Method for evaluating impedance performance of three-way electromagnetic load of vehicle generator assembly

Abstract

The invention discloses a method for evaluating the impedance performance of a three-way electromagnetic load of a vehicle generator assembly, and the method comprises the steps: splitting a vehicle generator assembly housing into a plurality of plates, carrying out the triangular grid discretization of the surface of each plate, and calculating the total area of each discretized plate; establishing a cylindrical coordinate system of the vehicle engine assembly; under the condition that only radial electromagnetic load, only tangential electromagnetic load and only axial electromagnetic load are applied, excitation is applied to the vertexes of the triangular discrete units on the plates, the three-direction vibration acceleration of the vertexes is obtained, the radiation noise value of each plate is calculated, and a sound radiation noise curve of the vehicle engine assembly within a preset frequency range is obtained; aiming at the sound radiation noise curve in each direction, calculating to obtain radial, tangential and axial impedance coefficients under the electromagnetic load in the direction; and performing weighted fusion on the radial, tangential and axial impedance coefficients through a weighted combination strategy to obtain a comprehensive impedance coefficient, and performing evaluation according to a preset rating standard.

Description

Technical Field

[0001] This invention relates to the field of new energy vehicle powertrain technology, specifically to a method for evaluating the three-dimensional electromagnetic load impedance performance of a vehicle generator assembly. Background Technology

[0002] In the new energy field, range-extended electric vehicles (REEVs) have gained widespread recognition for their ability to effectively alleviate users' range anxiety. To ensure efficient power generation, their vehicle generator assemblies typically employ permanent magnet synchronous motors. During operation, this type of motor generates radial, tangential, and axial electromagnetic forces simultaneously between the stator and rotor. These three types of electromagnetic forces have different mechanisms and contribution levels to the assembly structure vibration and overall vehicle noise, exhibiting significant coupling effects.

[0003] In the early stages of product development, especially in the absence of physical prototypes, conducting a comprehensive, forward-looking, and quantitative assessment of the excitation characteristics of electromagnetic schemes and the impedance performance of product structures has become a significant technical challenge in the industry. Currently, the industry lacks effective solutions and generally relies on later-stage bench testing and vehicle testing for problem identification and design iteration, resulting in long development cycles, high costs, and significant resource waste. Therefore, further consideration is needed on how to provide a method that can be implemented in the design phase to decouple and evaluate the structural response under triaxial electromagnetic force excitation, accurately identify design risks, guide structural optimization, thereby improving product performance and reducing development costs. Summary of the Invention

[0004] In view of the shortcomings of the prior art, the technical problem to be solved by the present invention is: how to provide a method for independently evaluating the impedance characteristics of the assembly structure to radial, tangential and axial electromagnetic forces through simulation under the condition of no physical prototype, and to conduct a comprehensive performance evaluation.

[0005] To solve the above-mentioned technical problems, the present invention adopts the following technical solution:

[0006] A method for evaluating the three-phase electromagnetic load impedance performance of an automotive generator assembly includes the following steps:

[0007] (1) The vehicle engine assembly housing is divided into multiple plates, and the surface of each plate is discretized into a triangular mesh. The discretization parameters are adjusted by iterative calculation so that the deviation rate between the total area of ​​each plate after discretization and the theoretical total area is controlled within the preset tolerance range.

[0008] (2) Establish a cylindrical coordinate system for the vehicle engine assembly. With the center of the spline end face of the rotor hub assembly in the vehicle engine assembly as the origin, apply preset proportional electromagnetic loads in the radial, tangential and axial directions independently on the stator teeth and rotor surfaces based on the cylindrical coordinate system.

[0009] (3) Through simulation calculation, under the conditions of applying only radial, only tangential and only axial electromagnetic loads, excitation is applied to the vertices of the triangular discrete elements on each plate, the triaxial vibration acceleration of the vertices of the triangular discrete elements is obtained, the radiation noise value of each plate is calculated, and the sound radiation noise curve of the vehicle engine assembly in the predetermined frequency range is obtained.

[0010] (4) For the sound radiation noise curve in each direction, extract its key feature point parameters and calculate the radial impedance coefficient RZ, tangential impedance coefficient TZ and axial impedance coefficient AZ that characterize the impedance characteristics of the vehicle engine assembly under electromagnetic load in that direction.

