Fault determination method and device of permanent magnet synchronous motor, and computer program product

Abstract

The invention discloses a fault determination method and device for a permanent magnet synchronous motor, and a computer program product. The method comprises the steps that in the operation process of the motor, the three-phase current of the motor is acquired according to a preset time period; if the maximum current in the three-phase current exceeds an upper limit current threshold value and the minimum current in the three-phase current is lower than a lower limit current threshold value, acquiring the current rotating speed and torque of the motor; if it is determined that the motor is not in the locked-rotor working condition according to the rotating speed and the torque, determining that the motor has an open-phase fault at present; and under the condition of determining that the motor is in a locked-rotor working condition according to the rotating speed and the torque, if the phase difference between any two phases in the motor does not meet a preset phase loss condition, determining that the motor has a locked-rotor fault at present, and otherwise, determining that the motor has the locked-rotor fault and the phase loss fault at the same time at present. According to the invention, the technical problem that the normal operation of the motor is affected by adopting a wrong protection mechanism due to the fact that misjudgment is easy to occur during motor fault detection in the prior art is solved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of motor control, in particular to a fault determination method and device of a permanent magnet synchronous motor, and a computer program product. BACKGROUND

[0002] In the existing motor fault detection method for new energy vehicles, the current amplitude characteristics of motor stall faults and open-phase faults overlap, which can easily cause misjudgment. Specifically, when the motor stalls, the current waveform is distorted due to the decrease of back electromotive force, which can cause the instantaneous value of a phase current to be abnormal, thereby simultaneously meeting the open-phase judgment condition and triggering the open-phase protection, thereby masking the actual stall fault. The root cause of this problem lies in the similarity of stall and open-phase faults in current characteristics, as well as the limitations of traditional current amplitude judgment methods, which make it difficult for the system to accurately distinguish between the two faults, thereby causing protection logic conflicts.

[0003] To address the issue of misjudgment during motor fault detection in the related art, which leads to the use of incorrect protection mechanisms and affects the normal operation of the motor, no effective solutions have been proposed. SUMMARY

[0004] Embodiments of the present application provide a fault determination method and device of a permanent magnet synchronous motor, and a computer program product, to at least solve the technical problem of misjudgment during motor fault detection in the related art, which leads to the use of incorrect protection mechanisms and affects the normal operation of the motor.

[0005] According to an aspect of an embodiment of the present application, a fault determination method of a permanent magnet synchronous motor is provided, including: obtaining three-phase currents of the motor in a predetermined time period during operation of the motor; in a case where a maximum current in the three-phase currents exceeds an upper current threshold and a minimum current in the three-phase currents is lower than a lower current threshold, obtaining a current speed and an output torque of the motor; in a case where it is determined that the motor is not in a stall working condition according to the speed and the output torque, determining that the motor currently has an open-phase fault; in a case where it is determined that the motor is in the stall working condition according to the speed and the output torque, if a phase difference between any two phases of the motor does not meet a preset open-phase condition, determining that the motor currently has a stall fault, and if at least one of the phase differences meets the preset open-phase condition, determining that the motor currently has both the stall fault and the open-phase fault.

[0006] Optionally, during the operation of the motor, the three-phase currents of the motor are obtained according to a predetermined time period, including: during the operation of the motor, the corresponding current is synchronously sampled by using the current sensor arranged in each phase of the motor, to obtain a three-phase current signal; the three-phase current signal is analog-to-digital converted to obtain a corresponding digital signal; the digital signal is normalized to obtain the three-phase current.

[0007] Optionally, after the current speed and output torque of the motor are obtained, the fault determination method of the permanent magnet synchronous motor further includes: obtaining a preset speed threshold and a preset torque threshold; in a case where the speed is lower than the preset speed threshold and the output torque is higher than the preset torque threshold for a first duration higher than a first preset duration threshold, it is determined that the motor is currently in the locked-rotor operating condition; in a case where the speed is not lower than the preset speed threshold and the output torque is not higher than the preset torque threshold or the output torque is higher than the preset torque threshold for the first duration not higher than the first preset duration threshold, it is determined that the motor is not currently in the locked-rotor operating condition.

[0008] Optionally, the fault determination method of the permanent magnet synchronous motor further includes: in a case where it is determined that the motor is in the locked-rotor operating condition according to the speed and the output torque, the three-phase currents are stored to a ring buffer, wherein the ring buffer is used to store a fixed number of continuous data samples; when the data in the ring buffer reaches a preset data capacity, the stored three-phase currents are subjected to Fourier transform to obtain a phase of each phase current in the three-phase currents; the phase difference between the arbitrary two phases is calculated according to the phase; and it is judged whether the phase difference satisfies the preset open-phase condition to obtain a judgment result.

[0009] Optionally, when the data in the ring buffer reaches the preset data capacity, the stored three-phase currents are subjected to Fourier transform to obtain a phase of each phase current in the three-phase currents, including: when the data in the ring buffer reaches the preset data capacity, the stored three-phase currents are subjected to Fourier transform to obtain a fundamental component corresponding to each phase current, wherein the fundamental component represents main frequency information of each phase current; and the phase corresponding to each phase current is determined according to the fundamental component by using a first formula, wherein an expression of the fundamental component is: , the first formula is: , i represents a label of each phase current, represents the phase corresponding to the i-th phase current, is a real part of the fundamental component of the i-th phase current, is an imaginary part of the fundamental component of the i-th phase current, and j is an imaginary unit.

[0010] Optionally, the determining whether the phase difference meets the preset open-phase condition to obtain a determination result comprises: in a case that at least one of the phase differences exceeds the preset phase difference range and the exceeding time length exceeds a second preset time length threshold, determining that the determination result is that the phase difference meets the preset open-phase condition; in a case that any one of the phase differences does not exceed the preset phase difference range or the exceeding time length of the phase difference that exceeds the preset phase difference range does not exceed the second preset time length threshold, determining that the determination result is that the phase difference does not meet the preset open-phase condition.

[0011] Optionally, the fault determination method of the permanent magnet synchronous motor further comprises: in a case that the motor currently exists the open-phase fault, controlling the motor to perform an open-phase protection operation; in a case that the motor currently exists the locked-rotor fault, controlling the motor to perform a locked-rotor protection operation; in a case that the motor currently exists both the open-phase fault and the locked-rotor fault, controlling the motor to perform the locked-rotor protection operation and then perform open-phase detection again to obtain a detection result, wherein the open-phase detection is a process of detecting whether the current three-phase currents exceed the upper limit current threshold and the lower limit current threshold; in a case that the detection result indicates that the motor currently still exists the open-phase fault, controlling the motor to perform the open-phase protection operation, in a case that the detection result indicates that the motor currently does not exist the open-phase fault, controlling the motor to maintain a current running state; in a case that the motor currently exists the open-phase fault and / or the locked-rotor fault, issuing a fault warning signal and recording fault information.

