Interference contact structure, finite element modeling calibration method and system for motor stator

Abstract

The present invention discloses a finite element modeling calibration method and system for an interference contact structure and a motor stator. The finite element modeling calibration method for the interference contact structure is applied to the interference contact structure. The interference contact structure includes a first component and a second component connected by interference fit. The method includes: dividing the first component into an equivalent contact portion and a remaining portion connected to the equivalent contact portion, wherein the equivalent contact portion is a portion contacting the second component; obtaining the modal calculation result of the interference contact structure after division; obtaining the modal test result of a sample of the interference contact structure, calibrating the parameters of the equivalent contact portion with the modal calculation result and the modal test result, and obtaining a modeling model after the calibration parameters. The present invention is a method for performing equivalent processing on key parts of the interference contact structure, optimizing the parameters of the equivalent structure, and compared with the method of directly modeling and calibrating the overall model, the present application can obtain a more accurate model structure, and the method is simple and easy to implement.

Description

Technical Field

[0001] The present invention relates to the technical field of motor design, and more specifically, to a finite element modeling calibration method and system for an interference contact structure. In addition, the present invention also relates to a finite element modeling calibration method for a motor stator including the above method, and a finite element modeling calibration system for a motor stator including the above system. Background Art

[0002] As a product that provides power, electric motors are widely used in industries such as rail transit and automobiles.

[0003] In the motor structure design, the stator system is one of the core components of the motor, and its dynamic design is crucial. The quality of the design will affect the vibration fatigue life and NVH of the motor. Modal calculation is the basis for analyzing dynamic characteristics. Therefore, it is necessary to establish an accurate motor stator system model through simulation methods for evaluation. However, the motor winding distribution is complex and difficult to model. The stator core is made of laminated sheets and has complex mechanical characteristics. In particular, the interference between the housing and the wire-embedded stator involves nonlinear problems. How to consider its impact on the dynamic characteristics of the motor is crucial.

[0004] Therefore, how to establish an accurate system modeling method has become an urgent problem that technical personnel in this field need to solve. Summary of the invention

[0005] In view of this, an object of the present invention is to provide a finite element modeling and calibration method and system for an interference contact structure, in which the results of modeling and calibration of the interference fit structure are more accurate.

[0006] Another object of the present invention is to provide a finite element modeling and calibration method of a motor stator including the above method and a finite element modeling and calibration system of a motor stator including the above system. Due to the use of the above interference contact processing method, the processing result of the motor stator is more accurate.

[0007] In order to achieve the above object, the present invention provides the following technical solutions:

[0008] A finite element modeling calibration method for an interference contact structure is applied to the interference contact structure, wherein the interference contact structure comprises a first component and a second component connected by interference fit, and the method comprises:

[0009] Dividing the first component into an equivalent contact portion and a remaining portion connected to the equivalent contact portion, wherein the equivalent contact portion is a portion contacting the second component; obtaining a modal calculation result of the interference contact structure after the division;

[0010] The modal test result of the sample of the interference contact structure is obtained, and the parameters of the equivalent contact part are calibrated with the modal calculation result and the modal test result, and the modeling model after the parameters are calibrated is obtained.

[0011] Preferably, obtaining the modal calculation results of the interference contact structure after division includes: processing the joint surface between the equivalent contact portion and the second component, and the joint surface between the equivalent contact portion and the remaining portion by a common node method, and obtaining the modal calculation results of the processed model.

[0012] Preferably, obtaining the modal calculation results of the processed model includes: obtaining several groups of frequencies and vibration modes of the modal calculation;

[0013] Calibrate the parameters of the equivalent contact part, including:

[0014] The initial values ​​of the parameters of the equivalent contact portion are obtained, and are corrected using an iterative algorithm. When the frequency deviation and vibration mode correlation between the modal calculation result and the modal test result are both within a preset range, the calibration values ​​of the parameters are determined.

[0015] Preferably, the preset range of the frequency deviation is less than 5%, the preset range of the vibration mode correlation is greater than 90%, and the vibration mode correlation MAC (ψ simulation ,ψ test )for:

[0016]

[0017] Among them, ψ simulation is the vibration mode of the modal calculation result; ψ test is the vibration shape of the modal test result.

[0018] Preferably, the parameters include elastic modulus, Poisson's ratio and density; obtaining the initial values ​​of the parameters of the equivalent contact portion includes: obtaining an initially set elastic modulus and an initial Poisson's ratio, and setting the density to the density of the first component.

[0019] A finite element modeling and calibration method for a motor stator, the motor stator comprising a housing and a stator core having an interference fit with the housing, the stator core being provided with a winding, the method comprising:

[0020] In the finite element modeling and calibration method for the interference contact structure described in any of the above items, the housing is the first component, and the stator core and the winding are the second components.

[0021] Preferably, before the finite element modeling and calibration of the interference contact structure, several components of the motor stator are optimized respectively, and the component optimization includes:

[0022] Performing finite element modeling and modal calculation on one of the components to extract the simulation frequency and simulation vibration shape of the component;

[0023] Performing modal testing on a sample of the component to extract a test frequency and a test vibration shape of the sample;

[0024] The simulation frequency and simulation vibration mode, the test frequency and test vibration mode are used to iteratively optimize the structural parameters of the component, and a structural model corresponding to the iteratively optimized structural parameters is obtained.

[0025] Preferably, the component optimization is performed on the housing, the stator core, and the combination of the stator core and the winding one by one, and the components of the motor stator include at least a housing, a stator core, and the combination of the stator core and the winding.

[0026] Preferably, the iterative optimization criteria include:

[0027] The preset range of the frequency deviation between the simulation frequency and the test frequency is less than 5%, the vibration mode correlation between the simulation vibration mode and the test vibration mode is greater than 90%, and the vibration mode correlation MAC (ψ simulation ,ψ test )for:

[0028]

[0029] Among them, ψ simulation is the simulation vibration shape; ψ test is the test vibration shape.

[0030] Preferably, in the modal test of the housing, the measuring points are arranged in the contact area between the housing and the stator core;

[0031] And / or, in the modal test of the housing, the measuring points are evenly distributed in the axial direction or the circumferential direction;

[0032] And / or, in the modal test of the stator core, at least three measuring points are arranged in the axial direction, or at least ten measuring points are arranged in the circumferential direction.

