as control abnormality or motor grounding causes overcurrent, the current flows through the motor windings and the current mutation is not large. However, when a phase short circuit occurs, the current does not flow through the motor windings and the current mutation is very large. Figure 4 and Figure 5 The schematic diagram of di / dt is shown in the figure. Figure 4 is the di / dt when the phases are short-circuited, Figure 5 This is a schematic diagram of di / dt when overcurrent is caused by abnormal control or motor grounding. It can be seen that di / dt is greater when there is a phase short circuit.

[0042] Step S202: perform interphase short circuit fault diagnosis based on the current change rate detection result to obtain a diagnosis result; wherein the diagnosis result is the location where there is no interphase short circuit fault or the presence of an interphase short circuit fault, and the diagnosis result is used to determine the fault protection strategy corresponding to the diagnosis result for fault protection.

[0043] Different diagnostic results are used to set corresponding fault protection strategies, ensuring that the fault protection strategies match the diagnostic results. This prevents the use of stringent fault protection strategies for all faults, improving the reliability and availability of the power system in which the motor is installed.

[0044] In this embodiment, when a power device of the inverter fails or the inverter outputs an overcurrent, the fault may be caused by a phase-to-phase short circuit, or it may not be caused by a phase-to-phase short circuit. In order to avoid missed detection of a phase-to-phase short circuit or untimely detection, when a power device of the inverter fails or the inverter outputs an overcurrent, the current change rate of the three-phase line is further detected. If the short-circuit current passes through the current sensor, the current change rate of the current signal detected by the current sensor will be very large. Therefore, the current change rate can be detected in combination with the current signal detected by the current sensor. The current change rate of each phase of the three-phase line is determined based on the current signal of each current sensor, and it is detected whether there are at least two phases with large current change rates among the current change rates of each phase. Based on the current change rate threshold, a current change rate detection result is obtained. Combined with the current change rate detection result, an accurate phase-to-phase short circuit fault diagnosis can be performed to obtain a diagnosis result. The diagnosis result is the location of the phase-to-phase short circuit fault or the location of the phase-to-phase short circuit fault. In this way, missed detection and false detection are avoided, and the location of the phase-to-phase short circuit fault can be obtained when an interphase short circuit fault occurs, and the location of the phase-to-phase short circuit fault is located, thereby improving the accuracy of the phase-to-phase short circuit fault diagnosis. The fault protection strategy corresponding to the diagnosis result is used for fault protection, so that the corresponding fault protection strategy is used for appropriate fault protection for phase-to-phase short circuits with no phase-to-phase short circuit fault and phase short circuits in different locations, thereby avoiding overprotection, reducing the impact of the fault, and improving the reliability and availability of the power system where the motor is located.

[0045] Exemplarily, the motor may be a permanent magnet synchronous motor or an asynchronous motor.

[0046] In some embodiments, each phase of the three-phase circuit has a first node, and the current sensor is arranged at the first node; the motor is a permanent magnet synchronous motor.

[0047] Accordingly, the interphase short circuit fault diagnosis is performed based on the current change rate detection result, and the diagnosis results obtained include: When the inverter blocks the pulse and stops working, if the current change rate detection result shows that the current change rate of at least two phase lines is greater than the current change rate threshold, it is determined that an interphase short circuit fault exists in the first location area, and the first location area includes the motor body and the area between the motor and the first node: If the current change rate detection result shows that there are no at least two phase lines with current change rates greater than the current change rate threshold, the sum of the instantaneous current values ​​and the effective current value of each phase line of the three-phase line is obtained based on the current signal of each current sensor, and based on the output current of the inverter, the sum of the instantaneous current values ​​of each phase line, and the effective current value of each phase line, it is determined whether the phase-to-phase short-circuit current characteristics are currently met, and a first judgment result is obtained; wherein the phase-to-phase short-circuit current characteristics include: the inverter is not outputting current, the sum of the instantaneous current values ​​of each phase line is less than a first threshold, the maximum value of the effective current value of each phase line is greater than a second threshold, and the ratio of the minimum value to the maximum value of the effective current value of each phase line is less than a third threshold; If the first judgment result satisfies the phase-to-phase short-circuit current characteristic, it is determined that an interphase short-circuit fault exists in the second location area, and the second location area includes the area between the first node and the inverter; If the first judgment result is that the inter-phase short-circuit current characteristic is not satisfied, it is determined that there is no inter-phase short-circuit fault.

[0048] The inter-phase short-circuit current characteristics are current characteristics corresponding to the current signals of the current sensors 108 and the output current of the inverter 104 when an inter-phase short circuit occurs.

[0049] The first nodes of each phase line are arranged side by side. In the case of two current sensors, for a phase line in a three-phase line without a current sensor, the instantaneous current value of that phase line is obtained based on the instantaneous current values ​​of the two phase lines with current sensors. This is the instantaneous current value of the first node. Accordingly, the current change rate of that phase line is the current change rate of the first node.

[0050] In practical applications, when a phase-to-phase short circuit occurs, if the short-circuit point (i.e., the location of the phase-to-phase short circuit) is located between the current sensor and the motor M, i.e., the first position region, the fault can be detected by the current rate of change. If the short-circuit point is between the current sensor and the inverter, the short-circuit current does not flow through the current sensor, making it impossible to accurately diagnose the characteristic of an excessive current rate of change. However, due to the presence of the motor's back EMF, the short-circuit phase current will be large, while the non-short-circuit phase current will be zero or small. Therefore, extracting this characteristic can support the precise location of the phase-to-phase short circuit fault.

[0051] When a power device in an inverter fails or outputs overcurrent, a corresponding protection strategy (i.e., a fault protection strategy) is triggered, causing the inverter to block pulses and stop operation. This means the inverter does not start and output current. Therefore, the phase-to-phase short-circuit current characteristic can include the inverter not outputting current.

[0052] If a ground short circuit occurs, the current rate of change may be excessive. To improve diagnostic accuracy, ground fault interference can be eliminated. The sum of the instantaneous three-phase current values ​​is close to zero, indicating no ground fault. Therefore, the phase-to-phase short circuit current signature can include the sum of the instantaneous current values ​​of each phase being less than a first threshold, K1, i.e., Ia+Ib+Ic<K1. Ia, Ib, and Ic are the instantaneous current values ​​of the three-phase lines, respectively. K1 should be close to zero, but sampling error must be taken into account.

[0053] The RMS current of a three-phase line is high, suggesting the presence of a phase-to-phase short circuit. Therefore, the phase-to-phase short circuit current signature can include the maximum RMS current value of each phase line being greater than a second threshold value, K2. Specifically, the maximum value, Iram_Max(Ia, Ib, Ic), is greater than K2. K2 is a high current threshold, and its specific value can be determined through actual short-circuit testing.

[0054] When the motor speed is low, the back electromotive force of the motor is small (the peak value is less than the DC voltage on the input side of the inverter 104), and the non-short-circuited phase current is close to zero; when the motor speed is high, the back electromotive force of the motor is large (the peak value is greater than the DC voltage on the input side of the inverter 104), and there is a certain current in the non-short-circuited phase, but it is less than the short-circuited phase current. Therefore, the phase-to-phase short-circuit current characteristic may include the ratio of the minimum value to the maximum value of the effective value of the current of the three-phase line being less than the third threshold K3, that is, the minimum value Iram_Min (Ia, Ib, Ic) / the maximum value Iram_Max (Ia, Ib, Ic) < K3.

[0055] The third threshold can be fixed or determined based on the motor's current speed. This can be obtained through actual phase-to-phase short-circuit testing and set as a fixed threshold. Alternatively, a variable threshold F(v) can be set based on the motor's back-EMF and speed characteristics, which is related to the speed v. A relationship F(v) between the speed and the third threshold can be pre-set, and the current third threshold can be determined by comparing the motor's current speed with this relationship. This dynamic third threshold setting can be matched to the effect of the back-EMF on the current corresponding to the current speed, further improving the accuracy of phase-to-phase short-circuit fault diagnosis.

[0056] If the current interphase short-circuit current characteristic is met, it indicates that an interphase short-circuit fault exists in the second location area, which includes the area between the first node and the inverter. If the current interphase short-circuit current characteristic is not met, it indicates that there is no interphase short-circuit fault, but only an inverter output overcurrent fault or a power device fault.

[0057] Take the control device as a transmission control device as an example, Figure 6 As shown, the transmission control device includes an inverter control unit, a digital processing unit, a signal processing unit, and a logic processing unit. Each unit can be an independent board or multiple units can be integrated into one board. The overall functions of each unit are as follows: Inverter control unit: Inverter pulse control, can receive start-up instructions in normal mode, used for motor traction and braking control, can control the inverter to enter protection mode in phase short-circuit mode, and has phase short-circuit circuit feature extraction and overcurrent protection functions. Digital processing unit: isolation contactor closing and opening control and closed state and open state monitoring function.

[0058] Signal processing unit: It has the function of processing the signal of the inverter status (whether the power device is faulty) and the current sensor system.

[0059] Logic processing unit: phase-to-phase short circuit fault diagnosis, timing control and motor power system protection functions.

[0060] Based on the above control device, a method for diagnosing phase-to-phase short circuit faults can be implemented. Specifically: The signal processing unit receives current signals from the current sensor system and power device fault signals issued by the inverter when a power device fault occurs. Based on the current signals from each current sensor, the unit detects whether the inverter outputs overcurrent and determines a power device fault based on the power device fault signals. If a power device fault or inverter output overcurrent is detected, the unit determines the current change rate of each phase circuit based on the current signals from each current sensor. The unit then detects whether the current change rate of at least two phase circuits exceeds a current change rate threshold (i.e., the current change rate is excessive), thereby obtaining a current change rate detection result.