[0012] According to another aspect of the embodiments of the present application, a fault determination device of a permanent magnet synchronous motor is further provided, comprising: a first acquisition unit, configured to acquire three-phase currents of the motor in a process of motor operation according to a predetermined time period; a second acquisition unit, configured to acquire a current rotating speed and output torque of the motor in a case that a maximum current in the three-phase currents exceeds an upper limit current threshold and a minimum current in the three-phase currents is lower than a lower limit current threshold; a first determination unit, configured to determine that the motor currently exists an open-phase fault in a case that the motor is determined not to be in a locked-rotor working condition according to the rotating speed and the output torque; and a second determination unit, configured to determine that the motor currently exists a locked-rotor fault in a case that the motor is determined to be in the locked-rotor working condition according to the rotating speed and the output torque, and that at least one of phase differences between any two phases of the motor meets a preset open-phase condition, and determine that the motor currently exists both the locked-rotor fault and the open-phase fault in a case that the phase differences between any two phases of the motor do not meet the preset open-phase condition.

[0013] Optionally, the first obtaining unit comprises: a first obtaining module, configured to obtain three-phase current signals by synchronously sampling currents of each phase of the motor by using current sensors arranged in the motor during operation of the motor; a second obtaining module, configured to perform analog-digital conversion on the three-phase current signals to obtain corresponding digital signals; and a third obtaining module, configured to perform normalization processing on the digital signals to obtain the three-phase currents.

[0014] Optionally, the fault determination apparatus for the permanent magnet synchronous motor further comprises: a third obtaining unit, configured to obtain a preset speed threshold and a preset torque threshold after obtaining the current speed and the output torque of the motor; a third determination unit, configured to determine that the motor is currently in the locked-rotor operating condition in a case where the speed is lower than the preset speed threshold and a first time length during which the output torque is higher than the preset torque threshold is higher than a first preset time length threshold; and a fourth determination unit, configured to determine that the motor is not currently in the locked-rotor operating condition in a case where the speed is not lower than the preset speed threshold and the output torque is not higher than the preset torque threshold or the first time length during which the output torque is higher than the preset torque threshold is not higher than the first preset time length threshold.

[0015] Optionally, the fault determination apparatus for the permanent magnet synchronous motor further comprises: a storage unit, configured to store the three-phase currents to a ring buffer in a case where it is determined that the motor is in the locked-rotor operating condition according to the speed and the output torque, wherein the ring buffer is configured to store a fixed number of continuous data samples; a fourth obtaining unit, configured to perform Fourier transform on the stored three-phase currents to obtain phases of each phase current in the three-phase currents when data in the ring buffer reaches a preset data capacity; a calculation unit, configured to calculate the phase difference between any two phases according to the phases; and a fifth obtaining unit, configured to determine whether the phase difference satisfies the preset open-phase condition to obtain a determination result.

[0016] Optionally, the fourth obtaining unit comprises: a fourth obtaining module, configured to perform Fourier transform on the stored three-phase currents to obtain fundamental components corresponding to each phase current when data in the ring buffer reaches a preset data capacity, wherein the fundamental components represent main frequency information of each phase current; and a first determination module, configured to determine the phase corresponding to each phase current by using a first formula according to the fundamental components, wherein an expression of the fundamental components is: the first formula is: wherein i represents a label of each phase current, represents the phase corresponding to the i-th phase current, is a real part of the fundamental component of the i-th phase current, and is an imaginary part of the fundamental component of the i-th phase current. ​​​​Imaginary part of the fundamental component of the i-th phase current, j is the imaginary unit.

[0017] Optionally, the fifth acquisition unit comprises: a second determination module, configured to determine that the phase difference meets the preset open-phase condition when at least one of the phase differences exceeds the preset phase difference range and the exceeding duration exceeds a second preset duration threshold; and a third determination module, configured to determine that the phase difference does not meet the preset open-phase condition when none of the phase differences exceeds the preset phase difference range or the exceeding duration of the phase difference that exceeds the preset phase difference range does not exceed the second preset duration threshold.

[0018] Optionally, the fault determination apparatus for the permanent magnet synchronous motor further comprises: a first control unit, configured to control the motor to perform an open-phase protection operation when the motor currently has the open-phase fault; a second control unit, configured to control the motor to perform a locked-rotor protection operation when the motor currently has the locked-rotor fault; a third control unit, configured to control the motor to perform the locked-rotor protection operation and then perform open-phase detection again to obtain a detection result when the motor currently has both the open-phase fault and the locked-rotor fault, wherein the open-phase detection is a process of detecting whether the current three-phase current exceeds the upper current threshold and the lower current threshold; a fourth control unit, configured to control the motor to perform the open-phase protection operation when the detection result indicates that the motor currently has the open-phase fault, and control the motor to maintain a current operating state when the detection result indicates that the motor currently does not have the open-phase fault; and a warning unit, configured to issue a fault warning signal and record fault information when the motor currently has the open-phase fault and / or the locked-rotor fault.

[0019] According to another aspect of the embodiments of the present application, a fault determination system for a permanent magnet synchronous motor is also provided, which uses any of the above-mentioned fault determination methods for the permanent magnet synchronous motor.

[0020] According to another aspect of the embodiments of the present application, a computer readable storage medium is also provided, which comprises a stored program, wherein the program executes any of the above-mentioned fault determination methods for the permanent magnet synchronous motor.

[0021] According to another aspect of the embodiments of the present application, a processor is also provided, which is used to run a program, wherein the program runs to execute any of the above-mentioned fault determination methods for the permanent magnet synchronous motor.

[0022] According to another aspect of the embodiments of the present application, a computer program product is also provided, which comprises computer instructions executed by a processor to perform any of the above-mentioned fault determination methods for a permanent magnet synchronous motor.

[0023] In the embodiments of the present application, during the operation of the motor, the three-phase currents of the motor can be acquired according to a predetermined time period; then in the case that the maximum current among the three-phase currents exceeds the upper current threshold and the minimum current among the three-phase currents is lower than the lower current threshold, the current speed and output torque of the motor are acquired; then in the case that the motor is determined not to be in the locked-rotor operating condition according to the speed and the output torque, it is determined that the motor currently has the open-phase fault; finally, in the case that the motor is determined to be in the locked-rotor operating condition according to the speed and the output torque, it is judged whether the phase difference between any two phases of the motor satisfies the preset open-phase condition, if the phase difference between any two phases of the motor does not satisfy the preset open-phase condition, it is determined that the motor currently has the locked-rotor fault, and if at least one phase difference satisfies the preset open-phase condition, it is determined that the motor currently has both the locked-rotor fault and the open-phase fault. Through the above technical solutions, the purpose of preliminarily judging whether there is a fault according to the three-phase currents of the motor, and then further distinguishing which fault exists by combining the speed, torque and phase difference among the three phases of the motor is achieved, the technical effect of accurately detecting the open-phase fault in the locked-rotor operating condition of the motor by combining the phase difference is achieved, and the identification precision and anti-interference ability of the open-phase fault in the locked-rotor operating condition of the motor are improved, thereby solving the technical problem in the related art that the motor fault detection is prone to misjudgment, resulting in the use of the wrong protection mechanism and affecting the normal operation of the motor. BRIEF DESCRIPTION OF DRAWINGS

