Method for optimizing non-uniform air gap structure of permanent magnet synchronous motor

Abstract

The invention provides a method for optimizing a non-uniform air gap structure of a permanent magnet synchronous motor, and relates to the technical field of motor air gap evaluation, and the method comprises the steps: collecting related parameters of the permanent magnet synchronous motor, carrying out the correlation analysis of an eccentricity evaluation coefficient of the permanent magnet synchronous motor, and outputting an eccentricity safety confidence value of the permanent magnet synchronous motor. According to the method, the parameters of the permanent magnet synchronous motor are collected, the gap of the permanent magnet synchronous motor is comprehensively analyzed and evaluated, the magnetic induction intensity of the permanent magnet synchronous motor is combined for analysis, and the magnetic induction intensity and the effective length of the mixed air gap are preprocessed; generating an eccentricity evaluation coefficient of the permanent magnet synchronous motor reflecting the eccentricity degree of the permanent magnet synchronous motor, comparing the eccentricity evaluation coefficient of the permanent magnet synchronous motor with a threshold value, outputting an eccentricity safety confidence value of the permanent magnet synchronous motor, and assisting a worker in evaluating the safety of the permanent magnet synchronous motor with the non-uniform gap.

Description

Technical Field

[0001] The invention relates to the technical field of motor air gap evaluation, and in particular to a method for optimizing the non-uniform air gap structure of a permanent magnet synchronous motor. Background Art

[0002] Motor air gap assessment is an important part of motor design and performance analysis. The air gap not only affects the efficiency, performance and thermal management of the motor, but also affects the noise, vibration and reliability of the motor. The air gap refers to the space between the stator and the rotor of the motor, and its length is a key parameter during design. The design and control of the air gap directly affects the magnetic field distribution, current distribution, and ultimately the torque output of the motor. Permanent magnet synchronous motor is a type of motor widely used in industrial and consumer electronics products, and is valued for its high efficiency, compactness and excellent performance. Its stator core is usually made of laminated silicon steel sheets to reduce eddy current losses. The stator is wound with a three-phase winding and powered by a three-phase AC power supply. The rotor is usually made of permanent magnet material (such as neodymium iron boron), which has high energy density and strong magnetism.

[0003] Generally, when a permanent magnet synchronous motor has a non-uniform air gap, since the stator and rotor of the motor are symmetrical, whether the non-uniform air gap of the permanent magnet synchronous motor will affect the motor performance during operation requires comprehensive consideration of the geometric parameters and motor performance, which makes it difficult for staff to comprehensively evaluate the air gap safety performance of the non-uniform permanent magnet synchronous motor.

[0004] The above information disclosed in this Background section is only for enhancement of understanding of the background of the present disclosure and therefore it may contain information that does not constitute the prior art that is already known to one of ordinary skill in the art. Summary of the invention

[0005] The object of the present invention is to provide a method for optimizing the non-uniform air gap structure of a permanent magnet synchronous motor to solve the problems raised in the above background technology.

[0006] To achieve the above object, the present invention provides the following technical solutions:

[0007] The non-uniform air gap structure optimization method of a permanent magnet synchronous motor comprises the following specific steps:

[0008] S1. Establish an air gap calculation model for a permanent magnet synchronous motor;

[0009] S2, collecting static air gap parameters and dynamic air gap parameters of the permanent magnet synchronous motor;

[0010] S3, performing correlation processing on the static air gap parameters of the permanent magnet synchronous motor to generate a static effective air gap length, where the static effective air gap length is used to reflect the air gap length data of the permanent magnet synchronous motor in a static state;

[0011] S4. Perform correlation processing on the dynamic air gap parameters of the permanent magnet synchronous motor to generate a dynamic effective air gap length, where the dynamic effective air gap length is used to reflect the air gap length data of the permanent magnet synchronous motor under working conditions;

[0012] S5. Preprocessing the static effective air gap length and the dynamic effective air gap length to generate a mixed air gap effective length, where the mixed air gap effective length is used to reflect the effective air gap length data of the permanent magnet synchronous motor calculated and generated under comprehensive conditions;