[0061] The signal processing unit can obtain the motor speed by acquiring the motor speed signal and provide it to the inverter control unit. The inverter control unit can obtain the current motor speed based on the speed signal and obtain the current third threshold value by comparing the current motor speed with the above relationship.

[0062] The inverter control unit can determine whether the phase-to-phase short-circuit current characteristic is currently met to obtain a first determination result.

[0063] The logic processing unit can perform phase-to-phase short-circuit fault diagnosis by integrating the power device fault signals fed back by the signal processing unit, the inverter controller unit and the digital processing unit, the excessive current change rate, the inverter output overcurrent fault, the first judgment result of whether the phase-to-phase short-circuit current characteristics are met, the closing state of the isolation contactor and other signals.

[0064] In this embodiment, each phase of the three-phase circuit has a first node, and the current sensor is set at the first node, and the motor is a permanent magnet synchronous motor. When the power device of the inverter fails or the inverter outputs an overcurrent, the overcurrent fault may be caused by a phase short circuit, or it may not be caused by a phase short circuit. In order to avoid missed detection of phase short circuits and untimely detection, when the power device of the inverter fails or the inverter outputs an overcurrent, the current change rate of the three-phase circuit is further detected. If the short-circuit current passes through the current sensor, the current change rate of the current signal detected by the current sensor will be very large. Therefore, the current change rate can be detected in combination with the current signal detected by the current sensor, and the phase short circuit fault diagnosis can be performed in combination with the current change rate. However, if the short-circuit point is between the current sensor and the inverter, and the short-circuit current does not flow through the current sensor, it cannot be accurately diagnosed by the current change rate. Therefore, when the inverter blocks the pulse and stops working, the current signals of each current sensor, the output current of the inverter and the preset phase-to-phase short-circuit current characteristics are further combined to perform phase-to-phase short-circuit fault diagnosis. The current signals of the current sensors of each phase line and the output current of the inverter can comprehensively reflect the current conditions at different positions. Combined with the phase-to-phase short-circuit current characteristics, the phase-to-phase short-circuit fault diagnosis can be accurately performed to obtain the diagnosis result, avoiding missed detection and false detection, and can further realize the accurate positioning of the phase-to-phase short-circuit fault when the phase-to-phase short-circuit fault occurs, thereby further improving the accuracy of the phase-to-phase short-circuit fault diagnosis.

[0065] The applicant found that the location and causes of the phase-to-phase short circuit mainly include the following: 1. Interphase short circuit of the stator winding of the motor body: Usually, the degradation and thinning of the weak point (single point) of the interturn insulation layer causes its equivalent resistance to gradually decrease, and further expands into grounding, interturn short circuit and interphase short circuit failure modes during the continuous application of four types of failure stresses: electrical, thermal, mechanical and environmental.

[0066] 2. Interphase short circuit of terminals in the motor's junction box: usually caused by overlapping foreign objects or abnormal insulation.

[0067] 3. Interphase short circuit at the cabinet terminals on the output side of the inverter: usually caused by overlapping foreign objects or abnormal insulation.

[0068] 4. The main contacts of the isolation contactor or the front and rear end terminals of the main contacts are short-circuited between phases: usually due to overlapping of foreign objects or abnormal insulation.

[0069] Phase-to-phase short circuit will result in higher short-circuit voltage, larger torque shock and torque ripple.

[0070] To further accurately diagnose the location of the phase-to-phase short circuit and minimize adverse effects, the relative positions of the current sensor and the isolation contactor can be further combined to perform phase-to-phase short circuit fault diagnosis, thereby covering all phase-to-phase short circuit locations as completely as possible. The following introduces the phase-to-phase short circuit fault diagnosis methods under two setting positions.

[0071] In some embodiments, as Figure 7 As shown, the inter-phase short circuit fault diagnosis system further includes an isolation contactor 105 , which is provided between the first node and the frequency converter 104 .

[0072] Accordingly, determining that an interphase short circuit fault exists in the second location area includes: Disconnect the isolation contactor and determine whether the current interphase short-circuit current characteristic is met based on the output current of the inverter, the sum of the instantaneous current values ​​of the phase lines, and the effective current value of the phase lines, to obtain a second determination result; If the second judgment result satisfies the phase-to-phase short-circuit current characteristic, it is determined that an interphase short-circuit fault exists in the third position area ③, and the third position area ③ includes the line between the isolation contactor 105 and the first node and the contact of the isolation contactor 105 close to the first node; If the second judgment result is that the interphase short-circuit current characteristic is not satisfied, it is determined that an interphase short-circuit fault exists in the fourth position area ④, where the fourth position area ④ includes the line between the isolation contactor 105 and the inverter 104 and the contacts of the isolation contactor 105 close to the inverter 104; The second position area includes the third position area ③ and the fourth position area ④.

[0073] When isolation contactor 105 is disconnected, the motor generates a back electromotive force (EMF) for current sensor 108, acting as a power source. If the interphase short-circuit current characteristic is met at this point, an interphase short-circuit fault exists between the isolation contactor 105 and the first node, i.e., in the third position region ③. If the interphase short-circuit current characteristic is not met, an interphase short-circuit fault exists between the isolation contactor 105 and the inverter 104, i.e., in the fourth position region ④. Thus, by controlling the disconnection of isolation contactor 105 and combining the interphase short-circuit current characteristic, the interphase short-circuit fault can be accurately located.

[0074] In this embodiment, in the case where the isolation contactor 105 is set between the first node and the inverter, the position of the phase-to-phase short circuit is further accurately located by controlling the disconnection of the isolation contactor and combining the phase-to-phase short circuit current characteristics, thereby improving the accuracy of phase-to-phase short circuit fault diagnosis.

[0075] In some embodiments, after the interphase short circuit fault diagnosis is performed based on the current change rate detection result and the diagnosis result is obtained, the method further includes: If the diagnosis result indicates that an interphase short circuit fault exists in the first position area, an active three-phase short circuit mode is executed for fault protection. In the active three-phase short circuit mode, all three-phase upper bridge arms or three-phase lower bridge arms of the inverter 104 are turned on, so that the three-phase windings of the motor form a loop through the inverter 104 to achieve demagnetization and braking. When the diagnosis result shows that there is an interphase short circuit fault in the third position area, the isolation contactor 105 is closed and an active three-phase short circuit mode is executed for fault protection; When the diagnosis result shows that there is an interphase short circuit fault in the fourth position area, the disconnecting state of the isolation contactor 105 is maintained for fault protection; When the diagnosis result shows that there is no interphase short circuit fault, the protection strategy for when a power device fails or the inverter 104 outputs an overcurrent is adopted for fault protection.

[0076] See also Figure 8 Taking the upper bridge arm of the inverter 104 as an example, in the active three-phase short-circuit mode, the three-phase upper bridge arm (i.e., all upper bridge arms of the three-phase bridge arm) or the three-phase lower bridge arm (i.e., all lower bridge arms of the three-phase bridge arm) of the inverter 104 are all turned on, so that the three-phase winding of the motor M forms a low-impedance circuit through the inverter 104 to achieve demagnetization and braking, thereby reducing the inter-phase short-circuit current and realizing inter-phase short-circuit fault protection. Figure 8 In , Z represents the equivalent impedance of the motor. Figure 6 As shown, the logic processing unit can issue an active three-phase short-circuit mode instruction to enable the inverter control unit to control the inverter to enter the active three-phase short-circuit mode, and can also synchronize the active three-phase short-circuit mode to other control units of the vehicle through the network control system for adaptive control.

[0077] For a vehicle, the traction system may include multiple motors. After the motor with a phase short circuit fault is isolated, the vehicle can continue to drive through the other motors. Therefore, the isolation contactor 105 is kept in the disconnected state. Under this protection strategy, the vehicle can continue to drive and return to the depot for processing.

[0078] In this embodiment, different protection measures are taken according to the location of different interphase short-circuit faults, thereby improving the reliability and availability of the system. In response to the short-circuit situation from the rear end of the isolation contactor 105 to the main body of the motor, a new active three-phase short-circuit mode is proposed to effectively protect after the interphase short-circuit fault, so that the three-phase winding of the motor forms a low-impedance circuit through the inverter 104, achieving rapid demagnetization and braking, and avoiding the negative impact of the interphase short-circuit on the power system where the motor is located. If the location of the interphase short circuit is located at the position from the isolation contactor 105 to the inverter 104, the location of the interphase short circuit can be separated from the main body of the motor by quickly disconnecting the motor and the isolation contactor 105, and the active three-phase short-circuit mode can be avoided. For the vehicle where the motor is located, the vehicle does not need to slow down, reducing the impact of the fault on the vehicle's operating order, and improving vehicle operation safety and system availability.

[0079] The following takes the case where the isolation contactor 105 is provided between the first node and the frequency converter 104 as an example to describe the interphase short circuit fault diagnosis method of this embodiment in more detail.

