Spatial Distribution Characteristics and Influencing Factors of Demagnetization of Permanent Magnet Motor for Electric Vehicle
Cui Gang1,2, Xiong Bin1,2, Huang Kangjie1,2, Li Zhenguo1,2, Ruan Lin1,2
1. Institute of Electrical Engineering Chinese Academy of Sciences Beijing 100190 China; 2. University of Chinese Academy of Sciences Beijing 100149 China
Abstract：High-performance Nd-Fe-B permanent magnet materials commonly used in permanent magnet synchronous motors for electric vehicles are prone to irreversible demagnetization under high temperatures and strong magnetic fields. It has become the main bottleneck of the high-reliability design of permanent magnet drive motors. The cavity structure and cooling method of the permanent magnet synchronous motor determine the spatial distribution differences of the working temperature of the permanent magnet. In order to study effective methods for preventing demagnetization faults in permanent magnet synchronous motors, it is necessary to accurately calculate the demagnetization spatial distribution characteristics of permanent magnets and understand their influencing factors. This paper uses the permanent magnet virtual partitioning method to establish a permanent magnet local demagnetization analysis model based on its magnetic characteristic parameters, working temperature, spatial position, and other variables. The spatial distribution and influencing factors of local demagnetization are studied using the three-dimensional and multi-physical field calculation method with a two-way coupling of the electromagnetic field and temperature field. Finally, the accuracy of the analysis method and results is verified by testing the permanent magnet operating temperature, the magnetic field distribution on the rotor, and the motor performance of a 115 kW-8 pole permanent magnet synchronous motor prototype. Simulation results show that when the demagnetization current is 600 A, 800 A, and 900 A, and the demagnetization current angle is 90°, the maximum demagnetization rate of the permanent magnet is 13.44%, 45.37%, and 62.13%, respectively. When the demagnetization current is 800 A and the demagnetization current angles are 0°, 30°, 60°, and 90°, the maximum demagnetization rates of the permanent magnet are 1.7%, 19.49%, 34.79%, and 45.37%, respectively. The maximum difference in the spatial distribution of the working temperature of the permanent magnet reaches 36℃. After the demagnetization fault occurred, the value of the no-load back electromotive decreased from 175.2 V to 110.16 V. The torque value decreased from 146.15 N·m to 115.6 N·m. The experimental results show that the working temperature difference at different positions of the same permanent magnet reaches 23℃. The temperature difference at the same position of different permanent magnets in the same pole reaches 35℃. The maximum deviation between the simulation and actual measurement of the no-load back electromotive is 4.97%. The maximum deviation between the simulation and the actual measurement of the output torque is 5.28%. The minimal difference between simulation and actual measurement results indicates that the research method proposed in this paper is accurate and effective. The following conclusions can be drawn from the simulation analysis and test results. (1) The spatial distribution of demagnetization of the permanent magnet synchronous motor is uneven. (2) When the motor malfunctions, there may be a situation where the entire motor only experiences slight demagnetization, but the local position of the permanent magnet has already experienced severe demagnetization. (3) The demagnetization distribution of the permanent magnet is affected by the working temperature, amplitude, and angle of the demagnetizing current. (4) The no-load back electromotive force and output torque can be used to evaluate the impact of demagnetization faults on the no-load and load characteristics of the motor.
崔刚, 熊斌, 黄康杰, 李振国, 阮琳. 电动汽车用永磁电机的失磁空间分布特性及影响因素[J]. 电工技术学报, 2023, 38(22): 5959-5974.
Cui Gang1,2, Xiong Bin1,2, Huang Kangjie1,2, Li Zhenguo1,2, Ruan Lin1,2. Spatial Distribution Characteristics and Influencing Factors of Demagnetization of Permanent Magnet Motor for Electric Vehicle. Transactions of China Electrotechnical Society, 2023, 38(22): 5959-5974.