[0024] The accompanying drawings, which are included to provide a further understanding of the present application and are incorporated in and constitute a part of this application, illustrate embodiments of the present application and serve to explain the present application, and do not limit the present application in any manner. In the drawings:

[0025] Figure 1 is a hardware structure block diagram of a mobile terminal of a fault determination method for a permanent magnet synchronous motor according to an embodiment of the present application;

[0026] Figure 2 is a flow chart of a fault determination method for a permanent magnet synchronous motor according to an embodiment of the present application;

[0027] Figure 3 is a flow chart of an optional fault determination method for a permanent magnet synchronous motor according to an embodiment of the present application;

[0028] Figure 4 is a schematic diagram of a fault determination apparatus for a permanent magnet synchronous motor according to an embodiment of the present application.

[0029] Among the above drawings, the following reference signs are included:

[0030] 102, processor; 104, memory; 106, transmission device; 108, input / output device. DETAILED DESCRIPTION

[0031] In order to make the personnel in the technical field better understand the scheme of the present application, the technical scheme in the embodiments of the present application will be clearly and completely described below in combination with the drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, not all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor should belong to the scope of protection of the present application.

[0032] It should be noted that the terms "first", "second" and the like in the specification and claims of the present application and the above-described drawings are used to distinguish similar objects, and do not necessarily indicate a specific order or a chronological sequence. It should be understood that the data thus used can be interchanged under appropriate circumstances, so that the embodiments of the present application described herein can be implemented in other than the order illustrated or described herein. In addition, the terms "include" and "have" and any variations thereof are intended to cover non-exclusive inclusion, for example, a process, method, system, product or device that includes a series of steps or units does not have to be limited to those steps or units clearly listed, but can include other steps or units not clearly listed or inherent to these processes, methods, products or devices.

[0033] As introduced in the background, the related art is prone to misjudgment when detecting motor faults, resulting in the use of incorrect protection mechanisms and affecting the normal operation of the motor. In view of the above defects, a permanent magnet synchronous motor fault determination method and device, and a computer program product are provided in the embodiments of the present application.

[0034] The technical scheme in the embodiments of the present application will be clearly and completely described below in combination with the drawings in the embodiments of the present application.

[0035] The method embodiments provided in the embodiments of the present application can be executed in a mobile terminal, a computer terminal or a similar computing device. Taking the case of running on a mobile terminal, Figure 1 is a hardware structure block diagram of a mobile terminal of a permanent magnet synchronous motor fault determination method of the embodiments of the present application. As Figure 1 shown, the mobile terminal can include one or more Figure 1The mobile terminal can further include a transmission device 106 for communication function and an input / output device 108. Those skilled in the art can understand that, Figure 1 The structure shown is only schematic, and does not limit the structure of the mobile terminal. For example, the mobile terminal can include more or less components than those shown, or have a different configuration of components. For example, Figure 1 The mobile terminal shown in the figure can include more or less components than those shown, or have a different configuration of components. Figure 1

[0036] The memory 104 can be used to store computer programs, such as software programs of application software and modules, such as the computer program corresponding to the fault determination method of the permanent magnet synchronous motor in the embodiments of the present application. The processor 102 can execute various functional applications and data processing by running the computer program stored in the memory 104, that is, implement the method described above. The memory 104 can include a high-speed random access memory, and can further include a non-volatile memory, such as one or more magnetic storage devices, flash memories, or other non-volatile solid-state memories. In some examples, the memory 104 can further include a memory remotely arranged with respect to the processor 102, and the remote memory can be connected to the mobile terminal through a network. Examples of the network include, but are not limited to, the Internet, an intranet, a local area network, a mobile communication network, and a combination thereof. The transmission device 106 is used to receive or send data via a network. The specific examples of the network can include a wireless network provided by a communication provider of the mobile terminal. In one example, the transmission device 106 includes a network adapter (Network Interface Controller, NIC for short), which can be connected to other network devices through a base station so as to communicate with the Internet. In one example, the transmission device 106 can be a radio frequency (Radio Frequency, RF for short) module, which is used to communicate with the Internet in a wireless manner.

[0037] According to the embodiments of the present application, a method embodiment of a fault determination method of a permanent magnet synchronous motor is provided. It should be noted that the steps shown in the flowchart of the drawings can be executed in a computer system such as a group of computer executable instructions, and although the logical order is shown in the flowchart, in some cases, the steps shown or described can be executed in an order different from that shown here.

[0038] Figure 2 is a flowchart of a fault determination method of a permanent magnet synchronous motor according to the embodiments of the present application, as shown in Figure 2 The method includes the following steps: ​

[0039] Step S202, during the operation of the motor, the three-phase currents of the motor are acquired according to a predetermined time period.

[0040] The above embodiments of the present application are described in detail below, Figure 3 The above embodiments of the present application are described in detail below, Figure 3 is a flowchart of an optional fault determination method of a permanent magnet synchronous motor according to an embodiment of the present application; as shown in the figure, in this embodiment, the three-phase currents of the motor can be monitored and acquired in real time during the operation of the motor, so as to determine whether the motor has a fault according to the amplitude characteristics thereof. Figure 3

[0041] Step S204, in the case where the maximum current among the three-phase currents exceeds the upper current threshold and the minimum current among the three-phase currents is lower than the lower current threshold, the current speed and output torque of the motor are acquired.

[0042] In this embodiment, as shown in the figure, Figure 3 If the maximum value of the three-phase currents exceeds the set upper current threshold and the minimum value of the three-phase currents is lower than the set lower current threshold, it can be preliminarily considered that the motor currently has a fault; however, under the locked-rotor working condition, due to the decrease of the back electromotive force, the current waveform of the motor will be distorted, which may make the instantaneous value of the current of a certain phase become abnormally large or small, so that the current amplitude judgment standard of the open-phase fault is met on the surface; since the open-phase fault often manifests as a significant decrease or disappearance of at least one phase current, and due to the increase of the mechanical resistance, the motor tries to overcome such resistance, which sometimes causes current imbalance, resulting in a relative decrease of the current of a certain phase, which looks like an open-phase; therefore, in order to further distinguish whether the motor currently has an open-phase fault or a locked-rotor fault, or both, the current speed and output torque of the motor can be further acquired for accurate distinction.

[0043] Step S206, in the case where it is determined according to the speed and output torque that the motor is not in the locked-rotor working condition, it is determined that the motor currently has an open-phase fault.