[0033] A finite element modeling and calibration system for an interference contact structure is applied to the interference contact structure, wherein the interference contact structure comprises a first component and a second component connected by interference fit, and the system comprises:

[0034] A modeling and calculation module, used for dividing the first component into an equivalent contact portion and a remaining portion connected to the equivalent contact portion, wherein the equivalent contact portion is a portion contacting the second component; and obtaining a modal calculation result of the interference contact structure after the division;

[0035] A test calibration module is used to obtain the modal test results of the interference contact structure, calibrate the parameters of the equivalent contact part with the modal calculation results and the modal test results, and obtain the modeling model after calibrating the parameters. The test calibration module is connected to the modeling calculation module.

[0036] Preferably, the modeling and calculation module includes:

[0037] a dividing unit, configured to divide the first component into an equivalent contact portion and a remaining portion connected to the equivalent contact portion, wherein the equivalent contact portion is a portion contacting the second component;

[0038] A processing unit is used to process the joint surface between the equivalent contact portion and the second component, and the joint surface between the equivalent contact portion and the remaining portion by using a common node method, and obtain the modal calculation result of the processed model. The processing unit is signal-connected to the division unit.

[0039] Preferably, the test calibration module comprises:

[0040] The optimization unit is used to obtain the initial value of the parameter of the equivalent contact part and correct the parameter by using the optimization algorithm. When the frequency deviation and vibration mode correlation between the modal calculation result and the modal test result are both within a preset range, the parameter is determined to be a calibration value.

[0041] Preferably, the optimization unit includes a judgment subunit, and the optimization conditions set in the judgment subunit include the preset range of the frequency deviation being less than 5%, the preset range of the vibration mode correlation being greater than 90%, and the vibration mode correlation MAC (ψ simulation ,ψ test )for:

[0042]

[0043] Among them, ψ simulation is the vibration mode of the modal calculation result; ψ test is the vibration shape of the modal test result.

[0044] Preferably, the optimization unit comprises an acquisition device for acquiring elastic modulus, Poisson's ratio and density, and the density is set as the density of the first component in the acquisition device.

[0045] A finite element modeling calibration system for a motor stator, the motor stator comprising a housing and a stator core having an interference fit with the housing, the stator core being provided with a winding, the finite element modeling test system comprising:

[0046] In the finite element modeling and calibration system of the interference contact structure described in any of the above items, the housing is the first component, and the stator core and the winding are the second components.

[0047] Preferably, it also includes:

[0048] A simulation module, used for performing finite element modeling and modal calculation on a component of the motor stator, and extracting a simulation frequency and a simulation vibration shape of the component;

[0049] A testing module, used to perform modal testing on a sample of the component and extract a test frequency and a test vibration shape of the sample;

[0050] The calibration module is used to iteratively optimize the structural parameters of the component according to the simulation frequency and simulation vibration mode, the test frequency and test vibration mode, and obtain a structural model corresponding to the iteratively optimized structural parameters.

[0051] Preferably, the plurality of components include at least a casing, a stator core, and a combination of the stator core and a winding.

[0052] Preferably, the conditions for optimizing the calibration module to obtain the structural parameters include:

[0053] The preset range of the frequency deviation between the simulation frequency and the test frequency is less than 5%, the vibration mode correlation between the simulation vibration mode and the test vibration mode is greater than 90%, and the vibration mode correlation MAC (ψ simulation ,ψ test )for:

[0054]

[0055] Among them, ψ simulation is the simulation vibration shape; ψ test is the test vibration shape.

[0056] Preferably, the measuring points for the modal test of the housing are arranged in the contact area between the housing and the stator core;

[0057] And / or, the measuring points of the modal test of the casing are evenly distributed in the axial direction or the circumferential direction;

[0058] And / or, the modal test of the stator core has at least three measuring points arranged in the axial direction, or at least ten measuring points arranged in the circumferential direction.

[0059] The solution provided by the present invention performs equivalent treatment on key parts of the interference contact structure and optimizes the parameters of the equivalent structure. Compared with the method of directly modeling and calibrating the overall model, the method of the present application optimizes and calibrates the parameters of the equivalent structure, which can obtain a more accurate model structure, and the method is simple and easy to implement. BRIEF DESCRIPTION OF THE DRAWINGS

[0060] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without paying creative work.

[0061] Figure 1 A flow chart of the finite element modeling calibration method for the interference contact structure provided by the present invention;

[0062] Figure 2 A flow chart of the finite element modeling and calibration method of the motor stator provided by the present invention;

[0063] Figure 3 is a cross-sectional view of a motor stator involved in the present invention;

[0064] Figure 4 A front cross-sectional view showing the arrangement of measuring points of the casing involved in the present invention;

[0065] Figure 5 A side sectional view showing the arrangement of measuring points of the housing involved in the present invention;

[0066] Figure 6 A front cross-sectional view showing the arrangement of measuring points of the stator core involved in the present invention;

[0067] Figure 7 It is a side sectional view showing the arrangement of measuring points of the stator core involved in the present invention.

[0068] Figure 1-7 middle:

[0069] 1 is the housing, 2 is the winding, 3 is the stator core, 4 is the remaining part, 5 is the equivalent contact part, and 6 is the measuring point; among them, Figure 4 The arrow direction is axial, Figure 6 The arrow direction is axial. DETAILED DESCRIPTION

[0070] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0071] The core of the present invention is to provide a finite element modeling and calibration method and system for an interference contact structure, in which the results of modeling and calibration of the interference fit structure are more accurate.

[0072] Another core of the present invention is to provide a finite element modeling and calibration method of a motor stator including the above method and a finite element modeling and calibration system of a motor stator including the above system. Due to the use of the above interference contact processing method, the processing result of the motor stator is more accurate.

[0073] The present application provides a finite element modeling calibration method for an interference contact structure, which is applied to the interference contact structure. The interference contact structure includes a first component and a second component connected by interference fit. The specific method includes the following steps:

[0074] Step S1, dividing the first component into an equivalent contact portion and a remaining portion connected to the equivalent contact portion, wherein the equivalent contact portion is a portion contacting the second component; and obtaining a modal calculation result of the interference contact structure after the division.

[0075] Step S2, obtaining the modal test results of the sample of the interference contact structure, calibrating the parameters of the equivalent contact part with the modal calculation results and the modal test results, and obtaining the modeling model after the calibration parameters.