[0013] S6, collecting motor parameters of the permanent magnet synchronous motor;

[0014] S7, performing correlation analysis on motor parameters of the permanent magnet synchronous motor to generate magnetic induction intensity;

[0015] S8. Preprocess the magnetic induction intensity and the effective length of the mixed air gap to generate an eccentricity assessment coefficient of the permanent magnet synchronous motor, compare the eccentricity assessment coefficient of the permanent magnet synchronous motor with a threshold value, and output an eccentricity safety confidence value of the permanent magnet synchronous motor. The eccentricity assessment coefficient of the permanent magnet synchronous motor is used to reflect the degree of eccentricity of the permanent magnet synchronous motor.

[0016] Furthermore, the static air gap parameters include static eccentricity e and air gap length g(θ), wherein the static eccentricity is the offset of the geometric center of the rotor relative to the geometric center of the stator, and the air gap length g(θ) is the air gap length between the stator and the rotor at an angle of θ. In S1, when establishing the calculation model, one of the symmetry planes of the stator is used as the reference plane, the geometric center of the stator is used as the collection origin, and the outer contour of the rotor is used as the collection point. The angle between the straight line connecting the collection origin and the collection point and the reference plane is recorded as θ. When collecting the static air gap parameters of the permanent magnet synchronous motor, the value range of θ is 0°, 1°, 2°, 3°…359°.

[0017] Furthermore, the air gap length g(θ) is subjected to correlation analysis to generate the static average air gap length g, based on the formula:

[0018]

[0019] Among them, the static average air gap length g is used to reflect the average distance between each contour point on the outer side of the rotor and the inner contour point on the stator at static state;

[0020] The correlation analysis between the static average air gap length g and the air gap length g(θ) is performed to generate the air gap change Δg(θ), based on the formula:

[0021] Δg(θ)=g(θ)-g

[0022] The air gap variation Δg(θ) is used to reflect the difference between the air gap spacing at each angle and the average air gap length g;

[0023] Let Δg(θ) = e*f(θ), f(θ) = k sinθ + a, generate the values ​​of k and a according to the least squares fitting method, and combine the above formula: Δg(θ) = g(θ) - g, to generate the static air gap length formula:

[0024] g(θ)=g+e*ksinθ+e*a

[0025] Perform correlation analysis on the static air gap length formula to generate the static effective air gap length L g , the formula based on is:

[0026]

[0027] Among them, the static effective air gap length L g It is used to reflect the estimated value of the static comprehensive air gap length between the stator and the rotor.

[0028] Furthermore, the dynamic air gap parameter includes the dynamic eccentricity e d (t) and dynamic air gap change Δg d (ω, t), where the dynamic eccentricity is the eccentric distance between the geometric center point of the rotor motion trajectory and the geometric center point of the stator when the motor is working. t starts from 0 seconds and the interval is Among them, T is the time required for the rotor to rotate one circle, and the dynamic air gap change is the distance between the outer contour of the rotor at an angle w at time t and the inner contour of the stator when the rotor is working.

[0029] Furthermore, the dynamic air gap length is set to g d (ω, t), then g d (ω, t) = g + Δg d (ω, t), and let Δg d (ω, t) = e d (t)*f d (w), define the periodic function f d (w) = s*sinθ+b, and the values ​​of s and b are generated by the least squares fitting method, and the dynamic air gap length g d (ω, t) to perform correlation analysis and generate the dynamic effective air gap length L gd , the formula based on is:

[0030]

[0031] Among them, the dynamic effective air gap length L gd An estimated value of the comprehensive air gap length used to reflect the working conditions between the stator and the rotor.