[0011] (5) Compare the maximum noise values ​​in the radial, tangential, and axial sound radiation noise curves, and select the corresponding weighted combination strategy to perform weighted fusion of RZ, TZ, and AZ according to the direction to which the minimum value belongs, to obtain the comprehensive impedance coefficient ZZ;

[0012] When the minimum value of the three values ​​belongs to the radial direction, ZZ = w*RZ + TZ + AZ;

[0013] When the minimum value of the three values ​​belongs to the tangential direction, ZZ = RZ + w*TZ + AZ;

[0014] When the minimum value of the three values ​​belongs to the axial direction, ZZ = RZ + TZ + w*AZ;

[0015] In the formula, w is the weighting coefficient; based on the ZZ value, the three-dimensional electromagnetic load impedance performance of the vehicle generator assembly is evaluated in accordance with the preset rating standard.

[0016] As an optimization, in step (1), the method for calculating the equivalent acoustic radiation area of ​​a single triangular discrete element is as follows:

[0017] Calculate the lengths of the three sides of a triangle:

[0018] a ef =sqrt((x ef1 -x ef2 ) 2 +(y ef1 -y ef2 ) 2 +(z ef1 -z ef2 ) 2 )

[0019] b ef =sqrt((x ef2 -x ef3 ) 2 +(y ef2 -y ef3 )2 +(z ef2 -z ef3 ) 2 )

[0020] c ef =sqrt((x ef1 -x ef3 ) 2 +(y ef1 -y ef3 ) 2 +(z ef1 -z ef3 ) 2 )

[0021] In the formula x efk y efk , z efk k = 1, 2, 3, representing the spatial coordinates of the kth point of the fth triangular discrete unit on the eth plate;

[0022] Calculate the area:

[0023] As an optimization, in step (1), the iterative calculation includes:

[0024] Calculate the area of ​​each discrete triangular unit and the total area of ​​the plate based on the spatial coordinates of the vertices of each discrete triangular unit after discretization, and calculate the total area deviation rate. If the deviation rate exceeds the tolerance range of ±2%, adjust the coordinate difference used to calculate the side length of the discrete triangular unit according to the proportional coefficient related to the deviation rate, and recalculate the area of ​​the discrete triangular unit until the total area deviation rate meets the tolerance requirements.

[0025] As an optimization, the formula for adjusting the side length of the triangular discrete element is as follows:

[0026] a ef =sqrt((1+0.5*PCV) e )*((x ef1 -x ef2 ) 2 +(y ef1 -y ef2 ) 2 +(z ef1 -z ef2 ) 2 ))

[0027] b ef =sqrt((1+0.5*PCV) e )*((x ef2 -x ef3 ) 2 +(y ef2 -y ef3 )2 +(z ef2 -z ef3 ) 2 ))

[0028] c ef =sqrt((1+0.5*PCV) e )*((x ef1 -x ef3 ) 2 +(y ef1 -y ef3 ) 2 +(z ef1 -z ef3 ) 2 ))

[0029] In the formula PCV e Let be the total area deviation rate of the e-th plate.

[0030] As an optimization, in step (1), the plate includes an electronic control top cover, an electronic control housing, an end cover, and a motor housing.

[0031] As an optimization, in step (2), the applied radial, tangential, and axial electromagnetic loads are respectively:

[0032] F 定子-径向 =1000*S 定子齿

[0033] F 转子-径向 =1000*S 转子表面

[0034] F 定子-切向 =500*S 定子齿

[0035] F 转子-切向 =500*S 转子表面

[0036] F 定子-轴向 =200*S 定子齿

[0037] F 转子-轴向 =200*S 转子表面

[0038] In the formula S 定子齿 S is the surface area of ​​the stator teeth. 转子表面 This represents the outer surface area of ​​the rotor.

[0039] As an optimization, in step (5), when the minimum value of the three belongs to the radial direction, the weight coefficient w satisfies 1.05≤w≤1.15; when the minimum value of the three belongs to the tangential direction, the weight coefficient w satisfies 1.2≤w≤1.3; and when the minimum value of the three belongs to the axial direction, the weight coefficient w satisfies 1.45≤w≤1.55.

[0040] As an optimization, when the minimum value of the three values ​​belongs to the radial direction, the weighting coefficient w = 1.1; when the minimum value of the three values ​​belongs to the tangential direction, the weighting coefficient w = 1.25; and when the minimum value of the three values ​​belongs to the axial direction, the weighting coefficient w = 1.5.