[0076] In the above method, the interference contact structure is explained by the interference fit of the first and second components, which are nested and have a close contact portion. There is no limitation on the structure of the first component and the second component. The interference contact structure includes but is not limited to the interference fit of the first component and the second component, and can be an interference fit of multiple structures.

[0077] In step S1, the first component is structurally divided, and a portion of the first component that contacts the second component is an equivalent contact portion, and the rest of the first component is a residual portion. Subsequently, mesh division and other operations will be performed on the contact surfaces of the equivalent contact portion that contact the residual portion and the second component, respectively. Therefore, the equivalent contact portion is a structure with a certain length and a certain thickness. The length and thickness can be determined according to specific circumstances, and a thinner sheet structure is preferably used.

[0078] The division of the first component is the modeling process of the interference contact structure. After the division, the equivalent contact part is regarded as a structure that contacts the remaining part and the second component respectively, and the modal calculation of the structure composed of the three is performed to obtain the corresponding modal calculation results.

[0079] In step S2, a modal test is performed on a sample of the interference contact structure, and a corresponding modal test result is obtained. The modal test is an actual measurement, and the corresponding result is the result of the actual measurement.

[0080] Then, the modal calculation results and modal test results are used for optimization calibration. The calibration object is the parameters of the equivalent contact part, which mainly include material parameters, such as elastic modulus, Poisson's ratio, density, etc. Convergence conditions need to be set during the optimization process. The optimization result obtained by optimization calibration is the optimal result under the convergence condition, that is, the optimized parameters of the equivalent contact part are obtained. The optimized calibration model of the interference contact structure can be obtained through the optimized parameters. Compared with the model before the first component is divided, the model after optimization calibration is a more accurate model.

[0081] It should be noted that, in the above process of optimizing parameters, the density can be selected as the density of the first component, and other parameters are calibrated accordingly so that the parameters are continuously approached to the parameters corresponding to the convergence conditions.

[0082] In the prior art, interference contact structures are usually treated by direct meshing, without performing a separate analysis on the joint surfaces of the interference contact. This usually results in a larger stiffness of the joint surfaces, and the obtained structural modal frequencies and vibration shapes are both too large, which in turn leads to larger deviations in the result values ​​of dynamic calculations and noise and vibration calculations.

[0083] Since the embodiment of the present application provides a method for performing equivalent treatment on the key parts of the interference contact structure and continuously optimizes the parameters of the equivalent structure, compared with the method of directly modeling and calibrating the overall model, the method of the present application optimizes and calibrates the parameters of the equivalent structure, which can obtain a more accurate model structure, and the method is simple and easy to implement.

[0084] On the basis of the above embodiment, the modal calculation result of the divided interference contact structure is obtained in step S1, which specifically includes the following steps:

[0085] Step S11, using a common node method to process the joint surface between the equivalent contact portion and the second component, and the joint surface between the equivalent contact portion and the remaining portion, to obtain the modal calculation result of the processed model.

[0086] The joining surface between the equivalent contact portion and the second component is the joining surface between the original first component and the second component, and the joining surface between the equivalent contact portion and the remaining portion is the cutting surface of the first component.

[0087] The two joint surfaces are processed with common nodes, that is, the grid division is processed by the common node method. There are many types of grid division in the modeling process in the prior art. In this embodiment, the common node method is used to obtain a more accurate modeling result. The two joint surfaces are processed with common nodes separately, so that the equivalent contact parts can be processed separately.

[0088] On the basis of the above embodiment, the modal calculation result of the processed model is obtained in step S11, which specifically includes the following steps:

[0089] Step S111, obtaining several groups of frequencies and vibration modes of the modal calculation.

[0090] In step S2, the parameters of the equivalent contact portion are calibrated, specifically including the following steps:

[0091] Step S21, obtaining the initial values ​​of the parameters of the equivalent contact part, modifying them using an iterative algorithm, and determining the calibration values ​​of the parameters when the frequency deviation and vibration mode correlation between the modal calculation result and the modal test result are both within a preset range.

[0092] This embodiment includes two parts. The first part is the output result of the modal calculation. The modal calculation obtains several groups of frequencies and vibration shapes.

[0093] The process of processing the bonding surface in the above step S11 is a common process in modeling, which specifically includes meshing and boundary processing of the established model, that is, processing of the bonding surface, and it is also necessary to set the initial value of the material property and perform modal calculation. In step S111, a series of frequencies and vibration modes are obtained through modal calculation. In the analysis of vibration and noise, the 2nd, 3rd, 4th and 0th order frequencies and vibration modes are usually concerned. Therefore, the corresponding frequencies and vibration modes can be extracted. Optionally, it is not limited to the above extraction content, and it can also be selected according to actual conditions.

[0094] The operation of calibrating the parameters of the equivalent contact part in the above step S2 can be specifically an iterative optimization, firstly setting the initial value of the parameters of the equivalent contact part, using the iterative algorithm, iterating under the set convergence conditions, and obtaining the optimization result under the convergence conditions, that is, the calibration value of the corresponding parameter.

[0095] For example, the elastic modulus and Poisson's ratio can be used as parameters to be calibrated, and corresponding convergence conditions can be set, such as setting the frequency or vibration mode of the target. Under the condition of gradually approaching the frequency and vibration mode of the target, the elastic modulus and Poisson's ratio gradually approach the optimized value, and finally the calibration value is obtained under the conditions met. In this embodiment, the frequency deviation and vibration mode correlation of modal calculation and modal test are used as convergence conditions, which is a more reliable convergence condition. Of course, the present application is not limited to the above convergence method.

[0096] On the basis of the above embodiment, the preset range of the frequency deviation is less than 5%, the preset range of the mode correlation is greater than 90%, and the mode correlation is:

[0097]

[0098] Among them, ψ simulation is the vibration shape of the modal calculation result; ψ test is the vibration shape of the modal test result.

[0099] With respect to the above-mentioned method of using frequency deviation and vibration mode correlation as convergence targets, the present application provides a more reliable embodiment, in which the frequency deviation range is set to less than 5%, that is, when the deviation between the frequency of modal calculation and the frequency of modal test is less than 5%, and when the correlation between the vibration mode of modal calculation and the vibration mode of modal test is greater than 90%, the parameters of the equivalent contact part are considered to be the optimized results, and the model corresponding to the parameters at this time is the optimized model.

