Three-phase current imbalance fault diagnosis method, device and equipment in steady state of position-control-free oil pump motor and medium

Abstract

The invention provides a three-phase current imbalance fault diagnosis method, device, equipment and medium in a steady state of a position-control-free oil pump motor, and the method comprises the steps: judging whether the oil pump motor is in the steady state or not according to the current state of the oil pump motor, and facilitating the subsequent steady-state three-phase current imbalance fault diagnosis of the oil pump motor. If yes, three-phase current is obtained, a three-phase current equivalent average value is obtained through calculation according to the three-phase current, whether the three-phase current equivalent average value and a required current vector of the oil pump motor meet a current preset relation or not is judged, and if yes, it is determined that the three-phase current imbalance fault exists, namely, the three-phase current imbalance fault is judged to be a three-phase current imbalance fault. The three-phase current equivalent average value can be utilized to realize simple and accurate diagnosis of the three-phase current imbalance fault.

Description

Technical Field

[0001] The present invention relates to the field of vehicles, and in particular to a method, device, equipment and medium for diagnosing a three-phase current imbalance fault in a steady state of a non-position-controlled oil pump motor. Background Art

[0002] With the continuous development of relevant social technologies, vehicles have become the main means of transportation for users. Vehicles can use oil pump motors to provide power. However, there may be oil pump motor failures, such as three-phase current imbalance failures in the steady state of the oil pump motor without position control, which needs to be diagnosed.

[0003] Currently, negative sequence components are used to diagnose three-phase current imbalance faults, which requires a large amount of filtering and the negative sequence components are small after filtering, which can easily cause false fault alarms.

[0004] In other words, there is currently a need for three-phase current imbalance fault diagnosis in the steady state of the oil pump motor without position control. Summary of the invention

[0005] In view of this, the purpose of the present application is to provide a method, device, equipment and medium for diagnosing the three-phase current imbalance fault of a position-free oil pump motor in steady state, which can realize simple, convenient and highly accurate three-phase current imbalance fault diagnosis.

[0006] The present application provides a method for diagnosing a three-phase current imbalance fault of a non-position-controlled oil pump motor in a steady state, the method comprising:

[0007] Determine whether the oil pump motor is in a steady state based on its current state;

[0008] If so, the three-phase current is obtained, and the equivalent average value of the three-phase current is calculated according to the three-phase current;

[0009] It is determined whether the three-phase current equivalent average value and the required current vector of the oil pump motor satisfy a preset current relationship. If so, it is determined that a three-phase current imbalance fault exists.

[0010] Optionally, judging whether the oil pump motor is in a steady state according to the current state thereof includes:

[0011] Obtain the current state of the oil pump motor including the estimated speed, required speed and rate of change of the required current vector;

[0012] If the difference between the estimated speed and the required speed is less than a first calibration value and the rate of change of the required current vector is less than a second calibration value, it is determined that the current state of the oil pump motor is in a steady state.

[0013] Optionally, before obtaining the three-phase current, the method further includes:

[0014] Determine whether it is controlled within the linear modulation area according to the modulation depth. If it is, continue the step of obtaining the three-phase current.

[0015] Optionally, judging whether the modulation depth is controlled within the linear modulation region according to the modulation depth includes:

[0016] Whether the modulation depth is less than 1 is used to determine whether it is controlled within the linear modulation area.

[0017] Optionally, the current preset relationship is:

[0018]

[0019] Among them, I avg is the equivalent average value of the three-phase current, I s is the demand current vector, and H2 is the third calibration value.

[0020] Optionally, the method further comprises:

[0021] Obtaining a three-phase required voltage, and calculating an equivalent average value of the three-phase required voltage according to the three-phase required voltage;

[0022] Determine whether the three-phase voltage requirement equivalent average value and the oil pump motor voltage requirement vector satisfy a preset voltage relationship, and if so, determine that a three-phase voltage imbalance fault exists;

[0023] According to the three-phase voltage imbalance fault and the three-phase current imbalance fault, a three-phase current imbalance fault alarm is issued.

[0024] Optionally, the voltage preset relationship is:

[0025]

[0026] Among them, U avg is the equivalent average value of the three-phase required voltage, U s is the required voltage vector, and H3 is the fourth calibration value.