[0080] In this embodiment, the motor is a traction motor of a vehicle's traction system. Figure 9 As shown, after the operation starts, an initial judgment is performed first. A flag indicating that the current change rate is too large can be pre-set to store the current change rate detection result. When the current change rate of at least two phase lines is greater than the current change rate threshold, the flag is valid; otherwise, the flag is invalid. A flag corresponding to the phase-to-phase short-circuit current characteristic is pre-set to store the judgment result of whether the phase-to-phase short-circuit current characteristic is met. When the phase-to-phase short-circuit current characteristic is met, the flag is valid; when the phase-to-phase short-circuit current characteristic is not met, the flag is invalid. The specific process of the initial judgment is as follows: When a converter output overcurrent or a power device fault is detected, the system determines whether the flag indicating excessive current rate of change is valid. If so, the interphase short-circuit location diagnosis indicates an interphase short-circuit fault in the first location area ①. The corresponding fault protection action (i.e., the action corresponding to the fault protection strategy) is to execute the active three-phase short-circuit mode. If not, the system continues to determine whether the flag corresponding to the interphase short-circuit current characteristic is valid. If not, the interphase short-circuit location diagnosis indicates an overcurrent fault or power device overcurrent fault not caused by an interphase short-circuit. This means that only the converter output is overcurrent or the power device is faulty, with no interphase short-circuit fault. The corresponding fault protection action is to use the protection strategy for converter output overcurrent or power device fault (the existing protection strategy).

[0081] When the flag corresponding to the interphase short-circuit current characteristic is valid, it is necessary to further execute the sequence and then judge. Specifically, the isolation contactor 105 can be disconnected to further judge whether the flag corresponding to the interphase short-circuit current characteristic is valid. When the flag corresponding to the interphase short-circuit current characteristic is valid, the result of the interphase short-circuit position diagnosis is that there is an interphase short-circuit fault in the third position area ③, and the corresponding fault protection action is to close the isolation contactor 105 and execute the active three-phase short-circuit mode. When the flag corresponding to the interphase short-circuit current characteristic is invalid, the result of the interphase short-circuit position diagnosis is that there is an interphase short-circuit fault in the fourth position area ④, and the corresponding fault protection action is to maintain the disconnected state of the isolation contactor 105. No more stringent protection action is required, and the vehicle can continue driving and return to the warehouse for processing.

[0082] End of diagnosis.

[0083] In some embodiments, as Figure 10 As shown, the inter-phase short circuit fault diagnosis system further includes an isolation contactor 105 , which is arranged between the first node and the motor.

[0084] Accordingly, determining that an interphase short circuit fault exists in the first location area includes: Disconnect the isolation contactor 105 and start the frequency converter 104 to output a test pulse; When the inverter 104 outputs the test pulse, it is determined whether there is still a power device failure or the inverter 104 outputs an overcurrent, and whether the current change rate of at least two-phase lines is greater than the current change rate threshold; if so, it is determined that there is an interphase short circuit fault in the fifth position area ⑤, and the fifth position area ⑤ includes the line between the isolation contactor 105 and the first node and the contact of the isolation contactor 105 close to the first node; otherwise, it is determined that there is an interphase short circuit fault in the sixth position area ⑥, and the sixth position area ⑥ includes the line between the isolation contactor 105 and the motor, the contact of the isolation contactor 105 close to the motor, and the body of the motor; The first position area includes the fifth position area ⑤ and the sixth position area ⑥.

[0085] When the isolation contactor 105 is disconnected, the connection between the motor and the current sensor 108 is cut off, and the pulse of the inverter 104 is blocked. The current sensor 108 cannot detect the current. At this time, the inverter 104 can be started to output a test pulse. When the inverter 104 outputs a test pulse, current passes through the current sensor 108 to determine whether there is still a power device failure or the inverter 104 outputs an overcurrent, and whether the current change rate of at least two-phase lines is greater than the current change rate threshold. If so, it indicates that there is a phase-to-phase short circuit fault from the first node to the isolation contactor 105, that is, the fifth position area ⑤. Otherwise, it indicates that there is a phase-to-phase short circuit fault from the isolation contactor 105 to the motor M, that is, the sixth position area ⑥.

[0086] In this embodiment, in the case where the isolation contactor 105 is set between the first node and the motor, the inverter 104 is controlled to send a test pulse, and the position of the phase short circuit is further accurately located in combination with the current change rate, thereby improving the accuracy of phase short circuit fault diagnosis.

[0087] In some embodiments, after performing interphase short circuit fault diagnosis based on the current change rate detection result and obtaining the diagnosis result, the method further includes: If the diagnosis result indicates that an interphase short circuit fault exists in the sixth position area, the isolation contactor 105 is closed and an active three-phase short circuit mode is executed for fault protection. The active three-phase short circuit mode is a mode in which the three-phase upper bridge arm or the three-phase lower bridge arm of the inverter 104 are all turned on, so that the three-phase winding of the motor forms a loop through the inverter 104 to achieve demagnetization and braking. When the diagnosis result shows that there is an interphase short circuit fault in the fifth position area, the isolation contactor 105 is maintained in an open state for fault protection; If the diagnosis result shows that there is an interphase short circuit fault in the second position area, disconnecting the isolation contactor 105 for fault protection; When the diagnosis result shows that there is no interphase short circuit fault, the protection strategy for when a power device fails or the inverter 104 outputs an overcurrent is adopted for fault protection.

[0088] The specific content of the active three-phase short-circuit mode can be referred to the above related embodiments and will not be repeated here.

[0089] In this embodiment, different protection measures are taken according to different short-circuit locations, thereby improving system reliability and availability. In response to the short-circuit situation from the rear end of the isolation contactor 105 to the main body of the motor, a new active three-phase short-circuit mode is proposed to effectively protect after an interphase short-circuit fault, so that the three-phase winding of the motor forms a low-impedance circuit through the inverter 104, achieving rapid demagnetization and braking, and avoiding the negative impact of the interphase short-circuit on the power system where the motor is located. If the position of the interphase short circuit is located between the isolation contactor 105 and the inverter 104, the position of the interphase short circuit can be separated from the main body of the motor by quickly disconnecting the motor and the isolation contactor 105, and the active three-phase short-circuit mode can be avoided. For the vehicle where the motor is located, the vehicle does not need to slow down, reducing the impact of the fault on the vehicle's operating order, and improving vehicle operation safety and system availability.

[0090] The following takes the case where the isolation contactor 105 is disposed between the first node and the motor as an example to describe the interphase short circuit fault diagnosis method of this embodiment in more detail.

[0091] In this embodiment, the motor is a traction motor of a vehicle's traction system. Figure 11As shown, after the operation starts, an initial judgment is performed first. A flag indicating that the current change rate is too large can be pre-set to store the current change rate detection result. When the current change rate of at least two phase lines is greater than the current change rate threshold, the flag is valid; otherwise, the flag is invalid. A flag corresponding to the phase-to-phase short-circuit current characteristic is pre-set to store the judgment result of whether the phase-to-phase short-circuit current characteristic is met. When the phase-to-phase short-circuit current characteristic is met, the flag is valid; when the phase-to-phase short-circuit current characteristic is not met, the flag is invalid. The specific process of the initial judgment is as follows: When an inverter output overcurrent or power device fault is detected, the system determines whether the flag indicating excessive current rate of change is valid. If not, the system continues to determine whether the flag corresponding to the interphase short-circuit current characteristic is valid. If the flag corresponding to the interphase short-circuit current characteristic is valid, the interphase short-circuit location diagnosis indicates an interphase short-circuit fault in the second location area ②. The corresponding fault protection action is to disconnect the isolation contactor 105. If the flag corresponding to the interphase short-circuit current characteristic is invalid, the interphase short-circuit location diagnosis indicates an overcurrent fault or power device fault not caused by an interphase short circuit. This means that only the inverter 104 output is overcurrent or the power device is faulty, with no interphase short-circuit fault. The corresponding fault protection action is to use the existing protection strategy for inverter 104 output overcurrent or power device faults.

[0092] When the excessive current rate of change flag is valid, further sequence execution is required for further judgment. Specifically, the isolation contactor 105 can be disconnected, and the inverter 104 can be started to output a test pulse to further determine whether the excessive current rate of change flag is valid. When the excessive current rate of change flag is valid, the result of the interphase short circuit position diagnosis indicates that an interphase short circuit fault exists in the fifth position area ⑤. The corresponding fault protection action is to maintain the disconnected state of the isolation contactor 105. When the excessive current rate of change flag is invalid, the result of the interphase short circuit position diagnosis indicates that an interphase short circuit fault exists in the sixth position area ⑥. The corresponding fault protection action is to close the isolation contactor 105 and execute the active three-phase short circuit mode.

[0093] End of diagnosis.

[0094] In addition to the current sensor, the interphase short circuit fault diagnosis system may also be provided with a voltage sensor. Based on this, the interphase short circuit fault diagnosis may be further performed in combination with the voltage sensor. This will be described in detail below through an embodiment.

[0095] In some embodiments, as Figure 12 and Figure 14As shown, each phase of the three-phase line has a first node, and the current sensor 108 is set at the first node; two or three voltage sensors 110 are set on the three-phase line for detecting voltage signals between different phase lines, and each phase of the three-phase line has a second node located between the first node and the inverter 104, and the voltage sensor 110 is set at the second node; the motor is a permanent magnet synchronous motor. Figure 12 and Figure 14 Three voltage sensors 110 are provided as an example.

