A Method for Canceling the Vibration of the Cogging Frequency Breathing Mode of a Permanent Magnet Motor

Abstract

The present invention relates to the technical field of permanent magnet motors, and discloses a method for canceling the vibration of the cogging frequency breathing mode of a permanent magnet motor, which includes the following steps: A) Determine whether the dominant vibration mode of the stator of the permanent magnet motor at the cogging frequency is the breathing mode. If so, proceed to step B); B) Analyze the harmonic voltage injection formula according to the d-q axis voltage equation of the permanent magnet motor; C) Open-loop inject harmonic voltage into the motor, and complete the cancellation of the cogging frequency vibration by adjusting the harmonic amplitude and phase. The method for canceling the vibration of the cogging frequency breathing mode of the permanent magnet motor in the present invention directly cancels the electromagnetic vibration source that generates the cogging frequency breathing mode vibration by additionally injecting a zero-order electromagnetic force with the same frequency. It has a clear physical meaning, is easy to implement, has strong versatility, and can significantly suppress the cogging frequency vibration of the motor.

Description

Technical Field

[0001] The present invention relates to the technical field of permanent magnet motors, and particularly relates to a method for canceling the vibration of the cogging frequency breathing mode of a permanent magnet motor. Background Art

[0002] Permanent magnet motors have the advantages of high power density, simple mechanical structure, high efficiency, etc., and have been widely used in the power systems of various carrier platforms such as electric propulsion ships and new energy vehicles. In the field of ship electric propulsion, the vibration and noise performance of the propulsion motor is crucial, directly affecting the acoustic stealth of military ships and the comfort of civilian ships; while in the vehicle electric drive system, the vibration and noise performance of the drive motor also directly affects the driving and riding comfort.

[0003] Cogging frequency vibration is one of the main characteristic frequency vibrations of permanent magnet motors. For medium and small permanent magnet motors with a conventional structure, it is generally considered that this vibration is excited by the cogging frequency torque ripple (zero-order circumferential force) during the rotation of the motor. There are many corresponding optimal design and control suppression methods for the cogging torque of the motor, and the technical maturity is also relatively high. However, for large permanent magnet motors or permanent magnet motors with a relatively thin stator structure (such as a shaftless propulsion motor), the breathing mode frequency of its stator is relatively low, close to the cogging frequency of the motor, and is easily excited by the zero-order radial force of the cogging frequency during the rotation of the motor. For the above-mentioned motor breathing mode vibration excited by the zero-order radial force of the cogging frequency, the industry has relatively little understanding, and there are few targeted suppression methods.

[0004] In view of the above problems, according to the causes of the breathing mode cogging frequency vibration, the relatively direct solutions are as follows:

[0005] 1) By increasing the air gap length or using magnetic slot wedges to weaken the electromagnetic vibration source and reduce the zero-order radial electromagnetic force generated by the cogging effect;

[0006] 2) By strengthening the support structure of the motor stator to increase the breathing mode frequency of the motor stator.

[0007] However, the above solutions will greatly increase the size and weight of the motor or reduce its reliability, and the practicability is poor.

[0008] Chinese Patent (Publication Date: June 7, 2022, Publication Number: CN114598224A) discloses a method for suppressing breathing mode vibration of a surface-mounted permanent magnet synchronous motor, which includes obtaining the electromagnetic force frequency that excites breathing mode vibration on the stator teeth; determining the order of the rotor harmonic magnetomotive force related to breathing mode vibration; adjusting the amplitude of the rotor harmonic magnetomotive force related to breathing mode vibration; injecting harmonic current and calculating the radial concentrated electromagnetic force on the stator teeth after injection; obtaining the amplitude and phase of the harmonic electromagnetic force with the same frequency as the breathing mode vibration; and calculating the influence of the harmonic current on losses and efficiency. By adjusting the rotor harmonic magnetomotive force and injecting positive-sequence and negative-sequence harmonic currents, the phase difference between the electromagnetic forces that excite breathing mode vibration on each stator tooth is changed, and the original breathing mode vibration is transformed into non-breathing mode vibration, thereby significantly suppressing electromagnetic vibration noise. However, this patent only provides the electromagnetic force formulas before and after injecting harmonic current, and does not provide the specific formula of the injected harmonic current and the implementation method of harmonic current injection. Summary of the Invention