[0032] Furthermore, a correlation analysis is performed on the static effective air gap length and the dynamic effective air gap length to generate the mixed air gap effective length 6, based on the formula:

[0033] δ=(L gd +L g )*(1-k s -k d )

[0034] Among them, k s Indicates the influence factor of static eccentricity, k d Indicates the influence factor of dynamic eccentricity, k s With k d The value of is no greater than 1, and k s +k d <1, the mixed air gap effective length 6 is used to reflect the evaluation value of the comprehensive air gap length between the stator and the rotor of the permanent magnet synchronous motor.

[0035] Furthermore, the motor parameters include the magnetic induction intensity B0, the number of pole pairs p, the number of turns N of the stator winding, and the magnetic permeability μ of the stator core under normal motor working conditions. Correlation analysis is performed on the motor parameters to generate the magnetic induction intensity B, and the formula based on which is:

[0036]

[0037] Among them, l d is the effective path length of the current through the stator winding, m is the number of phases of the stator winding, K is the winding distribution coefficient factor, the value range of K is [0.38,5.69], and I is the current intensity passing through the stator winding.

[0038] Furthermore, the correlation analysis is performed on the magnetic induction intensity B of the permanent magnet synchronous motor and the effective length δ of the mixed air gap, and the eccentricity evaluation coefficient PPX of the permanent magnet synchronous motor is outputted, and the formula based on it is:

[0039]

[0040] Among them, the eccentricity evaluation coefficient PPX of the permanent magnet synchronous motor is used to reflect the comprehensive eccentricity of the permanent magnet synchronous motor. The eccentricity evaluation coefficient PPX of the permanent magnet synchronous motor is compared with the threshold value γ to output the eccentricity safety confidence value of the permanent magnet synchronous motor. The threshold value γ is 3.96;

[0041] When PPX>γ, it means that the eccentricity safety level of the permanent magnet synchronous motor is poor, and the output eccentricity safety confidence value of the permanent magnet synchronous motor is 30%; when PPX<γ, it means that the eccentricity safety level of the permanent magnet synchronous motor is good, and the output eccentricity safety confidence value of the permanent magnet synchronous motor is 70%.

[0042] Compared with the prior art, the present invention has the following beneficial effects:

[0043] The present invention collects the parameters of the permanent magnet synchronous motor, conducts a comprehensive analysis and evaluation on the gap of the permanent magnet synchronous motor, and analyzes it in combination with the magnetic induction intensity of the permanent magnet synchronous motor, pre-processes the magnetic induction intensity and the effective length of the mixed air gap, generates an eccentricity evaluation coefficient of the permanent magnet synchronous motor that reflects the eccentricity degree of the permanent magnet synchronous motor, compares the eccentricity evaluation coefficient of the permanent magnet synchronous motor with a threshold value, outputs an eccentricity safety confidence value of the permanent magnet synchronous motor, and assists the staff in evaluating the safety of the permanent magnet synchronous motor with a non-uniform gap, thereby assisting the staff in structural optimization of the permanent magnet synchronous motor with a non-uniform air gap structure. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] Figure 1 It is a schematic diagram of the overall method flow of the present invention. DETAILED DESCRIPTION

[0045] In order to make the objectives, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with specific embodiments.

[0046] It should be noted that, unless otherwise defined, the technical terms or scientific terms used in the present invention should be understood by people with ordinary skills in the field to which the present invention belongs. The words "first", "second" and similar words used in the present invention do not indicate any order, quantity or importance, but are only used to distinguish different components. "Include" or "comprise" and similar words mean that the elements or objects appearing before the word include the elements or objects listed after the word and their equivalents, without excluding other elements or objects. "Connect" or "connected" and similar words are not limited to physical or mechanical connections, but may include electrical connections, whether direct or indirect. "Up", "down", "left", "right" and the like are only used to indicate relative positional relationships. When the absolute position of the described object changes, the relative positional relationship may also change accordingly.