[0100] On the basis of any of the above embodiments, the parameters include elastic modulus, Poisson's ratio and density; wherein, obtaining the initial values ​​of the parameters of the equivalent contact portion in step S21 specifically includes the following steps:

[0101] Step S211 , obtaining an initially set elastic modulus and an initial Poisson's ratio, and setting the density as the density of the first component.

[0102] Since the first component is actually still an integral structure, the density of the equivalent contact part still needs to be the density of the first component. In addition to the density, the Poisson's ratio and elastic modulus that need to be considered in the modeling process are usually used as optimization targets. If an iterative optimization algorithm is selected, the initial value of the optimization target needs to be given. The selection of the initial value can be given according to the common methods in the prior art.

[0103] Optionally, the acquisition operation in step S211 may be only an acquisition operation, or may be obtained by empirical selection. That is, the elastic modulus and initial Poisson's ratio set initially may be given manually, and only acquisition is performed in the steps of the above method, or the above steps are selected empirically from an existing candidate library.

[0104] In the present application, during the finite element modeling and calibration process of the two parts of the interference contact, the structure of one of them is simulated and divided, and the part contacting the other is virtualized as an equivalent contact part of an independent structure, and two independent bonding surfaces are obtained. The material parameters of the equivalent contact part are optimized through the results of modal calculation and modal testing, thereby obtaining the equivalent contact part and the overall optimization model. The method of dividing the equivalent contact part can make the material parameter results of this part more accurate, the results obtained in the whole process are more accurate, and the process is simple.

[0105] In addition to the finite element modeling and calibration methods for interference contact structures provided in the above embodiments, the present invention also provides a finite element modeling and calibration system for interference contact structures, which is mainly used to implement the above methods.

[0106] Specifically, the present application provides a finite element modeling and calibration system for an interference contact structure, which is applied to the interference contact structure. The interference contact structure includes a first component and a second component connected by interference fit. The finite element modeling and calibration system for the interference contact structure includes: a modeling calculation module and a test calibration module.

[0107] A modeling and calculation module is used to divide the first component into an equivalent contact portion and a remaining portion connected to the equivalent contact portion, wherein the equivalent contact portion is a portion that contacts the second component; and obtain a modal calculation result of the interference contact structure after the division;

[0108] The test calibration module is used to obtain the modal test results of the interference contact structure, calibrate the parameters of the equivalent contact part with the modal calculation results and the modal test results, and obtain the modeling model after the calibration parameters. The test calibration module is connected to the modeling calculation module.

[0109] It should be noted that the modeling calculation module and the test calibration module are virtual structures, which are mainly used to complete steps S1 and S2 in the above method. Therefore, the two can be the corresponding operation processing modules in the computer system that complete the above method, or can be independent integrated chips that can run or store the above method.

[0110] The modeling and calculation module corresponds to the steps of completing the modal calculation, and the test and calibration module corresponds to the steps of completing the modal test of the sample and the calibration with the modal calculation results. Both are virtual modules, and the corresponding physical structures are the hardware structures commonly used in the prior art for modeling and analysis.

[0111] The system provided in the present application performs equivalent processing, modeling and calibration on the key parts of the interference contact structure. By continuously optimizing the parameters of the equivalent structure, the calibration values ​​of the optimized calibration of the parameters of the equivalent structure can be obtained, and a more accurate model structure can be obtained. The method is simple and easy to implement. In addition, from the perspective of hardware structure, there is no need to add other structures, and the existing structure set can be selected to complete it.

[0112] On the basis of the above-mentioned embodiment, the modeling and calculation module includes: a division unit and a processing unit.

[0113] The dividing unit is used to divide the first component into an equivalent contact portion and a remaining portion connected to the equivalent contact portion, wherein the equivalent contact portion is a portion that contacts the second component;

[0114] The processing unit is used to process the joint surface between the equivalent contact part and the second component, and the joint surface between the equivalent contact part and the remaining part by using a common node method, and obtain the modal calculation result of the processed model. The processing unit is connected to the division unit signal.

[0115] The specific functions of the modeling and calculation module are completed by two parts. The division unit is mainly used to divide the first component. The division method can refer to the embodiment of the above method. The division unit is connected to the processing unit. The processing unit obtains the division result of the division unit and performs common node processing on the two joint surfaces of the equivalent contact part, which is a mesh division operation. The modal calculation is performed on the entire structure after the division to obtain the corresponding modal calculation frequency and vibration mode.

[0116] Specifically, the processing unit and the division unit may be a virtual structure or a specific physical structure, that is, they may be a computing processing unit in a computer system that performs the above method, or an independent integrated chip that can run or store the above method.

[0117] It should be noted that the above processing unit may include a grid division subunit and a modal calculation subunit, or include other functional units and subunits. In addition, other structures in the above modules may refer to the prior art.

[0118] Based on the above embodiment, the test calibration module includes an optimization unit.

[0119] The optimization unit can be used to obtain the initial values ​​of the parameters of the equivalent contact part and modify the parameters using the optimization algorithm. When the frequency deviation and vibration mode correlation between the modal calculation results and the modal test results are within the preset range, the parameters are determined to be calibration values.

[0120] The optimization unit may be a virtual unit or an integrated unit having the above functions. The operations and steps of the optimization algorithm, parameter acquisition, frequency deviation, and vibration mode correlation may refer to the above method embodiments.

[0121] On the basis of the above embodiment, the optimization unit at least includes a judgment subunit. The optimization conditions set in the judgment subunit include a preset range of frequency deviation less than 5%, a preset range of mode correlation greater than 90%, and a mode correlation of:

[0122]

[0123] Among them, ψ simulation is the vibration mode of the modal calculation result; ψ test is the vibration shape of the modal test result.

[0124] In a specific embodiment, the optimization unit at least includes an acquisition subunit, an optimization subunit and a judgment subunit.

[0125] The acquisition subunit is used to obtain the initial values ​​of the parameters of the equivalent contact part and send them to the optimization subunit for optimization. During the optimization process, the optimization subunit sends the optimization results to the judgment subunit. The judgment subunit judges the optimization results based on the above-mentioned optimization conditions and obtains the optimization results after meeting the optimization conditions.