[0027] The present application provides a device for diagnosing three-phase current imbalance fault of a non-position-controlled oil pump motor in a steady state, the device comprising:

[0028] A judgment unit, used to judge whether the oil pump motor is in a steady state according to the current state of the oil pump motor;

[0029] A calculation unit, configured to obtain the three-phase current if , and calculate the equivalent average value of the three-phase current according to the three-phase current;

[0030] The determination unit is used to determine whether the three-phase current equivalent average value and the required current vector of the oil pump motor meet a current preset relationship. If so, it is determined that a three-phase current imbalance fault exists.

[0031] The present application provides a device for diagnosing three-phase current imbalance faults of a non-position-controlled oil pump motor in steady state, the device comprising: a processor and a memory;

[0032] The memory is used to store instructions;

[0033] The processor is used to execute the instructions in the memory to perform the method as described above.

[0034] The present application provides a computer-readable medium, comprising instructions, which, when executed on a computer, enable the computer to execute the method described above.

[0035] The present application provides a method for diagnosing a three-phase current imbalance fault in a steady state of a non-position-controlled oil pump motor, the method comprising: judging whether the oil pump motor is in a steady state according to the current state of the oil pump motor, so as to facilitate the subsequent diagnosis of a three-phase current imbalance fault in a steady state of the oil pump motor. If it is, the three-phase current is obtained, and the equivalent average value of the three-phase current is calculated according to the three-phase current, and it is judged whether the equivalent average value of the three-phase current and the required current vector of the oil pump motor meet the current preset relationship. If they meet, it is determined that there is a three-phase current imbalance fault, that is, the use of the equivalent average value of the three-phase current can realize a simple and highly accurate diagnosis of the three-phase current imbalance fault. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0037] Figure 1 A schematic flow chart of a method for diagnosing a three-phase current imbalance fault of a non-position-controlled oil pump motor in a steady state provided in an embodiment of the present application is shown;

[0038] Figure 2 A schematic diagram of a three-phase current imbalance fault diagnosis process in a steady state of a non-position-controlled oil pump motor provided in an embodiment of the present application is shown;

[0039] Figure 3 A schematic structural diagram of a device for diagnosing a three-phase current imbalance fault in a steady state of a non-position-controlled oil pump motor provided in an embodiment of the present application is shown. DETAILED DESCRIPTION

[0040] In order to enable those skilled in the art to better understand the solution of the present application, the technical solution in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0041] The vehicle can use the oil pump motor to provide power. However, there may be a fault in the oil pump motor, such as a three-phase current imbalance fault in the steady state of the oil pump motor without position control, which needs to be diagnosed.

[0042] Currently, negative sequence components are used to diagnose three-phase current imbalance faults, which requires a large amount of filtering and the negative sequence components are small after filtering, which can easily cause false fault alarms.

[0043] In other words, there is currently a need for three-phase current imbalance fault diagnosis in the steady state of the oil pump motor without position control.

[0044] Based on this, the present application provides a method for diagnosing a three-phase current imbalance fault in a steady state of a non-position controlled oil pump motor, the method comprising: judging whether the oil pump motor is in a steady state according to the current state of the oil pump motor, so as to facilitate the subsequent diagnosis of a three-phase current imbalance fault in a steady state of the oil pump motor. If it is, the three-phase current is obtained, and the equivalent average value of the three-phase current is calculated according to the three-phase current, and it is judged whether the equivalent average value of the three-phase current and the required current vector of the oil pump motor meet the current preset relationship. If so, it is determined that there is a three-phase current imbalance fault, that is, the use of the equivalent average value of the three-phase current can realize a simple and highly accurate diagnosis of the three-phase current imbalance fault.

[0045] In order to better understand the technical solution and technical effects of the present application, specific embodiments will be described in detail below with reference to the accompanying drawings.

[0046] See also Figure 1 , which is a flow chart of a method for diagnosing a three-phase current imbalance fault of a position-free oil pump motor in steady state provided in an embodiment of the present application.

[0047] The method for diagnosing a three-phase current imbalance fault in a steady state of a non-position-controlled oil pump motor provided in this embodiment comprises the following steps:

[0048] S101, judging whether the oil pump motor is in a steady state according to the current state.

[0049] In the embodiments of the present application, considering that the present application requires fault diagnosis of three-phase current imbalance in steady state of oil pump motor without position control, it is possible to first determine whether the oil pump motor is in steady state based on its current state, and when the oil pump motor is in steady state, the three-phase current imbalance fault diagnosis in steady state can be continued.