[0096] Accordingly, the interphase short circuit fault diagnosis is performed based on the current change rate detection result, and the diagnosis results obtained include: When the inverter 104 blocks the pulse and stops working, if the current change rate detection result shows that the current change rate of at least two phase lines is greater than the current change rate threshold, it is determined that an interphase short circuit fault exists in the first location area, and the first location area includes the motor body and the area between the motor and the first node: If the current change rate detection result shows that there is no current change rate of at least two-phase lines greater than the current change rate threshold, the voltage value between each two-phase lines of the three-phase line is obtained based on the voltage signal of each voltage sensor 110, and based on the voltage value between each two-phase lines of the three-phase line, it is determined whether there is an inter-phase short circuit fault in the second position area, and the second position area includes the area between the first node and the inverter 104.

[0097] The first nodes between the phase lines are arranged side by side.

[0098] The second nodes between each phase line are arranged side by side. Voltage sensors 110 are connected between the second nodes of the corresponding two-phase lines. Obtaining a voltage value between each two-phase line of the three-phase line based on the voltage signal of each voltage sensor 110 may specifically include: when three voltage sensors 110 are provided, obtaining a voltage value between each two-phase line based on the voltage signal of each voltage sensor 110. When two voltage sensors 110 are provided, obtaining voltage values ​​between two two-phase lines based on the voltage signals of the two voltage sensors 110, and obtaining a third voltage value between two phase lines based on the obtained two voltage values ​​between the two phase lines.

[0099] In practical applications, when a phase-to-phase short circuit occurs, if the short circuit point is located between the current sensor 108 and the motor M, i.e., the first position region, the fault can be detected by the current rate of change. If the short circuit point is between the current sensor 108 and the inverter 104, the short circuit current does not flow through the current sensor 108, making it impossible to accurately diagnose the characteristic of an excessive current rate of change. Therefore, in this embodiment, voltage-assisted diagnosis is further employed.

[0100] In this embodiment, when each phase of the three-phase circuit has a first node, and the current sensor 108 is arranged at the first node, and the motor M is a permanent magnet synchronous motor, two or three voltage sensors 110 are provided on the three-phase circuit for detecting the voltage signal between different phase circuits, and each phase of the three-phase circuit has a second node located between the first node and the inverter 104, and the voltage sensor 110 is arranged at the second node. When a power device of the inverter 104 fails or the inverter 104 outputs an overcurrent, the overcurrent fault may be caused by a phase-to-phase short circuit, or it may not be caused by a phase-to-phase short circuit. In order to avoid missed detection of a phase-to-phase short circuit and untimely detection, when a power device of the inverter 104 fails or the inverter 104 outputs an overcurrent, the current of the three-phase circuit is further converted. Rate detection: if the short-circuit current passes through the current sensor 108, the current change rate of the current signal detected by the current sensor 108 will be very large. Therefore, the current change rate can be detected in combination with the current signal detected by the current sensor 108, and the phase-to-phase short-circuit fault diagnosis can be performed in combination with the current change rate. However, if the short-circuit point is between the current sensor 108 and the inverter 104, the short-circuit current does not flow through the current sensor 108, and it cannot be accurately diagnosed by the current change rate. The phase-to-phase short-circuit fault diagnosis can be further performed in combination with the voltage signals of each voltage sensor 110. The phase-to-phase short-circuit fault diagnosis can be accurately performed to obtain a diagnostic result, avoiding missed detection and false detection, and can further achieve accurate positioning of the phase-to-phase short-circuit fault when the phase-to-phase short-circuit fault occurs, thereby further improving the accuracy of the phase-to-phase short-circuit fault diagnosis.

[0101] To further accurately diagnose the location of the phase-to-phase short circuit and minimize adverse effects, the relative positions of the current sensor and the isolation contactor can be further combined to perform phase-to-phase short circuit fault diagnosis, thereby covering all phase-to-phase short circuit locations as completely as possible. The following introduces the phase-to-phase short circuit fault diagnosis methods under two setting positions.

[0102] In some embodiments, as Figure 12 As shown, the inter-phase short circuit fault diagnosis system further includes an isolation contactor 105 , which is provided between the first node and the second node.

[0103] Accordingly, determining whether an interphase short circuit fault exists in the second location area based on the voltage value between each two phases of the three-phase line includes: Based on the voltage values ​​between each two phases of the three-phase line, determining whether at least one interphase short-circuit voltage characteristic is present, thereby obtaining a third determination result; wherein the interphase short-circuit voltage characteristic includes: a voltage value dropping from a normal value to below a voltage threshold when the inverter 104 is in operation; and a voltage value remaining continuously zero and an overcurrent condition occurring in the current sensors 108 of the corresponding two phase lines after the inverter 104 is started from a shutdown state. If the third judgment result is no, it is determined that there is no interphase short circuit fault in the second position area; If the third judgment result is yes, disconnect the isolation contactor 105 and start the frequency converter 104 to output the test pulse; when the frequency converter 104 outputs the test pulse, determine whether at least one phase-to-phase short-circuit voltage characteristic still exists, and obtain a fourth judgment result; If the fourth judgment result is no, it is determined that an interphase short circuit fault exists in the third position area ③, and the third position area ③ includes the line between the isolation contactor 105 and the first node and the contact of the isolation contactor 105 close to the first node; If the fourth judgment result is yes, it is determined that an interphase short circuit fault exists in the fourth position area ④, and the fourth position area ④ includes the line between the isolation contactor 105 and the inverter 104 and the contact of the isolation contactor 105 close to the inverter 104; The second position area includes the third position area ③ and the fourth position area ④.

[0104] In the aforementioned interphase short-circuit voltage characteristics, when inverter 104 is operating, the voltage value drops from a normal value to below the voltage threshold, indicating that the voltage value has dropped to zero, reflecting the voltage characteristics of an interphase short-circuit. When inverter 104 is restarted from a shutdown state, if an interphase short-circuit occurs, the voltage value between the two phases will be zero and an overcurrent will be detected in current sensor 108. Therefore, interphase short-circuit fault diagnosis can be performed based on the aforementioned interphase short-circuit voltage characteristics.

[0105] The overcurrent of the current sensor 108 means that the instantaneous current value of the current sensor 108 is greater than the preset current threshold.

[0106] Specifically, it is determined whether at least one phase-to-phase short-circuit voltage feature occurs, that is, whether at least one of the two phase-to-phase short-circuit voltage features occurs: when the inverter 104 is in the working state, the voltage value drops from the normal value to below the voltage threshold; and after the inverter 104 is started from the shutdown state, the voltage value is continuously zero and the current sensor 108 of the corresponding two-phase line has an overcurrent.

[0107] In this embodiment, in the case where the isolation contactor 105 is set between the first node and the second node, the isolation contactor 105 is controlled to be disconnected, the inverter 104 is started to output a test pulse, and the position of the phase-to-phase short circuit is further accurately located in combination with the phase-to-phase short circuit voltage characteristics, thereby improving the accuracy of phase-to-phase short circuit fault diagnosis.

[0108] Based on this, the phase-to-phase short circuit fault diagnosis is performed based on the current change rate detection result. After obtaining the diagnosis result, the following is also included: If the diagnosis result indicates that an interphase short circuit fault exists in the first position area, an active three-phase short circuit mode is executed for fault protection. In the active three-phase short circuit mode, all three-phase upper bridge arms or three-phase lower bridge arms of the inverter 104 are turned on, so that the three-phase windings of the motor form a loop through the inverter 104 to achieve demagnetization and braking. When the diagnosis result shows that there is an interphase short circuit fault in the third position area, the isolation contactor 105 is closed and an active three-phase short circuit mode is executed for fault protection; When the diagnosis result shows that there is an interphase short circuit fault in the fourth position area, the disconnecting state of the isolation contactor 105 is maintained for fault protection; When the diagnosis result shows that there is no interphase short circuit fault, the protection strategy for when a power device fails or the inverter 104 outputs an overcurrent is adopted for fault protection.

[0109] The specific implementation of this embodiment can refer to the above related embodiments and will not be repeated here.

[0110] The following takes the case where the isolation contactor 105 is disposed between the first node and the second node as an example to describe the interphase short circuit fault diagnosis method of this embodiment in more detail.

[0111] In this embodiment, the motor is a traction motor of a vehicle's traction system. Figure 13 As shown, after the operation starts, an initial judgment is performed first. A flag indicating that the current change rate is too large can be pre-set to store the current change rate detection result. When the current change rate of at least two-phase lines is greater than the current change rate threshold, the flag is valid; otherwise, the flag is invalid. A flag corresponding to the phase-to-phase short-circuit voltage feature is pre-set to store the judgment result of whether there is at least one phase-to-phase short-circuit voltage feature. When there is at least one phase-to-phase short-circuit voltage feature, the flag is valid; when there is no phase-to-phase short-circuit voltage feature, the flag is invalid. The specific process of the initial judgment is as follows: When an inverter output overcurrent or a power device fault is detected, the system determines whether the flag indicating an excessive current rate of change is valid. If so, the interphase short circuit location diagnosis indicates an interphase short circuit fault in the first location region ①. The corresponding fault protection action (i.e., the action corresponding to the fault protection strategy) is to execute the active three-phase short circuit mode. If not, the system continues to determine whether the flag corresponding to the interphase short circuit voltage characteristic is valid. If not, the interphase short circuit location diagnosis indicates an overcurrent fault or power device overcurrent fault not caused by an interphase short circuit. This means that only the inverter 104 output is overcurrent or the power device is faulty, with no interphase short circuit fault. The corresponding fault protection action is to adopt the protection strategy for inverter 104 output overcurrent or power device fault.

