Vehicle driving motor stator assembly modal parameter identification method

Abstract

The invention discloses a method for identifying modal parameters of a stator assembly of a vehicle driving motor. The method comprises the following steps: 1) performing a modal test on the stator assembly; 2) performing modal shape identification of the stator assembly based on a modal test result; 3) establishing a finite element simulation model of the stator assembly; 4) establishing a test model of the response surface of the stator assembly; 5) simulation of a stator assembly finite element model; and 6) calculating a response surface function of the stator assembly and identifying modal parameters. According to the method, rapid identification of the modal parameters of the stator assembly is realized through a series of methods of modal test of the stator assembly, modal shape identification of the stator assembly, finite element simulation model establishment of the stator assembly, test model establishment of the response surface, simulation of the finite element model, response surface function calculation and modal parameter identification, so that the product development period is shortened; and the one-time off-line qualification rate of products is improved, and cost reduction and efficiency improvement are effectively achieved.

Description

Technical Field

[0001] The present invention relates to the field of new energy vehicle electric drive technology, and in particular to a method for identifying modal parameters of a stator assembly of a vehicle drive motor. Background Art

[0002] As new energy vehicles gain more and more market share, the automotive electric drive market is gradually expanding. As one of the core components of new energy vehicles, the drive motor is mainly responsible for converting electrical energy into mechanical energy to drive the vehicle. The requirements of new energy vehicles for drive motors include lightweight, high reliability, high pressure resistance, high efficiency, low speed and high torque characteristics, and electrical system safety. In electric vehicles, the drive motor can also perform brake energy recovery, convert the vehicle's kinetic energy into electrical energy, and charge the power battery in the form of electrical energy through the motor controller.

[0003] As the product iteration speed of the new energy vehicle industry is getting faster and faster, the structure and process iteration of the stator assembly of the drive motor for new energy vehicles are also changing with each passing day. The stator modal parameters are the most important parameters for analyzing and evaluating the stator stiffness, internal insulating paint damping, and process reliability. Therefore, a method that can quickly identify the stator modal parameters is urgently needed. Summary of the invention

[0004] In view of the above-mentioned deficiencies in the prior art, the technical problem to be solved by the present invention is: how to provide a method for identifying the modal parameters of the stator assembly of a vehicle drive motor so as to quickly identify the stator modal parameters, shorten the product development cycle, improve the first-time qualified rate of products off the line, and achieve cost reduction and efficiency improvement.

[0005] In order to solve the above technical problems, the present invention adopts the following technical solutions:

[0006] A method for identifying modal parameters of a stator assembly of a vehicle drive motor comprises the following steps:

[0007] Step 1) modal test of the stator assembly;

[0008] Step 2) performing modal vibration shape identification of the stator assembly based on the modal test results;

[0009] Step 3) establishing a finite element simulation model of the stator assembly;

[0010] Step 4) establishing an experimental model of the stator assembly response surface;

[0011] Step 5) simulation of the stator assembly finite element model;

[0012] Step 6) Calculate the response surface function and identify the modal parameters of the stator assembly.

[0013] Preferably, step 1) includes the following steps:

[0014] Step 1.1) Establish a modal test environment for the stator assembly;

[0015] Step 1.2) Arrange a three-dimensional vibration acceleration sensor assembly on the stator assembly, and each acceleration sensor in the acceleration sensor assembly collects signals in the three directions of X, Y, and Z; then establish a cylindrical coordinate system, with the radius direction of the stator assembly as the radial direction, the tangent direction of the outer circle of the stator assembly as the tangential direction, and the axial direction of the stator assembly as the axial direction, and input the corresponding coordinates of each acceleration sensor to establish a spatial relationship;

[0016] Step 1.3) Use a high-frequency exciter to perform pseudo-random excitation to input load to the stator assembly. During the excitation of the stator assembly by the high-frequency exciter, the excitation load signal of the high-frequency exciter and the vibration acceleration signal of the acceleration sensor assembly are collected.