[0050] Specifically, the current state of the oil pump motor may include the estimated speed, the required speed, and the change rate of the required current vector, that is, the estimated speed, the required speed, and the change rate of the required current vector may reflect the current state of the oil pump motor. If the difference between the estimated speed and the required speed is less than the first calibration value and the change rate of the required current vector is less than the second calibration value, it is determined that the current state of the oil pump motor is in a steady state.

[0051] refer to Figure 2 As shown, the first calibration value can be represented by H0, and the second calibration value can be represented by H1. If the absolute value of the difference between the estimated speed and the required speed is less than the first calibration value H0, the process continues, otherwise it returns to the starting state; if the required current vector I s If the rate of change of is less than the second calibration value H1, it is considered that the oil pump motor is currently in a steady state, otherwise it returns to the starting state.

[0052] S102: If yes, obtain the three-phase current, and calculate the equivalent average value of the three-phase current according to the three-phase current.

[0053] In the embodiment of the present application, when the oil pump motor is determined to be in a steady state according to the estimated speed, the required speed and the rate of change of the required current vector, the three-phase current can be obtained, and each phase of the three-phase current is represented by U, V and W respectively, then each phase of the three-phase current is I U ,I V and I W The three-phase current equivalent average value is calculated based on the three-phase current, and the three-phase current equivalent average value can be used to determine whether there is a three-phase current imbalance fault.

[0054] Specifically, the equivalent average value of the three-phase current can be calculated using the following formula according to the three-phase current.

[0055]

[0056] Among them, I avg is the equivalent average value of the three-phase current.

[0057] S103, judging whether the three-phase current equivalent average value and the required current vector of the oil pump motor satisfy a preset current relationship, and if so, determining that a three-phase current imbalance fault exists.

[0058] In an embodiment of the present application, after calculating the equivalent average value of the three-phase current, it can be determined whether the equivalent average value of the three-phase current and the required current vector of the oil pump motor satisfy the preset current relationship. If so, it is determined that a three-phase current imbalance fault exists.

[0059] That is to say, using the equivalent average value of the three-phase current combined with the demand current vector of the oil pump motor can achieve a simple and highly accurate diagnosis of the three-phase current imbalance fault.

[0060] Specifically, refer to Figure 2 As shown, the current preset relationship is

[0061]

[0062] Among them, I avg is the equivalent average value of the three-phase current, I s is the demand current vector, and H2 is the third calibration value.

[0063] When the oil pump motor is in steady state, if the three-phase current is balanced, Therefore, when the equivalent average value of the three-phase current combined with the demand current vector of the oil pump motor satisfies the preset current relationship, it means that there is a three-phase current unbalance fault, thereby achieving a simple diagnosis of the three-phase current unbalance fault.

[0064] In practical applications, when the diagnosis result is that there is a three-phase current unbalance fault, a three-phase current unbalance fault alarm needs to be issued.

[0065] In the embodiment of the present application, considering that the three-phase current balance is closely related to the three-phase voltage balance, in order to avoid the false alarm of the three-phase current imbalance fault, it is possible to continue to diagnose whether there is a three-phase voltage imbalance.

[0066] Specifically, the three-phase demand voltage is obtained, and the equivalent average value of the three-phase demand voltage is calculated based on the three-phase demand voltage. It is determined whether the equivalent average value of the three-phase demand voltage and the demand voltage vector of the oil pump motor satisfy the preset voltage relationship. If so, it is determined that there is a three-phase voltage imbalance fault. Based on the three-phase voltage imbalance fault and the three-phase current imbalance fault, a three-phase current imbalance fault alarm is issued, thereby further improving the accuracy of the three-phase current imbalance fault diagnosis.

[0067] refer to Figure 2 As shown, each phase of the three phases is represented by U, V and W respectively, then each phase of the three-phase required voltage is U U , U V and U W The equivalent average value of the three-phase demand voltage can be calculated using the following formula according to the three-phase demand voltage.

[0068]

[0069] Among them, U avg It is the equivalent average value of the three-phase demand voltage.

[0070] The voltage preset relationship is

[0071]

[0072] Among them, U avg is the equivalent average value of the three-phase required voltage, U s is the required voltage vector, and H3 is the fourth calibration value.

[0073] When the oil pump motor is in a steady state, if the three-phase voltage is balanced, Therefore, when the equivalent average value of the three-phase demand voltage combined with the demand voltage vector of the oil pump motor meets the voltage preset relationship, it means that there is a three-phase voltage unbalance fault.

