DV-07 Novel Electromagnetic Analysis Method for a YASA Motor Based on Multi-Dimensional Hybrid FEA
Creators: Ji-Chang Son and Dong-Kuk Lim
Publisher: name: IEEE
Year: 2025

Recently, an axial flux permanent magnet motor (AFPMM) has been received more attention due to high torque density [1], [2]. When analyzing the electromagnetic characteristics of the AFPMM, 3D periodic finite element analysis (P-FEA) is required to consider the complex magnetic flux distribution [2]. However, time-consuming 3D FEA is unsuitable for the design process as the repetitive analysis and comparison on various design variables are needed [3]. In this paper, multi-dimensional hybrid FEA (MD-FEA) method is proposed to alleviate the time cost of the AFPMM design. As shown in Fig. 1, the MD-FEA consists of the 2D FEA of the quasi 3D model and static FEA (S-FEA) of the 3D model, and the final results can be obtained by post-processing the analysis results of each method. For the quasi 3D method, the equivalent analysis results of the 3D model can be obtained by combining the results of the multiple 2D models, and the calculation time can be drastically reduced. Moreover, pulsation characteristics can be considered, as the cross sectional 2D models reflect the structure of the 3D model. However, the quasi 3D method has limitations in the accuracy, as the edge effects at the internal and external regions and flux between each cross section cannot be considered. The MD-FEA overcomes the limitations of the conventional quasi 3D method through the 3D S-FEA. The torque and voltage of the motor can be calculated using the phase flux linkage values obtained through the S-FEA, and reliable accuracy with the acceptable analysis time can be resulted as the 3D FEA is conducted only at the initial rotor position. However, the S-FEA cannot consider the pulsation characteristics as the other periodic part is neglected. Therefore, the MD-FEA combines two methods to ensure accuracy while considering the pulsation characteristics and reducing analysis time. Fig. 2 shows the analysis result at the operating point, and the MD-FEA shows superior performance on both calculation time and analysis accuracy. Detailed explanations on the MD-FEA, target YASA AFPMM, performance verification, and experimental validation will be described at the full paper.References: [1] W. Cheng, G. Cao, and Z. Deng, IEEE Transactions on Magnetics, vol. 57, no. 2, pp. 1-5 (2021) [2] F. Yi, C. Zhang, and S. Qiu, L, IEEE Transactions on Magnetics, vol. 59, no. 12, pp. 1-10 (2023) [3] A. Gu, B. Ruan, and W. Cao, IEEE Access, vol. 7, pp. 180251-180257 (2019)
Recently, an axial flux permanent magnet motor (AFPMM) has been received more attention due to high torque density [1], [2]. When analyzing the electromagnetic characteristics of the AFPMM, 3D periodic finite element analysis (P-FEA) is required to consider the complex magnetic flux distribution [2]. However, time-consuming 3D FEA is unsuitable for the design process as the repetitive analysis and comparison on various design variables are needed [3]. In this paper, multi-dimensional hybrid FEA (MD-FEA) method is proposed to alleviate the time cost of the AFPMM design. As shown in Fig. 1, the MD-FEA consists of the 2D FEA of the quasi 3D model and static FEA (S-FEA) of the 3D model, and the final results can be obtained by post-processing the analysis results of each method. For the quasi 3D method, the equivalent analysis results of the 3D model can be obtained by combining the results of the multiple 2D models, and the calculation time can be drastically reduced. Moreover, pulsation characteristics can be considered, as the cross sectional 2D models reflect the structure of the 3D model. However, the quasi 3D method has limitations in the accuracy, as the edge effects at the internal and external regions and flux between each cross section cannot be considered. The MD-FEA overcomes the limitations of the conventional quasi 3D method through the 3D S-FEA. The torque and voltage of the motor can be calculated using the phase flux linkage values obtained through the S-FEA, and reliable accuracy with the acceptable analysis time can be resulted as the 3D FEA is conducted only at the initial rotor position. However, the S-FEA cannot consider the pulsation characteristics as the other periodic part is neglected. Therefore, the MD-FEA combines two methods to ensure accuracy while considering the pulsation characteristics and reducing analysis time. Fig. 2 shows the analysis result at the operating point, and the MD-FEA shows superior performance on both calculation time and analysis accuracy. Detailed explanations on the MD-FEA, target YASA AFPMM, performance verification, and experimental validation will be described at the full paper.References: [1] W. Cheng, G. Cao, and Z. Deng, IEEE Transactions on Magnetics, vol. 57, no. 2, pp. 1-5 (2021) [2] F. Yi, C. Zhang, and S. Qiu, L, IEEE Transactions on Magnetics, vol. 59, no. 12, pp. 1-10 (2023) [3] A. Gu, B. Ruan, and W. Cao, IEEE Access, vol. 7, pp. 180251-180257 (2019)