[0017] Preferably, in step 1.1), the modal test environment of the stator assembly is: in an environment with a noise level lower than 25 dB, the stator assembly is suspended at a height of more than 400 mm from the ground using an elastic rope with a stiffness lower than 20 N / mm;

[0018] In step 1.2), three layers of acceleration sensor assemblies are evenly arranged along the axial direction on the stator assembly, and each layer of acceleration sensor assembly includes 12 acceleration sensors evenly arranged along the circumferential direction of the stator assembly;

[0019] In step 1.3), when the high-frequency exciter excites the stator assembly, there are 4 excitation points on the stator assembly, and each adjacent excitation point is spaced 90° apart in the circumferential direction and 1 / 2 of the axial length of the stator assembly in the axial direction.

[0020] Preferably, step 2) comprises the following steps:

[0021] Step 2.1) After the modal test of the stator assembly is completed, the vibration acceleration signal and the excitation load signal of each acceleration sensor are divided point by point according to the number of frequency intervals to obtain the frequency response function. The calculation formula of the frequency response function is:

[0022]

[0023] Where: ω is the frequency of the excitation load signal; Max is the maximum frequency of the excitation load signal; a mn (ω) is the vibration acceleration of the nth corresponding point at frequency ω caused by the mth excitation point; F m (ω) is the excitation generated by the mth excitation point at frequency ω; H mn (ω) is the frequency response curve of the nth corresponding point caused by the mth excitation point at frequency ω;

[0024] Step 2.2) performing maximum likelihood estimation on each frequency response curve obtained in step 2.1) and identifying the corresponding maximum likelihood estimation vector;

[0025] Step 2.3) Calculate the cumulative maximum likelihood estimation deviation and iterate until the cumulative error is less than 0.5%. The calculation formula for the maximum likelihood estimation deviation is:

[0026]

[0027] Where: is the frequency response function after the first maximum likelihood estimation; Estimate the deviation for a single frequency response function; is the maximum likelihood estimation parameter vector; is the cumulative error;

[0028] Step 2.4) Use the following formula to solve the modal vibration shape and poles of the frequency response function after maximum likelihood estimation:

[0029]

[0030] In the formula, s r is the vibration shape of the rth mode; t r is the frequency of the rth mode; l r is the corresponding correction coefficient, () * is the conjugate function; Le is the upper residual; Ue is the lower residual;

[0031] Step 2.5) Using the formula in step 2.4), calculate the vibration mode and frequency of all modes for each frequency response curve, and identify the stator (2,0) mode, (2,1) mode, (3,0) mode, (4,0) mode and (0,1) mode.

[0032] Preferably, the stator assembly includes a stator outer edge welding layer, a stator internal iron core, a stator copper wire winding and a stator insulating paint layer;

[0033] Step 3) includes the following steps:

[0034] Step 3.1) Discretize the stator outer edge welding layer, the stator internal iron core, the stator copper wire winding and the stator insulating paint layer into units, and perform end flattening on the stator copper wire winding;

[0035] Step 3.2) Model adhesion, wherein the inner side of the stator outer edge welding layer is bonded to the outer side of the stator inner core, the outer side of the stator insulating paint layer is bonded to the inner side of the slot of the stator inner core, and the inner side of the stator insulating paint layer is bonded to the outer side of the stator copper wire winding;

[0036] Step 3.3) Establish a finite element simulation model of the stator assembly.

[0037] Preferably, in step 4), 12 modal identification parameters are set, and the initial value of each modal identification parameter is set. Each modal identification parameter is designed with three variables for orthogonal experiment, and the three variables are initial value, initial value*0.75 and initial value*0.5, respectively, and a total of 108 sets of orthogonal experimental data are obtained.

[0038] Preferably, in step 5), the orthogonal test data obtained in step 4) is brought into the finite element simulation model to perform modal simulation of the stator assembly, and the error calculation is performed according to the following formula:

[0039] SS c =0.2*(|(2,0) e -(2,0) s |+|(2,1) e -(2,1) s |+|(3,0) e -(3,0) s |+|(4,0) e -(4,0) s |+|(0, 1) e -(0,1) s |)

[0040] Where: SS c is the error between simulation and experiment of group c parameters; () e Identify the modal frequencies for the test; () s Modal frequencies are calculated for simulation; (2, 0) is the (2, 0) mode of the stator assembly; (2, 1) is the (2, 1) mode of the stator assembly; (3, 0) is the (3, 0) mode of the stator assembly; (4, 0) is the (4, 0) mode of the stator assembly; (0, 1) is the (0, 1) mode of the stator assembly.