[0112] When the flag corresponding to the interphase short-circuit voltage characteristic is valid, it is necessary to further execute the sequence and then judge. Specifically, the isolation contactor 105 can be disconnected, and the frequency converter 104 can be started to output a test pulse. When the frequency converter 104 outputs a test pulse, it is further determined whether the flag corresponding to the interphase short-circuit voltage characteristic is valid. When the flag corresponding to the interphase short-circuit voltage characteristic is valid, the result of the interphase short-circuit position diagnosis is that there is an interphase short-circuit fault in the third position area ③. The corresponding fault protection action is to close the isolation contactor 105 and execute the active three-phase short-circuit mode. When the flag corresponding to the interphase short-circuit voltage characteristic is invalid, the result of the interphase short-circuit position diagnosis is that there is an interphase short-circuit fault in the fourth position area ④. The corresponding fault protection action is to maintain the disconnected state of the isolation contactor 105. No more stringent protection action is required. Continue driving and return to the warehouse for processing.

[0113] End of diagnosis.

[0114] In some embodiments, as Figure 14 As shown, the inter-phase short circuit fault diagnosis system further includes an isolation contactor 105 , which is arranged between the first node and the motor M.

[0115] Accordingly, determining that an interphase short circuit fault exists in the first location area includes: Disconnect the isolation contactor 105 and start the frequency converter 104 to output a test pulse; When the inverter 104 outputs the test pulse, it is determined whether there is still a power device failure or the inverter 104 outputs an overcurrent, and whether the current change rate of at least two-phase lines is greater than the current change rate threshold; if so, it is determined that there is an interphase short circuit fault in the fifth position area ⑤, and the fifth position area ⑤ includes the line between the isolation contactor 105 and the first node and the contact of the isolation contactor 105 close to the first node; otherwise, it is determined that there is an interphase short circuit fault in the sixth position area ⑥, and the sixth position area ⑥ includes the line between the isolation contactor 105 and the motor, the contact of the isolation contactor 105 close to the motor, and the body of the motor; The first position area includes the fifth position area ⑤ and the sixth position area ⑥.

[0116] When the isolation contactor 105 is disconnected, the connection between the motor M and the current sensor 108 is cut off, and the pulse of the inverter 104 is blocked. The current sensor 108 cannot detect the current. At this time, the inverter 104 can be started to output a test pulse. When the inverter 104 outputs the test pulse, current passes through the current sensor 108 to determine whether there is still a power device failure or the inverter 104 outputs an overcurrent, and whether the current change rate of at least two-phase lines is greater than the current change rate threshold. If so, it indicates that there is a phase-to-phase short circuit fault from the first node to the isolation contactor 105, that is, the fifth position area ⑤. Otherwise, it indicates that there is a phase-to-phase short circuit fault from the isolation contactor 105 to the motor M, that is, the sixth position area ⑥.

[0117] In this embodiment, in the case where the isolation contactor 105 is set between the first node and the motor, the inverter 104 is controlled to send a test pulse, and the position of the phase short circuit is further accurately located in combination with the current change rate, thereby improving the accuracy of phase short circuit fault diagnosis.

[0118] In some embodiments, the inter-phase short circuit fault diagnosis system further includes an isolation contactor 105 , which is disposed between the first node and the motor M; Determining whether there is an interphase short circuit fault in the second location area based on a voltage value between every two phases of the three-phase line includes: Disconnect the isolation contactor 105 and start the frequency converter 104 to output a test pulse; When the inverter 104 outputs a test pulse, a determination is made as to whether at least one interphase short-circuit voltage characteristic is present based on the voltage between each two phases of the three-phase line. The interphase short-circuit voltage characteristic includes: a voltage value dropping from a normal value to below a voltage threshold when the inverter 104 is in operation; and a voltage value remaining zero and an overcurrent condition in the current sensors 108 of the corresponding two phase lines after the inverter 104 is started from a shutdown state. If so, determining that an interphase short circuit fault exists in the second location area; If not, it is determined that there is no interphase short circuit fault in the second location area.

[0119] When the isolation contactor 105 is disconnected, the connection between the motor and the current sensor 108 is cut off, and the pulse of the inverter 104 is blocked. The current sensor 108 cannot detect the current. At this time, the inverter 104 can be started to output a test pulse. When the inverter 104 outputs the test pulse, if at least one phase-to-phase short-circuit voltage feature appears, it indicates that there is a phase-to-phase short-circuit fault in the second position area. Otherwise, there is no phase-to-phase short-circuit fault in the second position area.

[0120] In this embodiment, by controlling the on and off of the isolation contactor 105 and starting the frequency converter 104 to output a test pulse, combined with the interphase short-circuit voltage characteristics, the interphase short-circuit fault diagnosis can be accurately performed on the second location area.

[0121] Based on this, the phase-to-phase short circuit fault diagnosis is performed based on the current change rate detection result. After obtaining the diagnosis result, the following is also included: If the diagnosis result indicates that an interphase short circuit fault exists in the sixth position area, the isolation contactor 105 is closed and an active three-phase short circuit mode is executed for fault protection. The active three-phase short circuit mode is a mode in which the three-phase upper bridge arm or the three-phase lower bridge arm of the inverter 104 are all turned on, so that the three-phase winding of the motor forms a loop through the inverter 104 to achieve demagnetization and braking. When the diagnosis result shows that there is an interphase short circuit fault in the fifth position area, the isolation contactor 105 is maintained in an open state for fault protection; If the diagnosis result shows that there is an interphase short circuit fault in the second position area, disconnecting the isolation contactor 105 for fault protection; When the diagnosis result shows that there is no interphase short circuit fault, the protection strategy for when a power device fails or the inverter 104 outputs an overcurrent is adopted for fault protection.

[0122] If the diagnosis result indicates that an interphase short circuit fault exists in the second position area, the isolation contactor 105 is disconnected for fault protection. Specifically, if the isolation contactor 105 is disconnected, the disconnected state of the isolation contactor 105 is maintained for fault protection.

[0123] The specific implementation of this embodiment can refer to the above related embodiments and will not be described in detail here.

[0124] The following takes the case where the isolation contactor 105 is provided between the first node and the motor M as an example to describe the interphase short circuit fault diagnosis method of this embodiment in more detail.

[0125] In this embodiment, the motor is a traction motor of a vehicle's traction system. Figure 15As shown, after starting operation, an initial judgment is performed first. A flag indicating that the current change rate is too large can be pre-set to store the current change rate detection result. When the current change rate of at least two phase lines is greater than the current change rate threshold, the flag is valid; otherwise, the flag is invalid. A flag corresponding to the phase-to-phase short-circuit current characteristic can be pre-set to store the judgment result of whether the phase-to-phase short-circuit current characteristic is met. When the phase-to-phase short-circuit current characteristic is met, the flag is valid; when the phase-to-phase short-circuit current characteristic is not met, the flag is invalid. A flag corresponding to the phase-to-phase short-circuit voltage characteristic can be pre-set to store the judgment result of whether there is at least one phase-to-phase short-circuit voltage characteristic. When there is at least one phase-to-phase short-circuit voltage characteristic, the flag is valid; when there is no phase-to-phase short-circuit voltage characteristic, the flag is invalid.

[0126] The initial judgment process is as follows: When an inverter output overcurrent or a power device fault is detected, a determination is made as to whether the excessive current rate of change flag is valid. If not, the isolation contactor 105 is disconnected, and the inverter 104 is started to output a test pulse. While the inverter 104 is outputting the test pulse, a further determination is made as to whether the flag corresponding to the interphase short-circuit voltage characteristic is valid. If the flag corresponding to the interphase short-circuit voltage characteristic is valid, the interphase short-circuit location diagnosis result indicates an interphase short-circuit fault in the second location area ②. The corresponding fault protection action is to disconnect the isolation contactor 105, i.e., maintain the isolation contactor 105 open. If the flag corresponding to the interphase short-circuit voltage characteristic is invalid, the interphase short-circuit location diagnosis result indicates an overcurrent fault or power device fault not caused by an interphase short circuit. This means that only the inverter 104 output is overcurrent or the power device is faulty, with no interphase short-circuit fault. The corresponding fault protection action is to adopt the protection strategy for inverter 104 output overcurrent or power device fault.

[0127] When the excessive current rate of change flag is valid, further sequence execution is required for further judgment. Specifically, the isolation contactor 105 can be disconnected, and the inverter 104 can be started to output a test pulse to further determine whether the excessive current rate of change flag is valid. When the excessive current rate of change flag is valid, the result of the interphase short circuit position diagnosis indicates that an interphase short circuit fault exists in the fifth position area ⑤. The corresponding fault protection action is to maintain the disconnected state of the isolation contactor 105. When the excessive current rate of change flag is invalid, the result of the interphase short circuit position diagnosis indicates that an interphase short circuit fault exists in the sixth position area ⑥. The corresponding fault protection action is to close the isolation contactor 105 and execute the active three-phase short circuit mode.

[0128] End of diagnosis.

[0129] The solution of the present application can accurately diagnose the interphase short circuit of the motor body and the interphase short circuit of the external line, and adopt different protection strategies to improve the availability and maintainability of the power system in which the motor is located.

[0130] The solution of the present application can be widely used in the precise positioning and protection of phase-to-phase short-circuit faults in traction systems in the fields of rail transit vehicles, locomotives, urban rail, etc., and can also be applied to other required scenarios, such as production equipment in the new materials industry.

[0131] The above embodiment specifically introduces the method for diagnosing interphase short circuit faults by taking a permanent magnet synchronous motor as an example. The method can be adjusted to also be applicable to a power system equipped with an asynchronous motor.

