NVH (Noise Vibration and Harshness) simulation method and system for simultaneously loading electric drive excitation on stator and rotor structures

Abstract

The invention relates to the technical field of NVH simulation of an electric drive assembly, in particular to an NVH simulation method and system for loading electric drive excitation on a stator and rotor structure at the same time, and the method comprises the steps: building an electric drive system model; solving electromagnetic excitation; electromagnetic excitation is loaded on the stator and the rotor at the same time; and carrying out coupling calculation on the electromagnetic excitation and the electric drive system model, arranging measuring points, extracting corresponding data at each measuring point, and evaluating whether the NVH of the electric drive system is qualified or not. Electromagnetic excitation is loaded on the stator and the rotor at the same time, the process that the torsion and bending problems of the rotor are transmitted to the whole electric drive through the bearing can be achieved through coupling of electromagnetism and the rotor structure, the NVH problem caused by the rotor is recognized, and a rotor assembly is controlled more accurately.

Description

Technical Field

[0001] The present invention relates to the technical field of NVH simulation of electric drive assemblies, and in particular to a NVH simulation method and system for simultaneously loading electric drive excitation on a stator and rotor structure. Background Art

[0002] The innovation of electric drive technology has undoubtedly led to the rapid development of the new energy vehicle market. As the core sub-component of new energy electric vehicles, the electric drive assembly directly affects the power, energy consumption and overall performance of the vehicle. The NVH (Noise, Vibration, Harshness) of the vehicle is one of the important indicators to measure the quality of the whole vehicle. Excellent NVH performance improves users' evaluation of the product, and NVH performance is closely related to the driving experience.

[0003] Regarding the NVH simulation modeling method of electric drive excitation loading, the current mainstream method is: extract the concentrated force or distributed force on the stator tooth surface through electromagnetic software simulation, process the extracted electromagnetic force and load it on the stator tooth surface, calculate the displacement, velocity, acceleration, etc. through the stator and the electric drive housing, and if noise analysis is required, then load the vibration response as an excitation source into the acoustic analysis to obtain the sound pressure distribution and noise level.

[0004] Disadvantages of the above method:

[0005] First, it is impossible to evaluate the NVH performance of the assembly caused by the electric drive excitation loading on the rotor structure, resulting in the inability to discover NVH problems caused by the rotor in advance. Problems can only be identified through experiments and then optimized again, causing serious delays in the development cycle.

[0006] Second, it is impossible to evaluate the NVH performance caused by the path coupling of the excitation loading on the stator and rotor, resulting in incomplete control of the NVH level in the early stage of product development. Bench and vehicle matching tests are needed to assist in identifying NVH problems of the electric drive assembly.

[0007] 3. Currently, the commercial software on the market cannot achieve the simulation of excitation loading on the stator and rotor at the same time. For electric drive products, it is not possible to simulate and calculate the stator and rotor excitation separately, and the simulation and test have a large deviation. Summary of the invention

[0008] The purpose of the present invention is to address the defects of the prior art and provide an NVH simulation method and system in which electric drive excitation is simultaneously loaded on the stator and rotor structure. By loading electromagnetic excitation on the stator and rotor at the same time, the coupling of the electromagnetic and rotor structures can realize the process of transmitting the rotor torsion and bending problems through the bearings to the entire electric drive, identify the NVH problems caused by the rotor, and control the rotor assembly more accurately.

[0009] In order to solve the above technical problems, in a first aspect, the present invention provides an NVH simulation method in which electric drive excitation is simultaneously loaded on a stator and rotor structure, comprising:

[0010] Build an electric drive system model;

[0011] Electromagnetic excitation solution;

[0012] Applying electromagnetic excitation to the stator and the rotor simultaneously;

[0013] The electromagnetic excitation is coupled with the electric drive system model, the measuring points are arranged, the corresponding data at each measuring point is extracted, and the NVH of the electric drive system is evaluated to see whether it is qualified.

[0014] In some embodiments, the method of simultaneously applying electromagnetic excitation to the stator and the rotor includes:

[0015] Perform FFT calculation on the electromagnetic force calculated in Maxwell to obtain the amplitude and phase;

[0016] Stretch the electromagnetic force grid derived from Maxwell to a length that is consistent with the stator structure length;

[0017] Map the electromagnetic force to the stator tooth surface and derive the mapped matrix;

[0018] Modify the weight of the mapped matrix so that its mapping direction is consistent with the rotor direction;

[0019] The modified weighted matrix is ​​mapped to the rotor tooth surface.