[0041] Preferably, step 6) includes the following steps:

[0042] Step 6.1) Establish the relationship between the response function and the design variables according to the following formula

[0043]

[0044] In the formula, k c (X) is the response function of group C; X is the modal identification parameter, and X = [X1, X2, ...X 12 ] T ; A I is the coefficient of the band identification function, g l (X)(l=1,2...,12) is the basis function composed of modal identification parameters;

[0045] Step 6.2) Substitute 108 sets of orthogonal test data into the above formula and organize it into:

[0046] K=AG+E

[0047] Where K = [k1(X), k2(X), ...k 108 (X)] T ,A=[A1,A2,...A 12 ] T , G=[g l (X)1,g l (X)2,...g l (X) 108 ] T , E=[SS1,SS2,...SS 108 ] T .

[0048] The coefficient A to be confirmed is iteratively identified using the least squares method, and is specifically calculated using the following formula:

[0049] A=(G T G) -1 G T K

[0050] Step 6.3) Substitute the coefficient A into the following formula to find the minimum value of E in the formula. At this time, the function in G is the modal parameter of the identified stator assembly;

[0051] min(E)=AG-K.

[0052] Compared with the prior art, the present invention has the following advantages:

[0053] 1. The present invention realizes rapid identification of modal parameters of stator assembly through a series of methods including modal test of stator assembly, modal vibration type identification of stator assembly, finite element simulation model of stator assembly, establishment of test model of response surface, simulation of finite element model, calculation of response surface function and identification of modal parameters, thus shortening product development cycle, improving the first-time qualified rate of products, and effectively realizing cost reduction and efficiency improvement.

[0054] 2. The present invention establishes an accurate finite element model of the stator assembly, which can effectively improve the simulation accuracy and efficiency of the durability, torque transmission, vibration and noise of the electric drive assembly.

[0055] 3. The present invention realizes qualitative analysis of the structural design strength, process stability and damping characteristics of the insulating paint of the stator assembly by quickly identifying the modal parameters of the stator assembly.

[0056] 4. The method of the present invention can quantify and compare the effects of parameter changes on stator stiffness and damping when adjusting core parameters such as product design and process. BRIEF DESCRIPTION OF THE DRAWINGS

[0057] Figure 1 It is a flow chart of the modal parameter identification method of the stator assembly of the vehicle drive motor of the present invention;

[0058] Figure 2 A schematic diagram of the suspension of the stator assembly in the modal parameter identification method of the stator assembly of the vehicle drive motor of the present invention;

[0059] Figure 3 A schematic diagram of the distribution of acceleration sensors and excitation points in the modal parameter identification method of the stator assembly of a vehicle drive motor according to the present invention;

[0060] Figure 4 It is a time domain signal diagram of an acceleration sensor in a modal parameter identification method of a stator assembly of a vehicle drive motor of the present invention;

[0061] Figure 5 It is a time domain signal diagram of the excitation force of the exciter in the modal parameter identification method of the stator assembly of the vehicle drive motor of the present invention;

[0062] Figure 6 It is a frequency domain signal diagram of the acceleration sensor in the modal parameter identification method of the stator assembly of the vehicle drive motor of the present invention;

[0063] Figure 7 It is a frequency domain signal diagram of the excitation force of the exciter in the modal parameter identification method of the stator assembly of the vehicle drive motor of the present invention;

[0064] Figure 8 A frequency response function diagram calculated in the modal parameter identification method of the stator assembly of the vehicle drive motor of the present invention;

[0065] Fig. 9 It is a frequency response function diagram after maximum likelihood estimation in the modal parameter identification method of the stator assembly of the vehicle drive motor of the present invention;

[0066] Fig.10 This is a diagram showing the solution results of the modal vibration shape and the poles based on the frequency response function in the modal parameter identification method of the stator assembly of the vehicle drive motor of the present invention;

[0067] Fig.11 This is a diagram of the modal identification result of the stator assembly in the modal parameter identification method of the vehicle drive motor stator assembly of the present invention;