[0044] In this embodiment, as shown in the figure, Figure 3 If it is determined according to the speed and output torque that the motor is not in the locked-rotor working condition, it is determined that the motor currently has an open-phase fault.

[0045] Step S208, in the case where it is determined according to the speed and output torque that the motor is in the locked-rotor working condition, if the phase difference between any two phases of the motor does not satisfy the preset open-phase condition, it is determined that the motor currently has a locked-rotor fault, and if at least one phase difference satisfies the preset open-phase condition, it is determined that the motor currently has both a locked-rotor fault and an open-phase fault.

[0046] In this embodiment, as shown in the figure, Figure 3 ​As shown, if it can be determined according to the rotation speed and the output torque that the current motor is in the locked-rotor working condition, it can be first determined that the current motor has the locked-rotor fault, but there can still be the open-phase fault; generally, under the normal running condition, the phase currents of the three-phase alternating-current motor should have a stable phase difference, usually 120°, and when the motor has the open-phase fault, the phase balance will be broken; specifically, the open-phase fault can cause the current of the affected phase to be significantly reduced or even completely disappear, and the phase relationship of the currents of the other two phases will also change; therefore, it can be further judged from the perspective of the phase difference whether the motor still has the open-phase fault based on this point.

[0047] Specifically, if the phase difference between any two phases of the motor (i.e., the phase difference between the phase currents of the two phases) does not satisfy the preset open-phase condition, it can be considered that the current motor does not have the open-phase fault, and only has the locked-rotor fault; if at least one of the phase differences between any two phases (i.e., one of the phase differences between the phase currents of the two phases) satisfies the preset open-phase condition, it can be considered that the current motor still has the open-phase fault, i.e., there are both the locked-rotor fault and the open-phase fault.

[0048] From the above, by applying the technical solutions provided in the above embodiments of the present application, the three-phase currents of the motor can be first acquired according to the predetermined time period; then in the case that the maximum current in the three-phase currents exceeds the upper current threshold and the minimum current in the three-phase currents is lower than the lower current threshold, the current rotation speed and output torque of the motor are acquired; then in the case that it is determined according to the rotation speed and the output torque that the motor is not in the locked-rotor working condition, it is determined that the motor currently has the open-phase fault; finally, in the case that it is determined according to the rotation speed and the output torque that the motor is in the locked-rotor working condition, it is judged whether the phase difference between any two phases of the motor satisfies the preset open-phase condition, if the phase difference between any two phases of the motor does not satisfy the preset open-phase condition, it is determined that the current motor has the locked-rotor fault, and if at least one of the phase differences satisfies the preset open-phase condition, it is determined that the current motor has both the locked-rotor fault and the open-phase fault, thus achieving the purpose of preliminarily judging whether there is a fault according to the three-phase currents of the motor, and then further distinguishing which fault exists in combination with the rotation speed, torque and phase difference between the three phases of the motor, and realizing the technical effect of accurately detecting the open-phase fault under the locked-rotor working condition of the motor in combination with the phase difference, and improving the identification precision and anti-interference ability of the open-phase fault under the locked-rotor working condition of the motor.

[0049] Therefore, by the technical solutions provided in the above embodiments of the present application, the technical problem in the related art that the motor fault detection is prone to misjudgment, which affects the normal operation of the motor by using the wrong protection mechanism, is solved.

[0050] ​​​​​​It should be noted that the technical solutions provided by the above embodiments of the present application are not only applicable to permanent magnet synchronous motors, but also can be applied to other types of alternating current motors, including but not limited to induction motors (IM), brushless direct current motors (BLDC) and synchronous reluctance motors (SRM) and the like; in actual application, appropriate adjustment and calibration also need to be made according to the electrical characteristics, control requirements and working conditions of the specific motor; for example, the rated current, voltage and frequency of different motors can be quite different, and the set threshold values (such as current amplitude threshold value and phase difference range) also need to be optimized according to the specific parameters of the motor.

[0051] In an optional embodiment of the present application, during the operation of the motor, the three-phase currents of the motor are obtained according to a predetermined time period, including: during the operation of the motor, the current sensor arranged in each phase of the motor is used to synchronously sample the corresponding current to obtain three-phase current signals; the three-phase current signals are analog-to-digital converted to obtain corresponding digital signals; and the digital signals are normalized to obtain three-phase currents.

[0052] In this embodiment, the current sensors arranged in each phase of the motor can be used to synchronously collect three-phase current data at a sampling rate of 1 kHz, and then the 12-bit ADC is used to convert the digital signals and perform normalization processing, which can be normalized to the range of [-1, 1] to obtain three-phase current values for subsequent analysis and processing.

[0053] Specifically, high-precision current sensors can be used to monitor three-phase currents in real time, and these sensors can collect current data at a sampling rate of 1 kHz to ensure that the rapid changes of the current can be captured, which is crucial for early detection of open-phase faults; in order to facilitate subsequent digital signal processing, a 12-bit ADC can be used to convert the collected analog current signals into digital signals to provide higher resolution and ensure that the accuracy of the collected data meets the requirements of open-phase fault detection; after conversion, the digital signals can also be normalized, which usually limits the signal range to between [-1, 1], not only making signal processing more convenient, but also eliminating the differences in current signal amplitudes under different motors or different operating conditions, avoiding affecting the subsequent threshold judgment.

[0054] In a specific embodiment of the present application, after obtaining the current speed and output torque of the motor, the fault determination method of the permanent magnet synchronous motor further comprises: obtaining a preset speed threshold and a preset torque threshold; in the case that the speed is lower than the preset speed threshold and the output torque is higher than the preset torque threshold for a first duration higher than a first preset duration threshold, it is determined that the motor is currently in a locked-rotor operating condition; in the case that the speed is not lower than the preset speed threshold and the output torque is not higher than the preset torque threshold or the output torque is higher than the preset torque threshold for a first duration not higher than the first preset duration threshold, it is determined that the motor is not currently in a locked-rotor operating condition.

[0055] In this embodiment, when the real-time rotating speed of the motor continuously is lower than the preset rotating speed threshold value and the actual output torque continuously is higher than the preset torque threshold value, it can be considered that the motor enters the stall condition; the threshold value can be set according to the motor parameters, and the preset rotating speed threshold value can be usually set as a value slightly greater than 0 rpm, such as 50 rpm, and the preset torque threshold value can be usually set as half of the peak torque of the motor, which is only an optional example and is not limited specifically.

[0056] In an optional embodiment of the present application, the fault determination method of the permanent magnet synchronous motor further comprises: in the case of determining that the motor is in the stall condition according to the rotating speed and the output torque, storing the three-phase currents into a ring buffer, wherein the ring buffer is used to store a fixed number of continuous data samples; when the data in the ring buffer reaches a preset data capacity, performing Fourier transform on the stored three-phase currents to obtain the phase of each phase current in the three-phase currents; calculating the phase difference between any two phases according to the phase; and judging whether the phase difference satisfies a preset open-phase condition to obtain a judgment result.

