volume | PIER Journals

Abstract

To reduce the cogging torque of a 6-pole 36-slot permanent magnet synchronous motor, a method using a nonuniform air gap is proposed. By establishing the sinusoidal distribution subdomain model of the rotor with a nonuniform air gap and combining the energy method with Fourier decomposition, the analytical expressions of cogging torque under the conditions of uniform and nonuniform air gaps are derived. Electromagnetic and thermal performance simulations of uniform and nonuniform air gap motors were performed using ANSYS software. The influence of the nonuniform air gap on the motor's electromagnetic and thermal performance was analyzed by comparing simulation results. First, the finite element model of the motor was established in ANSYS Maxwell to analyze its electromagnetic performance under no-load and load conditions. The magnetic flux density distribution, no-load back EMF, output torque, cogging torque, core loss, copper loss, and eddy current loss of the permanent magnet were analyzed, and the rationality of using a nonuniform air gap was verified. The loss results obtained by the electromagnetic simulation were used as the heat source. It was imported into the steady-state thermal analysis module of ANSYS Workbench to build a three-dimensional temperature-field simulation model of the motor. Through a comparative analysis of electromagnetic performance and steady-state temperature rise results, it was confirmed that the design of the 6-pole 36-slot permanent magnet synchronous motor met the predetermined performance indicators and thermal safety requirements, and the feasibility of the nonuniform air-gap design scheme was verified.

1. Liu, Feng, Xiuhe Wang, and Zezhi Xing, "Design of a 35 kW permanent magnet synchronous motor for electric vehicle equipped with non-uniform air gap rotor," IEEE Transactions on Industry Applications, Vol. 59, No. 1, 1184-1198, 2023.
doi:10.1109/tia.2022.3206258 Google Scholar

2. Xing, Zezhi, Xiuhe Wang, Wenliang Zhao, Xian Li, Lixin Xiong, and Xin Zhang, "Optimization design of interior permanent magnet synchronous motor with U-shaped rotor for low-level torque ripple and electromagnetic vibration," IEEE Transactions on Transportation Electrification, Vol. 10, No. 1, 1995-2007, 2024.
doi:10.1109/tte.2023.3288892 Google Scholar

3. Zhang, Youguo, Yanbo Yang, Z. Y. Gu, Liangzi Li, and Tiancai Ma, "Multi-objective optimization for noise reduction of IPMSM based on non-uniform air gap," IEEE Access, Vol. 12, 48819-48829, 2024.
doi:10.1109/access.2024.3381776 Google Scholar

4. Alsawalhi, Jamal Yousuf and Scott D. Sudhoff, "Design optimization of asymmetric salient permanent magnet synchronous machines," IEEE Transactions on Energy Conversion, Vol. 31, No. 4, 1315-1324, 2016.
doi:10.1109/tec.2016.2575138 Google Scholar

5. Bang, Tae-Kyoung, Kyung-Hun Shin, Jeong-In Lee, Jong-Hyeon Woo, Han-Wook Cho, and Jang-Young Choi, "Design of high-speed permanent magnet synchronous machines considering thermal demagnetization and mechanical characteristic of permanent magnet," AIP Advances, Vol. 11, No. 2, 025129, 2021.
doi:10.1063/9.0000152 Google Scholar

6. Guo, Chao, Shoudao Huang, Jiabao Wang, Yaojing Feng, and Qingsong Wang, "Design of cryogenic permanent magnet synchronous motor for submerged liquefied natural gas pump," IEEE Transactions on Magnetics, Vol. 54, No. 11, 1-5, 2018.
doi:10.1109/tmag.2018.2832005 Google Scholar

7. Sun, Xiaodong, Zhou Shi, Gang Lei, Youguang Guo, and Jianguo Zhu, "Analysis and design optimization of a permanent magnet synchronous motor for a campus patrol electric vehicle," IEEE Transactions on Vehicular Technology, Vol. 68, No. 11, 10535-10544, 2019.
doi:10.1109/tvt.2019.2939794 Google Scholar

8. Xu, Yingying, Yiguang Chen, Zhihua Fu, Mingxia Xu, Haiyu Liu, and Li Cheng, "Design and analysis of an interior permanent magnet synchronous motor for a traction drive using multiobjective optimization," International Transactions on Electrical Energy Systems, Vol. 2024, No. 1, 3631384, 2024.
doi:10.1155/2024/3631384 Google Scholar