[0009] The object of the present invention is to address the above-mentioned technical deficiencies and provide a method for canceling the breathing mode vibration of the tooth-slot frequency of a permanent magnet motor. By additionally injecting a zero-order electromagnetic force with the same frequency, the electromagnetic vibration source that generates the breathing mode vibration of the tooth-slot frequency is directly canceled. It has a clear physical meaning, is easy to implement, has strong versatility, and can significantly suppress the tooth-slot frequency vibration of the motor.

[0010] To achieve the above object, the method for canceling the breathing mode vibration of the tooth-slot frequency of the permanent magnet motor involved in the present invention includes the following steps:

[0011] A) Determine whether the dominant vibration mode of the permanent magnet motor stator at the tooth-slot frequency is the breathing mode. If so, proceed to step B);

[0012] B) According to the d-q axis voltage equation of the permanent magnet motor, analyze the harmonic voltage injection formula. When analyzing the harmonic voltage injection formula, first introduce a zero-order electromagnetic force at the tooth-slot frequency, that is, inject a component with adjustable amplitude and phase and alternating at the tooth-slot frequency i d The formula is as follows:

[0013] i d,v = I v cos ( vθ e + θ v )

[0014] In the formula, i d,v represents the injected d-axis current component, vDenotes the number of cogging harmonics, i.e., the multiple of the cogging frequency relative to the electrical fundamental frequency, θ e Denotes the electrical angular position of the rotor of the permanent magnet motor, I v Denotes the injected i d Amplitude of the component, θ v Denotes the injected i d Phase of the component. Adopting the method of directly injecting harmonic voltage in open loop, according to the d-q axis voltage equation and the coordinate transformation matrix of the permanent magnet motor, the harmonic voltage injection formula is analyzed as: , where, u a,v , u b,v and u c,v Respectively denote the harmonic voltages injected into the a-phase, b-phase and c-phase windings, L d Denotes the d-axis inductance of the permanent magnet motor, ω e Denotes the electrical angular velocity;

[0015] C) Inject harmonic voltage into the motor in open loop, and complete the cancellation of the cogging frequency vibration by adjusting the harmonic amplitude and phase.

[0016] Preferably, in the step A), determining the dominant vibration mode of the stator of the permanent magnet motor at the cogging frequency includes the following steps:

[0017] A1) In the step A), determining the dominant vibration mode of the stator of the permanent magnet motor at the cogging frequency includes the following steps:

[0018] A1) Arrange a number of radial and tangential vibration measurement points at appropriate positions on the frame of the permanent magnet motor, and the positions of adjacent vibration measurement points are arbitrary;

[0019] A2) Extract the vibration amplitude and phase of the cogging frequency of the permanent magnet motor, and calculate the mutual phase information between different vibration signals;

[0020] A3) If the cogging frequency vibration at all circumferential positions of the frame of the permanent magnet motor is mainly radial vibration and the phases are basically in phase, it indicates that the dominant vibration mode of the stator of the permanent magnet motor at the cogging frequency is the breathing mode.

[0021] Preferably, in the step C), according to the form of the harmonic voltage, the motor controller is used to directly inject the harmonic voltage of the corresponding frequency, and by adjusting i d The amplitude and phase of the component make the cogging frequency vibration reach the optimum.

