This paper presents a new non-rare-earth axial-field magnetic variable gear (MVG). By real-time changing the numbers of permanent magnet (PM) pole-pairs in the input and output rotors, the gear ratio becomes controllable. The key is to propose a new stationary ring integrated with magnetizing windings in such a way that various PM pieces can be independently magnetized to form different pole-pair numbers. After introducing the unique features of the non-rare-earth PM material aluminum-nickel-cobalt (AlNiCo), the proposed topology and design principle are discussed. By using finite element analysis, the electromagnetic performances of the proposed MVG under different gear ratios are analyzed. In particular, the corresponding torque transmission capability is assessed, and the influence caused by the introduction of the magnetizing windings is discussed. Hence, the validity of the proposed MVG can be verified.
2. Chau, K.-T., W. Li, and C. H. T. Lee, "Challenges and opportunities of electric machines for renewable energy," Progress In Electromagnetics Research B, Vol. 42, 45-74, 2012.
3. Nakamura, K., M. Fukuoka, and O. Ichinokura, "Performance improvement of magnetic gear and efficiency comparison with conventional mechanical gear," Journal of Applied Physics, Vol. 115, 17A314, 2014.
4. Jian, L., K. T. Chau, Y. Gong, J. Z. Jiang, C. Yu, and W. Li, "Comparison of coaxial magnetic gears with different topologies," IEEE Transactions on Magnetics, Vol. 45, No. 10, 4526-4529, 2009.
5. Jian, L. and K.-T. Chau, "Analytical calculation of magnetic field distribution in coaxial magnetic gears," Progress In Electromagnetics Research, Vol. 92, 1-16, 2009.
6. Li, X., K.-T. Chau, M. Cheng, and W. Hua, "Comparison of magnetic-geared permanent-magnet machines," Progress In Electromagnetics Research, Vol. 133, 177-198, 2013.
7. Atallah, K. and D. Howe, "A novel high-performance magnetic gear," IEEE Transactions on Magnetics, Vol. 37, No. 4, 2844-2846, 2001.
8. Rasmussen, P. O., T. O. Andersen, F. T. Jorgensen, and O. Nielsen, "Development of a high-performance magnetic gear," IEEE Transactions on Industry Applications, Vol. 41, No. 3, 764-770, 2005.
9. Liu, X., K. T. Chau, J. Z. Jiang, and C. Yu, "Design and analysis of interior-magnet outer-rotor concentric magnetic gears," Journal of Applied Physics, Vol. 105, 07F101, 2009.
10. Jian, L. and K. T. Chau, "A coaxial magnetic gear with Halbach permanent magnet arrays," IEEE Transactions on Energy Conversion, Vol. 25, No. 2, 319-328, 2010.
11. Chau, K. T., Electric Vehicle Machines and Drives - Design, Analysis and Application, Wiley-IEEE Press, 2015.
12. Sun, X., M. Cheng, W. Hua, and L. Xu, "Optimal design of double-layer permanent magnet dual mechanical port machine for wind power application," IEEE Transactions on Magnetics, Vol. 45, No. 10, 4613-4616, 2009.
13. Chen, M., K. T. Chau, W. Li, C. Liu, and C. Qiu, "Design and analysis of a new magnetic gear with multiple gear ratios," IEEE Transactions on Applied Superconductivity, Vol. 24, No. 3, 0501904, 2014.
14. Mezani, S., K. Atallah, and D. Howe, "A high-performance axial-field magnetic gear," Journal of Applied Physics, Vol. 99, 08R303, 2006.
15. Li, W. and K.-T. Chau, "Analytical field calculation for linear tubular magnetic gears using equivalent anisotropic magnetic permeability," Progress In Electromagnetics Research, Vol. 127, 155-171, 2012.
16. Lee, C. H. T., K. T. Chau, C. Liu, T. W. Ching, and F. Li, "A high-torque magnetless axial-flux doubly-salient machine for in-wheel direct drive applications," IEEE Transactions on Magnetics, Vol. 50, No. 11, 8202405, 2014.
17. Kramer, M. J., R. W. McCallum, I. A. Anderson, and S. Constantinides, "Prospects for non-rare-earth permanent magnets for traction motors and generators," Journal of the Minerals, Metals and Materials Society, Vol. 64, No. 7, 752-763, 2012.
18. Chen, M., K. T. Chau, W. Li, and C. Liu, "Development of non-rare-earth magnetic gears for electric vehicles," Journal of Asian Electric Vehicles, Vol. 10, No. 2, 1607-1613, 2012.
19. Chen, M., K. T. Chau, W. Li, and C. Liu, "Cost-effectiveness comparison of coaxial magnetic gears with different magnet materials," IEEE Transactions on Magnetics, Vol. 50, No. 2, 7020304, 2014.
20. Ostovic, V., "Pole-changing permanent-magnet machines," IEEE Transactions on Industry Applications, Vol. 38, No. 6, 1493-1499, 2002.
21. Ostovic, V., "Memory motors," IEEE Industry Applications Magazine, Vol. 9, No. 1, 52-61, 2003.
22. Yu, C., K. T. Chau, and J. Z. Jiang, "A flux-mnemonic permanent magnet brushless machine for wind power generation," Journal of Applied Physics, Vol. 105, No. 7, 07F114, 2009.
23. Yu, C. and K. T. Chau, "Design, analysis and control of DC-excited memory motors," IEEE Transactions on Energy Conversion, Vol. 26, No. 2, 479-489, 2011.