[0132] The above related embodiments can be implemented in coordination with each other according to actual needs.

[0133] It should be understood that the size of the serial numbers of the steps in the above embodiments does not mean the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of this application.

[0134] Another embodiment of the present application relates to a phase-to-phase short circuit fault diagnosis device. The phase-to-phase short circuit fault diagnosis device described below and the phase-to-phase short circuit fault diagnosis method described above can be used for reference. The following is a detailed description of the implementation details of the phase-to-phase short circuit fault diagnosis device of this embodiment. The following content is only for the convenience of understanding the implementation details and is not necessary for the implementation of this solution. The schematic diagram of the phase-to-phase short circuit fault diagnosis device of this embodiment can be as follows: Figure 16 shown.

[0135] This embodiment relates to a phase-to-phase short circuit fault diagnosis device, which is applied to a phase-to-phase short circuit fault diagnosis system. The phase-to-phase short circuit fault diagnosis system includes: an inverter and a motor. The inverter is connected to the motor via a three-phase line. Current sensors are respectively provided on at least two phases of the three-phase line. The device includes: a rate of change detection module 1601 for determining, upon detecting a fault in a power device of the inverter or an overcurrent in the inverter output, a current change rate of each phase of the three-phase circuit based on the current signal of each current sensor, and detecting whether the current change rate of at least two phases of the current change rates of each phase is greater than a current change rate threshold, thereby obtaining a current change rate detection result; The short-circuit diagnosis module 1602 is used to perform phase-to-phase short-circuit fault diagnosis based on the current change rate detection result to obtain a diagnosis result; wherein, the diagnosis result is the location where there is no phase-to-phase short-circuit fault or the presence of an interphase short-circuit fault, and the diagnosis result is used to determine the fault protection strategy corresponding to the diagnosis result to perform fault protection.

[0136] In some embodiments, each phase of the three-phase circuit has a first node, and the current sensor is provided at the first node; the motor is a permanent magnet synchronous motor; The short circuit diagnosis module 1602 is specifically configured to: When the inverter blocks pulses and stops working, if the current change rate detection result shows that the current change rate of at least two phase lines is greater than the current change rate threshold, it is determined that an interphase short circuit fault exists in the first position area, and the first position area includes the body of the motor and the area between the motor and the first node: If the current change rate detection result shows that there are no at least two phase lines whose current change rates are greater than the current change rate threshold, the sum of the instantaneous current values ​​and the effective current value of each phase line of the three-phase line are obtained based on the current signals of each current sensor, and based on the output current of the inverter, the sum of the instantaneous current values ​​of each phase line and the effective current value of each phase line, it is judged whether the phase-to-phase short-circuit current characteristics are currently met, and a first judgment result is obtained; wherein the phase-to-phase short-circuit current characteristics include: the inverter does not output current, the sum of the instantaneous current values ​​of each phase line is less than a first threshold, the maximum value of the effective current value of each phase line is greater than a second threshold, and the ratio of the minimum value to the maximum value of the effective current value of each phase line is less than a third threshold; If the first judgment result satisfies the phase-to-phase short-circuit current characteristic, it is determined that an interphase short-circuit fault exists in a second location area, where the second location area includes an area between the first node and the inverter; If the first judgment result is that the inter-phase short-circuit current characteristic is not satisfied, it is determined that there is no inter-phase short-circuit fault.

[0137] In some embodiments, the interphase short circuit fault diagnosis system further includes an isolation contactor, wherein the isolation contactor is provided between the first node and the inverter; The short circuit diagnosis module 1602 is specifically configured to: Disconnecting the isolation contactor, and determining whether the interphase short-circuit current characteristic is currently satisfied based on the output current of the inverter, the sum of the instantaneous current values ​​of each phase line, and the effective current value of each phase line, to obtain a second determination result; If the second judgment result satisfies the phase-to-phase short-circuit current characteristic, it is determined that an interphase short-circuit fault exists in a third location area, where the third location area includes the line between the isolation contactor and the first node and the contact of the isolation contactor close to the first node; If the second judgment result is that the inter-phase short-circuit current characteristic is not satisfied, it is determined that an inter-phase short-circuit fault exists in a fourth position area, where the fourth position area includes the line between the isolation contactor and the inverter and the contact of the isolation contactor close to the inverter; The second location area includes the third location area and the fourth location area.

[0138] In some embodiments, the inter-phase short circuit fault diagnosis system further includes an isolation contactor, wherein the isolation contactor is provided between the first node and the motor; The short circuit diagnosis module 1602 is specifically configured to: Disconnecting the isolation contactor and starting the frequency converter to output a test pulse; When the frequency converter outputs the test pulse, determine whether the power device still fails or the frequency converter outputs overcurrent, and whether the current change rate of at least two-phase lines is greater than the current change rate threshold; if so, determine that an interphase short circuit fault exists in the fifth position area, and the fifth position area includes the line between the isolation contactor and the first node and the contact of the isolation contactor close to the first node; otherwise, determine that an interphase short circuit fault exists in the sixth position area, and the sixth position area includes the line between the isolation contactor and the motor, the contact of the isolation contactor close to the motor, and the body of the motor; The first location area includes the fifth location area and the sixth location area.

[0139] In some embodiments, the third threshold is a fixed threshold or is determined based on the current rotation speed of the motor.

[0140] In some embodiments, each phase of the three-phase circuit has a first node, and the current sensor is arranged at the first node; two or three voltage sensors are arranged on the three-phase circuit for detecting voltage signals between different phases; each phase of the three-phase circuit has a second node located between the first node and the inverter, and the voltage sensor is arranged at the second node; the motor is a permanent magnet synchronous motor; The short circuit diagnosis module 1602 is specifically configured to: When the inverter blocks pulses and stops working, if the current change rate detection result shows that the current change rate of at least two phase lines is greater than the current change rate threshold, it is determined that an interphase short circuit fault exists in the first position area, and the first position area includes the body of the motor and the area between the motor and the first node: If the current change rate detection result shows that there is no current change rate greater than the current change rate threshold in at least two-phase lines, the voltage value between each two-phase lines of the three-phase line is obtained based on the voltage signal of each voltage sensor, and based on the voltage value between each two-phase lines of the three-phase line, it is determined whether there is an inter-phase short circuit fault in the second position area, and the second position area includes the area between the first node and the inverter.

[0141] In some embodiments, the inter-phase short circuit fault diagnosis system further includes an isolation contactor, wherein the isolation contactor is provided between the first node and the second node; The short circuit diagnosis module 1602 is specifically configured to: Based on the voltage values ​​between each two phases of the three-phase circuit, determining whether at least one interphase short-circuit voltage characteristic exists, and obtaining a third judgment result; wherein the interphase short-circuit voltage characteristic includes: when the inverter is in an operating state, the voltage value drops from a normal value to below a voltage threshold; after the inverter is started from a stopped state, the voltage value remains zero continuously and the current sensors of the corresponding two phases have overcurrents; If the third judgment result is no, determining that there is no interphase short circuit fault in the second position area; If the third judgment result is yes, disconnect the isolation contactor and start the frequency converter to output a test pulse; when the frequency converter outputs the test pulse, determine whether at least one of the phase-to-phase short-circuit voltage characteristics still exists, and obtain a fourth judgment result; If the fourth judgment result is no, it is determined that an interphase short circuit fault exists in a third position area, where the third position area includes a line between the isolation contactor and the first node and a contact of the isolation contactor close to the first node; If the fourth judgment result is yes, it is determined that an interphase short circuit fault exists in a fourth position area, and the fourth position area includes the line between the isolation contactor and the inverter and the contact of the isolation contactor close to the inverter; The second location area includes the third location area and the fourth location area.

[0142] In some embodiments, the inter-phase short circuit fault diagnosis system further includes an isolation contactor, wherein the isolation contactor is provided between the first node and the motor; The short circuit diagnosis module 1602 is specifically configured to: Disconnecting the isolation contactor and starting the frequency converter to output a test pulse; When the frequency converter outputs the test pulse, determine whether the power device still fails or the frequency converter outputs overcurrent, and whether the current change rate of at least two-phase lines is greater than the current change rate threshold; if so, determine that an interphase short circuit fault exists in the fifth position area, and the fifth position area includes the line between the isolation contactor and the first node and the contact of the isolation contactor close to the first node; otherwise, determine that an interphase short circuit fault exists in the sixth position area, and the sixth position area includes the line between the isolation contactor and the motor, the contact of the isolation contactor close to the motor, and the body of the motor; The first location area includes the fifth location area and the sixth location area.

[0143] In some embodiments, the inter-phase short circuit fault diagnosis system further includes an isolation contactor, wherein the isolation contactor is provided between the first node and the motor; The short circuit diagnosis module 1602 is specifically configured to: Disconnecting the isolation contactor and starting the frequency converter to output a test pulse; When the inverter outputs the test pulse, based on the voltage value between each two phases of the three-phase circuit, it is determined whether at least one interphase short-circuit voltage characteristic occurs; wherein the interphase short-circuit voltage characteristic includes: when the inverter is in an operating state, the voltage value drops from a normal value to below a voltage threshold; after the inverter is started from a stopped state, the voltage value remains zero and the current sensors of the corresponding two phase circuits have overcurrent; If so, determining that an interphase short circuit fault exists in the second location area; If not, it is determined that there is no interphase short circuit fault in the second location area.