[0022] Preferably, in the step C), in order to find the i d adjustment process of the amplitude and phase of the component that optimizes the cogging frequency vibration is as follows:

[0023] C1) Arbitrarily select and fix the harmonic phase within the range of 0 to 2π, and change the harmonic amplitude within the range of 0 to I v-max until the cogging frequency vibration changes by more than 3 dB, and record the harmonic amplitude at this time I v1 ;

[0024] C2) Keep the harmonic amplitude I v1 unchanged, and change the harmonic phase at equal intervals of π / 3 within the range of 0 to 2π to determine the sector where the harmonic phase with the optimal cogging frequency vibration is located;

[0025] C3) Keep the harmonic amplitude I v1 unchanged, and within the sector determined in step C2), use the binary search method to find the harmonic phase with the minimum cogging frequency vibration and record it as θ v1 and record it;

[0026] C4) Keep the harmonic phase θ v1 unchanged, and near the harmonic amplitude I v1 use the binary search method to find the harmonic amplitude with the minimum cogging frequency vibration, which is I v2 and record it, I v2 and θ v1 are the i d amplitude and phase of the component sought.

[0027] Preferably, in the step C1), I v-max take 5% of the fundamental component of the phase current.

[0028] An electronic device includes: a memory and a processor, which are communicatively connected to each other. The memory stores computer instructions, and the processor executes the computer instructions to implement the method for canceling the cogging frequency breathing mode vibration of the permanent magnet motor.

[0029] A computer-readable storage medium stores a computer program, and when the computer program is executed by a processor, the method for canceling the cogging frequency breathing mode vibration of the permanent magnet motor is implemented.

[0030] Compared with the prior art, the present invention has the following advantages:

[0031] 1. Based on the harmonic voltage injection method, a cogging frequency harmonic component is injected into the i d component, adding a zero-order pulsating magnetic field in the air gap, which can significantly suppress the cogging frequency vibration of the motor;

[0032] 2. By adopting the method of open-loop injecting voltage harmonics, the injection of zero-order electromagnetic force can be achieved only by using the motor controller;

[0033] 3. By injecting a component with adjustable amplitude and phase and alternating at the cogging frequency, the amplitude of the main magnetic field of the permanent magnet motor can be modulated, and then an additional zero-order electromagnetic force at the cogging frequency can be generated; i d component, the amplitude of the main magnetic field of the permanent magnet motor can be modulated, and then an additional zero-order electromagnetic force at the cogging frequency can be generated;

[0034] 4. According to the change trend of the vibration amplitude of the motor cogging frequency, adjusting the i d component's amplitude and phase can significantly reduce the cogging frequency vibration;

[0035] 5. Clear physical meaning and easy to implement;

[0036] 6. No additional hardware is required, which is convenient for software integration with the motor control program and has strong versatility. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Figure 1 It is a schematic diagram of the vibration measurement point arrangement on the permanent magnet motor housing in an embodiment of the method for canceling the cogging frequency breathing mode vibration of a permanent magnet motor according to the present invention;

[0038] Figure 2 It is a schematic diagram of the zero-order radial electromagnetic force wave in an embodiment of the method for canceling the cogging frequency breathing mode vibration of a permanent magnet motor according to the present invention;

[0039] Figure 3 It is a schematic diagram of the simplified electromagnetic structure of a permanent magnet motor in an embodiment of the method for canceling the cogging frequency breathing mode vibration of a permanent magnet motor according to the present invention;

[0040] Figure 4 It is an example schematic diagram of the change trend of the cogging frequency vibration of a permanent magnet motor with the harmonic amplitude or phase in an embodiment of the method for canceling the cogging frequency breathing mode vibration of a permanent magnet motor according to the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0041] Next, the technical solutions in the embodiments of the present application will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of this solution, rather than all the embodiments. Based on the embodiments in this solution, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the scope of protection of this patent.

[0042] A method for canceling the vibration of the cogging frequency breathing mode of a permanent magnet motor includes the following steps:

[0043] A) Determine whether the dominant vibration mode of the permanent magnet motor stator at the cogging frequency is the breathing mode. If so, proceed to step B);

[0044] B) Analyze the harmonic voltage injection formula according to the d-q axis voltage equation of the permanent magnet motor;

[0045] C) Inject harmonic voltage into the motor in an open-loop manner, and complete the cancellation of the cogging frequency vibration by adjusting the harmonic amplitude and phase.