[0020] Furthermore, the method for modifying the weight of the mapped matrix includes: changing the weight of the mapped matrix from 1 to -1.

[0021] In some embodiments, the method of establishing an electric drive system model includes:

[0022] Conduct finite element modeling of the assembly shell;

[0023] Conduct finite element modeling for cover plates;

[0024] Conduct finite element modeling of the suspension bracket;

[0025] Finite element modeling of the stator;

[0026] Finite element modeling of the rotor;

[0027] Finite element modeling of shaft gears;

[0028] Assemble the above finite element model.

[0029] Furthermore, the method for establishing the electric drive system model includes: for sub-components without specific internal detailed models, the center of mass position and moment of inertia are used instead; if the center of mass position cannot be determined, the entire outer surface of the sub-component is filled with a finite element solid mesh, and the model is built by changing the material density to achieve the correctness of mass distribution.

[0030] Furthermore, the method for finite element modeling of the stator includes: modeling the stator, the mesh is a second-order hexagonal mesh, and the mesh size is 4 mm; modeling the winding, the mesh is a second-order hexagonal mesh, and the mesh size is 4 mm, the contact area between the winding and the stator is required to be at the same node, and the end winding is replaced by the center of mass.

[0031] Furthermore, the method for finite element modeling of the rotor includes: modeling the rotor, the mesh is a second-order hexagonal mesh, the mesh size is 4mm, the large and small magnetic steels are replaced by the center of mass, and if it is a segmented rotor, the torsional freedom is released when the segments are connected.

[0032] Furthermore, the method for establishing the electric drive system model includes: connecting the contact area of ​​the stator finite element model and the assembly housing finite element model with a common node, applying meshing stiffness at the gear meshing point, and imparting suspension stiffness under the whole vehicle state at the suspension bracket.

[0033] In some embodiments, the response data is subjected to secondary processing:

[0034] Set vibration measurement points and microphone measurement points;

[0035] Decompose the vibration or microphone response at the same measurement point to extract the responses generated by the stator side excitation and the rotor side excitation;

[0036] The response information is divided into real part and imaginary part respectively, and the parts are superimposed on each other;

[0037] Calculate the sound pressure level at the measuring point and compare it with the test data

[0038] In some embodiments, solving for electromagnetic excitation includes:

[0039] Draw the motor model and build the motor system model;

[0040] Add properties to the materials of each part of the motor and assign corresponding physical properties to the finite element models of the stator and rotor;

[0041] Setting an excitation source for the winding;

[0042] Set the magnetization direction of the permanent magnet to determine the direction of the magnetic field;

[0043] Set the motor's operating status, environment, and load;

[0044] Mesh the motor model and encrypt the finite element mesh of the stator tooth root;

[0045] Add field calculation, set solver parameters, and output the electromagnetic force at the stator tooth root.

[0046] In a second aspect, the present invention provides a system for the NVH simulation method of simultaneously loading the electric drive excitation on the stator and rotor structures, comprising:

[0047] Modeling module, used to build electric drive system model;

[0048] A calculation module, used for calculating the electromagnetic force at the stator tooth root;

[0049] Loading module for mapping electromagnetic forces onto the stator and rotor;

[0050] An evaluation module is used to determine whether the NVH of the electric drive system is qualified.

[0051] The beneficial effects of the present invention are:

[0052] 1. The present invention simultaneously loads electromagnetic excitation on the stator and rotor, and through the coupling of electromagnetic and rotor structures, it can realize the process of transmitting the rotor torsion and bending problems through the bearings to the entire electric drive, identify the NVH problems caused by the rotor, and control the rotor assembly more accurately.

[0053] 2. The present invention calculates the response caused by the combined force of electromagnetic excitation on the stator and rotor efficiently and quickly through secondary processing of the response data, thus saving simulation time and shortening the development cycle.

[0054] 3. The present invention more accurately simulates the actual operating conditions of the electric drive by loading electromagnetic excitation on the stator and the rotor at the same time, improves the accuracy of the simulation model, and makes the acoustic vibration result data more consistent with the measured data. BRIEF DESCRIPTION OF THE DRAWINGS

[0055] Figure 1 is a flow chart of the present invention;

[0056] Figure 2 This is a schematic diagram of the ID4-200 platform motor model of the present invention;

[0057] Figure 3 It is a schematic diagram of the ID4-200 platform excitation step-by-step mapping of the stator surface and the rotor surface of the present invention;

[0058] Figure 4 The corresponding comparison diagram of the ID4-200 platform excitation loading at different positions of the present invention;

[0059] Figure 5 This is a comparison chart of the simulation and test of the ID4-200 platform of the present invention. DETAILED DESCRIPTION

[0060] In order to make the technical problems, technical solutions and beneficial effects to be solved by the present application more clearly understood, the present application is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.