[0144] In some embodiments, as Figure 17 As shown, a fault protection module 1603 is also included, and the fault protection module 1603 is used to: If the diagnosis result indicates that an interphase short circuit fault exists in the first position area, an active three-phase short circuit mode is executed for fault protection, wherein the active three-phase short circuit mode is a mode in which the three-phase upper bridge arm or the three-phase lower bridge arm of the inverter are all turned on, so that the three-phase winding of the motor forms a loop through the inverter to achieve demagnetization and braking; When the diagnosis result indicates that an interphase short circuit fault exists in the third position area, closing the isolation contactor and executing the active three-phase short circuit mode for fault protection; When the diagnosis result indicates that an interphase short circuit fault exists in the fourth position area, maintaining the disconnected state of the isolation contactor for fault protection; When the diagnosis result shows that there is no interphase short circuit fault, fault protection is performed using a protection strategy when the power device fails or the inverter outputs an overcurrent.

[0145] In some embodiments, as Figure 17 As shown, a fault protection module 1603 is also included, and the fault protection module 1603 is used to: If the diagnosis result indicates that an interphase short circuit fault exists in the sixth position area, the isolation contactor is closed to execute an active three-phase short circuit mode for fault protection, wherein the active three-phase short circuit mode is a mode in which the three-phase upper bridge arm or the three-phase lower bridge arm of the inverter are all turned on, so that the three-phase winding of the motor forms a loop through the inverter to achieve demagnetization and braking; When the diagnosis result indicates that an interphase short circuit fault exists in the fifth position area, maintaining the disconnected state of the isolation contactor for fault protection; If the diagnosis result indicates that an interphase short circuit fault exists in the second position area, disconnecting the isolation contactor for fault protection; When the diagnosis result shows that there is no interphase short circuit fault, fault protection is performed using a protection strategy when the power device fails or the inverter outputs an overcurrent.

[0146] It is worth mentioning that all modules involved in this embodiment are logical modules. In actual applications, a logical unit can be a physical unit, a part of a physical unit, or a combination of multiple physical units. In addition, to highlight the innovation of this application, this embodiment does not include units that are not closely related to solving the technical problem proposed by this application. However, this does not mean that other units do not exist in this embodiment.

[0147] The present application also relates to a phase-to-phase short circuit fault diagnosis system, comprising: Motor; A frequency converter, the frequency converter being connected to the motor via a three-phase circuit, and current sensors being respectively provided on at least two phases of the three-phase circuit; A control device, wherein the control device is used to execute the inter-phase short circuit fault diagnosis method as described in any of the above embodiments.

[0148] In some embodiments, each phase of the three-phase circuit has a first node, and the current sensor is disposed at the first node; The interphase short circuit fault diagnosis system further includes an isolation contactor, which is arranged between the first node and the inverter or between the first node and the motor; The motor is a permanent magnet synchronous motor.

[0149] In some embodiments, each phase of the three-phase circuit has a first node, and the current sensor is provided at the first node; two or three voltage sensors are provided on the three-phase circuit for detecting voltage signals between different phases, and each phase of the three-phase circuit has a second node located between the first node and the inverter, and the voltage sensor is provided at the second node; The interphase short circuit fault diagnosis system further includes an isolation contactor, which is arranged between the first node and the second node or between the first node and the motor; The motor is a permanent magnet synchronous motor.

[0150] Another embodiment of the present application relates to an electronic device, such as Figure 18 As shown, it includes: at least one processor 1801; and a memory 1802 communicatively connected to the at least one processor 1801; wherein the memory 1802 stores instructions that can be executed by the at least one processor 1801, and the instructions are executed by the at least one processor 1801 to enable the at least one processor 1801 to execute the phase-to-phase short circuit fault diagnosis method in the above-mentioned embodiments.

[0151] The memory and processor are connected using a bus, which can include any number of interconnected buses and bridges. The bus connects various circuits of one or more processors and memories. The bus can also connect various other circuits such as peripheral devices, voltage regulators, and power management circuits. These are all well known in the art and are therefore not described further herein. The bus interface provides an interface between the bus and the transceiver. The transceiver can be a single component or multiple components, such as multiple receivers and transmitters, providing a unit for communicating with various other devices over a transmission medium. Data processed by the processor is transmitted over a wireless medium via an antenna. Furthermore, the antenna receives data and transmits it to the processor.

[0152] The processor is responsible for managing the bus and general processing, and can also provide various functions, including timing, peripheral interfaces, voltage regulation, power management, and other control functions. Memory can be used to store data used by the processor when performing operations.

[0153] Another embodiment of the present application relates to a computer-readable storage medium storing a computer program, which implements the above method embodiment when executed by a processor.

[0154] That is, those skilled in the art will understand that all or part of the steps in the above-mentioned embodiments can be implemented by instructing the relevant hardware through a program. The program is stored in a storage medium and includes a number of instructions for causing a device (which may be a single-chip microcomputer, chip, etc.) or a processor to execute all or part of the steps in the methods described in the various embodiments of this application. The aforementioned storage medium includes various media that can store program code, such as a USB flash drive, a mobile hard drive, a read-only memory (ROM), a random access memory (RAM), a magnetic disk, or an optical disk.

[0155] Those skilled in the art will appreciate that the above embodiments are specific embodiments for implementing the present application, and that in actual applications, various changes may be made thereto in form and detail without departing from the spirit and scope of the present application.

Claims

1. A method for diagnosing a phase-to-phase short circuit fault, characterized in that: The method is applied to a phase-to-phase short circuit fault diagnosis system, the phase-to-phase short circuit fault diagnosis system comprising: a frequency converter and a motor, the frequency converter being connected to the motor via a three-phase line, at least two phases of the three-phase line being respectively provided with current sensors, and the method comprising: When a fault is detected in a power device of the inverter or an overcurrent is detected in the inverter output, a current change rate of each phase of the three-phase circuit is determined based on the current signal of each current sensor, and whether the current change rate of at least two phases of the current change rate of each phase is greater than a current change rate threshold, to obtain a current change rate detection result; Based on the current change rate detection result, a phase-to-phase short circuit fault diagnosis is performed to obtain a diagnosis result; wherein, the diagnosis result is the location where there is no phase-to-phase short circuit fault or there is a phase-to-phase short circuit fault, and the diagnosis result is used to determine the fault protection strategy corresponding to the diagnosis result to perform fault protection.

2. The method for diagnosing interphase short circuit faults according to claim 1, wherein: Each phase of the three-phase circuit has a first node, and the current sensor is arranged at the first node; The motor is a permanent magnet synchronous motor; The interphase short circuit fault diagnosis based on the current change rate detection result is performed to obtain a diagnosis result, including: When the inverter blocks pulses and stops working, if the current change rate detection result shows that the current change rate of at least two phase lines is greater than the current change rate threshold, it is determined that an interphase short circuit fault exists in the first position area, and the first position area includes the body of the motor and the area between the motor and the first node: If the current change rate detection result shows that there are no at least two phase lines whose current change rates are greater than the current change rate threshold, the sum of the instantaneous current values ​​and the effective current value of each phase line of the three-phase line are obtained based on the current signals of each current sensor, and based on the output current of the inverter, the sum of the instantaneous current values ​​of each phase line and the effective current value of each phase line, it is determined whether the inter-phase short-circuit current characteristics are currently met, and a first judgment result is obtained; wherein the inter-phase short-circuit current characteristics include: the inverter does not output current, the sum of the instantaneous current values ​​of each phase line is less than a first threshold, the maximum value of the effective current value of each phase line is greater than a second threshold, and the ratio of the minimum value to the maximum value of the effective current value of each phase line is less than a third threshold; If the first judgment result satisfies the phase-to-phase short-circuit current characteristic, it is determined that an interphase short-circuit fault exists in a second location area, where the second location area includes an area between the first node and the inverter; If the first judgment result is that the inter-phase short-circuit current characteristic is not satisfied, it is determined that there is no inter-phase short-circuit fault.

3. The interphase short circuit fault diagnosis method according to claim 2, characterized in that: The interphase short circuit fault diagnosis system further includes an isolation contactor, which is arranged between the first node and the frequency converter; The determining that an interphase short circuit fault exists in the second location area includes: Disconnecting the isolation contactor, and determining whether the interphase short-circuit current characteristic is currently met based on the output current of the inverter, the sum of the instantaneous current values ​​of each phase line, and the effective current value of each phase line, to obtain a second determination result; If the second judgment result satisfies the inter-phase short-circuit current characteristic, it is determined that an inter-phase short-circuit fault exists in a third position area, where the third position area includes the line between the isolation contactor and the first node and the contact of the isolation contactor close to the first node; If the second judgment result is that the inter-phase short-circuit current characteristic is not satisfied, it is determined that an inter-phase short-circuit fault exists in a fourth position area, where the fourth position area includes the line between the isolation contactor and the inverter and the contact of the isolation contactor close to the inverter; The second location area includes the third location area and the fourth location area.

4. The method for diagnosing interphase short circuit faults according to claim 2, wherein: The interphase short circuit fault diagnosis system further includes an isolation contactor, which is arranged between the first node and the motor; The determining that an interphase short circuit fault exists in the first location area includes: Disconnecting the isolation contactor and starting the frequency converter to output a test pulse; When the frequency converter outputs the test pulse, determine whether the power device still fails or the frequency converter outputs overcurrent, and whether the current change rate of at least two-phase lines is greater than the current change rate threshold; if so, determine that an interphase short circuit fault exists in the fifth position area, and the fifth position area includes the line between the isolation contactor and the first node and the contact of the isolation contactor close to the first node; otherwise, determine that an interphase short circuit fault exists in the sixth position area, and the sixth position area includes the line between the isolation contactor and the motor, the contact of the isolation contactor close to the motor, and the body of the motor; The first location area includes the fifth location area and the sixth location area.

