Tradeoff Optimization and Multi-Physics Analysis of High-Power and High-Power-Density Permanent Magnet Propulsion Motors for Aircraft Electric Propulsion
Xue Han1, Zhang Zhuoran1, Lin Qiuyu1, Liu Ye2, Lu Jiawei1
1. College of Automation Engineering Nanjing University of Aeronautics and Astronautics Nanjing 211106 China; 2. School of Electrical & Automation Engineering Nanjing Normal University Nanjing 210098 China
Abstract：The high-power, high-power-density permanent magnet propulsion motor is a critical component of the aircraft electric propulsion system in the future. It is also a crucial challenge for enabling medium- or large-scale electric propulsion aircraft. In recent years, many institutions have conducted extensive research on medium- and low-power permanent magnet propulsion motors across various application scenarios, but studies on high-power permanent magnet propulsion motors remain relatively scarce. Therefore, this paper presents the trade-off design optimization and analysis of high-power-density permanent magnet propulsion motors in the hundred-kilowatt and megawatt classes. First, based on the load characteristics of the aircraft's electric propulsion system, the trade-off design rules for the key parameters of high-power propulsion motors are generalized. Achieving high power density in propulsion motors requires both high speed and high torque density. However, these objectives are constrained by loss suppression, thermal management, structural strength, and control stability, resulting in inherent design trade-offs. Thus, overall designs for hundred-kilowatt- and megawatt-class high-power-density propulsion motors are conducted. Secondly, to meet the requirements for high power density, efficiency, and reliability of propulsion motors, the reconfiguration mechanism of phase-shifted multiple three-phase windings and the topology of multi-segment Halbach-array permanent magnets are investigated using analytical and finite-element simulation methods. Then, the power density of the propulsion motor is ultimately improved through genetic-algorithm multi-objective optimization. Moreover, the electromagnetic and mechanical strength characteristics are analyzed, demonstrating the excellent output performance and high-speed operational capability of the propulsion motors. A comparative analysis of unidirectional and bidirectional oil-immersed cooling systems shows that the unidirectional system adequately meets the efficient cooling requirements of hundred-kilowatt-class motors under high current density. In contrast, the bidirectional system can further reduce temperature rise, particularly for high-speed, high-power motors with high loss density and slender geometries. Finally, electromagnetic and thermal experiments are conducted on a prototype of a 110 kW permanent magnet propulsion motor, providing a reference for the development and verification of future megawatt-class permanent magnet propulsion motors. The following conclusions can be drawn. (1) The phase-shifted multi-three-phase winding configuration can increase the output torque of the propulsion motor by 4.9%, while suppressing torque ripple, enhancing redundancy, and simplifying the end structure. (2) Multi-segment Halbach array permanent magnets are beneficial for improving torque density and magnetic field sinusoidality. However, excessive segmentation yields limited additional benefits and increases manufacturing complexity and cost, necessitating a trade-off in selection. (3) Compared with hundred-kilowatt-class motors, megawatt-class propulsion motors require higher rotor tip speeds, fundamental frequencies, and current densities, which place greater demands on structural strength and thermal management. (4) After optimization, the power density of the megawatt-class motor is expected to reach 17.3 kW/kg with an efficiency of 98.2%. (5) Stator sealed oil-immersed cooling allows for high current densities of up to 25 A/mm2, and the bidirectional oil channel system can further reduce temperature rise compared to the unidirectional system.
薛涵, 张卓然, 林秋雨, 刘业, 陆嘉伟. 飞机大功率高功率密度永磁推进电机权衡优化与多物理场分析[J]. 电工技术学报, 2026, 41(4): 1127-1141.
Xue Han, Zhang Zhuoran, Lin Qiuyu, Liu Ye, Lu Jiawei. Tradeoff Optimization and Multi-Physics Analysis of High-Power and High-Power-Density Permanent Magnet Propulsion Motors for Aircraft Electric Propulsion. Transactions of China Electrotechnical Society, 2026, 41(4): 1127-1141.
