Fault pole positioning method for partial demagnetization of rotor of multi-pair pole permanent magnet synchronous motor

Abstract

This application relates to a method for locating faulty magnetic poles in the case of partial demagnetization of the rotor of a multi-pole permanent magnet synchronous motor. The permanent magnet synchronous motor includes at least one detection coil. The method includes: calculating a demagnetization fault monitoring quantity based on the voltages at multiple ports of the at least one detection coil; calculating a demagnetization fault alarm value based on multiple rotor position signals of the permanent magnet synchronous motor; obtaining the sensitivity of demagnetization fault monitoring based on the ratio of the demagnetization fault monitoring quantity to the demagnetization fault alarm value; when the sensitivity meets a preset demagnetization condition; obtaining the mechanical angle between the center line of the reference magnetic pole of the permanent magnet synchronous motor and the center line of the at least one detection coil by extracting the instantaneous values ​​of the first and second fractional harmonics from multiple preset power frequency cycles; and locating the faulty magnetic pole based on the mechanical angle. This method solves the problem of fault deterioration caused by long-term demagnetization operation of the motor, improves the efficiency of demagnetization fault repair in multi-pole permanent magnet synchronous motors, and enhances the safety and reliability of permanent magnet synchronous motor operation.

Description

Technical Field

[0001] This application relates to the field of relay protection technology for power system equipment, and in particular to a fault magnetic pole location method for partial demagnetization of the rotor of a multi-pole permanent magnet synchronous motor. Background Technology

[0002] Permanent magnet synchronous motors (PMSMs) are increasingly widely used in various fields such as new energy power generation, electric vehicle drive, aerospace, and rail transportation due to their advantages of high power density, high efficiency, high reliability, and high torque. In PMSMs, permanent magnets are essential for normal operation. However, due to improper motor design or permanent magnet manufacturing processes, magnet aging, excessively high motor operating temperature, mechanical vibration, or external or internal faults, the permanent magnets may experience localized weakening of magnetism or even complete demagnetization. Once an irreversible demagnetization fault occurs, it severely affects the motor's load-carrying capacity. Furthermore, prolonged operation under fault conditions can lead to increased armature current (due to multi-branching), resulting in overheating; decreased average torque, resulting in increased pulsating torque; and intensified mechanical vibration. In severe cases, it can even burn out the PMSM.

[0003] There are two main types of demagnetization faults in permanent magnet synchronous motors: uniform demagnetization faults and localized demagnetization faults. The former refers to the demagnetization of permanent magnets under all poles of the motor, and the degree of demagnetization is the same. This has a very low probability of occurring in actual motor operation. More common is the localized demagnetization fault, in which only some magnetic poles are demagnetized, and demagnetization often starts from pole 1. If it is detected early and the machine is stopped for maintenance, the irreversible serious consequences of the demagnetization fault spreading to other poles can be avoided.

[0004] In related technologies, a method for arranging detection coils that can simultaneously detect internal short circuits in the generator stator and rotor is proposed. A novel detection coil is proposed, which adopts a special arrangement based on the number of pole pairs of the motor and the distribution and connection method of the stator windings. Theoretically, the port voltage of this detection coil is 0 when the motor is running normally; however, once the air gap magnetic field undergoes asymmetrical distortion, an AC voltage with a specific period will appear at the port of the detection coil.

[0005] If the aforementioned novel detection coil is installed in a multi-pole permanent magnet synchronous motor, under normal operating conditions, the symmetrical air gap magnetic field will not generate a port voltage in the detection coil. However, when the motor experiences rotor demagnetization, (the probability that the permanent magnets under all poles will demagnetize to the same degree is very small) the magnetic field distribution under each pole will no longer be the same. In addition to the fundamental wave, the air gap magnetic field will also exhibit fractional harmonics of the 1 / P order (P is the number of pole pairs of the motor), 2 / P order, etc. These fault-related additional harmonic magnetic fields will induce corresponding harmonic induced electromotive forces in the detection coil. Therefore, the different fractional harmonics (including the 1 / P order and other fractional harmonics) in the port voltage of the detection coil can be used as fault characteristic quantities of rotor demagnetization in permanent magnet synchronous motors.

[0006] Related technologies also propose a method and system for monitoring rotor demagnetization faults in permanent magnet synchronous motors. The aforementioned novel detection coil can detect local demagnetization faults in permanent magnet synchronous motors online.

[0007] Given that the permanent magnet propulsion motors used on ships have low speeds and a large number of poles, it is urgent to solve the problem of how to locate the demagnetized pole and effectively reduce downtime for inspection and maintenance. Summary of the Invention

[0008] This application provides a fault magnetic pole location method for partial demagnetization of the rotor of a multi-pole permanent magnet synchronous motor, in order to solve the problem of fault deterioration caused by long-term demagnetization operation of the motor, improve the demagnetization fault repair efficiency of the multi-pole permanent magnet synchronous motor, and improve the safety and reliability of the permanent magnet synchronous motor operation.

[0009] The first aspect of this application provides a method for locating faulty magnetic poles in a multi-pole permanent magnet synchronous motor where the rotor experiences partial demagnetization. The permanent magnet synchronous motor contains at least one detection coil. The method includes the following steps:

[0010] Collect multiple port voltages of the at least one detection coil and multiple rotor position signals of the permanent magnet synchronous motor;

[0011] The loss-of-excitation fault monitoring quantity is calculated based on the multiple port voltages, and the loss-of-excitation fault alarm value is calculated based on the multiple rotor position signals. The sensitivity of the loss-of-excitation fault monitoring is obtained based on the ratio of the loss-of-excitation fault monitoring quantity to the loss-of-excitation fault alarm value.

[0012] When the sensitivity of the loss of excitation fault monitoring meets the preset loss of excitation conditions, the instantaneous values ​​of the first fractional harmonic and the second fractional harmonic are extracted from multiple preset power frequency cycles. Based on the instantaneous values ​​of the first and second fractional harmonics, the mechanical angle by which the center line of the reference magnetic pole of the permanent magnet synchronous motor leads the center line of at least one detection coil is obtained, and the fault magnetic pole is located based on the mechanical angle.

[0013] According to one embodiment of this application, the step of calculating the demagnetization fault monitoring quantity based on the plurality of port voltages and calculating the demagnetization fault alarm value based on the plurality of rotor position signals includes:

[0014] The effective values ​​of multiple fractional harmonic voltages of the port voltages are obtained based on the multiple port voltages, and the actual speed of the permanent magnet synchronous motor is calculated based on the multiple rotor position signals.

[0015] The demagnetization fault monitoring value is calculated based on the effective values ​​of multiple fractional harmonic voltages of the port voltage, and the demagnetization fault alarm value is calculated based on the actual rotational speed.

[0016] According to one embodiment of this application, the formula for calculating the loss of excitation fault monitoring quantity is as follows:

[0017]

[0018] Where K is a natural number, N is the set of natural numbers, and P is the extreme pair number. The effective value of the K / P harmonic voltage in the port voltage;

[0019] The formula for calculating the demagnetization fault alarm value is:

[0020]

[0021] Among them, K tol U is the reliability coefficient for loss-of-excitation fault monitoring, n is the actual speed of the permanent magnet synchronous motor, and u is the reliability coefficient for loss-of-excitation fault monitoring. d_normal n represents the total effective value of the inherent voltage at the probe coil port during normal motor operation (during calibration parameters). normal For u d_normal The corresponding motor speed.