[0046] Specifically, in step A), the determination of the dominant vibration mode of the permanent magnet motor stator at the cogging frequency includes the following steps:

[0047] A1) Arrange a number of radial and tangential vibration measurement points at appropriate positions on the frame of the permanent magnet motor, and the positions of adjacent vibration measurement points are arbitrary;

[0048] A2) Extract the vibration amplitude and phase of the cogging frequency of the permanent magnet motor, and calculate the mutual phase information between different vibration signals;

[0049] A3) If the cogging frequency vibration at all points on the circumference of the permanent magnet motor frame is mainly radial vibration and the phases are basically in phase, it indicates that the dominant vibration mode of the permanent magnet motor stator at the cogging frequency is the breathing mode.

[0050] Taking Figure 1 as an example, Figure 1 is a schematic diagram of the arrangement of vibration measurement points on the frame of a permanent magnet motor for an embodiment. First, vibration sensors are arranged at each measurement point to simultaneously measure the radial and tangential vibrations of the permanent magnet motor frame, and the positions between adjacent vibration measurement points are arbitrary; then, calculate the cogging frequency according to the actual working conditions of the permanent magnet motor (equal to the product of the rotation frequency and the number of slots), extract the vibration amplitude and phase of the cogging frequency at each vibration measurement point, and calculate the mutual phase information between the vibration signals of different vibration measurement points; finally, determine the dominant vibration mode of the cogging frequency vibration based on the above information. In this embodiment, the determination basis for the breathing mode vibration is provided: the cogging frequency vibration at all points on the circumference of the permanent magnet motor frame is mainly radial vibration and the phases are basically in phase. When this condition is met, it indicates that there is a small amount of radial "same large and same small" deformation at each point on the circumference of the permanent magnet motor frame and it is affected by the zero-order radial electromagnetic force. Among them, asFigure 2 As shown, it is a schematic diagram of the zero-order radial electromagnetic force wave provided by this embodiment.

[0051] In step B), according to the d-q axis voltage equation of the permanent magnet motor, the harmonic voltage injection formula is analyzed. Since there are inevitably cogging harmonics in the permanent magnet motor and a zero-order radial electromagnetic force is generated, which in turn excites the breathing mode vibration mode at the cogging frequency. At the same time, considering that the frequency of the zero-order radial electromagnetic force generated by the cogging harmonics is fixed and the phase is deterministic, therefore, if an additional zero-order electromagnetic force at the cogging frequency is introduced, it is hoped to cancel the breathing mode vibration. Its implementation strategy is: inject a component with adjustable amplitude and phase and alternating at the cogging frequency, i d modulate the amplitude of the main magnetic field of the motor, and then generate an additional zero-order electromagnetic force at the cogging frequency. The specific principle is introduced as follows:

[0052] As Figure 3 shown, Figure 3 is a simplified schematic diagram of the electromagnetic structure of the permanent magnet motor provided by this embodiment, including a pair of permanent magnet poles and a phase winding ( a 1 phase), and define a the positive direction of the 1-phase axis and the positive direction of the permanent magnet pole axis (i.e., d axis). When the permanent magnet motor runs without load, the air-gap magnetic density B r The formula is as follows:

[0053] B r = B 0 cos( θ - θ r )

[0054] In the formula, B 0 represents the amplitude of the air-gap magnetic density, θ represents the circumferential angle of any circumferential position in the air gap relative to a the positive direction of the 1-phase axis, θ r represents d axis relative to a the positive direction of the 1-phase axis. The distribution of the air-gap electromagnetic force σ r is: , in the formula, u 0 represents the air permeability. The second term on the right side of the equal sign represents the electromagnetic force (main wave) of the 2 times the electrical fundamental frequency pole number order. In this embodiment, a zero-order electromagnetic force related to the cogging frequency is injected, that is, inject a component with adjustable amplitude and phase and alternating at the cogging frequency i dComponent, such that the amplitude of the main magnetic field varies slightly, and the formula is as follows:

[0055] i d,v = I v cos ( vθ e + θ v )

[0056] In the formula, i d,v represents the injected d-axis current component, v represents the number of cogging harmonics, that is, the multiple of the cogging frequency relative to the electrical fundamental frequency, θ e represents the electrical angular position of the permanent magnet motor rotor (usually θ r and θ e only differ by a fixed phase angle. After the resolver zero position calibration, θ r = θ e ) I v represents the amplitude of the injected i d component, θ v represents the phase of the injected i d component.