[0057] In this embodiment, in the case of determining that the motor is in the stall condition, the phase angle of the fundamental frequency of the three-phase currents can be obtained by the sliding window Fourier transform method, and the accurate judgment of the open-phase fault can be realized by combining the phase difference analysis; specifically, the obtained three-phase current data can be cached into a ring buffer with a length of 1024 points by using DMA (Direct Memory Access), which corresponds to 1.024 seconds in length at 50 Hz, and the 512-point step sliding is used to ensure the 50% data overlap rate; when the window is filled, the FFT processing is triggered to perform the fast Fourier transform on the 1024-point time domain data to calculate the phase of the three-phase currents at the same time, and further calculate the phase difference between each two-phase currents. Then, it can be judged whether the calculated phase difference satisfies the open-phase condition to obtain the corresponding judgment result.

[0058] In the above-mentioned embodiments of the present application, when the data in the ring buffer reaches the preset data capacity, the Fourier transform is performed on the stored three-phase currents to obtain the phase of each phase current in the three-phase currents, which comprises: when the data in the ring buffer reaches the preset data capacity, the Fourier transform is performed on the stored three-phase currents to obtain the fundamental component corresponding to each phase current, wherein the fundamental component represents the main frequency information of each phase current; and the phase corresponding to each phase current is determined according to the fundamental component by using a first formula, wherein the expression of the fundamental component is: , the first formula is: i represents the label of each phase current, represents the phase corresponding to the i-th phase current, is the real part of the fundamental component of the i-th phase current,​​ Let j be the imaginary part of the fundamental component of the i-th phase current, and j be the imaginary unit.

[0059] Specifically, when obtaining the phase of the three-phase current using the sliding window Fourier transform method, FFT processing can be triggered when the window is full. A Fast Fourier Transform is performed on the 1024-point time-domain data to extract the fundamental (50Hz) component of each phase current. The fundamental component corresponds to the 51st index position in the FFT output (calculated as: fundamental frequency × number of sampling points / sampling rate = 50 × 1024 / 1000 = 51.2, rounded to 51). The complex result of the fundamental current for each phase is obtained through complex decomposition. Then, the four-quadrant arctangent function is used. Calculate the phase of the three-phase current at the same moment.

[0060] In one specific embodiment of this application, determining whether the phase difference meets the preset phase loss condition and obtaining the determination result includes: if at least one phase difference exceeds the preset phase difference range and the duration of the exceedance exceeds the second preset duration threshold, determining that the phase difference meets the preset phase loss condition; if any phase difference does not exceed the preset phase difference range or the duration of the exceedance of the preset phase difference range does not exceed the second preset duration threshold, determining that the phase difference does not meet the preset phase loss condition.

[0061] In this embodiment, since the phase difference between any two phases of the motor is generally 120°, in order to adapt to ±20° load fluctuations, the normal phase difference range can be set to [100°, 140°]. At the same time, in order to avoid erroneous judgments caused by instantaneous interference, the phase difference judgment should be continuously performed within a certain time window. Therefore, if the phase difference between two phases of the current in the motor exceeds the preset phase difference range [100°, 140°], and the duration of the excess (i.e., the above-mentioned excess duration) reaches 0.5 seconds or more, it can be considered that the phase difference of the motor meets the preset phase loss condition, indicating that there is a phase loss fault; otherwise, it is considered that the phase difference of the motor meets the preset phase loss condition.

[0062] In an optional embodiment of this application, the fault determination method for the permanent magnet synchronous motor further includes: controlling the motor to perform a phase loss protection operation when a phase loss fault exists in the motor; controlling the motor to perform a stall protection operation when a stall fault exists in the motor; controlling the motor to perform a stall protection operation and then re-perform phase loss detection to obtain a detection result when both a phase loss fault and a stall fault exist in the motor; controlling the motor to perform a phase loss protection operation when both phase loss fault and stall fault exist in the motor, and recording fault information when both phase loss fault and / or stall fault exist in the motor.

[0063] like Figure 3 As shown, if a single-phase fault is detected in the motor, the motor can be controlled to perform a single-phase protection operation, such as immediately stopping the motor to prevent overheating or damage due to the single-phase fault. If a single-phase stall fault is detected in the motor, the motor can be controlled to perform a stall protection operation, such as gradually reducing the motor's power supply voltage or current to allow the motor to operate at a lower power, thus ensuring a certain level of safety while also providing the operator with time to identify and handle the stall situation. If both a stall fault and a single-phase fault are detected in the motor, stall protection measures may be implemented first to prevent motor damage. Then, the phase difference is monitored to confirm whether the single-phase fault still exists. If it still exists, the single-phase protection action is continued. If it does not exist, the motor can be controlled to maintain its current state.

[0064] It should be noted that locked rotor faults and phase loss faults are not directly related. In a few cases, phase loss faults may be resolved along with the locked rotor condition, but in most cases they may not be resolved. Therefore, after performing locked rotor protection operation, it is necessary to reconfirm whether the current phase loss fault still exists.

[0065] For example, in some cases, if the stall is caused by an excessive load, which in turn causes a circuit overload, this may indirectly exacerbate the phase loss. However, usually, relieving the stall does not directly fix the circuit problem, so the phase loss fault may still exist. In some special cases, such as when the phase loss is caused by the failure of a component inside the motor due to overheating, and this overheating is due to the high temperature environment during stall increasing the load on the component, relieving the stall may indirectly lower the motor temperature, thereby restoring the previously overheated component to a certain degree of functionality. In this case, the phase loss fault may be mitigated or eliminated as the stall is resolved.

[0066] In addition, in the case where it is detected that the motor has a fault, a warning signal can also be sent and fault information can be recorded to remind the staff to analyze and handle the fault in time.

[0067] It should be noted that, for the foregoing method embodiments, in order to simply describe, they are all expressed as a series of action combinations, but those skilled in the art should know that the present application is not limited to the action sequence described, because according to the present application, certain steps can be performed in other sequences or simultaneously. Secondly, those skilled in the art should know that the embodiments described in the specification are all preferred embodiments, and the actions and modules involved are not necessarily essential to the present application.

[0068] From the above description of the embodiments, those skilled in the art can clearly understand that the method according to the above embodiments can be realized by means of software and the necessary general hardware platform, of course, it can also be realized by hardware, but in many cases the former is a better embodiment. Based on such understanding, the technical solutions of the present application can be embodied in the form of a software product in essence or the part that contributes to the prior art, which is stored in a storage medium (such as ROM / RAM, magnetic disk, optical disk), and includes a number of instructions to make a terminal device (which can be a mobile phone, computer, server, or network device, etc.) execute the methods described in the embodiments of the present application.