[0022] According to one embodiment of this application, after the sensitivity of the demagnetization fault monitoring meets the preset demagnetization condition, the method further includes:

[0023] Generate a demagnetization fault alarm signal and perform a demagnetization fault alarm based on the demagnetization fault alarm signal.

[0024] According to one embodiment of this application, the step of obtaining the mechanical angle by which the center line of the permanent magnet synchronous motor reference pole leads the center line of at least one detection coil based on the instantaneous values ​​of the first and second fractional harmonics includes:

[0025] Obtain the target time when the instantaneous values ​​of the first and second fractional harmonics are equal and their derivatives have the same sign;

[0026] The mechanical angle by which the center line of the reference magnetic pole of the permanent magnet synchronous motor leads the center line of at least one detection coil is obtained based on the rotor position signal corresponding to the target time.

[0027] According to one embodiment of this application, the fault magnetic pole location based on the mechanical angle includes:

[0028] The faulty magnetic pole that has lost its magnetism is located according to the mechanical angle described above;

[0029] The faulty magnetic pole is located based on its faulty magnetic pole number.

[0030] According to one embodiment of this application, the step of locating the faulty magnetic pole number that has lost magnetism based on the mechanical angle includes:

[0031] Based on a preset fault pole location formula, the faulty magnetic pole number that has lost magnetism is located according to the mechanical angle, wherein the preset fault pole location formula is:

[0032]

[0033] Where θ is the rotor position signal, and i is the number of poles in which the reference pole leads the faulty pole.

[0034] The fault pole location method for partial rotor demagnetization of a multi-pole permanent magnet synchronous motor (PMSM) proposed in the embodiments hereby describes a method for fault pole location based on a method that includes at least one detection coil within the PMSM. The method calculates a demagnetization fault monitoring quantity based on the voltages at multiple ports of the at least one detection coil, and calculates a demagnetization fault alarm value based on multiple rotor position signals of the PMSM. The sensitivity of the demagnetization fault monitoring is obtained based on the ratio of the demagnetization fault monitoring quantity to the demagnetization fault alarm value. When the sensitivity meets a preset demagnetization condition, the mechanical angle between the center line of the reference magnetic pole of the PMSM and the center line of at least one detection coil is obtained by extracting the instantaneous values ​​of the first and second fractional harmonics from multiple preset power frequency cycles. The fault pole is then located based on this mechanical angle. This method solves the problem of fault deterioration caused by long-term demagnetization operation of the motor, improves the efficiency of demagnetization fault repair in multi-pole PMSMs, and enhances the safety and reliability of PMSM operation.

[0035] A second aspect of this application provides a fault magnetic pole location device for partial demagnetization of the rotor of a multi-pole permanent magnet synchronous motor. The permanent magnet synchronous motor contains at least one detection coil. The device includes:

[0036] The acquisition module is used to acquire multiple port voltages of the at least one detection coil and multiple rotor position signals of the permanent magnet synchronous motor;

[0037] The calculation module is used to calculate the demagnetization fault monitoring quantity based on the multiple port voltages, and to calculate the demagnetization fault alarm value based on the multiple rotor position signals, and to obtain the demagnetization fault monitoring sensitivity based on the ratio of the demagnetization fault monitoring quantity to the demagnetization fault alarm value; and

[0038] The positioning module is used to extract the instantaneous values ​​of the first fractional harmonic and the second fractional harmonic from a preset multiple power frequency cycles when the sensitivity of the loss of excitation fault monitoring meets the preset loss of excitation conditions, and to obtain the mechanical angle by which the center line of the reference magnetic pole of the permanent magnet synchronous motor leads the center line of at least one detection coil based on the first fractional harmonic instantaneous value and the second fractional harmonic instantaneous value, and to locate the faulty magnetic pole based on the mechanical angle.

[0039] According to one embodiment of this application, the computing module is specifically used for:

[0040] The effective values ​​of multiple fractional harmonic voltages of the port voltages are obtained based on the multiple port voltages, and the actual speed of the permanent magnet synchronous motor is calculated based on the multiple rotor position signals.

[0041] The demagnetization fault monitoring value is calculated based on the effective values ​​of multiple fractional harmonic voltages of the port voltage, and the demagnetization fault alarm value is calculated based on the actual rotational speed.

[0042] According to one embodiment of this application, the formula for calculating the loss of excitation fault monitoring quantity is as follows:

[0043]

[0044] Where K is a natural number, N is the set of natural numbers, and P is the extreme pair number. The effective value of the K / P harmonic voltage in the port voltage;

[0045] The formula for calculating the demagnetization fault alarm value is:

[0046]

[0047] Among them, K tol U is the reliability coefficient for loss-of-excitation fault monitoring, n is the actual speed of the permanent magnet synchronous motor, and u is the reliability coefficient for loss-of-excitation fault monitoring. d_normal n represents the total effective value of the inherent voltage at the probe coil port during normal motor operation (during calibration parameters). normal For u d_normal The corresponding motor speed.

[0048] According to one embodiment of this application, after the sensitivity of the demagnetization fault monitoring meets the preset demagnetization condition, the positioning module is further configured to:

[0049] Generate a demagnetization fault alarm signal and perform a demagnetization fault alarm based on the demagnetization fault alarm signal.

[0050] According to one embodiment of this application, the positioning module is specifically used for:

[0051] Obtain the target time when the instantaneous values ​​of the first and second fractional harmonics are equal and their derivatives have the same sign;

[0052] The mechanical angle by which the center line of the reference magnetic pole of the permanent magnet synchronous motor leads the center line of at least one detection coil is obtained based on the rotor position signal corresponding to the target time.

[0053] According to one embodiment of this application, the positioning module is specifically used for:

[0054] The faulty magnetic pole that has lost its magnetism is located according to the mechanical angle described above;

[0055] The faulty magnetic pole is located based on its faulty magnetic pole number.

[0056] According to one embodiment of this application, the positioning module, which locates the faulty magnetic pole number that has lost magnetization based on the mechanical angle, is specifically used for:

[0057] Based on a preset fault pole location formula, the faulty magnetic pole number that has lost magnetism is located according to the mechanical angle, wherein the preset fault pole location formula is:

[0058]

[0059] Where θ is the rotor position signal, and i is the number of poles in which the reference pole leads the faulty pole.