[0057] After injecting harmonics, the expression of the air-gap magnetic flux density amplitude is as follows:

[0058] B 0 ’ = B 0 + kI v cos ( vθ e + θ v )

[0059] In the formula, k represents the constant coefficient of the air-gap magnetic flux density amplitude variation. According to the Maxwell stress tensor method, the expression of the air-gap electromagnetic force after harmonic injection is: , neglecting the higher-order small quantities in the above formula and subtracting the air-gap electromagnetic force before injecting harmonic current, the air-gap electromagnetic force increment can be obtained, and the expression is as follows: , in the formula, the first term on the right side of the equal sign represents vThe 0th-order electromagnetic force of the fundamental frequency of the multiple electric base can be used to cancel the vibration of the cogging frequency breathing mode; the second and third terms respectively represent the v -2) times and v +2) times the pole number order electromagnetic force of the electric base fundamental frequency. Its spatial order is high and the amplitude is much smaller than that of the main wave, so the vibration generated by it can be ignored. From the above analysis, it can be seen that by injecting i d component, an additional zero-order electromagnetic force of the cogging frequency can indeed be generated.

[0060] However, for large-capacity propulsion motor systems, limited by the losses of power electronic devices, the switching frequency of the frequency converter is generally low, and there is no order-of-magnitude difference from the cogging frequency, resulting in poor closed-loop control effect of harmonic current. To solve this problem, directly injecting open-loop voltage harmonics related to the cogging frequency, according to the d-q axis voltage equation of the permanent magnet motor and the coordinate transformation matrix, the harmonic voltage injection formula is analyzed, and the specific form is derived as follows:

[0061] According to the voltage equation of the permanent magnet motor in the synchronous rotating coordinate system, since the amplitude of the harmonic current is very small, the resistance voltage drop term can be ignored, that is , after Park transformation, the specific form of the harmonic voltage in the stationary coordinate system can be obtained: , finally, in step C), according to the form of the harmonic voltage, the harmonic voltage of the corresponding frequency is directly injected by the motor controller, and by adjusting i d component amplitude and phase, the cogging frequency vibration is optimized.

[0062] In this embodiment, first, according to the form of the harmonic voltage provided in step B), the harmonic voltage is directly injected by the motor controller, and then, according to the change trend of the cogging frequency vibration of the motor, the i d component amplitude I v and phase θ v are adjusted until the vibration suppression effect meets the requirements, and the cancellation of the cogging frequency vibration is completed.

[0063] Specifically, as Figure 4 shown, Figure 4 is an example schematic diagram of the change trend of the cogging frequency vibration of the permanent magnet motor provided in this embodiment with the harmonic amplitude or phase. As Figure 4 can be seen, when injecting a certain fixed "effective" harmonic amplitude, as the harmonic phase changes, there is a minimum value in the motor vibration; similarly, when the injected harmonic phase is fixed, as the injected harmonic amplitude changes, there is a minimum value in the motor vibration.

[0064] Specifically, to find the id The adjustment process of the amplitude and phase of the component is as follows:

[0065] C1) Arbitrarily select and fix the harmonic phase within the range of 0 to 2π, and change the harmonic amplitude within the range of 0 to I v-max until the vibration of the cogging frequency changes by more than 3 dB, and record the harmonic amplitude at this time I v1 , where in step C1), I v-max take 5% of the fundamental component of the phase current;

[0066] C2) Keep the harmonic amplitude I v1 unchanged, and change the harmonic phase at equal intervals of π / 3 within the range of 0 to 2π to determine the sector where the optimal harmonic phase for the cogging frequency vibration is located;

[0067] C3) Keep the harmonic amplitude I v1 unchanged, and within the sector determined in step C2), use the binary search method to find the harmonic phase with the minimum cogging frequency vibration and record it as θ v1 ;

[0068] C4) Keep the harmonic phase θ v1 unchanged, and near the harmonic amplitude I v1 , use the binary search method to find the harmonic amplitude with the minimum cogging frequency vibration and record it as I v2 , I v2 and θ v1 are the amplitude and phase of the i d component found.

