Performance Assessment of a Variable-Flux Permanent-Magnet Memory Motor

Authors: Michel Han, Christophe Besson, Alain Savary, Yvan Becher

Abstract:

The variable flux permanent magnet synchronous motor (VF-PMSM), also called "Memory Motor", is a new generation of motor capable of modifying the magnetization state with short pulses of current during operation or standstill. The impact of such operation is the expansion of the operating range in the torque-speed characteristic and an improvement in energy efficiency at high-speed in comparison to conventional permanent magnet synchronous machines (PMSMs). This paper reviews the operating principle and the unique features of the proposed memory motor. The benefits of this concept are highlighted by comparing the performance of the rotor of the VF-PMSM to that of two PM rotors that are typically found in the industry. The investigation emphasizes the properties of the variable magnetization and presents the comparison of the torque-speed characteristic with the capability of loss reduction in a VF-PMSM by means of experimental results, especially when tests are conducted under identical conditions for each rotor (same stator, same inverter and same experimental setup). The experimental results demonstrated that the VF-PMSM gives an additional degree of freedom to optimize the efficiency over a wide speed range. Thus, with a design easy to manufacture and with the possibility of controlling the magnetization and the demagnetization of the magnets during operations, the VF-PMSM can be interesting for various applications.

Keywords: Efficiency, magnetization state, memory motors, performances, permanent-magnet, synchronous machine, variable-flux, variable magnetization, wide speed application.

Digital Object Identifier (DOI): doi.org/10.5281/zenodo.3298647

References:

[1] R. Owen, Z. Q. Zhu, J. B. Wang, D. A. Stone, and I. Urquhart, “Review of variable-flux permanent magnet machines,” in International Conference on Electrical Machines and Systems, 2011, pp. 1–6.
[2] A. Toba, A. Daikoku, N. Nishiyama, Y. Yoshikawa, and Y. Kawazoe, “Recent technical trends in variable flux motors,” in International Power Electronics Conference (IPEC-Hiroshima - ECCE ASIA), 2014, pp. 2011–2018.
[3] H. Jia, W. Xinjian, and S. Zechang, “Variable flux memory motors: A review,” in IEEE Conference and Expo Transportation Electrification Asia-Pacific (ITEC Asia-Pacific), 2014, pp. 1–6
[4] V. Ostovic, “Memory motors-a new class of controllable flux PM machines for a true wide speed operation,” in Conference Record of the IEEE Industry Applications Conference. 36th IAS Annual Meeting (Cat. No.01CH37248), 2001, vol. 4, pp. 2577–2584.
[5] C. Yiguang, P. Wei, W. Ying, T. Renyuan, and W. Jing, “Interior composite-rotor controllable-flux PMSM - memory motor,” in International Conference on Electrical Machines and Systems, 2005, vol. 1, p. 446–449.
[6] K. Sakai, K. Yuki, Y. Hashiba, N. Takahashi, and K. Yasui, “Principle of the variable-magnetic-force memory motor,” in International Conference on Electrical Machines and Systems, 2009, pp. 1–6.
[7] C. Besson, A. Savary, and M. Jaccard, “Brushless permanent-magnet synchronous motor with magnetization and demagnetization of magnets during operation,” ELECTROMOTION, no. 22, pp. 3–13, Jan. 2015.
[8] D. Wu, Z. Q. Zhu, X. Liu, A. Pride, R. Deodhar, and T. Sasaki, “Cross coupling effect in hybrid magnet memory motor,” in 7th IET International Conference on Power Electronics, Machines and Drives, 2014, pp. 1–6.
[9] Y. Zhou, W. Wang, and Y. Chen, “Design and analysis of a novel hybrid permanent magnet memory motor,” in 17th International Conference on Electrical Machines and Systems (ICEMS), 2014, pp. 2687–2692.
[10] A. Athavale, K. Sasaki, B. S. Gagas, T. Kato, and R. D. Lorenz, “Variable flux permanent magnet synchronous machine (VF-PMSM) design to meet electric vehicle traction requirements with reduced losses,” in IEEE Energy Conversion Congress and Exposition (ECCE), 2016, pp. 1–8.
[11] A. Sun, J. Li, R. Qu, J. Chen, and H. Lu, “Rotor design considerations for a variable-flux flux-intensifying interior permanent magnet machine with improved torque quality and reduced magnetization current,” in IEEE Energy Conversion Congress and Exposition (ECCE), 2015, pp. 784–790.
[12] M. Ibrahim, L. Masisi, and P. Pillay, “Design of Variable-Flux Permanent-Magnet Machines Using Alnico Magnets,” IEEE Trans. Ind. Appl., vol. 51, no. 6, pp. 4482–4491, Nov. 2015.
[13] N. Limsuwan, T. Kato, K. Akatsu, and R. D. Lorenz, “Design and Evaluation of a Variable-Flux Flux-Intensifying Interior Permanent-Magnet Machine,” IEEE Trans. Ind. Appl., vol. 50, no. 2, pp. 1015–1024, Mar. 2014.
[14] C. Yu, K. T. Chau, and J. Z. Jiang, “A permanent-magnet flux-mnemonic integrated-starter-generator for hybrid electric vehicles,” in IEEE Vehicle Power and Propulsion Conference, 2008, pp. 1–6.
[15] J. M. Kim, J. Y. Choi, K. S. Lee, and S. H. Lee, “Design and Analysis of Surface-Mounted-Type Variable Flux Permanent Magnet Motor for Wide-Speed Range Applications,” IEEE Trans. Magn., vol. 51, no. 11, pp. 1–4, Nov. 2015.
[16] A. Athavale, B. S. Gagas, R. D. Lorenz, K. Sasaki, and T. Kato, “Effect of dynamic magnetization manipulation on transient losses and magnet temperature in energy-saving VF-PMSM traction drives,” in 19th European Conference on Power Electronics and Applications (EPE’17 ECCE Europe), 2017, p. P.1-P.10.