[0074] That is to say, the three-phase voltage balance state is determined based on the equivalent average value of the three-phase demand voltages U, V, and W. If the equivalent average value of the three-phase demand voltage and the demand voltage vector of the oil pump motor meet the preset voltage relationship, it is considered to be in a three-phase voltage imbalance state, and a three-phase voltage imbalance warning is issued, otherwise it returns to the starting state. When both the three-phase current imbalance warning and the three-phase voltage imbalance warning are reported, the diagnosis is completed and the three-phase current imbalance fault is reported.

[0075] In an embodiment of the present application, before obtaining the three-phase current to calculate the equivalent average value of the three-phase current, it is also possible to determine whether it is controlled within the linear modulation area based on the modulation depth. If it is within the linear modulation area, the step of obtaining the three-phase current is continued, and the fault diagnosis of the three-phase current imbalance is continued. If it is close to or has entered the linear modulation area, it returns to the starting state.

[0076] Specifically, refer to Figure 2 As shown, the modulation depth is represented by K. Whether the modulation depth is controlled within the linear modulation area is determined based on whether the modulation depth is less than 1. If K < 1, it means that the modulation depth is within the linear modulation area.

[0077] As an example, the modulation depth may be calculated based on the required voltage vector and the bus voltage.

[0078]

[0079] Among them, U S is the required voltage vector, U dc is the bus voltage.

[0080] It can be seen that the present application provides a method for diagnosing the three-phase current imbalance fault of the oil pump motor in steady state without position control, and the method includes: judging whether the oil pump motor is in steady state according to the current state of the oil pump motor, so as to facilitate the subsequent diagnosis of the three-phase current imbalance fault of the oil pump motor in steady state. If it is, the three-phase current is obtained, and the equivalent average value of the three-phase current is calculated according to the three-phase current, and it is judged whether the equivalent average value of the three-phase current and the required current vector of the oil pump motor meet the preset current relationship. If they meet, it is determined that there is a three-phase current imbalance fault. In other words, the use of the equivalent average value of the three-phase current can realize a simple and highly accurate diagnosis of the three-phase current imbalance fault.

[0081] Based on the three-phase current imbalance fault diagnosis method of the oil pump motor without position control in steady state provided in the above embodiment, the embodiment of the present application also provides a three-phase current imbalance fault diagnosis device of the oil pump motor without position control in steady state, and its working principle is described in detail in conjunction with the accompanying drawings below.

[0082] See also Figure 3 , which is a structural block diagram of a three-phase current imbalance fault diagnosis device for a position-free oil pump motor in steady state provided in an embodiment of the present application.

[0083] The device 200 for diagnosing three-phase current imbalance fault of a non-position-controlled oil pump motor in steady state includes:

[0084] A judgment unit 210, used to judge whether the oil pump motor is in a steady state according to the current state of the oil pump motor;

[0085] A calculation unit 220 is used to obtain the three-phase current if , and calculate the equivalent average value of the three-phase current according to the three-phase current;

[0086] The determination unit 230 is used to determine whether the three-phase current equivalent average value and the required current vector of the oil pump motor meet a preset current relationship. If so, it is determined that a three-phase current imbalance fault exists.

[0087] Optionally, the determining unit 210 is configured to:

[0088] Obtain the current state of the oil pump motor including the estimated speed, required speed and rate of change of the required current vector;

[0089] If the difference between the estimated speed and the required speed is less than a first calibration value and the rate of change of the required current vector is less than a second calibration value, it is determined that the current state of the oil pump motor is in a steady state.

[0090] Optionally, before acquiring the three-phase current, the device further includes: a modulation depth judgment unit, the modulation depth judgment unit being configured to:

[0091] Determine whether it is controlled within the linear modulation area according to the modulation depth. If it is, continue the step of obtaining the three-phase current.

[0092] Optionally, the modulation depth judgment unit is used to:

[0093] Whether the modulation depth is less than 1 is used to determine whether it is controlled within the linear modulation area.

[0094] Optionally, the current preset relationship is:

[0095]

[0096] Among them, I avg is the equivalent average value of the three-phase current, I s is the demand current vector, and H2 is the third calibration value.

[0097] Optionally, the device further comprises: a fault diagnosis unit, the fault diagnosis unit being configured to:

[0098] Obtaining a three-phase required voltage, and calculating an equivalent average value of the three-phase required voltage according to the three-phase required voltage;

[0099] Determine whether the three-phase voltage requirement equivalent average value and the oil pump motor voltage requirement vector satisfy a preset voltage relationship, and if so, determine that a three-phase voltage imbalance fault exists;

[0100] According to the three-phase voltage imbalance fault and the three-phase current imbalance fault, a three-phase current imbalance fault alarm is issued.