[0068] Fig.12 The structure diagram of the stator assembly in the modal parameter identification method of the stator assembly of the vehicle drive motor of the present invention;

[0069] Fig.13 An exploded diagram of a stator assembly in a modal parameter identification method of a stator assembly of a vehicle drive motor according to the present invention;

[0070] Fig.14 A stator assembly discretization model diagram established in the vehicle drive motor stator assembly modal parameter identification method of the present invention;

[0071] Fig.15 This is a stator assembly model diagram obtained by the finite element simulation model in the vehicle drive motor stator assembly modal parameter identification method of the present invention.

[0072] Explanation of the reference numerals: stator assembly 1 , stator outer edge welding layer 101 , stator insulating paint layer 102 , stator copper wire winding 103 , stator internal iron core 104 , elastic rope 2 , fixing tool 3 . DETAILED DESCRIPTION

[0073] In order to make the purpose, technical scheme and advantages of the embodiments of the present invention clearer, the technical scheme in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. The components of the embodiments of the present invention generally described and shown in the drawings here can be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of the present invention provided in the drawings is not intended to limit the scope of the claimed invention, but merely represents selected embodiments of the present invention. Based on the embodiments in the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work belong to the scope of protection of the present invention.

[0074] It should be noted that similar numbers and letters represent similar items in the following drawings, so once an item is defined in one drawing, it does not need to be further defined and explained in the subsequent drawings. In the description of the present invention, it should be noted that the orientation or position relationship indicated by the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inside", "outside", etc. is based on the orientation or position relationship shown in the drawings, or the orientation or position relationship in which the invention product is usually placed when used, which is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation of the present invention. In addition, the terms "first", "second", "third", etc. are only used to distinguish the description, and cannot be understood as indicating or implying relative importance. In addition, the terms "horizontal", "vertical", etc. do not mean that the components are absolutely horizontal or suspended, but can be slightly tilted. For example, "horizontal" only means that its direction is more horizontal than "vertical", and does not mean that the structure must be completely horizontal, but can be slightly tilted. In the description of the present invention, it is also necessary to explain that, unless otherwise clearly specified and limited, the terms "set", "install", "connect", and "connect" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0075] As attached Figure 1 As shown, a method for identifying modal parameters of a stator assembly of a vehicle drive motor comprises the following steps:

[0076] Step 1) modal test of the stator assembly;

[0077] Step 1.1) Detailed instructions are as follows Figure 2 As shown, firstly, the outer diameter and axial length of the stator assembly 1 are measured, and then the stator assembly 1 is moved to an environment with a background noise lower than 25 dB, and the stator assembly 1 is suspended on a fixed tooling 3 at a height of more than 400 mm from the ground by using an elastic rope 2 with a stiffness lower than 20 N / mm.

[0078] Step 1.2) Arrange a three-dimensional vibration acceleration sensor assembly on the stator assembly, and each acceleration sensor in the acceleration sensor assembly collects signals in the three directions of X, Y, and Z. Specifically, three layers of acceleration sensor assemblies are evenly arranged along the axial direction on the stator assembly, and each layer of acceleration sensor assembly includes 12 acceleration sensors evenly arranged along the circumference of the stator assembly, totaling 12*3=36 vibration acceleration sensors, as shown in the attached Figure 3As shown; then establish a cylindrical coordinate system, with the radius direction of the stator assembly as the radial direction, the tangent direction of the outer circle of the stator assembly as the tangent direction, and the axial direction of the stator assembly as the axial direction, and input the corresponding coordinates of each acceleration sensor to establish a spatial relationship. The coordinates of each acceleration sensor are shown in Table 1:

[0079] Table 1: Coordinate values ​​of various acceleration sensors

[0080]

[0081]

[0082] Step 1.3) Use a high-frequency exciter to perform pseudo-random excitation to input load to the stator assembly. During the excitation process of the stator assembly by the high-frequency exciter, collect the excitation load signal of the high-frequency exciter (such as the attached Figure 5 ) and the vibration acceleration signal of the acceleration sensor assembly (as shown in the attached Figure 4 Specifically, when the high-frequency exciter excites the stator assembly, there are 4 excitation points on the stator assembly, and each adjacent excitation point is 90° apart in the circumferential direction and 1 / 2 of the axial length of the stator assembly in the axial direction, as shown in the attached figure. Figure 3 shown.

