Toroidal expansion based modeling and analysis of spherical motor with stepped cylindrical permanent magnets

Article type: Research Article

Authors: Zhou, Sili^{a; b} | Li, Guoli^{b; c} | Wang, Qunjing^{b; d;} | Qian, Zhe^{b; c} | Ye, Qiubo^e | Xu, Jiazi^{b; c} | Gao, Shihao^b

Affiliations: [a] School of Electrical and Information Engineering, Anhui University of Science \& Technology, Huainan, China | [b] National Engineering Laboratory of Energy-Saving Motor & Control Technology, Anhui University, Hefei, China | [c] School of Electrical Engineering and Automation, Anhui University, Hefei, China | [d] Anhui Collaborative Innovation Center of Industrial Energy-Saving and Power Quality Control, Anhui University, Hefei, China | [e] School of Ocean Information Engineering, Jimei University, Xiamen, China

Correspondence: [*] Corresponding author: Qunjing Wang, National Engineering Laboratory of Energy-Saving Motor & Control Technology, Anhui University, Hefei 230601, China; and Anhui Collaborative Innovation Center of Industrial Energy-Saving and Power Quality Control, Anhui University, Hefei 230601, China. E-mail: wangqunjing@ahu.edu.cn.  ORCIDs: https://orcid.org/0000-0003-0882-068X (S. Zhou); https://orcid.org/0000-0003-3592-5305 (G. Li); https://orcid.org/0000-0002-1916-8116 (Q. Wang); https://orcid.org/0000-0002-3273-2359 (Z. Qian); https://orcid.org/0000-0003-2659-2377 (Q. Ye); https://orcid.org/0000-0002-0247-6278 (J. Xu)

Abstract: A permanent magnet spherical motor (PMSpM) is a representative multiple degree-of-freedom electric apparatus. This paper proposes new analytical models for the PMSpM with stepped cylindrical permanent magnets (PMs). The research is not only to obtain the magnetic field and torque models of the PMSpM but also to yield a potential analytic tool for the spatial magnetic field and torque decomposition. The model decomposition aims to acquire a potential tool for the future research on PMSpM topology optimization and working mechanism. To achieve the two research targets above, the toroidal expansion method is used for magnetic field modeling, and the finite element method verification and experimental verification are conducted. Then, forces and torques are deduced from the Lorentz force law. In addition, a prototype PMSpM has been produced and the comparison studies of the air-gap flux density and torque among decomposed components are conducted using finite element analysis results and experimental results. It is concluded that the proposed analytical PMSpM models and the model decomposition method are proved.

Keywords: Toroidal expansion, magnetic field modeling, permanent magnet spherical motor, stepped cylindrical permanent magnets, finite element method

DOI: 10.3233/JAE-210220

Journal: International Journal of Applied Electromagnetics and Mechanics, vol. 70, no. 2, pp. 109-127, 2022