[0060] The fault pole location device for partial demagnetization of a multi-pole permanent magnet synchronous motor rotor, as proposed in the embodiments, includes at least one detection coil within the permanent magnet synchronous motor. The device calculates a demagnetization fault monitoring quantity based on the voltages at multiple ports of the at least one detection coil, and calculates a demagnetization fault alarm value based on multiple rotor position signals of the permanent magnet synchronous motor. The sensitivity of the demagnetization fault monitoring is obtained based on the ratio of the demagnetization fault monitoring quantity to the demagnetization fault alarm value. When the sensitivity meets a preset demagnetization condition, the mechanical angle between the center line of the reference magnetic pole of the permanent magnet synchronous motor and the center line of at least one detection coil is obtained by extracting the instantaneous values ​​of the first and second fractional harmonics from multiple preset power frequency cycles. The fault pole is then located based on this mechanical angle. This solves the problem of fault deterioration caused by long-term demagnetization operation of the motor, improves the demagnetization fault repair efficiency of multi-pole permanent magnet synchronous motors, and enhances the safety and reliability of permanent magnet synchronous motor operation.

[0061] A third aspect of this application provides an electronic device, including: a memory, a processor, and a computer program stored in the memory and executable on the processor. The processor executes the program to implement the fault magnetic pole location method for partial demagnetization of the rotor of a multi-pole permanent magnet synchronous motor as described in the above embodiments.

[0062] A fourth aspect of this application provides a computer-readable storage medium having a computer program stored thereon, which is executed by a processor to implement the fault magnetic pole location method for partial demagnetization of the rotor of a multi-pole permanent magnet synchronous motor as described in the above embodiments.

[0063] Additional aspects and advantages of this application will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of this application. Attached Figure Description

[0064] The above and / or additional aspects and advantages of this application will become apparent and readily understood from the following description of the embodiments taken in conjunction with the accompanying drawings, wherein:

[0065] Figure 1 This is a flowchart of a fault magnetic pole location method for partial demagnetization of the rotor of a multi-pole permanent magnet synchronous motor according to an embodiment of this application;

[0066] Figure 2 This is a flowchart of a fault magnetic pole location method for partial demagnetization of the rotor of a multi-pole permanent magnet synchronous motor according to an embodiment of this application;

[0067] Figure 3 This is a schematic diagram of the circumferential magnetic flux density distribution of the air gap generated by a rotor according to an embodiment of this application;

[0068] Figure 4 This is a schematic diagram of a simulated waveform of the voltage at port 1 of the detection coil according to an embodiment of this application;

[0069] Figure 5 This is a schematic diagram showing the relative positions of the demagnetizing pole and the stator according to an embodiment of this application;

[0070] Figure 6 This is a schematic diagram of the simulated waveforms of the unbalanced currents in the internal branches of each phase according to an embodiment of this application;

[0071] Figure 7 This is a schematic diagram of the unbalanced current spectrum of each phase according to an embodiment of this application;

[0072] Figure 8 This is a schematic diagram of the voltage at port 1 of the detection coil according to an embodiment of this application;

[0073] Figure 9This is a block diagram of a fault magnetic pole location device for partial demagnetization of the rotor of a multi-pole permanent magnet synchronous motor according to an embodiment of this application;

[0074] Figure 10 This is a schematic diagram of the structure of an electronic device according to an embodiment of this application. Detailed Implementation

[0075] The embodiments of this application are described in detail below. Examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain this application, and should not be construed as limiting this application.

[0076] The following describes a method for locating faulty magnetic poles in a multi-pole permanent magnet synchronous motor (PMSM) where the rotor experiences partial demagnetization, according to embodiments of this application, with reference to the accompanying drawings. Addressing the problem of long-term demagnetization operation leading to fault deterioration in motors, as mentioned in the background section, this application provides a method for locating faulty magnetic poles in a multi-pole PMSM where the rotor experiences partial demagnetization. The PMSM contains at least one detection coil. In this method, a demagnetization fault monitoring quantity is calculated based on the voltages at multiple ports of the at least one detection coil, and a demagnetization fault alarm value is calculated based on multiple rotor position signals of the PMSM. The sensitivity of the demagnetization fault monitoring is obtained based on the ratio of the demagnetization fault monitoring quantity to the demagnetization fault alarm value. When the sensitivity meets a preset demagnetization condition, the mechanical angle between the center line of the reference magnetic pole of the PMSM and the center line of the at least one detection coil is obtained by extracting the instantaneous values ​​of the first and second fractional harmonics from multiple preset power frequency cycles. The faulty magnetic pole is then located based on this mechanical angle. This solves the problem of fault deterioration caused by long-term demagnetization operation of the motor, improves the efficiency of demagnetization fault repair in multi-pole PMSMs, and enhances the safety and reliability of PMSM operation.

[0077] Specifically, Figure 1 The flowchart illustrates a fault magnetic pole location method for partial demagnetization of the rotor of a multi-pole permanent magnet synchronous motor, as provided in this application embodiment.

[0078] Before introducing the fault magnetic pole location method for partial demagnetization of the rotor of a multi-pole permanent magnet synchronous motor proposed in the embodiments of this application, the principle of the scheme adopted in this application will be introduced first.

[0079] This application, after detecting rotor demagnetization faults in a multi-pole permanent magnet synchronous motor, extracts the relative positional characteristics between the demagnetized pole and the detection coil based on various fractional harmonic voltages of the detection coil port voltage. Combined with the signal output by the rotor position sensor, it achieves accurate positioning of a single demagnetized pole.

[0080] It should be noted that the fault magnetic pole location method for partial demagnetization of the rotor of a multi-pole permanent magnet synchronous motor proposed in this application embodiment is applicable to permanent magnet synchronous motors with a novel detection coil installed inside and a rotor position sensor installed.

[0081] First, the inherent voltage of the new detection coil port under normal rated operating conditions of the motor is measured. The acquired inherent voltage is preprocessed using the TLS-ESPRIT+SA algorithm to determine the alarm value at various speeds. During actual motor operation, the motor speed and the voltage signal of the detection coil port are monitored in real time. The characteristic harmonics of rotor demagnetization fault are extracted using the TLS-ESPRIT+SA algorithm, and the monitoring value is obtained in real time. When the monitoring value is higher than the alarm value corresponding to the speed, a rotor demagnetization fault alarm is issued, prompting the staff to inspect the motor, thereby realizing online monitoring of rotor demagnetization fault of permanent magnet synchronous motor.

[0082] like Figure 1 As shown, this method for locating faulty magnetic poles in a multi-pole permanent magnet synchronous motor with partial rotor demagnetization includes at least one detection coil installed within the permanent magnet synchronous motor. The method comprises the following steps:

[0083] In step S101, multiple port voltages of at least one detection coil and multiple rotor position signals of the permanent magnet synchronous motor are acquired.

[0084] It should be understood that, before acquiring the port voltage of the detection coil and the rotor position signal of the permanent magnet synchronous motor in the embodiments of this application, the parameters of the permanent magnet synchronous motor, including the number of stator slots Z and the number of pole pairs P, must first be determined; according to the parameters of the motor, the detection coil arrangement method provided in the detection coil arrangement method that simultaneously detects internal short circuits in the generator stator and rotor is used to arrange a new type of detection coil at the wedge of the motor stator slot; and a rotor position sensor is installed for the permanent magnet synchronous motor to output the rotor position signal.

[0085] Furthermore, in the embodiments of this application, during the operation of the permanent magnet synchronous motor, multiple port voltages of at least one detection coil and multiple rotor position signals output by the resolver are collected and stored in real time using relevant technical means. To avoid redundancy, detailed descriptions are not provided here.

