在過去十年，永磁同步馬達在工業和消費市場方面獲得廣泛的應用，隨著近年電動車市場的成長，使這類馬達的需求日漸提高。然而，近年永磁體價格升高，驅動學界與業界積極尋找永磁馬達的替代方案。在眾多替代方案中，繞線式轉子馬達在近年逐漸開始受到各方研究的關注，被視為代替永磁馬達的選擇之一。然而，此種馬達必須依賴由電刷與滑環構成的傳電裝置，並透過機械式接觸的方式將電能傳遞至轉動中的轉子繞組，使得這種馬達需要定期停機維護、更換磨耗的電刷與滑環，成為其最致命的缺點。為了解決這個問題，許多研究開始應用非接觸式功率傳輸系統來代替繞線式轉子馬達的傳電裝置。其中旋轉變壓器受到廣泛的關注。
在此背景之下，本研究提出將旋轉變壓器應用於繞線式轉子馬達以替代傳統的傳電裝置，同時還包含整體的設計流程。本研究將現有的永磁馬達改裝成為搭載旋轉變壓器的繞線式轉子馬達，僅將永磁轉子移除，沿用原本的定子，同時設計相應的繞線式轉子並裝入。根據已設計完成的繞線式轉子馬達，提出相對應的旋轉變壓器設計和整流電路。最後透過有限元素分析以及實驗，證明所提出的繞線式轉子以及旋轉變壓器的設計理論與實作上的一致性。此結果對未來關於旋轉變壓器和繞線式轉子馬達結合的相關設計，提供了重要的參考價值。

In the past decade, permanent magnet synchronous motors (PMSMs) have gained wide-ranging applications in industrial and consumer markets. However, due to geopolitical issues, the instability of raw material supply has increased the cost of permanent magnet materials, resulting in academia and industries seeking substitutes for PMSM. Among various alternative solutions, the wound field synchronous motor (WFSM) has recently gained increasing attention in the research field. However, these motors rely on electrical brushes and slip rings as power transmission devices. While many studies employ contactless power transmission systems such as rotary transformer (RT) to replace the brushes and slip rings of WFSM, they focus on performance evaluation, control strategies, and individual rotary transformer design, lacking a comprehensive design for integrate motor with rotary transformer . Against this backdrop, we make the first attempt to utilize RT in WFSM, where we replace the permanent magnet rotor with a winding rotor, retain the original stator, and design the corresponding rotary transformer . Finally, we validate the consistency between the proposed WFSM and RT design theories and their implementation through finite element analysis and experience. This result provides valuable references for future designs involving the integration of RT and WFSM.

[1] "EV Motor Power and Motor Materials Tracker," Adamas intelligence., 2019.[Online].Available:https://www.adamasintel.com/subscription/ev-motor-power-and-motor-materials-tracker/
[2] Y. Yang et al., "REE recovery from end-of-life NdFeB permanent magnet scrap: a critical review," Journal of Sustainable Metallurgy, vol. 3, pp. 122-149, 2017.
[3] G. Pitron，稀有金屬戰爭，天下文化，2020.
[4] "Price development for neodymium magnets," magnosphere magnets., 2022.[Online].Available:https://www.magnosphere.co.uk/price-development-for-neodymium-magnets
[5] M.S. Lim and J.P. Hong, "Design of high efficiency wound field synchronous machine with winding connection change method," IEEE Transactions on Energy Conversion, vol. 33, no. 4, pp. 1978-1987, 2018.
[6] M. Koteich, A. Messali, and S. Daurelle, "Self-sensing control of the externally-excited synchronous machine for electric vehicle traction application," in 2017 IEEE International Symposium on Sensorless Control for Electrical Drives (SLED), 2017: IEEE, pp. 91-96.
[7] Dr James Edmondson, IDTechEx, "Electric Motors for Electric Vehicles: Technologies and Market Outlook," IDTechEx. [Online]. Available:https://fpc-event.co.uk/wp-content/uploads/2022/03/james.edmondson.electric_machines-1.pdf
[8] C. Ankang, Z. Hui, P. Bowei, and L. Hao, "Modal Analysis of A Novel Rotary Transformer Based on Finite Element Method," in 2019 14th IEEE Conference on Industrial Electronics and Applications (ICIEA), 2019: IEEE, pp. 2463-2466.
[9] "A Critical Comparison of Ferrites with Other Magnetic Materials," Magnetics,2000.[Online].Available:https://www.mag-inc.com/Media/Magnetics/File-Library/Product%20Literature/Ferrite%20Literature/cg-01.pdf?ext=.pdf
[10] J. Yang, Y. Zhang, and D. Jiang, "A Contactless Power transfer Device Applied to the CT System," in 2019 22nd International Conference on Electrical Machines and Systems (ICEMS), 2019: IEEE, pp. 1-5.