[1] 何绍民, 杨欢, 王海兵, 等. 电动汽车功率控制单元软件数字化设计研究综述及展望[J]. 电工技术学报, 2021, 36(24): 5101-5114. He Shaomin, Yang Huan, Wang Haibing, et al.Review and prospect of software digital design for electric vehicle power control unit[J]. Transactions of China Electrotechnical Society, 2021, 36(24): 5101-5114. [2] 温传新, 王培欣, 花为. 电动汽车驱动系统的研究现状与发展趋势[J]. 微电机, 2019, 52(10): 103-109. Wen Chuanxin, Wang Peixin, Hua Wei.Driving technology of electric vehicles: current developments and future prospects[J]. Micromotors, 2019, 52(10): 103-109. [3] 孙玉华, 赵文祥, 吉敬华, 等. 高转矩性能多相组永磁电机及其关键技术综述[J]. 电工技术学报, 2023, 38(6): 1403-1420. Sun Yuhua, Zhao Wenxiang, Ji Jinghua, et al.Overview of multi-star multi-phase permanent magnet machines with high torque performance and its key technologies[J]. Transactions of China Electro- technical Society, 2023, 38(6): 1403-1420. [4] 曹恒佩, 艾萌萌, 王延波. 永磁辅助同步磁阻电机研究现状及发展趋势[J]. 电工技术学报, 2022, 37(18): 4575-4592. Cao Hengpei, Ai Mengmeng, Wang Yanbo.Research status and development trend of permanent magnet assisted synchronous reluctance motor[J]. Transa- ctions of China Electrotechnical Society, 2022, 37(18): 4575-4592. [5] 林迎前, 孙毅, 王云冲, 等. 稀土和铁氧体混用永磁辅助同步磁阻电机[J]. 电工技术学报, 2022, 37(5): 1145-1157. Lin Yingqian, Sun Yi, Wang Yunchong, et al.A hybrid PM-assisted SynRM with ferrite and rare-earth magnets[J]. Transactions of China Electrotechnical Society, 2022, 37(5): 1145-1157. [6] You Yongmin, Yoon K Y.Multi-objective optimi- zation of permanent magnet synchronous motor for electric vehicle considering demagnetization[J]. Applied Sciences, 2021, 11(5): 2159. [7] Peng Peng, Zhang Julia, Li Wanfeng, et al.Time- dependent demagnetization of NdFeB magnets under DC and pulsed magnetic fields[J]. IEEE Transactions on Magnetics, 2020, 56(3): 1-10. [8] 周头军, 胡贤君, 潘为茂, 等. 工业应用中钕铁硼磁体不可逆磁通损失的影响因素研究[J]. 中国稀土学报, 2019, 37(3): 339-343. Zhou Toujun, Hu Xianjun, Pan Weimao, et al.Influencing factors on flux irreversible loss of Nd- Fe-B magnet application[J]. Journal of the Chinese Society of Rare Earths, 2019, 37(3): 339-343. [9] 崔刚, 熊斌, 阮琳, 等. 驱动电机用高性能钕铁硼永磁材料不可逆失磁扩散特性研究[J]. 中国稀土学报, 2023, 41(4): 725-735. Cui Gang, Xiong Bin, Ruan Lin, et al.Irreversible demagnetization and diffusion characteristics of high performance NdFeB permanent magnet for drive motor[J]. Journal of the Chinese Society of Rare Earths, 2023, 41(4): 725-735. [10] 李伟力, 程鹏, 吴振兴, 等. 并网永磁同步发电机转子永磁体局部失磁特征量的计算与分析[J]. 中国电机工程学报, 2013, 33(33): 95-105, 12. Li Weili, Cheng Peng, Wu Zhenxing, et al.Calculation and analysis on the permanent magnet partial demagnetization characteristics of the grid- connected permanent magnet synchronous generator rotor[J]. Proceedings of the CSEE, 2013, 33(33): 95-105, 12. [11] Kim H K, Hur J.Dynamic characteristic analysis of irreversible demagnetization in SPM- and IPM-type BLDC motors[J]. IEEE Transactions on Industry Applications, 2017, 53(2): 982-990. [12] 唐旭, 王秀和, 李莹, 等. 异步起动永磁同步电动机起动过程中永磁体退磁研究[J]. 中国电机工程学报, 2015, 35(4): 961-970. Tang Xu, Wang Xiuhe, Li Ying, et al.Demagneti- zation study for line-start permanent magnet syn- chronous motor during starting process[J]. Pro- ceedings of the CSEE, 2015, 35(4): 961-970. [13] 唐旭, 王秀和, 李莹. 