[0086] In step S102, the loss of excitation fault monitoring quantity is calculated based on multiple port voltages, and the loss of excitation fault alarm value is calculated based on multiple rotor position signals. The sensitivity of loss of excitation fault monitoring is obtained based on the ratio of the loss of excitation fault monitoring quantity to the loss of excitation fault alarm value.

[0087] It is understood that the embodiments of this application can calculate the demagnetization fault monitoring quantity and the demagnetization fault alarm value respectively by pre-collecting multiple port voltages and multiple rotor position signals, and then calculate the sensitivity of demagnetization fault monitoring based on the ratio of the demagnetization fault monitoring quantity and the demagnetization fault alarm value.

[0088] Furthermore, in some embodiments, calculating the demagnetization fault monitoring quantity based on multiple port voltages and calculating the demagnetization fault alarm value based on multiple rotor position signals includes: obtaining multiple fractional harmonic voltage RMS values ​​of the port voltages based on multiple port voltages, and calculating the actual speed of the permanent magnet synchronous motor based on multiple rotor position signals; calculating the demagnetization fault monitoring quantity based on the multiple fractional harmonic voltage RMS values ​​of the port voltages, and calculating the demagnetization fault alarm value based on the actual speed.

[0089] In some embodiments, the formula for calculating the loss of excitation fault monitoring quantity is as follows:

[0090]

[0091] Where K is a natural number, N is the set of natural numbers, and P is the extreme pair number. The effective value of the K / P harmonic voltage in the port voltage;

[0092] The formula for calculating the demagnetization fault alarm value is:

[0093]

[0094] Among them, K tol U is the reliability coefficient for loss-of-excitation fault monitoring, n is the actual speed of the permanent magnet synchronous motor, and u is the reliability coefficient for loss-of-excitation fault monitoring. d_normal n represents the total effective value of the inherent voltage at the probe coil port during normal motor operation (during calibration parameters). normal For u d_normal The corresponding motor speed.

[0095] It should be noted that the reliability coefficient K of the loss of excitation fault monitoring tol Generally, a value greater than 1.5 is used.

[0096] Specifically, in this application embodiment, data is pre-acquired using a digital oscilloscope or other acquisition system, including pre-acquiring the total effective value u of the probe coil port voltage under normal operating conditions of the permanent magnet synchronous motor. d_normal and rotational speed n normal From the voltage signals at the probe coil ports of the previous P power frequency cycles, calculated from the latest sampling data, the effective values ​​of various fractional harmonic voltages (<2) such as 1 / P, 2 / P, ..., (P-1) / P, (P+1) / P, (P+2) / P, ..., (2P-1) / P are calculated. Where K∈N, K<2P and K≠P; the actual speed of the permanent magnet synchronous motor is calculated from multiple rotor position signals over P power frequency cycles; the demagnetization fault monitoring quantity is calculated based on the effective values ​​of various fractional harmonics of the detection coil voltage over P power frequency cycles; and the demagnetization fault alarm value is calculated based on the actual speed of the permanent magnet synchronous motor; then, the sensitivity of the demagnetization fault monitoring, i.e., K, is calculated based on the ratio of the demagnetization fault monitoring quantity to the demagnetization fault alarm value. sen = Monitoring quantity / Alarm value.

[0097] In step S103, when the sensitivity of the loss of excitation fault monitoring meets the preset loss of excitation conditions, the instantaneous values ​​of the first fractional harmonic and the second fractional harmonic are extracted from multiple preset power frequency cycles. Based on the instantaneous values ​​of the first and second fractional harmonics, the mechanical angle by which the center line of the reference magnetic pole of the permanent magnet synchronous motor leads at least one detection coil center line is obtained, and the fault magnetic pole is located based on the mechanical angle.

[0098] The preset multiple power frequency cycles can be pre-set by those skilled in the art, obtained through a limited number of experiments, or obtained through a limited number of computer simulations; no specific limitations are made here.

[0099] Furthermore, in some embodiments, after the sensitivity of the demagnetization fault monitoring meets the preset demagnetization condition, the method further includes: generating a demagnetization fault alarm signal and performing a demagnetization fault alarm based on the demagnetization fault alarm signal.

[0100] Specifically, in this application embodiment, the demagnetization condition is preset as follows: the calculated sensitivity K of demagnetization fault monitoring. sen Greater than 1, and K is calculated over P power frequency cycles. sen All are greater than 1. Therefore, when the sensitivity of the demagnetization fault monitoring meets the preset demagnetization condition, i.e., K... sen >1, and K calculated over the next P power frequency cycles sen When both are greater than 1, an alarm signal for demagnetization fault can be issued.

[0101] If the sensitivity of the demagnetization fault monitoring does not meet the preset conditions, the system will return to continue collecting the voltage at the probe coil port and multiple rotor position signals, and recalculate the demagnetization fault monitoring quantity and the demagnetization fault alarm value, thereby obtaining the sensitivity of the demagnetization fault monitoring.

[0102] Furthermore, in some embodiments, obtaining the mechanical angle by which the center line of the reference magnetic pole of the permanent magnet synchronous motor leads at least one center line of the detection coil based on the instantaneous values ​​of the first and second fractional harmonics includes: obtaining a target moment when the instantaneous values ​​of the first and second fractional harmonics are equal and have the same derivative sign; and obtaining the mechanical angle by which the center line of the reference magnetic pole of the permanent magnet synchronous motor leads at least one center line of the detection coil based on the rotor position signal corresponding to the target moment.

[0103] The rotor position sensor installed on the permanent magnet synchronous motor can output a rotor position signal to obtain the mechanical angle by which the center line of the permanent magnet synchronous motor's reference magnetic pole leads at least one detection coil center line. For example, by installing a pair of resolvers on the motor shaft, with the resolver rotor coil center line aligned with the permanent magnet synchronous motor's reference magnetic pole center line and the resolver cosine output coil center line aligned with the detection coil center line, the decoder can output the mechanical angle by which the permanent magnet synchronous motor's reference magnetic pole center line leads the detection coil center line in real time.

[0104] Specifically, when the sensitivity of the loss-of-excitation fault monitoring meets the preset loss-of-excitation conditions, the sensitivity K of the loss-of-excitation fault monitoring... sen From the detection coil voltage data of >1 P power frequency cycles, extract the instantaneous values ​​of the 1 / P (i.e., the first fractional) and 2 / P (the second fractional) harmonics (i.e., the 1 / P and 2 / P harmonic voltage waveforms within these P power frequency cycles), and find the time t when the 1 / P and 2 / P harmonic values ​​are equal and their derivatives have the same sign (both positive or both negative). scPM (i.e., the target time), and t scPM The rotor position signal θ corresponding to time t is used to obtain t. scPM The mechanical angle by which the center line of the reference magnetic pole of the permanent magnet synchronous motor leads the center line of the detection coil at any given time is expressed in degrees.

[0105] Furthermore, in some embodiments, fault magnetic pole location based on mechanical angle includes: locating the fault magnetic pole number that has lost magnetism based on mechanical angle; and locating the fault magnetic pole and / or triggering a demagnetization fault alarm based on the fault magnetic pole number.