[0126] Optionally, the optimization unit includes an acquisition device for acquiring elastic modulus, Poisson's ratio and density, and the density is set as the density of the first component in the acquisition device. In other words, the acquisition subunit includes an acquisition device for acquiring elastic modulus, Poisson's ratio and density.

[0127] In the above embodiments of the finite element modeling and calibration system for interference contact structure, since the system can be a physical system or a virtual system, it is mainly introduced from the structure and connection method, and the specific steps and methods can refer to the embodiments of the above method.

[0128] The finite element modeling and calibration system of the interference contact structure provided in the present application divides the interference contact structure into equivalent contact parts and obtains two independent bonding surfaces. The material parameters of the equivalent contact parts are optimized through the results of modal calculation and modal testing, thereby obtaining the equivalent contact parts and the overall optimization model. The system makes the material parameter results of this part more accurate, the results obtained in the whole process are more accurate, and the process is simple.

[0129] In addition to the finite element modeling calibration method and system for the interference contact structure in the above-mentioned embodiments, the present invention also provides a finite element modeling calibration method and system for a motor stator.

[0130] Among them, a finite element modeling test method for a motor stator, the motor stator includes a housing and a stator core with an interference fit with the housing, and a winding is provided on the stator core, the method includes:

[0131] Step S100, the finite element modeling and calibration method of the interference contact structure described in any one of the above items, wherein the housing is the first component, and the stator core and the winding as a whole are the second component.

[0132] It should be noted that the motor stator provided in this application refers to the motor stator system in the motor, hereinafter referred to as the motor stator. The motor stator includes a housing 1, a winding 2, and a stator core 3. Among them, the winding 2 and the stator core 3 constitute an embedded stator. In order to bear the electromagnetic counter-torque of the motor, an interference fit is usually adopted between the housing 1 and the stator core 3 to form a contact joint surface.

[0133] Specifically, the housing 1 is divided into two parts, one is the part in contact with the stator core 3, and the other is the remaining part of the housing 1.

[0134] In the finite element modeling and calibration method of the motor stator of the present application, the interference-fitted casing 1 and the stator core 3 are treated as interference contact structures, and the equivalent contact portion is extracted from the casing 1, so that the characteristics of each part of the interference-fit structure can be analyzed and processed in a targeted manner. Compared with the method of analyzing the casing 1 as a whole in the prior art, the different functional structures on the casing 1 can be classified and processed, and the obtained optimization results are more in line with the optimization goals, avoiding the situation where the frequency and vibration mode values ​​are too large during the optimization process, and effectively avoiding the situation where it is difficult to converge. After the modal calculation of the simulation model and the modal analysis of the sample, the material parameters of the equivalent contact portion can be obtained in a targeted manner, and the overall modeling of the casing 1, the stator core 3, and the winding 2 can be further obtained. More accurate and more in line with the target optimization conditions.

[0135] The present application proposes a solution for dividing the housing 1 and the stator core 3. Of course, the motor stator as a whole can also be divided into multiple components for separate modeling, analysis, optimization and calibration.

[0136] In the prior art, finite element modeling, modal testing and model calibration are usually performed on the entire motor stator. The material parameters of each part are different. During the modeling and optimization process, static analysis and nonlinear calculation and processing are required, which is relatively complicated and it is not easy to form an optimization result.

[0137] In a specific embodiment provided by the present application, finite element modeling, modal testing and model calibration operations can be performed on each part respectively. Taking the motor stator including the housing 1, the winding 2 and the stator core 3 as an example, finite element modeling, modal testing and model calibration operations can be performed on these three parts respectively, so as to obtain targeted optimization models of each part.

[0138] In a specific embodiment, the above method comprises the following steps in sequence:

[0139] Finite element modeling and calibration of the housing 1;

[0140] Finite element modeling and calibration of the stator core 3;

[0141] Finite element modeling and calibration of wire-embedded stator;

[0142] Finite element modeling and calibration of interference contact structures.

[0143] The wire-embedded stator is an integral structure of the stator core 3 and the winding 2, and the interference contact structure is an interference fit structure formed by the housing 1 and the stator core 3. Finite element modeling and calibration refers to performing finite element modeling, modal calculation and modal testing on existing samples, comparing the results of the two, selecting the material parameters of the structure that meet the comparison results, and obtaining an optimized model based on the material parameters.

[0144] Specifically, before the finite element modeling and calibration of the interference contact structure in step S100, several components of the motor stator are optimized respectively, and the component optimization includes:

[0145] Step S201: perform finite element modeling and modal calculation on a component, and extract the simulation frequency and simulation vibration shape of the component.

[0146] Step S202: Perform modal testing on a sample of the component to extract the test frequency and test vibration shape of the sample.

[0147] Step S203: Iteratively optimize the structural parameters of the component using the simulation frequency and simulation vibration shape, the test frequency and the test vibration shape, and obtain a structural model corresponding to the iteratively optimized structural parameters.

[0148] In steps S201-S203, the operation of optimizing the components is always performed on the same component in the motor stator. Of course, the above component optimization can be performed on each component separately to obtain the optimization results of each component.

[0149] Finite element modeling of a component is to establish a simulation model, and the result is the simulation model, as well as the frequency and vibration mode of the simulation model. The sample refers to the existing actual model, and the modal test of the sample results in the test frequency and test vibration mode of the sample. The goal of optimization is to reduce the deviation between simulation and test, specifically the frequency deviation and vibration deviation.

[0150] It should be noted that the components of the above-mentioned motor stator include at least a casing 1, a stator core 3, and a combination of the stator core 3 and the winding 2. The above-mentioned component optimization can perform component optimization of steps S201-S203 on the casing 1, the stator core 3, and the combination of the stator core 3 and the winding 2 one by one, and obtain the optimization results of each component respectively.

[0151] In the prior art, the modeling analysis and optimization are usually performed on the whole motor stator, which is not very targeted, and the calculation process is relatively complicated, and it is easy to have the problem of non-convergence. In this application, independent finite element modeling and analysis are performed for each component, and the optimization results of each part can be obtained respectively, so as to be used for the overall optimization process in the subsequent steps, and the components can be optimized in a targeted manner, and finally the overall optimization result can be obtained.

[0152] It should be added that in the preferred solution, the analysis of each part is carried out in the following order: housing, motor stator, wire-embedded stator, interference contact structure. This order ensures that the part structure is analyzed first, and the overall structure is analyzed later.