[0083] Step 2) Identify the modal vibration shape of the stator assembly based on the modal test results; Figure 4 And attached Figure 5 The signal is Fourier transformed to achieve frequency decomposition and the frequency domain signal is obtained. Figure 6 and attached Figure 7 shown.

[0084] Step 2.1) After the modal test of the stator assembly is completed, the vibration acceleration signal and the excitation load signal of each acceleration sensor are divided point by point according to the number of frequency intervals to obtain the frequency response function. A total of 36*3*4=432 frequency response functions are obtained. The calculation formula of the frequency response function is:

[0085]

[0086] Where: ω is the frequency of the excitation load signal; Max is the maximum frequency of the excitation load signal; a mn (ω) is the vibration acceleration of the nth corresponding point at frequency ω caused by the mth excitation point; F m (ω) is the excitation generated by the mth excitation point at frequency ω; H mn (ω) is the frequency response curve of the nth corresponding point caused by the mth excitation point at frequency ω;

[0087] The calculated Figure 8 shown.

[0088] Step 2.2) performing maximum likelihood estimation on the 432 frequency response curves obtained in step 2.1) and identifying the corresponding maximum likelihood estimation vector;

[0089] Step 2.3) Calculate the cumulative maximum likelihood estimation deviation and iterate until the cumulative error is less than 0.5%, which indicates that the maximum likelihood estimation meets the accuracy requirements; the calculation formula for the maximum likelihood estimation deviation is:

[0090]

[0091] Where: is the frequency response function after the first maximum likelihood estimation; Estimate the deviation for a single frequency response function; is the maximum likelihood estimation parameter vector; is the cumulative error;

[0092] The maximum likelihood estimation frequency response function after iteration is shown in the attached figure. Fig. 9 shown.

[0093] Step 2.4) Use the following formula to solve the modal vibration shape and poles of the frequency response function after maximum likelihood estimation. The solution is shown in the attached figure. Fig.10 As shown;

[0094]

[0095] In the formula, s r is the vibration shape of the rth mode; t r is the frequency of the rth mode; l r is the corresponding correction coefficient, () * is the conjugate function; Le is the upper residual; Ue is the lower residual;

[0096] Step 2.5) Using the formula in step 2.4), the vibration modes and frequencies of all modes of the 432 frequency response curves are calculated, and the (2,0) mode, (2,1) mode, (3,0) mode, (4,0) mode and (0,1) mode of the stator assembly are identified. Specifically, in the (X,Y) mode, X indicates that there are X maximum values ​​of the circumferential vibration of the stator assembly, and Y indicates whether the vibrations of the two axial end surfaces are the same or opposite. Y = 0 indicates the same, and Y = 1 indicates the opposite. For example, the (2,0) mode indicates that there are 2 maximum values ​​of the circumferential vibration of the stator assembly, and the vibrations of the two axial end surfaces are the same. The specific recognition results of each mode are shown in the attached figure. Fig.11 shown.

[0097] Step 3) establishing a finite element simulation model of the stator assembly;

[0098] Step 3.1) As attached Fig.13As shown, the stator outer edge welding layer 101, the stator internal iron core 104, the stator copper wire winding 103 and the stator insulating paint layer 102 are discretized into units, and the stator copper wire winding 103 is cut flat at the end; the stator assembly structure diagram is shown in Fig.12 , see the exploded diagram Fig.13 The discretization model established is shown in Fig.14 ;

[0099] Step 3.2) Model adhesion, wherein the inner side of the stator outer edge welding layer 101 is bonded to the outer side of the stator inner core 104, the outer side of the stator insulating paint layer 102 is bonded to the inner side of the slot of the stator inner core 104, and the inner side of the stator insulating paint layer 102 is bonded to the outer side of the stator copper wire winding 103;

[0100] Step 3.3) Establish a finite element simulation model of the stator assembly.