[0069] According to the embodiments of the present application, a fault determination device of a permanent magnet synchronous motor is also provided, Figure 4 is a schematic diagram of the fault determination device of the permanent magnet synchronous motor according to the embodiments of the present application, as Figure 4 shown, the device includes a first acquisition unit 41, a second acquisition unit 43, a first determination unit 45, and a second determination unit 47. The fault determination device of the permanent magnet synchronous motor will be described in detail below.

[0070] The first acquisition unit 41 is configured to acquire three-phase currents of the motor according to a predetermined time period during operation of the motor.

[0071] The second acquisition unit 43 is configured to acquire a current speed and output torque of the motor in the case where a maximum current in the three-phase currents exceeds an upper current threshold and a minimum current in the three-phase currents is lower than a lower current threshold.

[0072] The first determination unit 45 is configured to determine that the motor currently has an open-phase fault in the case where it is determined according to the speed and the output torque that the motor is not in a locked-rotor operating condition.

[0073] The second determining unit 47 is configured to, in the case that the motor is determined to be in the locked-rotor working condition according to the rotation speed and the output torque, determine that the motor currently has the locked-rotor fault if the phase difference between any two phases of the motor does not satisfy the preset open-phase condition, and determine that the motor currently has both the locked-rotor fault and the open-phase fault if at least one phase difference satisfies the preset open-phase condition.

[0074] It should be noted that the first obtaining unit 41, the second obtaining unit 43, the first determining unit 45 and the second determining unit 47 correspond to steps S202 to S208 in the above embodiment, and the four units have the same examples and application scenarios as the corresponding steps, but are not limited to the content disclosed in the above embodiment.

[0075] As can be seen from the above, in the scheme disclosed in the above embodiment, the first obtaining unit is used to obtain the three-phase current of the motor in the process of motor operation according to a predetermined time period; the second obtaining unit is used to obtain the current rotation speed and output torque of the motor in the case that the maximum current in the three-phase current exceeds the upper current threshold and the minimum current in the three-phase current is lower than the lower current threshold; the first determining unit is used to determine that the motor currently has the open-phase fault in the case that the motor is determined not to be in the locked-rotor working condition according to the rotation speed and the output torque; and the second determining unit is used to determine that the motor currently has the locked-rotor fault if the phase difference between any two phases of the motor does not satisfy the preset open-phase condition, and determine that the motor currently has both the locked-rotor fault and the open-phase fault if at least one phase difference satisfies the preset open-phase condition, in the case that the motor is determined to be in the locked-rotor working condition according to the rotation speed and the output torque. Thus, the purpose of initially judging whether there is a fault according to the three-phase current of the motor, and then further distinguishing which fault exists by combining the rotation speed, the torque and the phase difference between the three phases of the motor is achieved, the technical effect of accurately detecting the open-phase fault in the locked-rotor working condition of the motor by combining the phase difference is achieved, and the identification precision and the anti-interference ability of the open-phase fault in the locked-rotor working condition of the motor are improved.

[0076] Therefore, the technical scheme provided in the above embodiment solves the technical problem in the related art that the motor fault detection is prone to misjudgment, and thus the normal operation of the motor is affected by using the wrong protection mechanism.

[0077] In an optional embodiment of the present application, the first obtaining unit comprises: a first obtaining module configured to obtain the three-phase current signal by synchronously sampling the current of each phase of the motor using the current sensor arranged in each phase of the motor in the process of motor operation; a second obtaining module configured to perform analog-to-digital conversion on the three-phase current signal to obtain a corresponding digital signal; and a third obtaining module configured to perform normalization processing on the digital signal to obtain the three-phase current.

[0078] In an optional embodiment of the present application, the fault determination apparatus of the permanent magnet synchronous motor further comprises: a third acquisition unit, configured to acquire a preset speed threshold and a preset torque threshold after acquiring the current speed and output torque of the motor; a third determination unit, configured to determine that the motor is currently in the locked-rotor operating condition if the speed is lower than the preset speed threshold and the output torque is higher than the preset torque threshold for a first duration higher than a first preset duration threshold; and a fourth determination unit, configured to determine that the motor is not currently in the locked-rotor operating condition if the speed is not lower than the preset speed threshold and the output torque is not higher than the preset torque threshold or the output torque is higher than the preset torque threshold for a first duration not higher than the first preset duration threshold.

[0079] In an optional embodiment of the present application, the fault determination apparatus of the permanent magnet synchronous motor further comprises: a storage unit, configured to store the three-phase current into a ring buffer if it is determined that the motor is in the locked-rotor operating condition according to the speed and the output torque, wherein the ring buffer is configured to store a fixed number of continuous data samples; a fourth acquisition unit, configured to perform Fourier transform on the stored three-phase current to obtain the phase of each phase current in the three-phase current when the data in the ring buffer reaches a preset data capacity; a calculation unit, configured to calculate the phase difference between any two phases according to the phase; and a fifth acquisition unit, configured to determine whether the phase difference meets a preset open-phase condition to obtain a determination result.

[0080] In an optional embodiment of the present application, the fourth acquisition unit comprises: a fourth acquisition module, configured to perform Fourier transform on the stored three-phase current to obtain a fundamental component corresponding to each phase current when the data in the ring buffer reaches the preset data capacity, wherein the fundamental component represents the main frequency information of each phase current; and a first determination module, configured to determine the phase corresponding to each phase current according to the fundamental component by using a first formula, wherein the expression of the fundamental component is: , the first formula is: , i represents the index of each phase current, represents the phase corresponding to the i-th phase current, is the real part of the fundamental component of the i-th phase current, is the imaginary part of the fundamental component of the i-th phase current, and j is an imaginary unit.

[0081] In an optional embodiment of the present application, the fifth acquisition unit comprises: a second determination module, configured to determine that the determination result is that the phase difference meets the preset open-phase condition if at least one phase difference exceeds the preset phase difference range and the exceeding duration exceeds a second preset duration threshold; and a third determination module, configured to determine that the determination result is that the phase difference does not meet the preset open-phase condition if none of the phase differences exceeds the preset phase difference range or the exceeding duration of the phase difference exceeding the preset phase difference range does not exceed the second preset duration threshold.

[0082] In an optional embodiment of the present application, the fault determination apparatus of the permanent magnet synchronous motor further comprises: a first control unit configured to control the motor to perform an open-phase protection operation in the case that the motor currently has an open-phase fault; a second control unit configured to control the motor to perform a locked-rotor protection operation in the case that the motor currently has a locked-rotor fault; a third control unit configured to control the motor to perform the locked-rotor protection operation and then perform open-phase detection in the case that the motor currently has both the open-phase fault and the locked-rotor fault, and obtain a detection result, wherein the open-phase detection is a process of detecting whether the current three-phase currents exceed the upper current threshold value and the lower current threshold value; a fourth control unit configured to control the motor to perform the open-phase protection operation in the case that the detection result indicates that the motor currently still has the open-phase fault, and control the motor to maintain the current operating state in the case that the detection result indicates that the motor currently does not have the open-phase fault; and a pre-warning unit configured to issue a fault pre-warning signal and record fault information in the case that the motor currently has the open-phase fault and / or the locked-rotor fault.