[0153] Based on the above embodiment, the iterative optimization criteria include:

[0154] The preset range of the frequency deviation between the simulation frequency and the test frequency is less than 5%, and the vibration mode correlation between the simulation vibration mode and the test vibration mode is greater than 90%, and the vibration mode correlation is:

[0155]

[0156] Among them, ψ simulation is the simulation vibration mode; ψ test To test vibration mode.

[0157] That is to say, when the above criteria are met, the parameters of the structure are optimized parameters, and in the iterative process, the above criteria are assessment indicators that can end the iterative optimization. Optionally, the optimization criteria given above are criteria in a specific implementation, and those skilled in the art can adjust them according to actual conditions.

[0158] On the basis of any of the above embodiments, in the modal test of the casing, the measuring point 6 is arranged in the contact area between the casing 1 and the stator core 3;

[0159] and / or, in the modal test of the housing 1, the measuring points 6 are arranged to be evenly distributed in the axial direction or the circumferential direction;

[0160] And / or, in the modal test of the stator core 3, the number of measuring points 6 arranged in the axial direction is at least 3 points, or the number of measuring points 6 arranged in the circumferential direction is at least 10 points.

[0161] In a preferred embodiment, the modeling and calibration method provided above specifically targets objects including the housing 1, the stator core 3, the wire-embedded stator and the interference contact structure. The operation steps of each part are introduced in sequence below.

[0162] First, in the finite element modeling and calibration of the housing 1, the finite element software is used to perform meshing and boundary processing on the three-dimensional model of the housing 1. The material property is the elastic modulus E housing , Poisson's ratio v housing , density ρ housing . Where ρ housing The value of ensures that the quality of the casing is the same as the actual test quality.

[0163] Elastic modulus E housing , Poisson's ratio v housingThe initial value of is the general property value of the housing 1. In the modal calculation, the frequencies and vibration modes of interest can be extracted. Usually, the 2nd, 3rd, 4th and 0th order frequencies and vibration modes are extracted in the vibration and noise calculation.

[0164] The modal test of the housing 1 is performed on an actual sample of the housing 1 . Specifically, a moving hammer method or a moving sensor method may be used to perform the modal test and obtain the required frequency and vibration mode.

[0165] The following principles should be followed for the arrangement of measuring points 6: measuring points 6 are mainly arranged within the contact area between the casing 1 and the stator core 3; if there is a water channel in the casing, the position of measuring points 6 within the contact area between the casing 1 and the stator core 3 should avoid the water channel area as much as possible; the measuring points 6 should be arranged in a uniform or nearly uniform distribution; there should be no less than 5 axial measuring points 6 of the casing 1, of which no less than 3 are within the contact area between the casing 1 and the stator core 3; no less than 10 measuring points 6 should be arranged in a section in the circumferential direction of the casing 1.

[0166] In the calibration of the housing 1 model, the elastic modulus E of the housing 1 is continuously and iteratively corrected according to the modal test results and modal calculation results. housing and Poisson's ratio v housing , so that the frequency deviation between the simulation model and the sample model is less than 5%, the MAC value is greater than 90%, and finally the housing 1 model consistent with the measured results is obtained.

[0167] Optionally, the arrangement of the measuring points 6 and the selection of parameters can be appropriately adjusted and changed based on the existing technology. This embodiment provides only a relatively reliable solution, and other solutions extended from this also belong to the protection scope of this application.

[0168] Then, in the finite element modeling and calibration of the stator core, the stator core 3 is modeled, and the stator core 3 can be equivalent to a solid, and its material properties include:

[0169] E 1_stator 、E 2_stator 、E 3_stator is the elastic modulus, μ 12_stator , μ 23_stator , μ 31_stator is Poisson's ratio, G 12_stator , G 23_stator , G 31_stator is the shear modulus.

[0170] Among them, 1, 2, and 3 represent the x, y, and z directions respectively. x and y are the end surface directions, correspondingly, 12 is the xy end surface direction, and z is the axial direction.

[0171] The density value needs to make the mass of the stator core 3 the same as the actual test mass. The elastic modulus, Poisson's ratio and shear modulus can be set as the initial value for the stator core 3 according to the linear elastic material of the structural steel. When performing modal calculations, the required frequency and vibration mode are obtained, and the frequencies and vibration modes of the 2nd, 3rd, 4th and 0th orders are usually selected. Optionally, the assignment of the above initial values ​​can be adjusted according to actual conditions.

[0172] In the modal test of the sample of the stator core 3, the moving hammer method or the moving sensor method can be used to perform the modal test and obtain the required frequency and vibration mode. The corresponding measurement point 6 arrangement principles include: the measurement points 6 of the stator core 3 are arranged in a uniform or nearly uniform manner, the axial measurement points 6 of the stator core 3 are arranged with no less than 3 measurement points 6, and no less than 10 measurement points 6 are arranged in a single row in the circumferential direction. Optionally, there is no correlation between the above measurement points 6 arrangements, and they can be adjusted according to specific circumstances.

[0173] During the calibration of the stator core model, the elastic modulus E of the stator core 3 is iteratively corrected through the optimization algorithm. housing and Poisson's ratio v housing , so that the frequency deviation between the simulation model and the measured results is less than 5%, the MAC value is greater than 90%, and finally a finite model of the stator core 3 consistent with the measured results is obtained. Optionally, the calibration standard can be adjusted according to actual conditions and is not limited to the case provided in this application.

[0174] The embedded stator is mainly composed of a stator core 3 and a winding 2. During the finite element modeling and calibration of the embedded stator, the stator core 3 has been modeled and calibrated, so the equivalence of the winding 2 is mainly focused on. Specifically, the winding part in the slot can be equivalent to a three-dimensional entity, which is treated with the stator core 3 in a common node manner, and the winding part outside the slot is specifically equivalent to a mass point. The material properties of the winding in the slot are elastic modulus, Poisson's ratio and density (E winding , μ winding , winding ). winding The value of ensures that the mass of the wire-embedded stator is the same as the actual test mass. Optionally, the elastic modulus, Poisson's ratio, and shear modulus are assigned to winding 2 according to the material properties of copper. When performing modal calculations, the frequencies and vibration modes of the 2nd, 3rd, 4th, and 0th orders are obtained.