[1] Ansell P J, Haran K S.Electrified airplanes: a path to zero-emission air travel[J]. IEEE Electrification Magazine, 2020, 8(2): 18-26. [2] Buticchi G, Wheeler P, Boroyevich D.The more- electric aircraft and beyond[J]. Proceedings of the IEEE, 2023, 111(4): 356-370. [3] 孔祥浩, 张卓然, 陆嘉伟, 等. 分布式电推进飞机电力系统研究综述[J]. 航空学报, 2018, 39(1): 021651. Kong Xianghao, Zhang Zhuoran, Lu Jiawei, et al.Review of electric power system of distributed electric propulsion aircraft[J]. Acta Aeronautica et Astronautica Sinica, 2018, 39(1): 021651. [4] Flightpath 2050 Europe’s vision for aviation[R].Flightpath 2050 Europe’s vision for aviation[R]. Belgium: European Union, 2011. [5] 孙侠生, 程文渊, 穆作栋, 等. 电动飞机发展白皮书[J]. 航空科学技术, 2019, 30(11): 1-7. Sun Xiasheng, Cheng Wenyuan, Mu Zuodong, et al.White paper on the development of electric aircraft[J]. Aeronautical Science & Technology, 2019, 30(11): 1-7. [6] 鞠孝伟, 龙佳兴, 张凤阁, 等. 电动飞行汽车用推进电机发展现状和研究综述[J]. 电工技术学报, 2025, 40(17): 5402-5421. Ju Xiaowei, Long Jiaxing, Zhang Fengge, et al.Development status and research overview of propulsion motors for eVTOL[J]. Transactions of China Electrotechnical Society, 2025, 40(17): 5402-5421. [7] Paul S, Chang J.Fast model-based design of high performance permanent magnet machine for next generation electric propulsion for urban aerial vehicle application[J]. CES Transactions on Electrical Machines and Systems, 2021, 5(2): 143-151. [8] Zhang Xiaolong, Bowman C L, O’Connell T C, et al. Large electric machines for aircraft electric pro- pulsion[J]. IET Electric Power Applications, 2018, 12(6): 767-779. [9] El-Refaie A, Osama M.High specific power electrical machines: a system perspective[J]. CES Transactions on Electrical Machines and Systems, 2019, 3(1): 88-93. [10] Sayed E, Abdalmagid M, Pietrini G, et al.Review of electric machines in more-/ hybrid-/ turbo-electric aircraft[J]. IEEE Transactions on Transportation Electrification, 2021, 7(4): 2976-3005. [11] Bird J Z.A review of electric aircraft drivetrain motor technology[J]. IEEE Transactions on Magnetics, 2022, 58(2): 8201108. [12] 张卓然, 陆嘉伟, 张伟秋, 等. 飞机电推进系统高效能电机及其驱动控制技术[J]. 中国电机工程学报, 2024, 44(16): 6610-6632. Zhang Zhuoran, Lu Jiawei, Zhang Weiqiu, et al.High-performance electric machine and drive tech- nologies for aircraft electric propulsion systems[J]. Proceedings of the CSEE, 2024, 44(16): 6610-6632. [13] Dubois A, van der Geest M, Bevirt J, et al. Design of an electric propulsion system for SCEPTOR’s outboard nacelle[C]//16th AIAA Aviation Technology, Integration, and Operations Conference, Washington D C, 2016: 3925. [14] Hwang S W, Son D K, Park S H, et al.Design and analysis of dual stator PMSM with separately controlled dual three-phase winding for eVTOL propulsion[J]. IEEE Transactions on Transportation Electrification, 2022, 8(4): 4255-4264. [15] Vertical takeoff and landing aircraft electric engine configuration: US11787551[P].2023-10-17. [16] Mellor P H, Heath C, Collins S, et al.Addressing the challenges of lightweight aircraft electric propulsion through electrical machines with air-gap windings[C]// 2019 IEEE Energy Conversion Congress and Expo- sition (ECCE), Baltimore, MD, USA, 2019: 4470-4476. [17] Yoon A, Yi Xuan, Martin J, et al.A high-speed, high-frequency, air-core PM machine for aircraft application[C]//2016 