5. The interphase short circuit fault diagnosis method according to claim 2, characterized in that: The third threshold is a fixed threshold or is determined based on the current rotation speed of the motor.

6. The method for diagnosing interphase short circuit faults according to claim 1, characterized in that: Each phase of the three-phase circuit has a first node, and the current sensor is arranged at the first node; two or three voltage sensors are arranged on the three-phase circuit for detecting voltage signals between different phases, and each phase of the three-phase circuit has a second node located between the first node and the inverter, and the voltage sensor is arranged at the second node; The motor is a permanent magnet synchronous motor; The interphase short circuit fault diagnosis based on the current change rate detection result is performed to obtain a diagnosis result, including: When the inverter blocks pulses and stops working, if the current change rate detection result shows that the current change rate of at least two phase lines is greater than the current change rate threshold, it is determined that an interphase short circuit fault exists in the first position area, and the first position area includes the body of the motor and the area between the motor and the first node: If the current change rate detection result shows that there is no current change rate greater than the current change rate threshold in at least two-phase lines, the voltage value between each two-phase lines of the three-phase line is obtained based on the voltage signal of each voltage sensor, and based on the voltage value between each two-phase lines of the three-phase line, it is determined whether there is an inter-phase short circuit fault in the second position area, and the second position area includes the area between the first node and the inverter.

7. The interphase short circuit fault diagnosis method according to claim 6, characterized in that: The interphase short circuit fault diagnosis system further includes an isolation contactor, which is arranged between the first node and the second node; The determining whether there is an interphase short circuit fault in the second location area based on the voltage value between each two phases of the three-phase line includes: Based on the voltage values ​​between each two phases of the three-phase circuit, determining whether at least one interphase short-circuit voltage characteristic exists, and obtaining a third judgment result; wherein the interphase short-circuit voltage characteristic includes: when the inverter is in an operating state, the voltage value drops from a normal value to below a voltage threshold; after the inverter is started from a stopped state, the voltage value remains zero continuously and the current sensors of the corresponding two phases have overcurrents; If the third judgment result is no, determining that there is no interphase short circuit fault in the second position area; If the third judgment result is yes, disconnect the isolation contactor and start the frequency converter to output a test pulse; when the frequency converter outputs the test pulse, determine whether at least one of the phase-to-phase short-circuit voltage characteristics still exists, and obtain a fourth judgment result; If the fourth judgment result is no, it is determined that an interphase short circuit fault exists in a third position area, where the third position area includes a line between the isolation contactor and the first node and a contact of the isolation contactor close to the first node; If the fourth judgment result is yes, it is determined that an interphase short circuit fault exists in a fourth position area, and the fourth position area includes the line between the isolation contactor and the inverter and the contact of the isolation contactor close to the inverter; The second location area includes the third location area and the fourth location area.

8. The method for diagnosing interphase short circuit faults according to claim 6, wherein: The interphase short circuit fault diagnosis system further includes an isolation contactor, which is arranged between the first node and the motor; The determining that an interphase short circuit fault exists in the first location area includes: Disconnecting the isolation contactor and starting the frequency converter to output a test pulse; When the frequency converter outputs the test pulse, determine whether the power device still fails or the frequency converter outputs overcurrent, and whether the current change rate of at least two-phase lines is greater than the current change rate threshold; if so, determine that an interphase short circuit fault exists in the fifth position area, and the fifth position area includes the line between the isolation contactor and the first node and the contact of the isolation contactor close to the first node; otherwise, determine that an interphase short circuit fault exists in the sixth position area, and the sixth position area includes the line between the isolation contactor and the motor, the contact of the isolation contactor close to the motor, and the body of the motor; The first location area includes the fifth location area and the sixth location area.

9. The interphase short circuit fault diagnosis method according to claim 6, characterized in that: The interphase short circuit fault diagnosis system further includes an isolation contactor, which is arranged between the first node and the motor; The determining whether there is an interphase short circuit fault in the second location area based on the voltage value between each two phases of the three-phase line includes: Disconnecting the isolation contactor and starting the frequency converter to output a test pulse; When the inverter outputs the test pulse, based on the voltage value between each two phases of the three-phase circuit, it is determined whether at least one interphase short-circuit voltage characteristic occurs; wherein the interphase short-circuit voltage characteristic includes: when the inverter is in an operating state, the voltage value drops from a normal value to below a voltage threshold; after the inverter is started from a stopped state, the voltage value remains zero and the current sensors of the corresponding two phase circuits have overcurrent; If so, determining that an interphase short circuit fault exists in the second location area; If not, it is determined that there is no interphase short circuit fault in the second location area.

10. The interphase short circuit fault diagnosis method according to claim 3 or 7, characterized in that: After the interphase short circuit fault diagnosis is performed based on the current change rate detection result and the diagnosis result is obtained, the method further includes: If the diagnosis result indicates that an interphase short circuit fault exists in the first position area, an active three-phase short circuit mode is executed for fault protection, wherein the active three-phase short circuit mode is a mode in which the three-phase upper bridge arm or the three-phase lower bridge arm of the inverter are all turned on, so that the three-phase winding of the motor forms a loop through the inverter to achieve demagnetization and braking; When the diagnosis result indicates that an interphase short circuit fault exists in the third position area, closing the isolation contactor and executing the active three-phase short circuit mode for fault protection; When the diagnosis result indicates that an interphase short circuit fault exists in the fourth position area, maintaining the disconnected state of the isolation contactor for fault protection; When the diagnosis result shows that there is no interphase short circuit fault, fault protection is performed using a protection strategy when the power device fails or the inverter outputs an overcurrent.

11. The interphase short circuit fault diagnosis method according to claim 4 or 8, characterized in that: After the interphase short circuit fault diagnosis is performed based on the current change rate detection result and the diagnosis result is obtained, the method further includes: If the diagnosis result indicates that an interphase short circuit fault exists in the sixth position area, the isolation contactor is closed to execute an active three-phase short circuit mode for fault protection, wherein the active three-phase short circuit mode is a mode in which the three-phase upper bridge arm or the three-phase lower bridge arm of the inverter are all turned on, so that the three-phase winding of the motor forms a loop through the inverter to achieve demagnetization and braking; When the diagnosis result indicates that an interphase short circuit fault exists in the fifth position area, maintaining the disconnected state of the isolation contactor for fault protection; If the diagnosis result indicates that an interphase short circuit fault exists in the second position area, disconnecting the isolation contactor for fault protection; When the diagnosis result shows that there is no interphase short circuit fault, fault protection is performed using a protection strategy when the power device fails or the inverter outputs an overcurrent.

12. A phase short circuit fault diagnosis device, characterized in that: Applicable to a phase-to-phase short circuit fault diagnosis system, the phase-to-phase short circuit fault diagnosis system includes: a frequency converter and a motor, the frequency converter is connected to the motor via a three-phase line, at least two phases of the three-phase line are respectively provided with current sensors, the device includes: a change rate detection module, configured to, upon detecting a fault in a power device of the inverter or an overcurrent in the inverter output, determine a current change rate of each phase of the three-phase circuit based on the current signal of each current sensor, and detect whether the current change rate of at least two phases of the current change rates of each phase is greater than a current change rate threshold, thereby obtaining a current change rate detection result; A short-circuit diagnostic module is used to diagnose an interphase short-circuit fault based on the current change rate detection result to obtain a diagnostic result; wherein, the diagnostic result is the location where there is no interphase short-circuit fault or the presence of an interphase short-circuit fault, and the diagnostic result is used to determine the fault protection strategy corresponding to the diagnostic result to perform fault protection.

13. A phase short circuit fault diagnosis system, characterized in that: include: Motor; A frequency converter, the frequency converter being connected to the motor via a three-phase circuit, and current sensors being respectively provided on at least two phases of the three-phase circuit; A control device, wherein the control device is used to execute the inter-phase short circuit fault diagnosis method according to any one of claims 1 to 11.

14. The interphase short circuit fault diagnosis system according to claim 13, characterized in that: Each phase of the three-phase circuit has a first node, and the current sensor is arranged at the first node; The interphase short circuit fault diagnosis system further includes an isolation contactor, which is arranged between the first node and the inverter or between the first node and the motor; The motor is a permanent magnet synchronous motor.

15. The interphase short circuit fault diagnosis system according to claim 13, characterized in that: Each phase of the three-phase circuit has a first node, and the current sensor is arranged at the first node; two or three voltage sensors are arranged on the three-phase circuit for detecting voltage signals between different phases, and each phase of the three-phase circuit has a second node located between the first node and the inverter, and the voltage sensor is arranged at the second node; The interphase short circuit fault diagnosis system further includes an isolation contactor, which is arranged between the first node and the second node or between the first node and the motor; The motor is a permanent magnet synchronous motor.

16. An electronic device, characterized in that: include: at least one processor; as well as, a memory communicatively connected to the at least one processor; wherein, The memory stores instructions that can be executed by the at least one processor. The instructions are executed by the at least one processor to enable the at least one processor to perform the inter-phase short circuit fault diagnosis method according to any one of claims 1 to 11.

17. A computer-readable storage medium storing a computer program, characterized in that: When the computer program is executed by a processor, the inter-phase short circuit fault diagnosis method according to any one of claims 1 to 11 is implemented.

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