[11] J. Veitengruber, "Optimal design of a highly integrated brushless rotor power supply for electrically-excited generators in vehicle-related applications," in 2015 IEEE Vehicle Power and Propulsion Conference (VPPC), 2015: IEEE, pp. 1-7.
[12] H. R. Mohabati, J. S. Moghani, and S. Taghipour Boroujeni, "Fully laminated shell‐type three‐phase rotating transformer for brushless applications," IET Electric Power Applications, vol. 9, no. 5, pp. 349-357, 2015.
[13] N. L. Zietsman and N. Gule, "Evaluation of a single‐phase 50‐Hz axial rotary transformer for DFIG systems," IEEJ Transactions on Electrical and Electronic Engineering, vol. 13, no. 2, pp. 311-321, 2018.
[14] S. Botha, "Three phase rotary transformer for a rotor tied doubly fed induction Machine," Stellenbosch: Stellenbosch University, 2022.
[15] Xu, Y. Kilowatt Three-Phase Rotary Transformer Design for Permanent Magnet DC Motor with On-Rotor Drive System. Master’s Thesie, Mid Sweden University, Sundsvall, Sweden, 2016.
[16] J. Haruna and T. Raminosoa, "Modeling and steady-state analysis of a rotary transformer-based field excitation system for wound rotor synchronous machine," in 2019 IEEE Transportation Electrification Conference and Expo (ITEC), 2019: IEEE, pp. 1-8.
[17] R. Manko, M. Vukotić, D. Makuc, D. Vončina, D. Miljavec, and S. Čorović, "Modelling of the Electrically Excited Synchronous Machine with the Rotary Transformer Design Influence," Energies, vol. 15, no. 8, p. 2832, 2022.
[18] H. Krupp and A. Mertens, "Rotary transformer design for brushless electrically excited synchronous machines," in 2015 IEEE Vehicle Power and Propulsion Conference (VPPC), 2015: IEEE, pp. 1-6.
[19] S. Udema and C. Fräger, "Rotary transformer for contactless excitation of synchronous machines fed through neutral conductor," in 2019 IEEE International Electric Machines & Drives Conference (IEMDC), 2019: IEEE, pp. 1724-1730.
[20] C. Stancu, T. Ward, K. M. Rahman, R. Dawsey, and P. Savagian, "Separately excited synchronous motor with rotary transformer for hybrid vehicle application," IEEE Transactions on Industry Applications, vol. 54, no. 1, pp. 223-232, 2017.
[21] M.R. Park, D.M. Kim, Y.H. Jung, M.S. Lim, and J.P. Hong, "Modeling, design and control of wound-field synchronous motor for high energy efficiency of electric vehicle," in 2019 IEEE Energy Conversion Congress and Exposition (ECCE), 2019: IEEE, pp. 3960-3967.
[22] W. Chai, J.-W. Kwon, and B.-I. Kwon, "Analytical design of a hybrid-excited wound field synchronous machine for the improvement of torque characteristics," IEEE Access, vol. 8, pp. 87414-87421, 2020.
[23] J. Tang, "Design and control of electrically excited synchronous machines for vehicle applications," Chalmers Tekniska Hogskola (Sweden), 2021.
[24] Mirlenko, "Control of electrically excited synchronous motor in the field weakening range," 2017.
[25] F. GRAFFEO, "Design and analysis of different rotor configurations for wound field synchronous machines," POLITECNICO DI TORINO, 2019.
[26] E. M. Illiano, "Design of a highly efficient brushless current excited synchronous motor for automotive purposes," ETH Zurich, 2014.
[27] R. Manko, S. Čorović, and D. Miljavec, "Analysis and design of rotary transformer for wireless power transmission," in 2020 IEEE Problems of Automated Electrodrive. Theory and Practice (PAEP), 2020: IEEE, pp. 1-6.
[28] E. E. Landsman, "Rotary transformer design," in 1970 IEEE Power Electronics Specialists Conference, 1970: IEEE, pp. 139-152.
[29] S. J Chapman, Electric machinery fundamentals. McGraw-hill, 2004.
[30] M. Tosi, N. Bianchi, and H. Herzog, "Rotary transformer design for brushless electrically excited synchronous machines," University of Padua, Padua, 2014.
[31] McLyman, Transformer and inductor design handbook. CRC press, 2004.
[32] "Matchservo Motor & D310 Driver," ADLEEPOWER. [Online]. Available: https://webbuilder5.asiannet.com/3000/files/Matchservo%20Motor%20%EF%BC%86%20D310%20Drive.pdf
[33] K. Fujiwara, Y. Okamoto, A. Kameari, and A. Ahagon, "The Newton-Raphson method accelerated by using a line search-comparison between energy functional and residual minimization," IEEE transactions on magnetics, vol. 41, no. 5, pp. 1724-1727, 2005.