[0061] like Figure 1 As shown, the present invention provides an NVH simulation method in which electric drive excitation is simultaneously loaded on the stator and rotor structure (taking the ID4-200 platform assembly model as an example), comprising:

[0062] Establish the electric drive system model, that is, Figure 1 The overall acoustic structure model in;

[0063] Electromagnetic excitation solution;

[0064] By applying electromagnetic excitation to the stator and rotor at the same time, we can obtain Figure 1 The overall sound radiation model in;

[0065] The electromagnetic excitation is coupled with the electric drive system model, the measuring points are arranged, the corresponding data at each measuring point is extracted, and the NVH of the electric drive system is evaluated to see whether it is qualified.

[0066] It can be understood that by loading electromagnetic excitation on the stator and rotor at the same time, the coupling of electromagnetic and rotor structures can realize the process of transmitting rotor torsion and bending problems through bearings to the entire electric drive, identify NVH problems caused by the rotor, and more accurately control the rotor assembly, thereby improving the accuracy of the simulation model and making the simulation result data more consistent with the measured data.

[0067] In some embodiments, the method of establishing an electric drive system model includes:

[0068] Conduct finite element modeling of the assembly shell;

[0069] Conduct finite element modeling for cover plates;

[0070] Conduct finite element modeling of the suspension bracket;

[0071] Finite element modeling of the stator;

[0072] Finite element modeling of the rotor;

[0073] Finite element modeling of shaft gears;

[0074] Assemble the above finite element model.

[0075] Among them, the assembly shell adopts a second-order tetrahedral mesh with a mesh size of 4mm, and the bearing seat and suspension hole positions are partially refined with a 3mm size;

[0076] The controller cover corresponding to the ID4-200 platform assembly model is a silent cover, using a first-order quadrilateral mesh with a mesh size of 4 mm. The middle layer defines the composite material properties. The rear end cover is finite element modeled using a second-order tetrahedral mesh with a mesh size of 4 mm. The rear end cover is a cast aluminum plate.

[0077] The suspension bracket uses a second-order tetrahedral grid with a grid size of 4mm. An additional mass of 80g is added to the bushing to simulate the rubber structure. One end of the suspension bracket constrains six degrees of freedom and the other end is connected to the assembly model.

[0078] The shaft gear mesh is required to be a second-order hexagonal mesh with a mesh size of 4mm, and the differential model is required to have a straight bar structure;

[0079] The stator grid is a second-order hexagonal grid with a grid size of 4 mm; the winding grid is a second-order hexagonal grid with a grid size of 4 mm. The contact area between the winding and the stator is required to have the same node, and the end winding is replaced by the center of mass.

[0080] The rotor grid is a second-order hexagonal grid with a grid size of 4mm. The large and small magnetic steels are replaced by the center of mass. If it is a segmented rotor, the torsional freedom is released when the segments are connected.

[0081] Furthermore, the method for establishing the electric drive system model includes: for sub-components without specific internal detailed models, the center of mass position and moment of inertia are used instead; if the center of mass position cannot be determined, the entire outer surface of the sub-component is filled with a finite element solid mesh, and the model is built by changing the material density to achieve the correctness of mass distribution.

[0082] Furthermore, the method for establishing the electric drive system model includes: connecting the contact area of ​​the stator finite element model and the assembly housing finite element model with a common node, applying meshing stiffness at the gear meshing point, and imparting suspension stiffness under the whole vehicle state at the suspension bracket.

[0083] In some embodiments, the electromagnetic excitation solution includes: using Ansys Maxwell simulation software, according to the actual structure of the electric drive assembly, establishing a two-dimensional model including a stator and a rotor, and calculating the electromagnetic force. Specifically, it includes:

[0084] like Figure 2 As shown, the motor model is drawn in Maxwell software, and the motor system model is established. The model is a three-phase permanent magnet synchronous motor with one pole pair, 6 poles and 54 slots, a maximum speed of 18000rpm, and a maximum power of 200kW;

[0085] Add properties to the materials of each part of the motor, and assign corresponding physical properties to the finite element models of the stator and rotor, such as density, elastic modulus, and magnetic permeability. The units must be consistent to avoid errors.