[0047] Example:

[0048] See also Figure 1 , the present invention provides a technical solution:

[0049] The method for optimizing the non-uniform air gap structure of a permanent magnet synchronous motor adopts a laser range finder to collect data when collecting the air gap length, and an ammeter to collect data on the current intensity. The specific steps include:

[0050] Step 1, establishing an air gap calculation model of a permanent magnet synchronous motor;

[0051] Step 2: Collect static air gap parameters and dynamic air gap parameters of the permanent magnet synchronous motor;

[0052] The static air gap parameters include static eccentricity e and air gap length g(θ), where the static eccentricity is the offset of the geometric center of the rotor relative to the geometric center of the stator, and the air gap length g(θ) is the air gap length between the stator and the rotor at an angle of θ. In S1, when establishing the calculation model, one of the symmetry planes of the stator is used as the reference plane, the geometric center of the stator is used as the collection origin, and the outer contour of the rotor is used as the collection point. The angle between the straight line connecting the collection origin and the collection point and the reference plane is recorded as θ. When collecting the static air gap parameters of the permanent magnet synchronous motor, the value range of θ is 0°, 1°, 2°, 3°…359°.

[0053] Dynamic air gap parameters include dynamic eccentricity e d (t) and dynamic air gap change Δg d (ω, t), where the dynamic eccentricity is the eccentric distance between the geometric center point of the rotor motion trajectory and the geometric center point of the stator when the motor is working, t starts from 0 seconds, and the interval of the value is Among them, T is the time required for the rotor to rotate one circle, and the dynamic air gap change is the distance between the outer contour of the rotor at an angle w at time t and the inner contour of the stator when the rotor is working.

[0054] Step 3, performing correlation processing on the static air gap parameters of the permanent magnet synchronous motor to generate a static effective air gap length, where the static effective air gap length is used to reflect the air gap length data of the permanent magnet synchronous motor in a static state;

[0055] Correlation analysis of the air gap length g(θ) is performed to generate the static average air gap length g based on the formula:

[0056]

[0057] Among them, the static average air gap length g is used to reflect the average distance between each contour point on the outer side of the rotor and the inner contour point on the stator at static state;

[0058] The correlation analysis between the static average air gap length g and the air gap length g(θ) is performed to generate the air gap change Δg(θ), based on the formula:

[0059] Δg(θ)=g(θ)-g

[0060] The air gap variation Δg(θ) is used to reflect the difference between the air gap spacing at each angle and the average air gap length g;

[0061] Let Δg(θ)=e*f(θ), f(θ)=ksinθ+a, and generate the values ​​of k and a according to the least squares method. The least squares method is a statistical method used to fit the regression model by minimizing the sum of squares of the errors between the collected data and the model prediction values. The data is fit by defining a function that is close to the curve form, and the closest function is finally output. At the same time, the above formula is combined: Δg(θ)=g(θ)-g to generate the static air gap length formula:

[0062] g(θ)=g+e*ksinθ+e*a

[0063] Perform correlation analysis on the static air gap length formula to generate the static effective air gap length L g , the formula based on is:

[0064]

[0065] Among them, the static effective air gap length L g It is used to reflect the estimated value of the static comprehensive air gap length between the stator and the rotor.

[0066] Step 4: performing correlation processing on the dynamic air gap parameters of the permanent magnet synchronous motor to generate a dynamic effective air gap length, where the dynamic effective air gap length is used to reflect the air gap length data of the permanent magnet synchronous motor under working conditions;

[0067] Set the dynamic air gap length to g d (ω, t), then g d (ω, t) = g + Δg d (ω, t), and let Δg d (ω, t) = e d (t)*f d (w), define the periodic function f d (w) = s*sinθ + b, and the values ​​of s and b are generated by the least squares method. The least squares method is a statistical method used to fit the regression model by minimizing the sum of squares of the errors between the collected data and the model prediction values. The data are fitted by defining a function that is close to the curve form, and finally the closest function is output for the dynamic air gap length g. d (ω, t) to perform correlation analysis and generate the dynamic effective air gap length L gd , the formula based on is:

[0068]

[0069] Among them, the dynamic effective air gap length L gd An estimated value of the comprehensive air gap length used to reflect the working conditions between the stator and the rotor.