[0041] Compared with existing technologies, the present invention has the following advantages: the present invention can independently and quantitatively evaluate the impedance performance of a structure to excitation in different directions and accurately identify weak directions; it can be implemented in the product design stage without physical prototypes, achieving accurate prediction and risk assessment of structural vibration and noise performance, greatly reducing reliance on later tests; and it can significantly shorten the product development iteration cycle, reduce test verification costs, save development resources, and ultimately improve the vibration and noise performance and reliability of the product. Attached Figure Description

[0042] Figure 1 This is a flowchart of the present invention;

[0043] Figure 2 This is a radial electromagnetic force surface acoustic radiation curve of the vehicle generator assembly in this invention;

[0044] Figure 3 This is a surface acoustic radiation curve of the tangential electromagnetic force of the vehicle generator assembly in this invention;

[0045] Figure 4 This is a surface acoustic radiation curve of the axial electromagnetic force of the vehicle generator assembly in this invention. Detailed Implementation

[0046] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely represents selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

[0047] like Figure 1 As shown, the method for evaluating the three-phase electromagnetic load impedance performance of the vehicle generator assembly in this specific embodiment includes the following steps:

[0048] (1) The vehicle engine assembly housing is divided into multiple plates, and the surface of each plate is discretized into a triangular mesh. The discretization parameters are adjusted by iterative calculation so that the deviation rate between the total area of ​​each plate after discretization and the theoretical total area is controlled within the preset tolerance range.

[0049] (2) Establish a cylindrical coordinate system for the vehicle engine assembly. With the center of the spline end face of the rotor hub assembly in the vehicle engine assembly as the origin, apply preset proportional electromagnetic loads in the radial, tangential and axial directions independently on the stator teeth and rotor surfaces based on the cylindrical coordinate system.

[0050] (3) Through simulation calculation, under the conditions of applying only radial, only tangential and only axial electromagnetic loads, excitation is applied to the vertices of the triangular discrete elements on each plate, the triaxial vibration acceleration of the vertices of the triangular discrete elements is obtained, the radiation noise value of each plate is calculated, and the sound radiation noise curve of the vehicle engine assembly in the predetermined frequency range is obtained.

[0051] (4) For the sound radiation noise curve in each direction, extract its key feature point parameters and calculate the radial impedance coefficient RZ, tangential impedance coefficient TZ and axial impedance coefficient AZ that characterize the impedance characteristics of the vehicle engine assembly under electromagnetic load in that direction.

[0052] (5) Compare the maximum noise values ​​in the radial, tangential, and axial sound radiation noise curves, and select the corresponding weighted combination strategy to perform weighted fusion of RZ, TZ, and AZ according to the direction to which the minimum value belongs, to obtain the comprehensive impedance coefficient ZZ;

[0053] When the minimum value of the three values ​​belongs to the radial direction, ZZ = w*RZ + TZ + AZ;

[0054] When the minimum value of the three values ​​belongs to the tangential direction, ZZ = RZ + w*TZ + AZ;

[0055] When the minimum value of the three values ​​belongs to the axial direction, ZZ = RZ + TZ + w*AZ;

[0056] In the formula, w is the weighting coefficient; based on the ZZ value, the three-dimensional electromagnetic load impedance performance of the vehicle generator assembly is evaluated in accordance with the preset rating standard.

[0057] In step (1), the method for calculating the equivalent acoustic radiation area of ​​a single triangular discrete element is as follows:

[0058] Calculate the lengths of the three sides of a triangle:

[0059] a ef =sqrt((x ef1 -x ef2 ) 2 +(y ef1 -y ef2 ) 2 +(z ef1 -z ef2 ) 2 )

[0060] b ef =sqrt((x ef2 -x ef3 ) 2 +(y ef2 -y ef3 ) 2 +(z ef2 -z ef3 ) 2 )

[0061] c ef =sqrt((x ef1 -x ef3 ) 2 +(y ef1 -y ef3 ) 2 +(z ef1 -z ef3 ) 2 )

[0062] In the formula x efk y efk , z efk k = 1, 2, 3, representing the spatial coordinates of the kth point of the fth triangular discrete unit on the eth plate;

[0063] Calculate the area:

[0064] In step (1), the iterative calculation includes:

[0065] Calculate the area of ​​each discrete triangular unit and the total area of ​​the plate based on the spatial coordinates of the vertices of each discrete triangular unit after discretization, and calculate the total area deviation rate. If the deviation rate exceeds the tolerance range of ±2%, adjust the coordinate difference used to calculate the side length of the discrete triangular unit according to the proportional coefficient related to the deviation rate, and recalculate the area of ​​the discrete triangular unit until the total area deviation rate meets the tolerance requirements.