[0086] Set the excitation source for the winding; it is required to simulate the actual working state of the motor. The real phase current collected by bench test can be used, and the amplitude of the fundamental current and harmonic current can be extracted by frequency domain processing of the current data and brought into I=Irms*sqrt(2)*sin(2*pi*Ele_freq*time+Gamma) and loaded into the model;

[0087] Set the magnetization direction of the permanent magnet to determine the direction of the magnetic field;

[0088] Set the motor's operating status, environment, and load; the operating condition is 500-10000rpm under full throttle load;

[0089] The motor model is meshed and the finite element mesh of the stator tooth root is encrypted. The maximum mesh size is 0.75 mm and the mode is selected as adaptive encryption, which is beneficial to improve the accuracy of electromagnetic force output.

[0090] Add field calculation, including output position, output force type, etc. In this method, only the force density of the stator tooth surface node can be output;

[0091] Set the solver parameters, which include the number of iterations, time step, convergence conditions, etc. In this method, only one mechanical cycle can be solved, 201 steps;

[0092] Output the electromagnetic force at the stator tooth root, and save the output electromagnetic force in UNV file format.

[0093] In some embodiments, the method of simultaneously applying electromagnetic excitation to the stator and the rotor includes:

[0094] Perform FFT calculation on the electromagnetic force calculated in Maxwell to obtain the amplitude and phase, and extract the 6p and 12p orders;

[0095] Stretch the electromagnetic force mesh derived from Maxwell. The stretching length is consistent with the stator structure length. The stator length is 120 mm. The stretched electromagnetic force mesh needs to correspond to the stator tooth mesh by moving and selecting.

[0096] like Figure 3 As shown in (a), the electromagnetic force is mapped to the stator tooth surface, and the mapped matrix is ​​derived;

[0097] Modify the weight of the mapped matrix so that its mapping direction is consistent with the rotor direction;

[0098] The modified weighted matrix is ​​mapped to the rotor tooth surface, such as Figure 3 As shown in (b) in .

[0099] Furthermore, since the motor is affected by the stator-rotor air gap magnetic field during actual operation, the stator and rotor are simultaneously affected by electromagnetic force, and the force is mutual in the system, with equal magnitude and opposite direction. Therefore, the method for modifying the weight of the mapped matrix includes: changing the weight of the mapped matrix from 1 to -1, so that the electromagnetic force mapped to the stator tooth surface can be reversely mapped to the rotor tooth surface.

[0100] like Figure 5 As shown, the simulation results of simultaneously loading electromagnetic excitation on the stator and the rotor using the present invention and the results of actual tests are shown. It can be found that the simulation results of simultaneously loading electromagnetic excitation on the stator and the rotor are closer to the actual results and more in line with reality.

[0101] In some embodiments, the present invention further includes performing secondary processing on the response data:

[0102] Set vibration measurement points and microphone measurement points to simulate the semi-anechoic test, and set microphone detection points 1m above, left, right, front, and back of the model;

[0103] Decompose the vibration or microphone response at the same measurement point to extract the responses generated by the stator side excitation and the rotor side excitation;

[0104] The response information is divided into real part and imaginary part respectively, and the parts are superimposed on each other;

[0105] Calculate the sound pressure level at the measuring point and compare it with the test data.

[0106] It can be understood that by extracting the response generated by the stator side excitation and the rotor side excitation for the same measuring point, the real part and the imaginary part are extracted by Python calculation, and the two response curves are superimposed on each other to generate a new curve for comparison with the test data, such as Figure 4 This is a comparison curve of the ID4-200 platform assembly model after simultaneous application of stator and rotor excitation and after application of resultant force. It can be seen from the figure that the response peak caused by the rotor torsional mode is reflected when the stator and rotor excitation are applied simultaneously, which can evaluate the NVH problem caused by the rotor model.

[0107] The present invention also provides a system for the NVH simulation method of simultaneously loading the electric drive excitation on the stator and rotor structures, comprising:

[0108] Modeling module, used to build electric drive system model;

[0109] A calculation module, used for calculating the electromagnetic force at the stator tooth root;

[0110] Loading module for mapping electromagnetic forces onto the stator and rotor;

[0111] An evaluation module is used to determine whether the NVH of the electric drive system is qualified.