[0101] Step 4) establishing an experimental model of the stator assembly response surface;

[0102] Set 12 modal identification parameters and set the initial value of each modal identification parameter. The 12 parameter names and initial values ​​are shown in Table 2.

[0103] Table 2: Modal identification parameters and initial values ​​Unit: MPa

[0104] Stator outer circle welding layer Inside the stator core Stator insulation paint Radial elastic modulus 210000 180000 1000 Axial elastic modulus 120000 100000 500 Radial shear modulus 80000 60000 300 Axial shear modulus 20000 10000 100

[0105] The 12 parameters to be identified in Table 2 are used as variables. For each variable, an orthogonal test is designed with initial value, initial value*0.75, and initial value*0.5 as three variables, and 108 sets of orthogonal test tables are completed. The designed orthogonal test table is shown in Table 3.

[0106] Table 3: Designed orthogonal test table (unit: MPa)

[0107]

[0108]

[0109]

[0110]

[0111]

[0112] Step 5) simulation of the stator assembly finite element model;

[0113] (Take the parameter with serial number 1 in Table 3 as an example) The test parameters in Table 3 are brought into the finite element simulation model to perform modal simulation of the stator assembly, and the Langeshaus method is used to extract the stiffness and mass matrix. Ignoring the stiffness matrix parameters with stiffness coefficients lower than 0.1% of the maximum coefficient and their corresponding mass matrix parameters, the simulation obtains (2,0) mode; (2,1) mode; (3,0) mode; (4,0) mode; (0,1) mode frequency, and the error calculation is performed according to the following formula:

[0114] SS c =0.2*(|(2,0) e -(2,0) s |+|(2,1) e -(2, 1) s +|(3,0) e -(3,0) s |+|(4,0) e -(4,0) s |+|(0, 1) e -(0, 1) s |)

[0115] Where: SS C is the error between simulation and experiment of group c parameters; () e Identify the modal frequencies for the test; () s Modal frequencies are calculated for simulation; (2, 0) is the (2, 0) mode of the stator assembly; (2, 1) is the (2, 1) mode of the stator assembly; (3, 0) is the (3, 0) mode of the stator assembly; (4, 0) is the (4, 0) mode of the stator assembly; (0, 1) is the (0, 1) mode of the stator assembly.

[0116] The modal vibration shapes obtained by stator finite element simulation are shown in Fig.15 , the simulation and test modal frequencies and error calculation results are shown in Table 4.

[0117] Table 4: Comparison of simulation and test modal frequencies and error calculation results

[0118] (2,0) mode (2,1) mode (3,0) mode (4,0) mode (0,1) mode error test 959 996 2485 4835 5341 <![CDATA[SS1=195.6]]> simulation 1047 1128 2837 5051 5531

[0119] Step 6) Calculate the response surface function and identify the modal parameters of the stator assembly.

[0120] Step 6.1) Establish the relationship between the response function and the design variables according to the following formula

[0121]

[0122] In the formula, k c (X) is the response function of group C; X is the modal identification parameter, and X = [X1, X2, ...X12 ] T ; A l is the coefficient of the band identification function, g l (X)(l=1,2...,12) is the basis function composed of modal identification parameters;

[0123] Step 6.2) Substitute 108 sets of orthogonal test data into the above formula and organize it into:

[0124] K=AG+E

[0125] Where K = [k1(X), k2(X), ...k 108 (X)] T ,A=[A1,A2,...A 12 ] T , G=[g l (X)1,g l (X)2,...g l (X) 108 ] T , E=[SS1,SS2,...SS 108 ] T .

[0126] The coefficient A to be confirmed is iteratively identified using the least squares method, and is specifically calculated using the following formula:

[0127] A=(G T G) -1 G T K

[0128] The iterated coefficient A is shown in Table 5;

[0129] Table 5: Iterated coefficient table

[0130] <![CDATA[A1]]> <![CDATA[A2]]> <![CDATA[A3]]> <![CDATA[A4]]> <![CDATA[A5]]> <![CDATA[A6]]> 0.0874 0.0025 0.0450 0.0154 0.0359 0.0245 <![CDATA[A7]]> <![CDATA[A8]]> <![CDATA[A9]]> <![CDATA[A 10 ]]> <![CDATA[A 11 ]]> <![CDATA[A 12 <!-- 12 -->]]> 0.0021 0.0078 0.0326 0.0061 0.0523 0.0043

[0131] Step 6.3) Substitute the coefficient A into the following formula to find the minimum value of E in the formula. At this time, the function in G is the modal parameter of the identified stator assembly;

[0132] min(E))=AG-K.