[0175] In the modal test of the embedded stator, the moving hammer method or the moving sensor method can be used to perform the modal test, and the required frequency and vibration mode can also be extracted. Since it is a connection structure with the stator core 3, its point arrangement method is the same as the stator core 3.

[0176] During the model calibration process, the elastic modulus E of winding 2 can be corrected by iteration housing and Poisson's ratio v housing, so that the frequency deviation between the simulation model and the test model is less than 5%, the MAC value is greater than 90%, and finally a finite model of the embedded stator that is consistent with the measured results is obtained.

[0177] Finally, for the finite element modeling and calibration method of the interference contact structure, the parts that are the same as the above parts will not be repeated.

[0178] A portion of the housing 1 near the stator core 3 is divided to form an equivalent contact portion 5, and the remaining portion is a remaining portion 4. The bonding surface of the remaining portion 4 and the equivalent contact portion 5 is processed in a common node manner, and the bonding surface of the equivalent contact portion 5 and the stator core 3 is processed in a common node manner.

[0179] The modal test of the interference contact structure is based on the actual assembled stator system sample. The modal test can be performed using a moving hammer method or a moving sensor method. The selection of frequency, vibration mode and distribution point can refer to the selection of housing 1.

[0180] In the calibration of the interference contact structure, the material parameters of the equivalent contact portion 5 may include the elastic modulus E contact , Poisson's ratio v contact , density ρ contact Among them, the density ρ contact The value of is the same as the density ρ of the casing 1 contact The same is used to ensure that the quality of the housing 1 remains unchanged. According to the modal test results, the elastic modulus and Poisson's ratio of the equivalent contact part 5 are continuously and iteratively corrected, so that the frequency deviation between the simulation model and the actual measurement result is less than 5%, and the MAC value is greater than 90%.

[0181] In the finite element modeling and testing method of the motor stator provided above, the motor stator as a whole is divided into several components for separate modeling and testing. In the process, the large structure is determined by determining the small structure, and the divided structure processing is implemented for the casing 1 component, so that the material parameters at the joint surface can be accurately optimized.

[0182] In addition to the methods provided in the above embodiments, the present application also provides a finite element modeling test system for a motor stator, wherein the motor stator comprises a housing and a stator core having an interference fit with the housing, and the stator core is provided with a winding. The finite element modeling test system for the motor stator comprises:

[0183] In the finite element modeling and calibration system of the interference contact structure described in any of the above items, the housing 1 is the first component, and the stator core 3 and the winding 2 are the second components.

[0184] The finite element modeling test system of the motor stator is mainly used to implement the finite element modeling test method of the motor stator. The system divides the overall structure formed by the housing 1, the stator core 3, and the winding 2, and proposes a scheme for dividing the housing 1 and the stator core 3, so that the material parameters of the equivalent contact part can be obtained in a targeted manner. The overall modeling of the housing 1, the stator core 3, and the winding 2 can be more accurate and more in line with the target optimization conditions.

[0185] On the basis of the above embodiment, it also includes:

[0186] A simulation module, used for performing finite element modeling and modal calculation on a component of the motor stator, and extracting a simulation frequency and a simulation vibration shape of the component;

[0187] A testing module, used to perform modal testing on a sample of the component and extract a test frequency and a test vibration shape of the sample;

[0188] The calibration module is used to iteratively optimize the structural parameters of the component according to the simulation frequency and simulation vibration mode, the test frequency and test vibration mode, and obtain a structural model corresponding to the iteratively optimized structural parameters.

[0189] The simulation module, test module and calibration module respectively correspond to step S201, step S202 and step S203 in the completion method, wherein the simulation module, test module and calibration module can be virtual modules, or physical structures, that is, integrated circuits capable of running or storing the above method.

[0190] Optionally, the plurality of components include at least a casing, a stator core, and a combination of a stator core and a winding.

[0191] On the basis of the above embodiment, the calibration module includes a judgment submodule for optimizing the structural parameters, and the judgment submodule is used to determine the optimized structural parameters under the following conditions:

[0192] The preset range of frequency deviation between the simulation frequency and the test frequency is less than 5%, and the vibration mode correlation between the simulation vibration mode and the test vibration mode is greater than 90%. The vibration mode correlation is:

[0193]

[0194] Among them, ψ simulation is the simulation vibration mode; ψ test To test vibration mode.

[0195] Specifically, the measurement point 6 of the modal test of the casing is arranged in the contact area between the casing and the stator core;

[0196] And / or, the measuring points 6 of the modal test of the casing are evenly distributed in the axial direction or the circumferential direction;

[0197] And / or, the number of measuring points 6 arranged in the axial direction for the modal test of the stator core is at least 3, or the number of measuring points 6 arranged in the circumferential direction is at least 10.

[0198] In addition to the descriptions of the methods and systems in the above embodiments, the operations for finite element modeling analysis and optimization can refer to the prior art. At the same time, the description of the virtual structure in the system can also refer to the prior art. For the structures of other parts of the integrated circuit, please refer to the prior art, which will not be repeated in this article.

[0199] The various embodiments in this specification are described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts between the various embodiments can be referenced to each other.

[0200] The above is a detailed introduction to the interference contact structure, the finite element modeling calibration method and system of the motor stator provided by the present invention. This article uses specific examples to illustrate the principles and implementation methods of the present invention. The description of the above embodiments is only used to help understand the method of the present invention and its core idea. It should be pointed out that for ordinary technicians in this technical field, without departing from the principles of the present invention, several improvements and modifications can be made to the present invention, and these improvements and modifications also fall within the scope of protection of the claims of the present invention.

Claims

1. A finite element modeling and calibration method for a motor stator, characterized in that: Applied to a motor stator, the motor stator is an interference contact structure, the motor stator comprises a housing and a stator core which is interference fit with the housing, a winding is arranged on the stator core, the housing is a first component, and the stator core and the winding are a second component; the method comprises: Dividing the first component into an equivalent contact portion and a remaining portion connected to the equivalent contact portion, wherein the equivalent contact portion is a portion contacting the second component; obtaining a modal calculation result of the interference contact structure after the division; Obtaining a modal test result of a sample of the interference contact structure, calibrating parameters of the equivalent contact portion using the modal calculation result and the modal test result, and obtaining a modeling model after calibrating the parameters; Obtaining the modal calculation result of the interference contact structure after division includes: processing the joint surface between the equivalent contact portion and the second component, and the joint surface between the equivalent contact portion and the remaining portion by using a common node method, and obtaining the modal calculation result of the processed model; Acquiring the modal calculation results of the processed model includes: acquiring several groups of frequencies and vibration modes of the modal calculation; Calibrate the parameters of the equivalent contact part, including: Obtaining initial values ​​of parameters of the equivalent contact portion, correcting them using an iterative algorithm, and determining calibration values ​​of the parameters when the frequency deviation and vibration mode correlation between the modal calculation result and the modal test result are both within a preset range; The preset range of the frequency deviation is less than 5%, the preset range of the vibration type correlation is greater than 90%, and the vibration type correlation is greater than 90%. for: ； in, is the vibration shape of the modal calculation result; is the vibration shape of the modal test result.

