Optimal Design of Magnetic Geared PM Synchronous Motor Pole Shape to Improve Magnetic Field Distribution and reduce Cogging Torque

Document Type : Original Article

Author

Faculty of Computer and Electrical Engineering, University of Kashan, Kashan, Iran, P.O. Box 8731753153.

Abstract

In this paper, the combined axial flux structure of a permanent magnet synchronous motor with a magnetic gearbox is investigated to increase the torque density. The motor has two rotors with tangential magnetized spoke type PMs and coreless structure. Modulators play the role of magnetic field modulation for the stator and rotor over the air gaps. The shape of permanent magnets allows higher efficiency and at the same time lower axial length. Soft magnetic poles of the rotor located between the magnets play a decisive role in the magnetic field distribution as well as the torque and magnetic field profile of the machine. In this paper, the shape of the soft magnetic pole is optimized to obtain a higher sine field distribution and higher output torque as well as lower cogging torque using the variable airgap.

Keywords


[1]     Z. Zhang, F. Profumo, and A. Tenconi, “Axial flux versus radial flux PM motors,” in Proc. SPEEDAM, Capri, Italy, 1996, pp. A4-19–A4-25.##
[2]     Z. Zhang, F. Profumo, and A. Tenconi, “Axial flux versus radial flux PM motors,” in Proc. SPEEDAM, Capri, Italy, 1996, pp. A4-19–A4-25.##
[3]     M. Aydin, S. Huang and T. A. Lipo, "Torque quality and comparison of internal and external rotor axial flux surface-magnet disc machines", IEEE Trans. on Ind. Electrn., 822-830 pp., 2006.##
[4]     S. Huang, J. Luo, F. Leonardi, and T. A. Lipo, “A general approach to sizing and power density equations for comparison of electrical machines,” IEEE Trans. Ind. Appl., vol. 34, no. 1, pp. 92–97, Jan./Feb. 1998.##
[5]     F. Zhao, T. A. Lipo, B. Kwon, “A novel dual-stator axial-flux spoke-type permanent magnet vernier machine for direct-drive applications,” IEEE Trans. on Mag., vol 50, no. 50, 2014.##
[6]     F. Zhao, T. A. Lipo, B. Kwon, “Novel dual-rotor, axial field, fault-tolerant flux switching permanent magnet machine with high torque performance,” IEEE Trans. on Mag., to be published, 2015.##
[7]     F. Zhao, T. A. Lipo, B. Kwon, “Design and analysis of a novel dual stator axial flux spoke-type ferrite permanent magnet machine,” in Proc. IEEE - 39th Annual Conference of Industrial Electronics Society, Vienna, Austria, 2013, pp. 2714-2719.##
[8]     R. Benlamine, F. Dubas, S. Randi, D. Lhotellier and C. Espanet, “3-D numerical hybrid method for PM eddy-current losses calculation: Application to axial-flux PMSMs,” IEEE Trans. on Magn., vol. 51, no. 7, July 2015.##
[9]     R. Bojoi, G. Pellegrino, A. Cavagnino and P. Guglielmi, “Direct flux vector control of axial flux IPM motors for in-wheel traction solutions,” in Proc. IEEE Annual Conference of Industrial Electronics Society, Arizona, USA, 2010, pp. 2224-2229.##
[10]  R. Benlamine, F. Dubas, C. Espanet, S. A. Randi, D. Lhotellier, “Design of an axial-flux interior permanent-magnet synchronous motor for automotive application: Performance comparison with electric motors used in EVs and HEVs,” in Proc. IEEE Vehicle Power and Propulsion Conference, Coimbra, Portugal, 2014, pp. 1-6.##
[11]  K. Li and J. Z. Bird, “A review of the volumetric torque density of rotary magnetic gear designs,” XIII International Conference on Electrical Machines (ICEM) Alexandroupoli, pp. 2016-2022, 2018.##
[12]  B. Dianati, H. Heydari, S.A. Afsari, “Analytical Computation of Air-Gap Magnetic Field in a Viable Superconductive Magnetic Gear,” IEEE Trans. on Applied Supercon., vol. 26, pp. 1-12, 2016.##
 [13]  S. A. Afsari Kashani, “Rotor Pole Design of Radial Flux Magnetic Gear for Reduction of Flux Density Harmonics and Cogging Torque,” IEEE Transactions on Applied Superconductivity, (Early Access).##
 
[14]  S.A. Afsari, H. Heydari, B. Dianati, “Cogging Torque Mitigation in Axial Flux Magnetic Gear System Based on Skew Effects Using an Improved Quasi 3-D Analytical Method,” IEEE Trans. on Magn., vol. 51, pp. 1-11, 2015.##
[15]  K. Atallah, J. B. Wang, and D. Howe, “A high-performance linear magnetic gear,” Journal of Applied Physics., vol. 97, no. 10, pp. 10N516-1-3, May. 2005.##
[16]  S.A. Afsari, H. Heydari, and E. Bashar, “Viable arcuate double-sided magnetic gear for competitive torque density transmission capability,” Journal of Scientia Iranica D, vol. 23, no. 3, pp. 1251-1260, June 2016.##
[17]  S.A. Afsari, “Performance analysis and optimization of a novel arcuate double-sided magnetic gear using quasi 3-D analytical modeling for wind power application,” Journal of Applied Electromagnetics, vol. 6, no. 2, pp. 1-9, 2018.##
[18]  X. Ren, D. Li, R. Qu and T. Pei, “Back EMF harmonic analysis of permanent magnet magnetic geared machine,” IEEE Transactions on Industrial Electronics, (Early Access).##
[19]  K. Wang, Z. Q. Zhu and G. Ombach, “Torque Enhancement of Surface-Mounted Permanent Magnet Machine Using Third-Order Harmonic,” IEEE Transactions on Magnetics, vol. 50, no. 3, pp. 104-113, March 2014.##
[20]  K. Wang, Z. Q. Zhu, G. Ombach and W. Chlebosz, “Average Torque Improvement of Interior Permanent-Magnet Machine Using Third Harmonic in Rotor Shape,” IEEE Transactions on Industrial Electronics, vol. 61, no. 9, pp. 5047-5057, Sept. 2014.##