[0106] In some embodiments, locating the faulty magnetic pole number that has lost magnetization based on a mechanical angle includes: locating the faulty magnetic pole number that has lost magnetization based on a preset fault pole location formula, wherein the preset fault pole location formula is:

[0107]

[0108] Where θ is the rotor position signal, and i is the number of poles in which the reference pole leads the faulty pole.

[0109] It should be noted that the reference magnetic pole is based on the direction of rotation, and the [x] function represents rounding down. This is because each magnetic pole occupies... (Degree, mechanical angle), therefore the reference magnetic pole leads the faulty magnetic pole. Each extreme.

[0110] In summary, as Figure 2 As shown in the embodiment of this application, a baseline value for the demagnetization fault monitoring alarm can be preset. Based on the collected probe coil port voltage signal and the rotor position signal output by the resolver, the monitoring alarm value is calculated. The fractional harmonics of the probe coil voltage are extracted and the demagnetization fault monitoring quantity is calculated. It is determined whether the monitoring quantity for P consecutive fundamental cycles (power frequency cycles) is greater than the monitoring alarm value. If it is not greater, the process returns to continue collecting the probe coil port voltage and multiple rotor position signals and recalculates the demagnetization fault monitoring quantity and the demagnetization fault alarm value. Otherwise, a demagnetization fault alarm signal is output to trigger a demagnetization fault alarm. In the probe coil voltage data of P fundamental cycles, the moment when the 1 / Pth and 2 / Pth harmonic voltage values ​​are equal and their derivatives have the same sign is determined, and the rotor position signal corresponding to this moment is recorded. Based on this rotor position signal, the faulty magnetic pole that has lost excitation is located, and the faulty magnetic pole number is output.

[0111] To facilitate a better understanding by those skilled in the art of the fault magnetic pole location method for partial demagnetization of the rotor of a multi-pole permanent magnet synchronous motor proposed in the embodiments of this application, a detailed description is provided below with reference to examples.

[0112] Specifically, this application takes a six-phase permanent magnet synchronous motor with 48 stator slots and 8 poles as an example. Under the 2D Maxwell software interface, a field-circuit coupling model of this prototype is established to simulate the magnetic field distribution, stator current and voltage, and probe coil port voltage caused by a fault of complete demagnetization of one N pole (i.e., 12.5% ​​local demagnetization of the permanent magnet). The prototype has three probe coils with a pitch of 12 slots. The main parameters are shown in Table 1.

[0113] Table 1

[0114] Rated power 10kW Rated speed 600r / min Rated frequency 40Hz Extreme logarithm 4 Number of phases 6 Number of stator slots 48 Number of branches per phase 1 Rated voltage (Y-connection) 400V Rated current (Y-connection) 8A Rated power factor 0.92 RMS value of no-load back EMF per phase 204V

[0115] It is understandable that after a permanent magnet rotor partially loses its magnetism, the amplitude of the magnetic field generated by the permanent magnet under the demagnetized pole is much smaller than that under other normal magnetic poles. Figure 3 A schematic diagram of the circumferential magnetic flux density distribution in the air gap of the rotor when one N pole is 100% demagnetized, as shown below. Figure 3 The magnetic field simulation results show that (the horizontal axis is a spatial coordinate established on the rotor circumference, with the center line of the demagnetized magnetic pole as the zero point of the horizontal axis, and the unit is mechanical angle). After performing spatial Fourier decomposition, the spatial fundamental, 1 / 2 and 1 / 4 harmonic magnetic fields can be extracted.

[0116] The simulation results show that the amplitudes of the fundamental magnetic field and the various fractional harmonic magnetic fields added by the fault (such as the 1 / P, 2 / P, and 3 / P spatial harmonic magnetic fields, with the number of pole pairs P=4 for this prototype) are all located at the center line of the demagnetized pole (i.e., the zero point of the spatial coordinates). Moreover, the polarity of the various fractional harmonic magnetic fields added by the fault is the same and is opposite to the polarity of the fundamental magnetic field inherent in normal operation.

[0117] Since the pitch of the three detection coils is 1 pair of poles (i.e., 12 slots), when the permanent magnet synchronous motor is running normally, the fundamental magnetic field (and other odd-order harmonic magnetic fields) will not generate alternating magnetic flux in the detection coils, so the voltage at the detection coil ports is 0. When the permanent magnet rotor is partially demagnetized, the permanent magnets with different poles will generate 1 / P-order harmonic magnetic fields, which move relative to the detection coils at synchronous speed n. Alternating magnetic flux and corresponding 1 / P-order harmonic induced electromotive force can be generated in the open-circuit detection coils.

[0118] Figure 4 This is a simulated waveform diagram of the voltage at port 1 of the detection coil caused by 100% demagnetization of one N pole in a six-phase single-branch permanent magnet synchronous motor. The rotational speed is set to n = 600 r / min, and the power frequency of the permanent magnet synchronous motor is f = 40 Hz. The simulated waveform of the voltage at port 1 of the detection coil is as follows: Figure 4 As shown, the 1 / 2 and 1 / 4 harmonic voltages can also be obtained through Fourier decomposition. Theoretically, these do not exist when the permanent magnet synchronous motor is running normally. They are fault characteristic quantities of local demagnetization of the rotor, and can be used to detect local demagnetization faults.

[0119] Furthermore, Figure 5 This is a schematic diagram showing the relative positions of the demagnetizing pole and the stator according to one embodiment of this application. The positions of the center lines of the three detection coils (on the stator side) are marked in the figure. Figure 5 As shown in (a), it has been set that at t=0, the center line of the demagnetized pole coincides with stator slot 0 (i.e., stator slot number Z=48), and the rotor rotates counterclockwise at n=600r / min. Figure 5 In the diagram, the pole without a grid represents the N pole, the pole with a grid represents the S pole, and the black pole represents the demagnetized N pole.

[0120] Since the stator winding of this permanent magnet synchronous motor has only one branch per phase, that is, each phase winding consists of 8 coils connected in series (distributed at the same position under 8 poles), as long as the stator winding does not experience an internal short circuit fault, each phase winding will only generate a spatial fundamental magnetic field (and other odd-order harmonic magnetic fields). Therefore, the armature reaction magnetic field of this single-branch permanent magnet synchronous motor will not generate alternating magnetic flux and induced electromotive force in the special detection coil used in the embodiments of this application. Figure 4 The voltage at the probe coil ports shown is caused by the magnetic field of the permanent magnet.

[0121] like Figure 5 As shown in (a), the rotor rotates counterclockwise at n = 600 r / min, completing one revolution every 100 ms. At t = 14.6 ms, the center line of the demagnetizing pole has been selected to be aligned with the axis of probe coil 1 (slot 7). Combined with... Figure 3 (b) shows the simulated waveforms of the 1 / 4 and 2 / 4 harmonic spatial magnetic fields generated by the rotor with one pole demagnetized. At this time, the axis of the No. 1 detection coil (which is the center line of the demagnetized pole) is at the horizontal coordinate x = 0. Then the 1 / 4 and 2 / 4 harmonic flux linkages in the detection coil are the largest and have the same polarity. The corresponding theoretical values ​​of the 1 / 4 and 2 / 4 harmonic electromotive forces are 0 and their derivatives are either positive or negative.