[0069] The above experimental example proves the effectiveness of the cogging frequency breathing mode vibration cancellation method based on harmonic voltage injection proposed in this application.

[0070] This embodiment also provides an electronic device, including: a memory and a processor, which are communicatively connected to each other. The memory stores computer instructions, and the processor realizes the cogging frequency breathing mode vibration cancellation method of the permanent magnet motor by executing the computer instructions. And a computer-readable storage medium stores a computer program, and when the computer program is executed by the processor, it realizes the cogging frequency breathing mode vibration cancellation method of the permanent magnet motor.

[0071] The method for canceling the cogging frequency breathing mode vibration of the permanent magnet motor in the present invention starts from the control perspective and artificially introduces a zero-order electromagnetic force of the cogging frequency by using the technical approach of harmonic injection to cancel the zero-order electromagnetic force generated by the rotation of the motor, aiming to solve the problem of cogging frequency breathing mode vibration at the lowest cost.

[0072] Harmonic injection is divided into two types: harmonic current injection and harmonic voltage injection. For a large-capacity permanent magnet motor system, its frequency converter switching frequency is generally low, and there is no significant difference in magnitude from the cogging frequency, so the closed-loop control effect of harmonic current is not good. Therefore, this application adopts the method of directly injecting harmonic voltage in an open loop and theoretically derives the harmonic voltage injection formula.

[0073] The method for canceling the cogging frequency breathing mode vibration of the permanent magnet motor in the present invention is based on the harmonic voltage injection method. Inject the harmonic component of the cogging frequency into the i d component, add a zero-order pulsating magnetic field in the air gap, which can significantly suppress the cogging frequency vibration of the motor; adopt the method of injecting voltage harmonics in an open loop, and only use the motor controller to realize the injection of zero-order electromagnetic force; by injecting an i d component with adjustable amplitude and phase and alternating at the cogging frequency, the amplitude of the main magnetic field of the permanent magnet motor can be modulated, and then an additional zero-order electromagnetic force of the cogging frequency can be generated; according to the change trend of the vibration amplitude of the motor cogging frequency, adjust the i d amplitude and phase of the component, which can significantly reduce the cogging frequency vibration; its physical meaning is clear and easy to implement; no additional hardware is required, which is convenient for software integration with the motor control program and has strong versatility.

[0074] In the above-mentioned embodiments, the descriptions of each embodiment have their own emphases. For the parts not detailed or recorded in a certain embodiment, reference can be made to the relevant descriptions of other embodiments.

[0075] The above-described embodiments are only used to illustrate the technical solutions of this application, rather than to limit them; although this application has been described in detail with reference to the above-mentioned embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions recorded in the foregoing embodiments, or perform equivalent replacements for some of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of each embodiment of this application, and should all be included within the protection scope of this application.