[0083] According to another aspect of the embodiments of the present application, there is also provided a fault determination system of a permanent magnet synchronous motor, which uses any of the above fault determination methods of the permanent magnet synchronous motor.

[0084] According to another aspect of the embodiments of the present application, there is also provided a computer-readable storage medium comprising a stored program, wherein the program executes any of the above fault determination methods of the permanent magnet synchronous motor.

[0085] Optionally, in the present embodiment, the above computer-readable storage medium can be located in any of the computer terminals in a computer terminal group in a computer network, or in any of the communication devices in a communication device group.

[0086] Optionally, in the present embodiment, the computer-readable storage medium is configured to store program code for performing the following steps: obtaining the three-phase currents of the motor according to a predetermined time period during the operation of the motor; obtaining the current speed and output torque of the motor in the case that the maximum current in the three-phase currents exceeds the upper current threshold value and the minimum current in the three-phase currents is lower than the lower current threshold value; determining that the motor currently has an open-phase fault in the case that the motor is determined not to be in a locked-rotor operating condition according to the speed and the output torque; and determining that the motor currently has a locked-rotor fault and an open-phase fault in the case that the motor is determined to be in the locked-rotor operating condition according to the speed and the output torque, and at least one of the phase differences between any two phases of the motor satisfies a preset open-phase condition.

[0087] Optionally, in the embodiment, the computer readable storage medium is configured to store program code for performing the following steps: obtaining three-phase current signals by synchronously sampling currents of each phase of the motor using current sensors arranged in the motor during operation of the motor; performing analog-to-digital conversion on the three-phase current signals to obtain corresponding digital signals; and performing normalization processing on the digital signals to obtain the three-phase current.

[0088] Optionally, in the embodiment, the computer readable storage medium is configured to store program code for performing the following steps: obtaining a preset speed threshold and a preset torque threshold; determining that the motor is currently in a locked-rotor operating condition when the speed is lower than the preset speed threshold and a first duration during which the output torque is higher than the preset torque threshold is higher than a first preset duration threshold; and determining that the motor is not currently in the locked-rotor operating condition when the speed is not lower than the preset speed threshold and the output torque is not higher than the preset torque threshold or a first duration during which the output torque is higher than the preset torque threshold is not higher than the first preset duration threshold.

[0089] Optionally, in the embodiment, the computer readable storage medium is configured to store program code for performing the following steps: storing the three-phase current to a ring buffer when it is determined that the motor is in the locked-rotor operating condition according to the speed and the output torque, wherein the ring buffer is used to store a fixed number of continuous data samples; performing Fourier transform on the stored three-phase current to obtain a phase of each phase current of the three-phase current when data in the ring buffer reaches a preset data capacity; calculating a phase difference between any two phases according to the phase; and determining whether the phase difference satisfies a preset open-phase condition to obtain a determination result.

[0090] Optionally, in the embodiment, the computer readable storage medium is configured to store program code for performing the following steps: performing Fourier transform on the stored three-phase current to obtain a fundamental component corresponding to each phase current when data in the ring buffer reaches a preset data capacity, wherein the fundamental component represents main frequency information of each phase current; and determining a phase corresponding to each phase current according to the fundamental component using a first formula, wherein an expression of the fundamental component is: , the first formula is: i represents a label of each phase current, represents a phase corresponding to the i-th phase current, is a real part of the fundamental component of the i-th phase current, is an imaginary part of the fundamental component of the i-th phase current, and j is an imaginary unit.

[0091] Optionally, in the embodiment, the computer readable storage medium is configured to store program code for performing the following steps: determining that the phase difference meets the preset open-phase condition when at least one phase difference exceeds the preset phase difference range and the exceeding duration exceeds the second preset duration threshold; determining that the phase difference does not meet the preset open-phase condition when none of the phase differences exceeds the preset phase difference range or the exceeding duration of the phase difference that exceeds the preset phase difference range does not exceed the second preset duration threshold.

[0092] Optionally, in the embodiment, the computer readable storage medium is configured to store program code for performing the following steps: controlling the motor to perform the open-phase protection operation when the motor currently has the open-phase fault; controlling the motor to perform the stall protection operation when the motor currently has the stall fault; controlling the motor to perform the stall protection operation and then re-performing the open-phase detection to obtain a detection result when the motor currently has both the open-phase fault and the stall fault, wherein the open-phase detection is a process of detecting whether the current three-phase currents exceed the upper and lower current thresholds; controlling the motor to perform the open-phase protection operation when the detection result indicates that the motor currently has the open-phase fault, and controlling the motor to keep the current running state when the detection result indicates that the motor currently does not have the open-phase fault; and issuing a fault warning signal and recording fault information when the motor currently has the open-phase fault and / or the stall fault.

[0093] According to another aspect of the embodiments of the present application, a processor is also provided, which is configured to run a program, wherein the program performs any one of the above-mentioned fault determination methods for the permanent magnet synchronous motor when running.

[0094] According to another aspect of the embodiments of the present application, a computer program product is also provided, which includes computer instructions, and the computer instructions perform any one of the above-mentioned fault determination methods for the permanent magnet synchronous motor when executed by a processor.

[0095] The above-mentioned serial numbers of the embodiments of the present application only serve for description, and do not represent the advantages or disadvantages of the embodiments.

[0096] In the above-mentioned embodiments of the present application, the description of each embodiment has its own focus, and the parts not described in detail in a certain embodiment can be referred to the relevant description of other embodiments.

[0097] In several embodiments provided in the present application, it should be understood that the disclosed technical contents can be implemented by other manners. Among them, the above-described device embodiments are only illustrative, for example, the division of the units can be a logical function division, and actual implementation can have another division manner, for example, a plurality of units or components can be combined or integrated into another system, or some features can be ignored or not executed. In addition, the coupling or direct coupling or communication connection between the units or modules shown or discussed can be indirect coupling or communication connection between the units or modules through some interfaces, and can be electrical or other forms.

[0098] The technical features of the above-described embodiments can be combined arbitrarily. In order to make the description simple, all possible combinations of the technical features in the above-described embodiments are not described, however, as long as the combination of the technical features does not exist contradictory, it should be considered as the scope of the present disclosure.

[0099] The units described as separate components can or can not be physically separated, and the components shown as units can or can not be physical units, that is, they can be located in one place, or they can be distributed to multiple units. Part or all of the units can be selected to achieve the purpose of the embodiment scheme according to actual needs.