[0122] also, Figure 4 (b) The simulated waveform also conforms to the above theoretical analysis conclusions. At t = 14.6 ms, the 1 / 4 and 2 / 4 harmonic voltages of the detection coil are both 0, and both of these harmonic voltages are at the moment of crossing from negative to zero and about to become positive, and their derivatives are both positive; at the target time t scPM At 14.6ms, the center line of the demagnetized pole is directly opposite the center line of the (1) detection coil, while the rotor reference magnetic pole output by the rotor position sensor leads the (1) detection coil by θ (mechanical angle), indicating that the rotor reference magnetic pole leads the demagnetized magnetic pole by θ (mechanical angle).

[0123] It should be noted that if each phase of the stator of a permanent magnet synchronous motor has several parallel branches, local demagnetization of the rotor may also cause fractional harmonic unbalanced currents between the parallel branches inside the phase winding. This unbalanced current inside the armature may also cause voltages of the 1 / P and 2 / P harmonic components in the detection coil, thereby changing the time of the zero-crossing of the 1 / P and 2 / P harmonic voltages in the detection coil, causing a certain error in the positioning of the demagnetized pole.

[0124] If the permanent magnet synchronous motor is changed from the original single branch per phase to two parallel branches per phase, then each branch inside the phase winding is composed of coils connected in series at the same position under adjacent four poles.

[0125] like Figure 6 As shown, Figure 6 To simulate the unbalanced current in each phase's internal branches caused by 100% demagnetization of one N-pole in a six-phase, two-branch permanent magnet synchronous motor, and without considering saturation effects, the magnitude of the unbalanced current in the phase windings caused by a local demagnetization fault is unaffected by the load. Therefore, after modifying the stator winding connection method of the above field-circuit coupling model, a simulation of a 100% demagnetization fault of one N-pole was performed when the (six-phase, two-branch) permanent magnet synchronous motor was running under generator no-load conditions. The first branch current in each phase caused by 12.5% ​​local demagnetization was calculated. At this time, the phase current is 0, and the two branch currents in each phase are equal in magnitude but opposite in direction. Figure 6 The calculated first branch current of each phase is the unbalanced branch current inside the phase winding caused by the demagnetization of the permanent magnet.

[0126] It is understandable that the frequency characteristics of the unbalanced current inside the phase winding caused by a local loss of excitation fault are mainly determined by the distribution and connection relationship within the phase winding. Theoretical analysis shows that in this six-phase double-branch permanent magnet synchronous motor, the unbalanced current in the phase winding contains only k / P (P = 4, k = 1, 3, 5…) harmonics, such as… Figure 6 , Figure 7 The simulation results shown are consistent with the theoretical analysis results. Furthermore, the 1 / 4 harmonic currents of all branches of the six phases jointly generate a 1 / 4 harmonic magnetic field rotating forward at synchronous speed n, a 5 / 4 harmonic magnetic field rotating in reverse at n / 5, and a 7 / 4 harmonic magnetic field rotating forward at n / 7, etc. These armature reaction magnetic fields all generate 1 / 4 harmonic component voltages in the detection coil. The stator unbalanced current does not generate 1 / 2, 3 / 2, etc. harmonic magnetic fields. Therefore, the armature reaction magnetic field does not affect the 1 / 2 harmonic voltage of the detection coil.

[0127] Furthermore, Figure 8 In a six-phase, dual-branch permanent magnet synchronous motor, the voltage at the port of probe coil 1 caused by 100% demagnetization of one N pole is given. Figure 8 (a) is the 1 / 4 harmonic voltage, including the part caused by the magnetic field of the permanent magnet and the part caused by the unbalanced 1 / 4 harmonic current of each branch; Figure 8 (b) is the 1 / 2 harmonic voltage, entirely caused by the magnetic field of the permanent magnet, and is related to... Figure 4 The half-harmonic voltages in (b) are almost equal; Figure 8 (c) Display of the time-domain waveform of the voltage at the port of probe coil 1; Figure 8 (d) shows the 1 / 4 and 1 / 2 harmonic waveforms of the voltage at the port of probe coil 1.

[0128] from Figure 8 The simulation results in (a) show that the unbalanced 1 / 4 harmonic current in each branch causes the 1 / 4 harmonic U of the probe coil port voltage. ubc,1 / 4 The voltage at the probe coil port caused by the magnetic field of the permanent magnet is less than the 1 / 4 harmonic U. pm,1 / 4 One-tenth of the total, therefore the total 1 / 4 harmonic voltage U k / 4 At midnight, with U pm,1 / 4 The difference in the zero-crossing time is only about 0.8ms. For a motor with a speed of 600r / min, the rotor only rotates 2.88° (mechanical angle) in 0.8ms. This has little impact on the judgment of the fault pole and is not affected by the degree of demagnetization.

[0129] Therefore, for the six-phase dual-branch permanent magnet synchronous motor of this application embodiment, although the 1 / 4 harmonic (including the armature reaction voltage generated in the detection coil due to the stator unbalance current caused by local demagnetization) and 1 / 2 harmonic in the detection coil port voltage do not have the same moment of simultaneous zero crossing in the same direction as in a single-branch motor of each phase, there is still a unique moment when the 1 / 4 harmonic and 1 / 2 harmonic are equal and the derivatives are of the same sign for each revolution of the rotor. Since the motor does not need to compensate for the influence caused by the unbalance current, this moment can be regarded as the moment when the axis of the demagnetized pole coincides with the axis of the (1) detection coil during one revolution of the rotor. The fault magnetic pole location method for local demagnetization of the rotor of the multi-pole permanent magnet synchronous motor proposed in this application is also applicable to the six-phase dual-branch permanent magnet synchronous motor.

[0130] The fault pole location method for partial rotor demagnetization of a multi-pole permanent magnet synchronous motor (PMSM) proposed in this application involves at least one detection coil within the PMSM. A demagnetization fault monitoring quantity is calculated based on the voltages at multiple ports of the at least one detection coil, and a demagnetization fault alarm value is calculated based on multiple rotor position signals of the PMSM. The sensitivity of the demagnetization fault monitoring is obtained based on the ratio of the demagnetization fault monitoring quantity to the demagnetization fault alarm value. When the sensitivity meets a preset demagnetization condition, the mechanical angle between the center line of the reference magnetic pole of the PMSM and the center line of at least one detection coil is obtained by extracting the instantaneous values ​​of the first and second fractional harmonics from multiple preset power frequency cycles. The fault pole is then located based on this mechanical angle. This method solves the problem of fault deterioration caused by long-term demagnetization operation of the motor, improves the demagnetization fault repair efficiency of multi-pole PMSMs, and enhances the safety and reliability of PMSM operation.

[0131] Next, referring to the accompanying drawings, a fault magnetic pole positioning device for partial demagnetization of the rotor of a multi-pole permanent magnet synchronous motor according to an embodiment of this application is described.