[0101] Optionally, the voltage preset relationship is:

[0102]

[0103] Among them, U avg is the equivalent average value of the three-phase required voltage, U s is the required voltage vector, and H3 is the fourth calibration value.

[0104] The units involved in the embodiments described in this application may be implemented by software or hardware, wherein the name of a unit does not, in some cases, constitute a limitation on the unit itself.

[0105] The functions described above herein may be performed at least in part by one or more hardware logic components. For example, without limitation, exemplary types of hardware logic components that may be used include: field programmable gate arrays (FPGAs), application specific integrated circuits (ASICs), application specific standard products (ASSPs), systems on chips (SOCs), complex programmable logic devices (CPLDs), and the like.

[0106] Based on the method for diagnosing a three-phase current imbalance fault in a steady state of a position-free oil pump motor provided in the above embodiment, the embodiment of the present application further provides a device for diagnosing a three-phase current imbalance fault in a steady state of a position-free oil pump motor. The device for diagnosing a three-phase current imbalance fault in a steady state of a position-free oil pump motor includes:

[0107] The processor and the memory may be one or more processors. In some embodiments of the present application, the processor and the memory may be connected via a bus or other means.

[0108] The memory may include a read-only memory and a random access memory, and provides instructions and data to the processor. A portion of the memory may also include an NVRAM. The memory stores an operating system and operating instructions, executable modules or data structures, or a subset thereof, or an extended set thereof, wherein the operating instructions may include various operating instructions for implementing various operations. The operating system may include various system programs for implementing various basic services and processing hardware-based tasks.

[0109] The processor controls the operation of the terminal device and may also be referred to as a CPU.

[0110] The method disclosed in the above embodiment of the present application can be applied to a processor or implemented by a processor. The processor can be an integrated circuit chip with signal processing capabilities. In the implementation process, each step of the above method can be completed by an integrated logic circuit of hardware in the processor or an instruction in the form of software. The above processor can be a general-purpose processor, DSP, ASIC, FPGA or other programmable logic device, discrete gate or transistor logic device, discrete hardware component. The methods, steps and logic block diagrams disclosed in the embodiments of the present application can be implemented or executed. The general-purpose processor can be a microprocessor or the processor can also be any conventional processor, etc. The steps of the method disclosed in the embodiment of the present application can be directly embodied as a hardware decoding processor to perform, or the hardware and software modules in the decoding processor can be combined to perform. The software module can be located in a mature storage medium in the field such as a random access memory, a flash memory, a read-only memory, a programmable read-only memory or an electrically erasable programmable memory, a register, etc. The storage medium is located in the memory, and the processor reads the information in the memory and completes the steps of the above method in combination with its hardware.

[0111] The embodiment of the present application also provides a computer-readable medium for storing program code, where the program code is used to execute any one of the methods of the aforementioned embodiments.

[0112] It should be noted that the computer-readable medium mentioned above in the present application may be a computer-readable signal medium or a computer-readable storage medium or any combination of the above two. The computer-readable storage medium may be, for example, but not limited to, an electrical, magnetic, optical, electromagnetic, infrared, or semiconductor system, device or device, or any combination of the above. More specific examples of computer-readable storage media may include, but are not limited to: an electrical connection with one or more wires, a portable computer disk, a hard disk, a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or flash memory), an optical fiber, a portable compact disk read-only memory (CD-ROM), an optical storage device, a magnetic storage device, or any suitable combination of the above. In the present application, a computer-readable storage medium may be any tangible medium containing or storing a program that can be used by or in combination with an instruction execution system, device or device. In the present application, a computer-readable signal medium may include a data signal propagated in a baseband or as part of a carrier wave, which carries a computer-readable program code. This propagated data signal may take a variety of forms, including but not limited to electromagnetic signals, optical signals, or any suitable combination of the above. The computer readable signal medium may also be any computer readable medium other than a computer readable storage medium, which may send, propagate or transmit a program for use by or in conjunction with an instruction execution system, apparatus or device. The program code contained on the computer readable medium may be transmitted using any suitable medium, including but not limited to: wires, optical cables, RF (radio frequency), etc., or any suitable combination of the above.

[0113] The computer-readable medium may be included in the electronic device, or may exist independently without being incorporated into the electronic device.