9. Avsar, Yusuf, Ahmet Fenercioglu, and Mucahit Soyaslan, "Design optimization of PM synchronous motor: Rail mounted belt drive elevator systems," IEEE Transactions on Industry Applications, Vol. 60, No. 1, 301-311, 2024.
doi:10.1109/tia.2023.3311781 Google Scholar

10. Zhao, Fei, Zijiang Yu, Jiwei Cao, and Liyi Li, "Design and optimization of a high-speed permanent magnet synchronous machine for gas compressors," IEEE Transactions on Magnetics, Vol. 58, No. 2, 1-5, 2022.
doi:10.1109/tmag.2021.3078464 Google Scholar

11. Ma, Shilun, Jianwei Ma, Keqi Chen, and Changwei Li, "Analytical modeling of eddy current losses and thermal analysis of non-uniform-air-gap combined-pole permanent magnet motors for electric vehicles," Machines, Vol. 12, No. 6, 377, 2024.
doi:10.3390/machines12060377 Google Scholar

12. Zhang, Chao, Lixiang Chen, Xiaoyu Wang, and Renyuan Tang, "Loss calculation and thermal analysis for high-speed permanent magnet synchronous machines," IEEE Access, Vol. 8, 92627-92636, 2020.
doi:10.1109/access.2020.2994754 Google Scholar

13. Zhang, Yue, Sean McLoone, Wenping Cao, Fengyi Qiu, and Chris Gerada, "Power loss and thermal analysis of a MW high-speed permanent magnet synchronous machine," IEEE Transactions on Energy Conversion, Vol. 32, No. 4, 1468-1478, 2017.
doi:10.1109/tec.2017.2710159 Google Scholar

14. Jiang, Yapeng, Dong Wang, Junquan Chen, Qinghu Zhang, and Teng Xuan, "Electromagnetic-thermal-fluidic analysis of permanent magnet synchronous machine by bidirectional method," IEEE Transactions on Magnetics, Vol. 54, No. 3, 1-5, 2018.
doi:10.1109/tmag.2017.2760928 Google Scholar

15. Jia, Meixia, Jianjun Hu, Feng Xiao, Ying Yang, and Chenghao Deng, "Modeling and analysis of electromagnetic field and temperature field of permanent-magnet synchronous motor for automobiles," Electronics, Vol. 10, No. 17, 2173, 2021.
doi:10.3390/electronics10172173 Google Scholar

16. Wu, Zengyan, Shiliang Li, and Peng Bai, "Optimized design and magneto-thermal coupling simulation analysis of automotive permanent magnet synchronous motor," Journal of Physics: Conference Series, Vol. 2918, No. 1, 012025, 2024.
doi:10.1088/1742-6596/2918/1/012025

17. Lee, Byeong-Hwa, Kyu-Seob Kim, Jae-Woo Jung, Jung-Pyo Hong, and Young-Kyoun Kim, "Temperature estimation of IPMSM using thermal equivalent circuit," IEEE Transactions on Magnetics, Vol. 48, No. 11, 2949-2952, 2012.
doi:10.1109/tmag.2012.2196503 Google Scholar

18. Wang, Lingzi, Yifan Wu, Yi Guo, Jianmei Feng, and Xueyuan Peng, "Analysis of the cooling performance based on the three-dimensional magnetic-thermal coupling in high-speed permanent magnet synchronous motor," Journal of Traffic and Transportation Engineering (English Edition), Vol. 12, No. 5, 1397-1414, 2025.
doi:10.1016/j.jtte.2025.03.003 Google Scholar

19. Ge, Shuaishuai, Jiayin Zhao, Huan Wang, Zhigang Zhang, and Wenjie Qi, "Electromagnetic thermal coupling characteristics of permanent magnet synchronous motor for electric vehicles," Proceedings of the Institution of Mechanical Engineers, Part D: Journal of Automobile Engineering, Vol. 239, No. 13, 6065-6083, 2025.
doi:10.1177/09544070251341946 Google Scholar

20. Tong, Wenming, Ruolan Sun, Shiqi Li, and Renyuan Tang, "Loss and thermal analysis for high-speed amorphous metal PMSMs using 3-D electromagnetic-thermal bi-directional coupling," IEEE Transactions on Energy Conversion, Vol. 36, No. 4, 2839-2849, Dec. 2021.
doi:10.1109/tec.2021.3065336 Google Scholar

Mr. Xiaojun Wang

Dr. Hongbin Yin

Dr. Mingyang Luo

Dr. Zhongbiao Li

Dr. Xinfei Li

Dr. Pengcheng Zheng