[0066] The formula for adjusting the side length of the triangular discrete element is as follows:

[0067] a ef =sqrt((1+0.5*PCV) e )*((xef1 -x ef2 ) 2 +(y ef1 -y ef2 ) 2 +(z ef1 -z ef2 ) 2 ))

[0068] b ef =sqrt((1+0.5*PCV) e )*((x ef2 -x ef3 ) 2 +(y ef2 -y ef3 ) 2 +(z ef2 -z ef3 ) 2 ))

[0069] c ef =sqrt((1+0.5*PCV) e )*((x ef1 -x ef3 ) 2 +(y ef1 -y ef3 ) 2 +(z ef1 -z ef3 ) 2 ))

[0070] In the formula PCV e Let be the total area deviation rate of the e-th plate.

[0071] In step (1), the plate includes an electronic control top cover, an electronic control shell, an end cover, and a motor shell.

[0072] In step (2), the applied radial, tangential, and axial electromagnetic loads are respectively:

[0073] F 定子-径向 =1000*S 定子齿

[0074] F 转子-径向 =1000*S 转子表面

[0075] F 定子-切向 =500*S 定子齿

[0076] F 转子-切向 =500*S 转子表面

[0077] F 定子-轴向 =200*S定子齿

[0078] F 转子-轴向 =200*S 转子表面

[0079] In the formula S 定子齿 S is the surface area of ​​the stator teeth. 转子表面 This represents the outer surface area of ​​the rotor.

[0080] In step (5), when the minimum value of the three belongs to the radial direction, the weighting coefficient w satisfies 1.05≤w≤1.15; when the minimum value of the three belongs to the tangential direction, the weighting coefficient w satisfies 1.2≤w≤1.3; and when the minimum value of the three belongs to the axial direction, the weighting coefficient w satisfies 1.45≤w≤1.55.

[0081] In practice, the vehicle generator assembly is disassembled into four parts: the electronic control cover, the electronic control housing, the end cover, and the motor housing. Each part is then discretized using triangles with an average side length of 4mm. The spatial coordinates of each point in all triangular elements are recorded. The equivalent acoustic radiation area of ​​each triangle on the surface of each plate is calculated using the following formula.

[0082]

[0083] In the formula: DD ef The equivalent acoustic radiation area of ​​the f-th triangular unit on the e-th plate (e = electrical control top cover, electrical control shell, end cover, motor shell). ef b ef c ef This represents the side lengths of the three sides of a triangular element. Sqrt represents the square root.

[0084] Where: a ef =sqrt((x ef1 -x ef2 ) 2 +(y ef1 -y ef2 ) 2 +(z ef1 -z ef2 ) 2 )

[0085] b ef =sqrt((x ef2 -x ef3 ) 2 +(y ef2 -y ef3 ) 2 +(z ef2 -z ef3 ) 2 )

[0086] c ef =sqrt((x ef1 -x ef3 ) 2 +(y ef1 -y ef3 ) 2 +(z ef1 -z ef3 ) 2 )

[0087] In the formula: x efk y efk , z efk (k = 1, 2, 3) represents the spatial coordinates of the kth point (out of three) of the triangular unit.

[0088] The deviation rate between the total area calculated for each panel and the actual area of ​​that panel is calculated using the following formula.

[0089] PCV e1 =(DD) et -DD e ) / DD e

[0090] In the formula: DD et DD e Let represent the area obtained after discretization of the e-th plate and the actual area, respectively. e1 This represents the actual area deviation rate calculated for the e-th panel in the first round. If -2% <PCV e1 If the deviation rate is less than 2%, the discrete model meets the standard. If the deviation rate is not less than 2%, iterative processing is required according to the following formula:

[0091] a ef =sqrt((1+0.5*PCV) e )*((x ef1 -x ef2 ) 2 +(y ef1 -y ef2 ) 2 +(z ef1 -z ef2 ) 2 ))

[0092] b ef =sqrt((1+0.5*PCV) e )*((x ef2 -x ef3 ) 2 +(y ef2 -y ef3 ) 2 +(z ef2-z ef3 ) 2 ))

[0093] c ef =sqrt((1+0.5*PCV) e )*((x ef1 -x ef3 ) 2 +(y ef1 -y ef3 ) 2 +(z ef1 -z ef3 ) 2 ))

[0094] The iterated a ef b ef c ef Substitute into DD ef The formula is used for calculation, and then PCV is calculated. e1 PCV e2 This represents the actual area deviation rate calculated in the second round for the e-th panel. Then, it is determined whether the following condition is met: -2%. <PCV e2 <2%. If satisfied, stop iterating. If not satisfied, continue iterating until satisfied.