[0112] The embodiments described above are only used to illustrate the technical solutions of the present application, rather than to limit them. Although the present application has been described in detail with reference to the aforementioned embodiments, a person skilled in the art should understand that the technical solutions described in the aforementioned embodiments may still be modified, or some of the technical features may be replaced by equivalents. Such modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present application, and should all be included in the protection scope of the present application.

Claims

1. A NVH simulation method in which electric drive excitation is simultaneously loaded on the stator and rotor structure, characterized in that: include: Build an electric drive system model; Electromagnetic excitation solution; Applying electromagnetic excitation to the stator and the rotor simultaneously; The electromagnetic excitation is coupled with the electric drive system model, the measuring points are arranged, the corresponding data at each measuring point is extracted, and the NVH of the electric drive system is evaluated to see whether it is qualified.

2. The NVH simulation method of simultaneously loading the stator and rotor structures with electric drive excitation according to claim 1 is characterized in that: Methods for applying electromagnetic excitation to both the stator and the rotor include: Perform FFT calculation on the electromagnetic force calculated in Maxwell to obtain the amplitude and phase; Stretch the electromagnetic force grid derived from Maxwell to a length that is consistent with the stator structure length; Map the electromagnetic force to the stator tooth surface and derive the mapped matrix; Modify the weight of the mapped matrix so that its mapping direction is consistent with the rotor direction; The modified weighted matrix is ​​mapped to the rotor tooth surface.

3. The NVH simulation method of simultaneously loading the stator and rotor structures with electric drive excitation according to claim 2 is characterized in that: The method for modifying the weight of the mapped matrix includes: changing the weight of the mapped matrix from 1 to -1.

4. The NVH simulation method according to any one of claims 1 to 3, wherein the electric drive excitation is simultaneously loaded on the stator and rotor structures, characterized in that: Methods for building an electric drive system model include: Conduct finite element modeling of the assembly shell; Conduct finite element modeling for cover plates; Conduct finite element modeling of the suspension bracket; Finite element modeling of the stator; Finite element modeling of the rotor; Finite element modeling of shaft gears; Assemble the above finite element model.

5. The NVH simulation method of simultaneously loading the stator and rotor structures with electric drive excitation according to claim 4 is characterized in that: The method of establishing an electric drive system model includes: for sub-components without specific internal detailed models, the center of mass position and moment of inertia are used instead; if the center of mass position cannot be determined, the entire outer surface of the sub-component is filled with a finite element solid mesh, and the model is modeled by changing the material density to achieve correct mass distribution.

6. The NVH simulation method of simultaneously loading the stator and rotor structures with electric drive excitation according to claim 4 is characterized in that: The method for finite element modeling of the stator includes: modeling the stator, the mesh is a second-order hexagonal mesh, and the mesh size is 4mm; modeling the winding, the mesh is a second-order hexagonal mesh, and the mesh size is 4mm, the contact area between the winding and the stator is required to have the same node, and the end winding is replaced by the center of mass.

7. The NVH simulation method of simultaneously loading the stator and rotor structures with electric drive excitation according to claim 4 is characterized in that: The method for finite element modeling of the rotor includes: modeling the rotor, the mesh is a second-order hexagonal mesh, the mesh size is 4mm, the large and small magnetic steels are replaced by the center of mass, and if it is a segmented rotor, the torsional freedom is released when the segments are connected.

8. The NVH simulation method of simultaneously loading the stator and rotor structures with electric drive excitation according to claim 4 is characterized in that: The method for establishing an electric drive system model includes: connecting the contact area of ​​the stator finite element model and the assembly housing finite element model with a common node, applying meshing stiffness at the gear meshing point, and giving the suspension stiffness under the whole vehicle state at the suspension bracket.

9. The NVH simulation method of simultaneously loading the electric drive excitation on the stator and rotor structures according to any one of claims 1 to 3 is characterized in that: Including secondary processing of response data: Set vibration measurement points and microphone measurement points; Decompose the vibration or microphone response at the same measurement point to extract the responses generated by the stator side excitation and the rotor side excitation; The response information is divided into real part and imaginary part respectively, and the parts are superimposed on each other; Calculate the sound pressure level at the measuring point and compare it with the test data.

10. A system for NVH simulation method according to any one of claims 1 to 9, wherein the electric drive excitation is simultaneously loaded on the stator and rotor structure, characterized in that: include: Modeling module, used to build electric drive system model; A calculation module, used for calculating the electromagnetic force at the stator tooth root; Loading module for mapping electromagnetic forces onto the stator and rotor; An evaluation module is used to determine whether the NVH of the electric drive system is qualified.

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