[0100] In addition, the functional units in each embodiment of the present application can be integrated in one processing unit, or each unit can exist physically, or two or more units can be integrated in one unit. The integrated unit can be realized in the form of hardware or in the form of a software functional unit.

[0101] The integrated unit, if realized in the form of a software functional unit and sold or used as an independent product, can be stored in a computer-readable storage medium. Based on this understanding, the technical solutions of the present application essentially or the part of the prior art that makes a contribution or the whole or part of the technical solutions can be embodied in the form of a software product. The computer software product is stored in a storage medium and includes a plurality of instructions for causing a computer device (which can be a personal computer, a server or a network device, etc.) to execute all or part of the steps of the method described in each embodiment of the present application. The foregoing storage medium includes: a U disk, a read-only memory (ROM), a random access memory (RAM), a mobile hard disk, a magnetic disk or an optical disk, and various media that can store program codes.

[0102] The above merely describes the preferred embodiments of the present application, and it should be pointed out that, for those skilled in the art, some improvements and refinements can be made without departing from the principles of the present application, and these improvements and refinements should also be considered as the protection scope of the present application.

Claims

1. A method for determining faults in a permanent magnet synchronous motor, characterized in that, include: During the operation of the motor, the three-phase current of the motor is acquired according to a predetermined time period; When the maximum current in the three-phase current exceeds the upper limit current threshold and the minimum current in the three-phase current is lower than the lower limit current threshold, the current speed and output torque of the motor are obtained. If it is determined that the motor is not in a stalled condition based on the speed and the output torque, it is determined that the motor currently has a phase loss fault; If the motor is determined to be in the stall condition based on the rotational speed and the output torque, and if the phase difference between any two phases of the motor does not meet the preset phase loss condition, then the motor is determined to have a stall fault. If at least one phase difference meets the preset phase loss condition, then the motor is determined to have both the stall fault and the phase loss fault.

2. The fault determination method for a permanent magnet synchronous motor according to claim 1, characterized in that, During motor operation, the three-phase current of the motor is acquired according to a predetermined time period, including: During the operation of the motor, the corresponding current is sampled synchronously using a current sensor installed in each phase of the motor to obtain a three-phase current signal; The three-phase current signals are converted from analog to digital to obtain the corresponding digital signals; The digital signal is normalized to obtain the three-phase current.

3. The fault determination method for a permanent magnet synchronous motor according to claim 1, characterized in that, After obtaining the current speed and output torque of the motor, the method further includes: Obtain preset speed thresholds and preset torque thresholds; If the rotational speed is lower than the preset rotational speed threshold and the output torque is higher than the preset torque threshold for a first duration that is higher than the first preset duration threshold, it is determined that the motor is currently in the stall condition. If the rotational speed is not lower than the preset rotational speed threshold and the output torque is not higher than the preset torque threshold, or if the first duration for which the output torque is higher than the preset torque threshold is not higher than the first preset duration threshold, it is determined that the motor is not currently in the stall condition.

4. The fault determination method for a permanent magnet synchronous motor according to claim 1, characterized in that, The method further includes: When it is determined that the motor is in the stall condition based on the rotational speed and the output torque, the three-phase current is stored in an annular buffer, wherein the annular buffer is used to store a fixed number of continuous data samples; When the data in the ring buffer reaches the preset data capacity, a Fourier transform is performed on the stored three-phase current to obtain the phase of each phase current in the three-phase current. Calculate the phase difference between any two phases based on the phase; Determine whether the phase difference meets the preset phase loss condition, and obtain the determination result.

5. The fault determination method for a permanent magnet synchronous motor according to claim 4, characterized in that, When the data in the annular buffer reaches a preset data capacity, a Fourier transform is performed on the stored three-phase currents to obtain the phase of each phase current, including: When the data in the ring buffer reaches the preset data capacity, the stored three-phase current is subjected to Fourier transform to obtain the fundamental component corresponding to each phase current, wherein the fundamental component represents the main frequency information of each phase current. The phase corresponding to each phase current is determined using the first formula based on the fundamental component, wherein the expression for the fundamental component is: The first formula is: , i represents the label of each phase current, The term represents the phase corresponding to the i-th phase current. Let the real part of the fundamental component of the i-th phase current be denoted as . Let j be the imaginary part of the fundamental component of the i-th phase current, where j is the imaginary unit.

6. The fault determination method for a permanent magnet synchronous motor according to claim 4, characterized in that, Determining whether the phase difference meets the preset phase loss condition and obtaining the determination result includes: If at least one of the phase differences exceeds the preset phase difference range and the duration of the excess exceeds the second preset duration threshold, the determination result is that the phase difference satisfies the preset phase loss condition. If any of the phase differences does not exceed the preset phase difference range, or if the duration of the phase difference exceeding the preset phase difference range does not exceed the second preset duration threshold, the determination result is that the phase difference does not meet the preset phase loss condition.

7. The fault determination method for a permanent magnet synchronous motor according to claim 1, characterized in that, The method further includes: When the motor is currently experiencing a phase loss fault, control the motor to perform a phase loss protection operation; If the motor is currently experiencing a stall fault, control the motor to perform a stall protection operation; When the motor is currently experiencing both the phase loss fault and the stall fault, the motor is controlled to perform the stall protection operation and then the phase loss detection is performed again to obtain the detection result. The phase loss detection is the process of detecting whether the current three-phase current exceeds the upper limit current threshold and the lower limit current threshold. If the detection result indicates that the motor still has the phase loss fault, control the motor to perform the phase loss protection operation; if the detection result indicates that the motor does not currently have the phase loss fault, control the motor to maintain the current operating state. If the motor is currently experiencing the phase loss fault and / or the stall fault, a fault warning signal is issued and the fault information is recorded.

8. A fault determination device for a permanent magnet synchronous motor, characterized in that, include: The first acquisition unit is used to acquire the three-phase current of the motor according to a predetermined time period during the operation of the motor. The second acquisition unit is used to acquire the current speed and output torque of the motor when the maximum current in the three-phase current exceeds the upper limit current threshold and the minimum current in the three-phase current is lower than the lower limit current threshold. The first determining unit is used to determine that the motor currently has a phase loss fault when it is determined from the speed and the output torque that the motor is not in a stall condition; The second determining unit is used to determine that the motor currently has a stall fault when the motor is determined to be in the stall condition based on the rotational speed and the output torque. If the phase difference between any two phases of the motor does not meet the preset phase loss condition, the motor currently has both the stall fault and the phase loss fault.

9. A computer-readable storage medium, characterized in that, The computer-readable storage medium includes a stored program, wherein the program executes the fault determination method for a permanent magnet synchronous motor according to any one of claims 1 to 7.

10. A computer program product comprising computer instructions, characterized in that, When the computer instructions are executed by the processor, the fault determination method for the permanent magnet synchronous motor according to any one of claims 1 to 7 is performed.

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