[0095] After the iteration is completed, the area of ​​all triangles of the above four plates is calculated and recorded, thus completing the discretization of the acoustic radiation surface of the vehicle generator assembly.

[0096] Triaxial electromagnetic load application:

[0097] Establish the cylindrical coordinate system of the vehicle generator assembly: take the center of the arc of the spline side end face of the rotor hub assembly as the origin of the cylindrical coordinate system, take the direction from the center of the rotor hub assembly to the outer edge of the rotor as the radial direction, take the direction of the rotor hub shaft as the axial direction of the cylindrical coordinate system, and take the tangential direction of the arc of the outer surface of the rotor hub assembly as the tangential direction of the cylindrical coordinate system.

[0098] Apply radial force F to the stator teeth. 定子-径向 =1000*S 定子齿

[0099] A radial force F is applied to the rotor surface. 转子-径向 =1000*S 转子表面

[0100] In the formula: S 定子齿 S represents the surface area of ​​the stator teeth; 转子表面 This refers to the outer surface of the rotor.

[0101] A tangential force F is applied to the stator teeth. 定子-切向 =500*S 定子齿

[0102] A tangential force is applied to the rotor surface: F 转子-切向 =500*S 转子表面

[0103] An axial force is applied to the stator teeth: F 定子-轴向 =200*S 定子齿

[0104] An axial force is applied to the rotor surface: F 转子-轴向 =200*S 转子表面

[0105] Once all electromagnetic forces have been applied according to the formula above, this step is complete.

[0106] Acquisition of surface acoustic radiation curves of automotive alternator assembly

[0107] Under the condition of simultaneously applying radial electromagnetic force to the stator teeth and radial electromagnetic force to the rotor surface, calculate the triaxial vibration acceleration at three points on all triangular units of the four plates in 1000Hz to 6000Hz intervals. Calculate the radiated noise value of each plate under each frequency condition according to the following formula:

[0108]

[0109] In the formula: Z e径向 (P) represents the radiated noise value of the e-th plate under the condition of excitation frequency P and only the radial electromagnetic force on the surface of the stator teeth is applied. Vx ef1 Let f be the vibration velocity of the e-th plate at the f-th point under the excitation frequency P. The meanings of the remaining variables are deduced accordingly.

[0110] The total noise value caused by the radial electromagnetic force is then calculated using the following formula:

[0111] Z t径向 (P) = 10*

[0112] log((10^(Z 1径向 (P) / 10))+(10^(Z 2径向 (P) / 10))+(10^(Z 3径向 (P) / 10))+(10^(Z 4径向 (P) / 10)))

[0113] In the formula: Z t径向 (P) represents the total noise value caused by the radial electromagnetic force at a frequency equal to P. Plot frequency on the x-axis, Z... t径向 The radial electromagnetic force surface acoustic radiation curve of the vehicle generator assembly is obtained by plotting the (P) value on the ordinate. Figure 2 .

[0114] The total noise value Z caused by the tangential electromagnetic force is calculated using the method described above. t切向 (P) and the total noise value Z caused by axial electromagnetic force t轴向 (P) The tangential electromagnetic force surface acoustic radiation curves and the axial electromagnetic force surface acoustic radiation curves of the vehicle generator assembly were plotted. See the specific curves below. Figure 3 and Figure 4 .

[0115] Calculation of radial electromagnetic load impedance coefficient of assembly:

[0116] Based on the radial electromagnetic force surface acoustic radiation curve of the vehicle generator assembly obtained above, key points are identified.

[0117] Find the three points on the curve with the highest amplitudes and record their corresponding frequencies and amplitudes. Denote this as Z. t径向 (Pmax1), P_horizonmax1, Z t径向 (Pmax2), P_horizonmax2, Z t径向 (Pmax3), P_horizontal_max3. In this example, the above 6 parameters are: 72.9, 3200, 68.1, 3554, 56.0, 1987.