[0070] Step 5, pre-processing the static effective air gap length and the dynamic effective air gap length to generate a mixed air gap effective length, where the mixed air gap effective length is used to reflect the effective air gap length data of the permanent magnet synchronous motor calculated and generated under comprehensive conditions;

[0071] The correlation analysis of the static effective air gap length and the dynamic effective air gap length is performed to generate the mixed air gap effective length 6, based on the formula:

[0072] δ=(L gd +L g )*(1-k s -k d )

[0073] Among them, k s Indicates the influence factor of static eccentricity, k d Indicates the influence factor of dynamic eccentricity, k s With k d The value of is no greater than 1, and k s +k d <1, the mixed air gap effective length 6 is used to reflect the evaluation value of the comprehensive air gap length between the stator and the rotor of the permanent magnet synchronous motor.

[0074] Step 6: Collect motor parameters of the permanent magnet synchronous motor;

[0075] Step 7: Perform correlation analysis on the motor parameters of the permanent magnet synchronous motor to generate magnetic induction intensity;

[0076] When the permanent magnet synchronous motor rotor is eccentric, the air gap length between the stator and rotor changes, and the magnetic field strength through the air gap changes. Therefore, the degree of rotor eccentricity of the permanent magnet synchronous motor can be evaluated by the magnetic field strength.

[0077] The motor parameters include the magnetic induction intensity B0, the number of pole pairs p, the number of turns N of the stator winding, and the magnetic permeability μ of the stator core under normal motor working conditions. The correlation analysis of the motor parameters is performed to generate the magnetic induction intensity B. The formula based on this is:

[0078]

[0079] Among them, l d is the effective path length of the current through the stator winding, m is the number of phases of the stator winding, K is the winding distribution coefficient factor, the value range of K is [0.38,5.69], and I is the current intensity passing through the stator winding.

[0080] Step 8: Preprocess the magnetic induction intensity and the effective length of the mixed air gap to generate an eccentricity assessment coefficient of the permanent magnet synchronous motor, compare the eccentricity assessment coefficient of the permanent magnet synchronous motor with the threshold, and output the eccentricity safety confidence value of the permanent magnet synchronous motor. The eccentricity assessment coefficient of the permanent magnet synchronous motor is used to reflect the degree of eccentricity of the permanent magnet synchronous motor.

[0081] The correlation analysis of the magnetic induction intensity B of the permanent magnet synchronous motor and the effective length δ of the mixed air gap is performed to output the eccentricity evaluation coefficient PPX of the permanent magnet synchronous motor. The formula is as follows:

[0082]

[0083] Among them, the eccentricity evaluation coefficient PPX of the permanent magnet synchronous motor is used to reflect the comprehensive eccentricity of the permanent magnet synchronous motor. The eccentricity evaluation coefficient PPX of the permanent magnet synchronous motor is compared with the threshold value γ to output the eccentricity safety confidence value of the permanent magnet synchronous motor. The threshold value γ is 3.96:

[0084] When PPX>γ, it indicates that the eccentricity safety of the permanent magnet synchronous motor is poor, and the output eccentricity safety confidence value of the permanent magnet synchronous motor is 30%; when PPX<γ, it indicates that the eccentricity safety of the permanent magnet synchronous motor is good, and the output eccentricity safety confidence value of the permanent magnet synchronous motor is 70%. The smaller the eccentricity assessment coefficient of the permanent magnet synchronous motor, the higher the eccentricity safety confidence value of the permanent magnet synchronous motor. The higher the eccentricity safety confidence value of the permanent magnet synchronous motor, the smaller the eccentricity of the permanent magnet synchronous motor, and the better the eccentricity and air gap state of the permanent magnet synchronous motor.

[0085] The above formulas are all dimensionless and numerical calculations. The formula is a formula for the most recent real situation obtained by collecting a large amount of data and performing software simulation. The preset parameters in the formula are set by technicians in this field according to actual conditions.