IEEE Power and Energy Con- ference at Illinois (PECI), Urbana, IL, USA, 2016: 1-4. [18] Sanchez R, Yoon A, Yi Xuan, et al.Mechanical validation of a high power density external canti- levered rotor[J]. IEEE Transactions on Industry Applications, 2018, 54(4): 3208-3216. [19] Andersen, Henry, Chen Yuankang, et al. Design and manufacturing of a high-specific-power electric machine for aircraft propulsion[C]//Proceedings of AIAA Aviation Forum, San Diego, USA: AIAA, 2023: 4158. [20] Spakovszky Z S, Chen Yuankang, Greitzer E M, et al.A megawatt-class electrical machine technology demo- nstrator for turbo-electric propulsion[C]//Proceedings of AIAA Aviation Forum, San Diego, USA: AIAA, 2023: 4157. [21] Swanke J, Bobba D, Jahns T, et al.Design of high- speed permanent magnet machine for aerospace propulsion[C]//AIAA Propulsion and Energy 2019 Forum, Indianapolis, IN, 2019: 4483. [22] Swanke J, Zeng Hao, Bobba D, et al.Design and testing of a modular high-speed permanent-magnet machine for aerospace propulsion[C]//2021 IEEE International Electric Machines & Drives Conference (IEMDC), Hartford, CT, USA, 2021: 1-8. [23] Golovanov D, Gerada D, Sala G, et al.4-MW class high-power-density generator for future hybrid- electric aircraft[J]. IEEE Transactions on Trans- portation Electrification, 2021, 7(4): 2952-2964. [24] 陆嘉伟, 张卓然, 李进才, 等. 电推进飞机移相双绕组永磁电机特性分析[J]. 航空学报, 2022, 43(5): 402-411. Lu Jiawei, Zhang Zhuoran, Li Jincai, et al.Characteristic analysis of dual-winding permanent magnet syn- chronous machine with phase-shifted windings for electric propulsion aircraft[J]. Acta Aeronautica et Astronautica Sinica, 2022, 43(5): 402-411. [25] Xue Han, Zhang Zhuoran, Liu Ye, et al.Analysis of lightweight dual-rotor yokeless-stator PMSM for electrified aircraft propulsion considering thermal benefits of heat pipes[J]. IEEE Transactions on Transportation Electrification, 2025, 11(5): 11030-11040. [26] Gao Huamin, Zhang Zhuoran, Liu Ye, et al.Development and analysis of dual three-phase PMSM with phase-shifted hybrid winding for aircraft electric propulsion application[J]. IEEE Transactions on Transportation Electrification, 2024, 10(3): 6497-6508. [27] 张凤阁, 杜光辉, 王天煜, 等. 高速电机发展与设计综述[J]. 电工技术学报, 2016, 31(7): 1-18. Zhang Fengge, Du Guanghui, Wang Tianyu, et al.Review on development and design of high speed machines[J]. Transactions of China Electrotechnical Society, 2016, 31(7): 1-18. [28] 宋承林, 吴志鹏, 黎明, 等. 永磁同步电机电磁振动和噪声研究综述[J]. 电工技术学报, DOI: 10.19595/j.cnki.1000-6753.tces.250439. Song Chenglin, Wu Zhipeng, Li Ming, et al.A review of research on electromagnetic vibration and noise of permanent magnet synchronous motors[J]. Transa- ctions of China Electrotechnical Society, DOI: 10.19595/j.cnki.1000-6753.tces.250439. [29] He Kaiwei, Zhao Wenxiang, Wu Zhongze, et al.Modeling of AC losses in high-speed PMSM windings: methods, challenges, and prospects[J]. CES Transactions on Electrical Machines and Systems, 2025, 9(2): 163-176. [30] Zhou Yu, Li Huaishu, Meng Guangwei, et al.Analytical calculation of magnetic field and cogging torque in surface-mounted permanent-magnet machines accounting for any eccentric rotor shape[J]. IEEE Transactions on Industrial Electronics, 2015, 62(6): 3438-3447.
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