[0118] Find the three lowest amplitude points on the curve and record their corresponding frequencies and amplitudes. Denote this as Z. t径向 (Pmin1), P_min1, Z t径向 (Pmin2), P_min2, Z t径向 (Pmin3), P_min3. In this example, the above 6 parameters are: 33.2, 1000, 43.0, 1450, 44, 1283.

[0119] Calculate Z in the range of 1000Hz to 6000Hz. t径向 The average value of (P) is denoted as: Z t径向 (ave), in this example Z t径向 (ave) = 49.0.

[0120] The radial electromagnetic load impedance coefficient is calculated using the following formula:

[0121] RZ = 1 / Z t径向 (ave)+0.2*(1 / Z t径向 (Pmax1)+1 / Z t径向 (Pmax2)+1 / Z t径向 (Pmax3))+0.001*(Z t径向 (Pmin1) / Z t径向 (Pmax1)+Z t径向 (Pmin2) / Z t径向(Pmax2)+Z t径向 (Pmin3) / Z t径向 (Pmax3))+1e-6*(P_min1 / P_max1+P_min2 / P_max2+P_min3 / P_max3)

[0122] In the formula: RZ represents the radial electromagnetic load impedance coefficient. In this example, RZ = 0.0315.

[0123] Calculation of tangential electromagnetic load impedance coefficient of assembly

[0124] Based on the previously obtained surface acoustic radiation curve of the tangential electromagnetic force of the vehicle generator assembly, key points are identified.

[0125] Find the three points on the curve with the highest amplitudes and record their corresponding frequencies and amplitudes. Denote this as Z. t切向 (Pmax1), P_cut max1, Z t切向 (Pmax2), P_cut max2, Z t切向 (Pmax3), P_cut_max3. In this example, the above 6 parameters are: 72.1, 1200, 67.4, 1341, 65.2, 2725.

[0126] Find the three lowest amplitude points on the curve and record their corresponding frequencies and amplitudes. Denote this as Z. t切向 (Pmin1), Pmin1, Z t切向 (Pmin2), Pmin2, Z t切向 (Pmin3), Pmin3. In this example, the above 6 parameters are: 51.1, 6000, 51.7, 4254, 53.5, 4833.

[0127] Calculate Z in the range of 1000Hz to 6000Hz. t切向 The average value of (P) is denoted as: Z t切向 (ave). In this example, Z t切向 (ave) = 47.5.

[0128] The impedance coefficient of the tangential electromagnetic load is calculated using the following formula:

[0129] TZ = 1 / Z t切向 (ave)+0.2*(1 / Z t切向 (Pmax1)+1 / Z t切向 (Pmax2)+1 / Z t切向 (Pmax3))+0.001*(Z t切向 (Pmin1) / Z t切向 (Pmax1)+Z t切向 (Pmin2) / Zt切向 (Pmax2)+Z t切向 (Pmin3) / Z t切向 (Pmax3))+1e-6*(Pcutmin1 / Pcutmax1+Pcutmin2 / Pcutmax2+Pcutmin3 / Pcutmax3)

[0130] In the formula: TZ represents the tangential electromagnetic load impedance coefficient. In this example, TZ = 0.0322.

[0131] Calculation of axial electromagnetic load impedance coefficient of assembly

[0132] Based on the previously obtained surface acoustic radiation curve of the axial electromagnetic force of the vehicle generator assembly, key points are identified.

[0133] Find the three points on the curve with the highest amplitudes and record their corresponding frequencies and amplitudes. Denote this as Z. t轴向 (Pmax1), P-axis max1, Z-axis max1 t轴向 (Pmax2), P-axis max2, Z t轴向 (Pmax3), P-axis max3. In this example, the above 6 parameters are: 68.2, 1362, 60.6, 2583, 58.8, 3608.

[0134] Find the three lowest amplitude points on the curve and record their corresponding frequencies and amplitudes. Denote this as Z. t轴向 (Pmin1), P-axis min1, Z t轴向 (Pmin2), P-axis min2, Z t轴向 (Pmin3), P-axis min3. In this example, the above 6 parameters are: 39, 6000, 43.5, 5500, 47.0, 4450.