三相不对称供电异步起动永磁同步电动机的退磁研究[J]. 中国电机工程学报, 2015, 35(23): 6172-6178. Tang Xu, Wang Xiuhe, Li Ying.Demagnetization study for line-start permanent magnet synchronous motor fed by three-phase unbalanced voltages[J]. Proceedings of the CSEE, 2015, 35(23): 6172-6178. [14] Almandoz G, Gómez I, Ugalde G, et al.Study of demagnetization risk in PM machines[J]. IEEE Transactions on Industry Applications, 2019, 55(4): 3490-3500. [15] Zhang Yue, McLoone S, Cao Wenping. Electro- magnetic loss modeling and demagnetization analysis for high speed permanent magnet machine[J]. IEEE Transactions on Magnetics, 2018, 54(3): 1-5. [16] Kim B C, Lee J H, Kang D W.A study on the effect of eddy current loss and demagnetization characteri- stics of magnet division[J]. IEEE Transactions on Applied Superconductivity, 2020, 30(4): 1-5. [17] Guo Baocheng, Huang Yunkai, Peng Fei, et al.General analytical modeling for magnet demag- netization in surface mounted permanent magnet machines[J]. IEEE Transactions on Industrial Elec- tronics, 2019, 66(8): 5830-5838. [18] 徐敦煌, 王东, 林楠, 等. 失磁故障下交错磁极混合励磁发电机的等效二维解析磁场模型[J]. 电工技术学报, 2017, 32(21): 87-93. Xu Dunhuang, Wang Dong, Lin Nan, et al.An equivalent two-dimensional analytical model for the consequent-pole hybrid-excitation generator with demagnetization fault[J]. Transactions of China Electrotechnical Society, 2017, 32(21): 87-93. [19] 唐旭, 王秀和, 徐定旺. 异步起动永磁同步电动机起动过程中永磁体平均工作点的解析计算[J]. 电机与控制学报, 2017, 21(5): 8-14. Tang Xu, Wang Xiuhe, Xu Dingwang.Analytical calculation of permanent magnets’ average operating point for line-start permanent magnet synchronous motor during starting process[J]. Electric Machines and Control, 2017, 21(5): 8-14. [20] 卢伟甫, 罗应立, 赵海森. 自起动永磁同步电机起动过程电枢反应退磁分析[J]. 电机与控制学报, 2012, 16(7): 29-33. Lu Weifu, Luo Yingli, Zhao Haisen.Armature reaction demagnetization analysis for line-start permanent magnet synchronous motor during start process[J]. Electric Machines and Control, 2012, 16(7): 29-33. [21] 上官璇峰, 周敬乐, 蒋思远. 双转子双鼠笼永磁感应电机起动过程中永磁体退磁研究[J]. 电机与控制学报, 2019, 23(12): 126-134. Shangguan Xuanfeng, Zhou Jingle, Jiang Siyuan.Demagnetization of dual-rotor permanent magnet induction motor with double squirrel cage during the starting process[J]. Electric Machines and Control, 2019, 23(12): 126-134. [22] 张志艳, 秦鹏, 徐金涛, 等. 永磁同步电动机失磁故障电磁参数分析[J]. 微特电机, 2018, 46(8): 31-34, 44. Zhang Zhiyan, Qin Peng, Xu Jintao, et al.Electro- magnetic parameters analysis of PMSM demagneti- zation[J]. Small & Special Electrical Machines, 2018, 46(8): 31-34, 44. [23] Nishiyama N, Uemura H, Honda Y.Highly demag- netization performance IPMSM under hot environ- ments[J]. IEEE Transactions on Industry Applications, 2019, 55(1): 265-272. [24] Lee K D, Kim W H, Jin C S, et al.Local demag- netisation analysis of a permanent magnet motor[J]. IET Electric Power Applications, 2015, 9(3): 280-286. [25] Ruoho S, Haavisto M, Takala E, et al.Temperature dependence of resistivity of sintered rare-earth permanent-magnet materials[J]. IEEE Transactions on Magnetics, 2010, 46(1): 15-20. [26] 唐任远. 现代永磁电机理论与设计[M]. 北京: 机械工业出版社, 2016.
2023, Vol. 38 