[0114] It should be noted that a person skilled in the art can understand that all or part of the processes in the above method embodiments can be implemented by instructing related hardware through a computer program, and the program can be stored in a computer-readable medium, and when the program is executed, it can include the processes in the above method embodiments. The medium can be a disk, an optical disk, a read-only memory (ROM) or a random access memory (RAM), etc.

[0115] Each embodiment in this specification is described in a progressive manner, and the same or similar parts between the embodiments can be referred to each other, and each embodiment focuses on the differences from other embodiments. In particular, for the device embodiment, since it is basically similar to the method embodiment, the description is relatively simple, and the relevant parts can be referred to the partial description of the method embodiment. The device embodiment described above is merely schematic, and the units and modules described as separate components may or may not be physically separated. In addition, some or all of the units and modules may be selected according to actual needs to achieve the purpose of the scheme of this embodiment. A person of ordinary skill in the art can understand and implement it without paying creative work.

[0116] The above is only a preferred implementation of the present application. Although the present application has been disclosed as a preferred embodiment, it is not intended to limit the present application. Any technician familiar with the art can use the above disclosed methods and technical contents to make many possible changes and modifications to the technical solution of the present application without departing from the scope of the technical solution of the present application, or modify it into an equivalent embodiment of equivalent changes. Therefore, any simple modification, equivalent change and modification made to the above embodiments based on the technical essence of the present application without departing from the content of the technical solution of the present application still falls within the scope of protection of the technical solution of the present application.

Claims

1. A method for diagnosing three-phase current imbalance fault of a non-position-controlled oil pump motor in steady state, characterized in that: The method comprises: Determine whether the oil pump motor is in a steady state based on its current state; If so, the three-phase current is obtained, and the equivalent average value of the three-phase current is calculated according to the three-phase current; It is determined whether the three-phase current equivalent average value and the required current vector of the oil pump motor satisfy a preset current relationship. If so, it is determined that a three-phase current imbalance fault exists.

2. The method according to claim 1, characterized in that: The determining whether the oil pump motor is in a steady state according to the current state thereof comprises: Obtain the current state of the oil pump motor including the estimated speed, required speed and rate of change of the required current vector; If the difference between the estimated speed and the required speed is less than a first calibration value and the rate of change of the required current vector is less than a second calibration value, it is determined that the current state of the oil pump motor is in a steady state.

3. The method according to claim 1, characterized in that Before obtaining the three-phase current, the method further includes: Determine whether it is controlled within the linear modulation area according to the modulation depth. If it is, continue the step of obtaining the three-phase current.

4. The method according to claim 3, characterized in that The determining whether the modulation depth is controlled within the linear modulation region comprises: Whether the modulation depth is less than 1 is used to determine whether it is controlled within the linear modulation area.

5. The method according to claim 1, characterized in that The current preset relationship is: Among them, I avg is the equivalent average value of the three-phase current, I s is the demand current vector, and H2 is the third calibration value.

6. The method according to claim 1, characterized in that The method further comprises: Obtaining a three-phase required voltage, and calculating an equivalent average value of the three-phase required voltage according to the three-phase required voltage; Determine whether the three-phase voltage requirement equivalent average value and the oil pump motor voltage requirement vector satisfy a preset voltage relationship, and if so, determine that a three-phase voltage imbalance fault exists; According to the three-phase voltage imbalance fault and the three-phase current imbalance fault, a three-phase current imbalance fault alarm is issued.

7. The method according to claim 6, characterized in that The voltage preset relationship is: Among them, U avg is the equivalent average value of the three-phase required voltage, U s is the required voltage vector, and H3 is the fourth calibration value.

8. A device for diagnosing three-phase current imbalance fault of a non-position-controlled oil pump motor in steady state, characterized in that: The device comprises: A judgment unit, used to judge whether the oil pump motor is in a steady state according to the current state of the oil pump motor; A calculation unit, configured to obtain the three-phase current if , and calculate the equivalent average value of the three-phase current according to the three-phase current; The determination unit is used to determine whether the three-phase current equivalent average value and the required current vector of the oil pump motor meet a current preset relationship. If so, it is determined that a three-phase current imbalance fault exists.

9. A three-phase current imbalance fault diagnosis device for a non-position-controlled oil pump motor in steady state, characterized in that: The device comprises: a processor and a memory; The memory is used to store instructions; The processor is used to execute the instructions in the memory to perform the method according to any one of claims 1 to 7.

10. A computer-readable medium, characterized in that The method comprises instructions which, when executed on a computer, cause the computer to execute the method according to any one of claims 1 to 7.

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