[0133] The identified modal parameters are shown in Table 6;

[0134] Table 6: Identified modal parameters Unit: MPa

[0135] Stator outer circle welding layer Inside the stator core Stator insulation paint Radial elastic modulus 184000 135000 640 Axial elastic modulus 92000 730000 350 Radial shear modulus 69000 56000 190 Axial shear modulus 12000 6700 60

[0136] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention rather than to limit the technical solution. Those skilled in the art should understand that those modifications or equivalent substitutions of the technical solution of the present invention that do not depart from the purpose and scope of the technical solution should be included in the scope of the claims of the present invention.

Claims

1. A method for identifying modal parameters of a stator assembly of a vehicle drive motor, characterized in that: The following steps are involved: Step 1) modal test of stator assembly; Step 2) performing modal vibration shape identification of the stator assembly based on the modal test results; Step 3) establishing a finite element simulation model of the stator assembly; Step 4) establishing an experimental model of the stator assembly response surface; Step 5) simulation of the stator assembly finite element model; Step 6) Calculate the response surface function and identify the modal parameters of the stator assembly.

2. The method for identifying modal parameters of a stator assembly of a vehicle drive motor according to claim 1, characterized in that: Step 1) includes the following steps: Step 1.1) Establish a modal test environment for the stator assembly; Step 1.2) Arrange a three-dimensional vibration acceleration sensor assembly on the stator assembly, and each acceleration sensor in the acceleration sensor assembly collects signals in the three directions of X, Y, and Z; then establish a cylindrical coordinate system, with the radius direction of the stator assembly as the radial direction, the tangent direction of the outer circle of the stator assembly as the tangential direction, and the axial direction of the stator assembly as the axial direction, and input the corresponding coordinates of each acceleration sensor to establish a spatial relationship; Step 1.3) Use a high-frequency exciter to perform pseudo-random excitation to input load to the stator assembly. During the excitation of the stator assembly by the high-frequency exciter, the excitation load signal of the high-frequency exciter and the vibration acceleration signal of the acceleration sensor assembly are collected.

3. The method for identifying modal parameters of a stator assembly of a vehicle drive motor according to claim 2, characterized in that: In step 1.1), the modal test environment of the stator assembly is: in an environment with a noise level lower than 25 dB, the stator assembly is suspended more than 400 mm from the ground using an elastic rope with a stiffness lower than 20 N / mm; In step 1.2), three layers of acceleration sensor assemblies are evenly arranged along the axial direction on the stator assembly, and each layer of acceleration sensor assembly includes 12 acceleration sensors evenly arranged along the circumferential direction of the stator assembly; In step 1.3), when the high-frequency exciter excites the stator assembly, there are 4 excitation points on the stator assembly, and each adjacent excitation point is spaced 90° apart in the circumferential direction and 1 / 2 of the axial length of the stator assembly in the axial direction.

4. The method for identifying modal parameters of a stator assembly of a vehicle drive motor according to claim 2, characterized in that: Step 2) includes the following steps: Step 2.1) After the modal test of the stator assembly is completed, the vibration acceleration signal and the excitation load signal of each acceleration sensor are divided point by point according to the number of frequency intervals to obtain the frequency response function. The calculation formula of the frequency response function is: Where: ω is the frequency of the excitation load signal; Max is the maximum frequency of the excitation load signal; a mn (ω) is the vibration acceleration of the nth corresponding point at frequency ω caused by the mth excitation point; F m (ω) is the excitation generated by the mth excitation point at frequency ω; H mn (ω) is the frequency response curve of the nth corresponding point caused by the mth excitation point at frequency ω; Step 2.2) performing maximum likelihood estimation on each frequency response curve obtained in step 2.1) and identifying the corresponding maximum likelihood estimation vector; Step 2.3) Calculate the cumulative maximum likelihood estimation deviation and iterate until the cumulative error is less than 0.5%. The calculation formula for the maximum likelihood estimation deviation is: Where: is the frequency response function after the first maximum likelihood estimation; Estimate the deviation for a single frequency response function; is the maximum likelihood estimation parameter vector; is the cumulative error; Step 2.4) Use the following formula to solve the modal vibration shape and poles of the frequency response function after maximum likelihood estimation: In the formula, s r is the vibration shape of the rth mode; t r is the frequency of the rth mode; l r is the corresponding correction coefficient, () * is the conjugate function; Le is the upper residual; Ue is the lower residual; Step 2.5) Using the formula in step 2.4), calculate the vibration mode and frequency of all modes for each frequency response curve, and identify the (2,0) mode, (2,1) mode, (3,0) mode, (4,0) mode and (0,1) mode of the stator assembly.