Claims

1. A method for canceling the vibration of the cogging frequency breathing mode of a permanent magnet motor, characterized in that: Including the following steps: A) Determine whether the dominant vibration mode of the permanent magnet motor stator at the cogging frequency is the breathing mode. If the cogging frequency vibration at all circumferential positions of the permanent magnet motor frame is mainly radial vibration and the phases are basically in phase, it indicates that the dominant vibration mode of the permanent magnet motor stator at the cogging frequency is the breathing mode, and proceed to step B); B) According to the d-q axis voltage equation of the permanent magnet motor, the harmonic voltage injection formula is analyzed. When analyzing the harmonic voltage injection formula, first introduce a cogging frequency zero-order electromagnetic force, that is, inject a component with adjustable amplitude and phase and alternating at the cogging frequency. The formula is as follows: i d Component, the formula is as follows: i d,v = I v cos ( vθ e + θ v ) Wherein, i d,v represents the injected d-axis current component, v represents the cogging harmonic order, that is, the multiple of the cogging frequency relative to the electrical fundamental frequency, θ e represents the electrical angular position of the permanent magnet motor rotor, I v represents the injected i d component amplitude, θ v represents the injected i d component phase. By adopting the direct open-loop injection harmonic voltage method, according to the d-q axis voltage equation and the coordinate transformation matrix of the permanent magnet motor, the harmonic voltage injection formula is analyzed as: , wherein, u a,v , u b,v and u c,v respectively represent the harmonic voltages injected into the a-phase, b-phase and c-phase windings, L d represents the d-axis inductance of the permanent magnet motor, ω e represents the electrical angular velocity; C) Open-loop inject harmonic voltage into the motor and complete the cancellation of the cogging frequency vibration by adjusting the harmonic amplitude and phase.

2. The method for canceling the vibration of the cogging frequency breathing mode of the permanent magnet motor according to claim 1, characterized in that: In the said step A), determining the dominant vibration mode of the permanent magnet motor stator at the cogging frequency includes the following steps: A1) Arrange a number of radial and tangential vibration measurement points at appropriate positions on the permanent magnet motor frame, and the positions of adjacent vibration measurement points are arbitrary; A2) Extract the vibration amplitude and phase of the cogging frequency of the permanent magnet motor and calculate the mutual phase information between different vibration signals; A3) If the cogging frequency vibration at all circumferential positions of the permanent magnet motor frame is mainly radial vibration and the phases are basically in phase, it indicates that the dominant vibration mode of the permanent magnet motor stator at the cogging frequency is the breathing mode.

3. The permanent magnet motor cogging frequency breathing mode vibration cancellation method according to claim 1, characterized in that: In step C), according to the form of the harmonic voltage, the motor controller directly injects the harmonic voltage of the corresponding frequency, and by adjusting i d the amplitudes and phases of the components, the vibration of the cogging frequency is optimized.

4. The method for canceling the vibration of the cogging frequency breathing mode of the permanent magnet motor according to claim 1, wherein: In the said step C), to find the i d adjustment process of the amplitude and phase of the component is as follows: C1) Arbitrarily select and fix the harmonic phase within the range of 0 to 2π, and change the harmonic amplitude within the range of 0 to I v-max until the vibration of the cogging frequency changes by more than 3 dB, and record the harmonic amplitude at this time I v1 ; C2) Harmonic amplitude I v1 Remain unchanged, the harmonic phase changes at equal intervals of π / 3 within the range of 0 to 2π, and determine the sector where the optimal harmonic phase of the cogging frequency vibration is located; C3) Harmonic amplitude I v1 Remain unchanged. In the sector determined in step C2), use the binary search method to find the harmonic phase with the minimum cogging frequency vibration and denote it as θ v1 and record it; C4) Harmonic Phase θ v1 remain unchanged. Near the harmonic amplitude I v1 using the binary search method, find the harmonic amplitude with the minimum vibration of the cogging frequency, which is I v2 and record it I v2 and θ v1 which are the i d component amplitude and phase we are looking for.

5. The method for canceling the vibration of the cogging frequency breathing mode of the permanent magnet motor according to claim 4, characterized in that: In the said step C1), I v-max Take 5% of the fundamental component of the phase current.

6. An electronic device, characterized in that, Including: A memory and a processor, which are communicatively connected to each other. The memory stores computer instructions, and the processor realizes the method for canceling the breathing mode vibration of the cogging frequency of the permanent magnet motor as described in any one of claims 1 to 5 by executing the computer instructions.

7. A computer-readable storage medium storing a computer program, characterized in that: When the computer program is executed by the processor, it realizes the method for canceling the breathing mode vibration of the cogging frequency of the permanent magnet motor as described in any one of claims 1 to 5.

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