[0135] Calculate Z in the range of 1000Hz to 6000Hz. t轴向 The average value of (P) is denoted as: Z t轴向 (ave). In this example, Z t轴向 (ave) = 49.3.

[0136] The axial electromagnetic load impedance coefficient is calculated using the following formula:

[0137] AZ = 1 / Z t轴向 (ave)+0.2*(1 / Z t轴向 (Pmax1)+1 / Z t轴向 (Pmax2)+1 / Z t轴向 (Pmax3))+0.001*(Z t轴向 (Pmin1) / Z t轴向 (Pmax1)+Z t轴向 (Pmin2) / Zt轴向 (Pmax2)+Z t轴向 (Pmin3) / Z t轴向 (Pmax3))+1e-6*(Paxismin1 / Paxismax1+Paxismin2 / Paxismax2+Paxismin3 / Paxismax3)

[0138] In the formula: AZ represents the axial electromagnetic load impedance coefficient. In this example, AZ = 0.0320.

[0139] Three-dimensional electromagnetic load impedance performance analysis of the assembly:

[0140] Calculate the three-dimensional electromagnetic load impedance coefficient of the assembly according to the following judgment criteria and calculation formula.

[0141] If Min(Z) t径向 (Pmax1), Z t切向 (Pmax1), Z t轴向 (Pmax1))=Z t径向 (Pmax1)

[0142] Then ZZ = 1.1 * RZ + TZ + AZ

[0143] If Min(Z) t径向 (Pmax1), Z t切向 (Pmax1), Z t轴向 (Pmax1))=Z t切向 (Pmax1)

[0144] Then ZZ = RZ + 1.25 * TZ + AZ

[0145] If Min(Z) t径向 (Pmax1), Z t切向 (Pmax1), Z t轴向 (Pmax1))=Z t轴向 (Pmax1)

[0146] Then ZZ = RZ + TZ + 1.5 * AZ

[0147] In the formula: ZZ represents the comprehensive impedance coefficient of the three-dimensional electromagnetic load of the assembly; in this example, ZZ = 0.104. Finally, according to Table 1, the impedance performance of the three-dimensional electromagnetic load of the automotive alternator assembly is scored and rated. In this example, the alternator assembly is scored 4 points, and the level is high risk.

[0148]

[0149] Table 1

[0150] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit the technical solutions. Those skilled in the art should understand that any modifications or equivalent substitutions to the technical solutions of the present invention without departing from the spirit and scope of the present invention should be covered within the scope of the claims of the present invention.

Claims

1. A method for evaluating the three-phase electromagnetic load impedance performance of a vehicle generator assembly, characterized in that: Includes the following steps: (1) The vehicle engine assembly housing is divided into multiple plates, and the surface of each plate is discretized into a triangular mesh. The discretization parameters are adjusted by iterative calculation so that the deviation rate between the total area of ​​each plate after discretization and the theoretical total area is controlled within the preset tolerance range. (2) Establish a cylindrical coordinate system for the vehicle engine assembly. With the center of the spline end face of the rotor hub assembly in the vehicle engine assembly as the origin, apply preset proportional electromagnetic loads in the radial, tangential and axial directions independently on the stator teeth and rotor surfaces based on the cylindrical coordinate system. (3) Through simulation calculation, under the conditions of applying only radial, only tangential and only axial electromagnetic loads, excitation is applied to the vertices of the triangular discrete elements on each plate, the triaxial vibration acceleration of the vertices of the triangular discrete elements is obtained, the radiation noise value of each plate is calculated, and the sound radiation noise curve of the vehicle engine assembly in the predetermined frequency range is obtained. (4) For the sound radiation noise curve in each direction, extract its key feature point parameters and calculate the radial impedance coefficient RZ, tangential impedance coefficient TZ and axial impedance coefficient AZ that characterize the impedance characteristics of the vehicle engine assembly under electromagnetic load in that direction. (5) Compare the maximum noise values ​​in the radial, tangential, and axial sound radiation noise curves, and select the corresponding weighted combination strategy to perform weighted fusion of RZ, TZ, and AZ according to the direction to which the minimum value belongs, to obtain the comprehensive impedance coefficient ZZ; When the minimum value of the three values ​​belongs to the radial direction, ZZ = w*RZ + TZ + AZ; When the minimum value of the three values ​​belongs to the tangential direction, ZZ = RZ + w*TZ + AZ; When the minimum value of the three values ​​belongs to the axial direction, ZZ = RZ + TZ + w*AZ; In the formula, w is the weighting coefficient; based on the ZZ value, the three-dimensional electromagnetic load impedance performance of the vehicle generator assembly is evaluated in accordance with the preset rating standard.