5. The method for identifying modal parameters of a stator assembly of a vehicle drive motor according to claim 1, characterized in that: The stator assembly includes a stator outer edge welding layer, a stator internal iron core, a stator copper wire winding and a stator insulating paint layer; Step 3) includes the following steps: Step 3.1) Discretize the stator outer edge welding layer, the stator internal iron core, the stator copper wire winding and the stator insulating paint layer into units, and perform end flattening on the stator copper wire winding; Step 3.2) Model adhesion, wherein the inner side of the stator outer edge welding layer is bonded to the outer side of the stator inner core, the outer side of the stator insulating paint layer is bonded to the inner side of the slot of the stator inner core, and the inner side of the stator insulating paint layer is bonded to the outer side of the stator copper wire winding; Step 3.3) Establish a finite element simulation model of the stator assembly.

6. The method for identifying modal parameters of a stator assembly of a vehicle drive motor according to claim 5, characterized in that: In step 4), 12 modal identification parameters are set, and the initial value of each modal identification parameter is set. Each modal identification parameter is designed with three variables for orthogonal test. The three variables are initial value, initial value*0.75 and initial value*0.5, respectively. A total of 108 sets of orthogonal test data are obtained.

7. The method for identifying modal parameters of a stator assembly of a vehicle drive motor according to claim 6, characterized in that: In step 5), the orthogonal test data obtained in step 4) is brought into the finite element simulation model to perform modal simulation of the stator assembly, and the error calculation is performed according to the following formula: SS c =0.2*(|(2,0) e -(2,0) s |+|(2,1) e -(2,1 s |+|(3,0) e -(3,0) s |+|(4,0) e -(4,0) s |+|(0,1) e -(0,1) s |) Where: SS C is the error between simulation and experiment of group c parameters; () e Identify the modal frequencies for the test; () s Modal frequencies are calculated for simulation; (2, 0) is the (2, 0) mode of the stator assembly; (2, 1) is the (2, 1) mode of the stator assembly; (3, 0) is the (3, 0) mode of the stator assembly; (4, 0) is the (4, 0) mode of the stator assembly; (0, 1) is the (0, 1) mode of the stator assembly.

8. The method for identifying modal parameters of a stator assembly of a vehicle drive motor according to claim 7, characterized in that: Step 6) includes the following steps: Step 6.1) Establish the relationship between the response function and the design variables according to the following formula In the formula, k c (X) is the response function of group C; X is the modal identification parameter, and X = [X1, X2, ... X 12 ] T ; A l is the coefficient of the band identification function, g l (X)(l=1,2…,12) is the basis function composed of modal identification parameters; Step 6.2) Substitute 108 sets of orthogonal test data into the above formula and organize it into: K=AG+E where K = [k1(X), k2(X), … k 108 (X)] T , A = [A1, A2, … A 12 T , G = [g l (X)1, g l (X)2, … g l (X) 108 T , E = [SS1, SS2, … SS 108 T .​​​ The coefficient A to be confirmed is iteratively identified using the least squares method, and is specifically calculated using the following formula: A=(G T G) -1 G T K Step 6.3) Substitute the coefficient A into the following formula to find the minimum value of E in the formula. At this time, the function in G is the modal parameter of the identified stator assembly; min(E)=AG-K.

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