2. The finite element modeling and calibration method of a motor stator according to claim 1, characterized in that: The parameters include elastic modulus, Poisson's ratio and density; obtaining the initial values ​​of the parameters of the equivalent contact portion includes: obtaining the initially set elastic modulus and initial Poisson's ratio, and setting the density to the density of the first component.

3. The finite element modeling and calibration method of a motor stator according to claim 1, characterized in that: Before the finite element modeling and calibration of the interference contact structure, several components of the motor stator are optimized respectively, and the component optimization includes: Performing finite element modeling and modal calculation on one of the components to extract the simulation frequency and simulation vibration shape of the component; Performing modal testing on a sample of the component to extract a test frequency and a test vibration shape of the sample; The simulation frequency and simulation vibration mode, the test frequency and test vibration mode are used to iteratively optimize the structural parameters of the component, and a structural model corresponding to the iteratively optimized structural parameters is obtained.

4. The finite element modeling and calibration method of a motor stator according to claim 3, characterized in that: The component optimization is performed on the housing, the stator core, and the combination of the stator core and the winding one by one, and the components of the motor stator at least include a housing, a stator core, and the combination of the stator core and the winding.

5. The finite element modeling and calibration method of a motor stator according to claim 3, characterized in that: The criteria for iterative optimization include: The preset range of the frequency deviation between the simulation frequency and the test frequency is less than 5%, the vibration mode correlation between the simulation vibration mode and the test vibration mode is greater than 90%, and the vibration mode correlation for: ； in, is the simulation vibration shape; is the test vibration shape.

6. The finite element modeling and calibration method of a motor stator according to any one of claims 1 to 5, characterized in that: In the modal test of the housing, the measuring points are arranged in the contact area between the housing and the stator core; And / or, in the modal test of the housing, the measuring points are evenly distributed in the axial direction or the circumferential direction; And / or, in the modal test of the stator core, at least three measuring points are arranged in the axial direction, or at least ten measuring points are arranged in the circumferential direction.

7. A finite element modeling and calibration system for a motor stator, characterized in that: Applied to a motor stator, the motor stator is an interference contact structure, the motor stator comprises a housing and a stator core which is interference fit with the housing, the stator core is provided with a winding, the housing is a first component, and the stator core and the winding are a second component; The finite element modeling calibration system comprises: A modeling and calculation module, used for dividing the first component into an equivalent contact portion and a remaining portion connected to the equivalent contact portion, wherein the equivalent contact portion is a portion contacting the second component; and obtaining a modal calculation result of the interference contact structure after the division; A test calibration module, used for obtaining the modal test result of the interference contact structure, calibrating the parameters of the equivalent contact portion with the modal calculation result and the modal test result, and obtaining the modeling model after calibrating the parameters, wherein the test calibration module is connected to the modeling calculation module; The modeling and calculation module comprises: a dividing unit, configured to divide the first component into an equivalent contact portion and a remaining portion connected to the equivalent contact portion, wherein the equivalent contact portion is a portion contacting the second component; A processing unit, used for processing the joint surface between the equivalent contact portion and the second component and the joint surface between the equivalent contact portion and the remaining portion by using a common node method, and obtaining the modal calculation result of the processed model, wherein the processing unit is signal-connected to the division unit; The test calibration module comprises: An optimization unit, used for obtaining an initial value of a parameter of the equivalent contact portion, and correcting the parameter using an optimization algorithm, and determining that the parameter is a calibration value when the frequency deviation and the vibration mode correlation between the modal calculation result and the modal test result are both within a preset range; The optimization unit includes a judgment subunit, wherein the optimization conditions set in the judgment subunit include that the preset range of the frequency deviation is less than 5%, the preset range of the vibration mode correlation is greater than 90%, and the vibration mode correlation is greater than 90%. for: ； in, is the vibration shape of the modal calculation result; is the vibration shape of the modal test result.

8. The finite element modeling and calibration system for a motor stator according to claim 7, characterized in that: The optimization unit comprises an acquisition device for acquiring elastic modulus, Poisson's ratio and density, and the density is set as the density of the first component in the acquisition device.

9. The finite element modeling and calibration system for a motor stator according to claim 7, characterized in that: Also includes: A simulation module, used for performing finite element modeling and modal calculation on a component of the motor stator, and extracting a simulation frequency and a simulation vibration shape of the component; A testing module, used to perform modal testing on a sample of the component and extract a test frequency and a test vibration shape of the sample; The calibration module is used to iteratively optimize the structural parameters of the component according to the simulation frequency and simulation vibration mode, the test frequency and test vibration mode, and obtain a structural model corresponding to the iteratively optimized structural parameters.

10. The finite element modeling and calibration system of the motor stator according to claim 9, characterized in that: The plurality of components include at least a housing, a stator core, and a combination of the stator core and a winding.

11. The finite element modeling and calibration system of a motor stator according to claim 9, characterized in that: The conditions for optimizing the structural parameters by the calibration module include: The preset range of the frequency deviation between the simulation frequency and the test frequency is less than 5%, the vibration mode correlation between the simulation vibration mode and the test vibration mode is greater than 90%, and the vibration mode correlation for: ； in, is the simulation vibration shape; is the test vibration shape.

12. The finite element modeling and calibration system for a motor stator according to any one of claims 7 to 11, characterized in that: The measuring points for the modal test of the housing are arranged in the contact area between the housing and the stator core; And / or, the measuring points of the modal test of the casing are evenly distributed in the axial direction or the circumferential direction; And / or, the modal test of the stator core has at least three measuring points arranged in the axial direction, or at least ten measuring points arranged in the circumferential direction.

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