[0132] Figure 9 This is a block diagram of a fault magnetic pole location device for partial demagnetization of the rotor of a multi-pole permanent magnet synchronous motor according to an embodiment of this application.

[0133] like Figure 9 As shown, the fault magnetic pole positioning device 10 for partial demagnetization of the rotor of the multi-pole permanent magnet synchronous motor has at least one detection coil installed inside the permanent magnet synchronous motor. The device 10 includes: a data acquisition module 100, a calculation module 200 and a positioning module 300.

[0134] The acquisition module 100 is used to acquire multiple port voltages of at least one detection coil and multiple rotor position signals of the permanent magnet synchronous motor.

[0135] The calculation module 200 is used to calculate the loss-of-excitation fault monitoring quantity based on multiple port voltages, and to calculate the loss-of-excitation fault alarm value based on multiple rotor position signals. The sensitivity of the loss-of-excitation fault monitoring is then calculated based on the ratio of the loss-of-excitation fault monitoring quantity to the loss-of-excitation fault alarm value.

[0136] The positioning module 300 is used to extract the instantaneous values ​​of the first fractional harmonic and the second fractional harmonic from multiple preset power frequency cycles when the sensitivity of the loss of excitation fault monitoring meets the preset loss of excitation conditions. Based on the instantaneous values ​​of the first and second fractional harmonics, the module obtains the mechanical angle by which the center line of the reference magnetic pole of the permanent magnet synchronous motor leads at least one detection coil center line, and locates the faulty magnetic pole based on the mechanical angle.

[0137] Furthermore, in some embodiments, the computing module 200 is specifically used for:

[0138] The effective values ​​of multiple fractional harmonic voltages of the port voltages are obtained based on multiple port voltages, and the actual speed of the permanent magnet synchronous motor is calculated based on multiple rotor position signals.

[0139] The demagnetization fault monitoring value is calculated based on the effective values ​​of multiple fractional harmonic voltages of the port voltage, and the demagnetization fault alarm value is calculated based on the actual rotational speed.

[0140] Furthermore, in some embodiments, the formula for calculating the loss-of-magnetism fault monitoring quantity is as follows:

[0141]

[0142] Where K is a natural number, N is the set of natural numbers, and P is the extreme pair number. The effective value of the K / P harmonic voltage in the port voltage;

[0143] The formula for calculating the demagnetization fault alarm value is:

[0144]

[0145] Among them, K tol U is the reliability coefficient for loss-of-excitation fault monitoring, n is the speed of the permanent magnet synchronous motor, and u is the speed of the permanent magnet synchronous motor. d_normal n represents the total effective value of the inherent voltage at the probe coil port during normal motor operation (during calibration parameters). normal For u d_normal The corresponding motor speed.

[0146] Furthermore, in some embodiments, after the sensitivity of the demagnetization fault monitoring meets the preset demagnetization condition, the positioning module 300 is further configured to:

[0147] Generate a demagnetization fault alarm signal and trigger a demagnetization fault alarm based on the demagnetization fault alarm signal.

[0148] Furthermore, in some embodiments, the positioning module 300 is specifically used for:

[0149] Obtain the target time when the instantaneous values ​​of the first and second fractional harmonics are equal and their derivatives have the same sign;

[0150] The mechanical angle by which the center line of the reference magnetic pole of the permanent magnet synchronous motor leads the center line of at least one detection coil is obtained based on the rotor position signal corresponding to the target time.

[0151] Furthermore, in some embodiments, the positioning module 300 is specifically used for:

[0152] The faulty magnetic pole that has lost its magnetism is located based on the mechanical angle.

[0153] Locate the faulty magnetic pole based on its number.

[0154] Furthermore, in some embodiments, the positioning module 300, which locates the faulty magnetic pole that has lost its magnetism based on a mechanical angle, is specifically used for:

[0155] Based on a preset fault pole location formula, the fault pole number that has lost its magnetism is located according to the mechanical angle. The preset fault pole location formula is as follows:

[0156]

[0157] Where θ is the rotor position signal, and i is the number of poles in which the reference pole leads the faulty pole.

[0158] It should be noted that the explanation of the above-mentioned method for locating fault magnetic poles in the rotor of a multi-pole permanent magnet synchronous motor with partial demagnetization also applies to the fault magnetic pole locating device for the rotor of a multi-pole permanent magnet synchronous motor with partial demagnetization in this embodiment, and will not be repeated here.

[0159] According to the embodiment of this application, a fault magnetic pole location device for partial rotor demagnetization of a multi-pole permanent magnet synchronous motor is provided. The permanent magnet synchronous motor is equipped with at least one detection coil. A demagnetization fault monitoring quantity is calculated based on the voltages at multiple ports of the at least one detection coil, and a demagnetization fault alarm value is calculated based on multiple rotor position signals of the permanent magnet synchronous motor. The sensitivity of the demagnetization fault monitoring is obtained based on the ratio of the demagnetization fault monitoring quantity to the demagnetization fault alarm value. When the sensitivity meets a preset demagnetization condition, the mechanical angle between the center line of the reference magnetic pole of the permanent magnet synchronous motor and the center line of at least one detection coil is obtained by extracting the instantaneous values ​​of the first and second fractional harmonics from multiple preset power frequency cycles. The fault magnetic pole is located based on this mechanical angle. This solves the problem of fault deterioration caused by long-term demagnetization operation of the motor, improves the demagnetization fault repair efficiency of multi-pole permanent magnet synchronous motors, and enhances the safety and reliability of permanent magnet synchronous motor operation.

[0160] Figure 10 A schematic diagram of the structure of an electronic device provided in an embodiment of this application. The electronic device may include:

[0161] The memory 1001, the processor 1002, and the computer program stored on the memory 1001 and capable of running on the processor 1002.

[0162] When the processor 1002 executes the program, it implements the fault magnetic pole location method for partial demagnetization of the rotor of a multi-pole permanent magnet synchronous motor provided in the above embodiments.

[0163] Furthermore, electronic devices also include:

[0164] Communication interface 1003 is used for communication between memory 1001 and processor 1002.

[0165] The memory 1001 is used to store computer programs that can run on the processor 1002.

[0166] The memory 1001 may include high-speed RAM (Random Access Memory) memory, and may also include non-volatile memory, such as at least one disk storage.

[0167] If the memory 1001, processor 1002, and communication interface 1003 are implemented independently, then the communication interface 1003, memory 1001, and processor 1002 can be interconnected via a bus to complete communication between them. The bus can be an ISA (Industry Standard Architecture) bus, a PCI (Peripheral Component Interconnect) bus, or an EISA (Extended Industry Standard Architecture) bus, etc. The bus can be divided into address bus, data bus, control bus, etc. For ease of representation, Figure 10 The bus is represented by a single thick line, but this does not mean that there is only one bus or one type of bus.

[0168] Optionally, in a specific implementation, if the memory 1001, processor 1002, and communication interface 1003 are integrated on a single chip, then the memory 1001, processor 1002, and communication interface 1003 can communicate with each other through an internal interface.

[0169] The processor 1002 may be a CPU (Central Processing Unit), an ASIC (Application Specific Integrated Circuit), or one or more integrated circuits configured to implement the embodiments of this application.