[0086] The above embodiments may be implemented in whole or in part by software, hardware, firmware or any other combination thereof. When implemented by software, the above embodiments may be implemented in whole or in part in the form of a computer program product. Those skilled in the art may appreciate that the units and algorithm steps of each example described in conjunction with the embodiments disclosed herein may be implemented by electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are performed by hardware or software methods depends on the specific application and design constraints of the technical solution.

[0087] The units described as separate components may or may not be physically separated, and the components shown as units may or may not be physical units, and may be located in one place or distributed on multiple network units. Some or all of the units may be selected according to actual needs to achieve the purpose of the solution of this embodiment.

[0088] The above description is only a specific implementation manner of the present application, but the protection scope of the present application is not limited thereto. Any technician familiar with the technical field can easily think of changes or substitutions within the technical scope disclosed in the present application, which should be included in the protection scope of the present application.

Claims

1. A method for optimizing the non-uniform air gap structure of a permanent magnet synchronous motor, characterized in that: The specific steps include: S1. Establish an air gap calculation model for a permanent magnet synchronous motor; S2, collecting static air gap parameters and dynamic air gap parameters of the permanent magnet synchronous motor; S3, performing correlation processing on the static air gap parameters of the permanent magnet synchronous motor to generate a static effective air gap length, where the static effective air gap length is used to reflect the air gap length data of the permanent magnet synchronous motor in a static state; S4. Perform correlation processing on the dynamic air gap parameters of the permanent magnet synchronous motor to generate a dynamic effective air gap length, where the dynamic effective air gap length is used to reflect the air gap length data of the permanent magnet synchronous motor under working conditions; S5. Preprocessing the static effective air gap length and the dynamic effective air gap length to generate a mixed air gap effective length, where the mixed air gap effective length is used to reflect the effective air gap length data of the permanent magnet synchronous motor calculated and generated under comprehensive conditions; S6, collecting motor parameters of the permanent magnet synchronous motor; S7, performing correlation analysis on motor parameters of the permanent magnet synchronous motor to generate magnetic induction intensity; S8. Preprocess the magnetic induction intensity and the effective length of the mixed air gap to generate an eccentricity assessment coefficient of the permanent magnet synchronous motor, compare the eccentricity assessment coefficient of the permanent magnet synchronous motor with a threshold value, and output an eccentricity safety confidence value of the permanent magnet synchronous motor. The eccentricity assessment coefficient of the permanent magnet synchronous motor is used to reflect the degree of eccentricity of the permanent magnet synchronous motor.

2. The method for optimizing the non-uniform air gap structure of a permanent magnet synchronous motor according to claim 1, characterized in that: The static air gap parameters include static eccentricity e and air gap length g(θ), wherein the static eccentricity is the offset of the geometric center of the rotor relative to the geometric center of the stator, and the air gap length g(θ) is the air gap length between the stator and the rotor at an angle of θ. In S1, when establishing the calculation model, one of the symmetry planes of the stator is used as the reference plane, the geometric center of the stator is used as the collection origin, and the outer contour of the rotor is used as the collection point. The angle between the straight line connecting the collection origin and the collection point and the reference plane is recorded as θ. When collecting the static air gap parameters of the permanent magnet synchronous motor, the value range of θ is 0°, 1°, 2°, 3°...359°.

3. The method for optimizing the non-uniform air gap structure of a permanent magnet synchronous motor according to claim 2, characterized in that: Correlation analysis of the air gap length g(θ) is performed to generate the static average air gap length g based on the formula: Among them, the static average air gap length g is used to reflect the average distance between each contour point on the outer side of the rotor and the inner contour point on the stator at static state; The correlation analysis between the static average air gap length g and the air gap length g(θ) is performed to generate the air gap change Δg(θ), based on the formula: Δg(θ)=g(θ)-g The air gap variation Δg(θ) is used to reflect the difference between the air gap spacing at each angle and the average air gap length g; Let Δg(θ) = e*f(θ), f(θ) = k sinθ + a, generate the values ​​of k and a according to the least squares fitting method, and combine the above formula: Δg(θ) = g(θ) - g, to generate the static air gap length formula: g(θ)=g+e*ksinθ+e*a Perform correlation analysis on the static air gap length formula to generate the static effective air gap length L g , the formula based on is: Among them, the static effective air gap length L g It is used to reflect the estimated value of the static comprehensive air gap length between the stator and the rotor.