2. The method for evaluating the three-dimensional electromagnetic load impedance performance of the vehicle generator assembly according to claim 1, characterized in that: In step (1), the method for calculating the equivalent acoustic radiation area of ​​a single triangular discrete element is as follows: Calculate the lengths of the three sides of a triangle: a ef =sqrt((x ef1 -x ef2 ) 2 +(y ef1 -y ef2 ) 2 +(z ef1 -z ef2 ) 2 ) b ef =sqrt((x ef2 -x ef3 ) 2 +(y ef2 -y ef3 ) 2 +(z ef2 -z ef3 ) 2 ) c ef =sqrt((x ef1 -x ef3 ) 2 +( y ef1 -y ef3 ) 2 +(z ef1 -z ef3 ) 2 ) In the formula x efk y efk , z efk k = 1, 2, 3, representing the spatial coordinates of the kth point of the fth triangular discrete unit on the eth plate; Calculate the area:

3. The method for evaluating the three-phase electromagnetic load impedance performance of the vehicle generator assembly according to claim 1, characterized in that: In step (1), the iterative calculation includes: Calculate the area of ​​each discrete triangle unit and the total area of ​​the plate based on the spatial coordinates of the vertices of each discrete triangle unit after discretization, and calculate the total area deviation rate. If the deviation rate exceeds the tolerance range of ±2%, adjust the coordinate difference used to calculate the side length of the discrete triangle unit according to the proportional coefficient related to the deviation rate, and recalculate the area of ​​the discrete triangle unit until the total area deviation rate meets the tolerance requirements.

4. The method for evaluating the three-dimensional electromagnetic load impedance performance of the vehicle generator assembly according to claim 3, characterized in that: The formula for adjusting the side length of the triangular discrete element is as follows: a ef =sqrt((1+0.5*PCV e )*((x ef1 -x ef2 ) 2 +(y ef1 -y ef2 ) 2 +(z ef1 -z ef2 ) 2 )) b ef =sqrt((1+0.5*PCV e )*((x ef2 -x ef3 ) 2 +(y ef2 -y ef3 ) 2 +(z ef2 -z ef3 ) 2 )) c ef =sqrt((1+0.5*PCV e )*((x ef1 -x ef3 ) 2 +(y ef1 -y ef3 ) 2 +(z ef1 -z ef3 ) 2 )) In the formula PCV e Let be the total area deviation rate of the e-th plate.

5. The method for evaluating the three-dimensional electromagnetic load impedance performance of the vehicle generator assembly according to claim 1, characterized in that: In step (1), the plate includes an electronic control top cover, an electronic control shell, an end cover, and a motor shell.

6. The method for evaluating the three-phase electromagnetic load impedance performance of the vehicle generator assembly according to claim 1, characterized in that: In step (2), the applied radial, tangential, and axial electromagnetic loads are respectively: F 定子-径向 =1000*S 定子齿 F 转子-径向 =1000*S 转子表面 F 定子-切向 =500*S 定子齿 F 转子-切向 =500*S 转子表面 F 定子-轴向 =200*S 定子齿 F 转子-轴向 =200*S 转子表面 In the formula S 定子齿 S is the surface area of ​​the stator teeth. 转子表面 This represents the outer surface area of ​​the rotor.

7. The method for evaluating the three-dimensional electromagnetic load impedance performance of the vehicle generator assembly according to claim 1, characterized in that: In step (5), when the minimum value of the three belongs to the radial direction, the weighting coefficient w satisfies 1.05≤w≤1.15; when the minimum value of the three belongs to the tangential direction, the weighting coefficient w satisfies 1.2≤w≤1.3; and when the minimum value of the three belongs to the axial direction, the weighting coefficient w satisfies 1.45≤w≤1.

55.

8. The method for evaluating the three-phase electromagnetic load impedance performance of the vehicle generator assembly according to claim 7, characterized in that: When the minimum value of the three values ​​belongs to the radial direction, the weighting coefficient w = 1.1; when the minimum value of the three values ​​belongs to the tangential direction, the weighting coefficient w = 1.25; and when the minimum value of the three values ​​belongs to the axial direction, the weighting coefficient w = 1.5.

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