[0170] This application also provides a computer-readable storage medium storing a computer program that, when executed by a processor, implements the above-described method for locating faulty magnetic poles in the rotor of a multi-pole permanent magnet synchronous motor with partial demagnetization.

[0171] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of this application. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0172] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this application, "N" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0173] Any process or method described in the flowchart or otherwise herein can be understood as representing a module, segment, or portion of code comprising one or more N executable instructions for implementing custom logic functions or processes, and the scope of the preferred embodiments of this application includes additional implementations in which functions may be performed not in the order shown or discussed, including substantially simultaneously or in reverse order depending on the functions involved, as should be understood by those skilled in the art to which embodiments of this application pertain.

[0174] It should be understood that the various parts of this application can be implemented using hardware, software, firmware, or a combination thereof. In the above embodiments, the N steps or methods can be implemented using software or firmware stored in memory and executed by a suitable instruction execution system. For example, if implemented in hardware, as in another embodiment, it can be implemented using any one or a combination of the following techniques known in the art: discrete logic circuits having logic gates for implementing logical functions on data signals, application-specific integrated circuits (ASICs) having suitable combinational logic gates, programmable gate arrays (FPGAs), field-programmable gate arrays (FPGAs), etc.

[0175] Those skilled in the art will understand that all or part of the steps of the methods described in the above embodiments can be implemented by a program instructing related hardware, and the program can be stored in a computer-readable storage medium. When executed, the program includes one or a combination of the steps of the method embodiments.

[0176] Although embodiments of this application have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting this application. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of this application.

Claims

1. A method for locating faulty magnetic poles in a multi-pole permanent magnet synchronous motor rotor with partial demagnetization, characterized in that, The permanent magnet synchronous motor is equipped with at least one detection coil, wherein the method includes the following steps: Collect multiple port voltages of the at least one detection coil and multiple rotor position signals of the permanent magnet synchronous motor; The loss-of-excitation fault monitoring quantity is calculated based on the multiple port voltages, and the loss-of-excitation fault alarm value is calculated based on the multiple rotor position signals. The sensitivity of the loss-of-excitation fault monitoring is obtained based on the ratio of the loss-of-excitation fault monitoring quantity to the loss-of-excitation fault alarm value. When the sensitivity of the loss of excitation fault monitoring meets the preset loss of excitation conditions, the instantaneous values ​​of the first fractional harmonic and the second fractional harmonic are extracted from multiple preset power frequency cycles. Based on the instantaneous values ​​of the first and second fractional harmonics, the mechanical angle by which the center line of the reference magnetic pole of the permanent magnet synchronous motor leads the center line of at least one detection coil is obtained, and the fault magnetic pole is located based on the mechanical angle. The step of obtaining the mechanical angle by which the center line of the reference magnetic pole of the permanent magnet synchronous motor leads the center line of the at least one detection coil based on the instantaneous values ​​of the first and second fractional harmonics includes: obtaining a target time when the instantaneous values ​​of the first and second fractional harmonics are equal and have the same derivative sign; and obtaining the mechanical angle by which the center line of the reference magnetic pole of the permanent magnet synchronous motor leads the center line of the at least one detection coil based on the rotor position signal corresponding to the target time.

2. The method according to claim 1, characterized in that, The calculation of the demagnetization fault monitoring quantity based on the multiple port voltages and the calculation of the demagnetization fault alarm value based on the multiple rotor position signals include: The effective values ​​of multiple fractional harmonic voltages of the port voltages are obtained based on the multiple port voltages, and the actual speed of the permanent magnet synchronous motor is calculated based on the multiple rotor position signals. The demagnetization fault monitoring value is calculated based on the effective values ​​of multiple fractional harmonic voltages of the port voltage, and the demagnetization fault alarm value is calculated based on the actual rotational speed.

3. The method according to claim 1, characterized in that, The formula for calculating the loss of excitation fault monitoring quantity is as follows: in, K For natural numbers, N For the set of natural numbers, P For extreme logarithms, For the port voltage K / P Effective value of subharmonic voltage; The formula for calculating the demagnetization fault alarm value is: in, K tol The reliability coefficient for loss of excitation fault monitoring. n This represents the actual speed of the permanent magnet synchronous motor. This is the total effective value of the inherent voltage at the probe coil port during normal motor operation. for The corresponding motor speed.

4. The method according to claim 1, characterized in that, After the sensitivity of the loss of excitation fault monitoring meets the preset loss of excitation condition, the method further includes: Generate a demagnetization fault alarm signal and perform a demagnetization fault alarm based on the demagnetization fault alarm signal.

5. The method according to claim 1, characterized in that, The fault magnetic pole location based on the mechanical angle includes: The faulty magnetic pole that has lost its magnetism is located according to the mechanical angle described above; The faulty magnetic pole is located based on its faulty magnetic pole number.

6. The method according to claim 5, characterized in that, The method of locating the faulty magnetic pole number that has lost its magnetism based on the mechanical angle includes: Based on a preset fault pole location formula, the faulty magnetic pole number that has lost magnetism is located according to the mechanical angle, wherein the preset fault pole location formula is: in, For rotor position signal, i The reference magnetic pole is the pole number of the leading faulty magnetic pole.

7. A fault magnetic pole location device for partial demagnetization of the rotor of a multi-pole permanent magnet synchronous motor, characterized in that, The permanent magnet synchronous motor is equipped with at least one detection coil, wherein the device includes: The acquisition module is used to acquire multiple port voltages of the at least one detection coil and multiple rotor position signals of the permanent magnet synchronous motor; The calculation module is used to calculate the demagnetization fault monitoring quantity based on the multiple port voltages, and to calculate the demagnetization fault alarm value based on the multiple rotor position signals, and to obtain the demagnetization fault monitoring sensitivity based on the ratio of the demagnetization fault monitoring quantity to the demagnetization fault alarm value; and The positioning module is used to extract the instantaneous values ​​of the first fractional harmonic and the second fractional harmonic from a preset multiple power frequency cycles when the sensitivity of the loss of excitation fault monitoring meets the preset loss of excitation conditions, and to obtain the mechanical angle by which the center line of the reference magnetic pole of the permanent magnet synchronous motor leads the center line of at least one detection coil based on the first fractional harmonic instantaneous value and the second fractional harmonic instantaneous value, and to locate the faulty magnetic pole based on the mechanical angle. Specifically, the positioning module is used to: obtain a target time when the instantaneous values ​​of the first fractional harmonic and the second fractional harmonic are equal and have the same derivative sign; and obtain the mechanical angle by which the center line of the reference magnetic pole of the permanent magnet synchronous motor leads the center line of at least one detection coil based on the rotor position signal corresponding to the target time.

8. An electronic device, characterized in that, include: The system includes a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the program to implement the fault magnetic pole location method for partial demagnetization of the rotor of a multi-pole permanent magnet synchronous motor as described in any one of claims 1-6.

9. A computer-readable storage medium having a computer program stored thereon, characterized in that, The program is executed by the processor to implement the fault magnetic pole location method for partial demagnetization of the rotor of a multi-pole permanent magnet synchronous motor as described in any one of claims 1-6.

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