4. The method for optimizing the non-uniform air gap structure of a permanent magnet synchronous motor according to claim 3, characterized in that: The dynamic air gap parameters include the dynamic eccentricity e d (t) and dynamic air gap change Δg d (ω, t), where the dynamic eccentricity is the eccentric distance between the geometric center point of the rotor motion trajectory and the geometric center point of the stator when the motor is working. t starts from 0 seconds and the interval is Among them, T is the time required for the rotor to rotate one circle, and the dynamic air gap change is the distance between the outer contour of the rotor at an angle w at time t and the inner contour of the stator when the rotor is working.

5. The method for optimizing the non-uniform air gap structure of a permanent magnet synchronous motor according to claim 4, characterized in that: Set the dynamic air gap length to g d (ω,t), then g d (ω,t)=g+Δg d (ω,t), and let Δg d (ω,t)=e d (t)*f d (w), define the periodic function f d (w) = s*sinθ+b, and the values ​​of s and b are generated by the least squares fitting method, and the dynamic air gap length g d (ω,t) to perform correlation analysis and generate the dynamic effective air gap length L gd , the formula based on is: Among them, the dynamic effective air gap length L gd An estimated value of the comprehensive air gap length used to reflect the working conditions between the stator and the rotor.

6. The method for optimizing the non-uniform air gap structure of a permanent magnet synchronous motor according to claim 5, characterized in that: The correlation analysis of the static effective air gap length and the dynamic effective air gap length is performed to generate the mixed air gap effective length δ, based on the formula: δ=(L gd +L g )*(1-k s -k d ) Among them, k s Indicates the influence factor of static eccentricity, k d Indicates the influence factor of dynamic eccentricity, k s With k d The value of is no greater than 1, and k s +k d <1, the mixed air gap effective length δ is used to reflect the evaluation value of the comprehensive air gap length between the stator and the rotor of the permanent magnet synchronous motor.

7. The method for optimizing the non-uniform air gap structure of a permanent magnet synchronous motor according to claim 1, characterized in that: The motor parameters include the magnetic induction intensity B0, the number of pole pairs p, the number of turns N of the stator winding, and the magnetic permeability μ of the stator core under normal motor working conditions. The motor parameters are subjected to correlation analysis to generate the magnetic induction intensity B, and the formula based on this is: Among them, l d is the effective path length of the current through the stator winding, m is the number of phases of the stator winding, K is the winding distribution coefficient factor, the value range of K is [0.38,5.69], and I is the current intensity passing through the stator winding.

8. The method for optimizing the non-uniform air gap structure of a permanent magnet synchronous motor according to claim 6 or 7, characterized in that: The correlation analysis of the magnetic induction intensity B of the permanent magnet synchronous motor and the effective length δ of the mixed air gap is performed to output the eccentricity evaluation coefficient PPX of the permanent magnet synchronous motor. The formula is as follows: Among them, the eccentricity evaluation coefficient PPX of the permanent magnet synchronous motor is used to reflect the comprehensive eccentricity of the permanent magnet synchronous motor. The eccentricity evaluation coefficient PPX of the permanent magnet synchronous motor is compared with the threshold value γ to output the eccentricity safety confidence value of the permanent magnet synchronous motor. The threshold value γ is 3.96; When PPX>γ, it means that the eccentricity safety level of the permanent magnet synchronous motor is poor, and the output eccentricity safety confidence value of the permanent magnet synchronous motor is 30%; when PPX<γ, it means that the eccentricity safety level of the permanent magnet synchronous motor is good, and the output eccentricity safety confidence value of the permanent magnet synchronous motor is 70%.

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