volume | PIER Journals

Abstract

This paper presents the design investigation and experimental testing of a flux-focusing magnetic gearbox with a fully laminated rotor structure. The unique feature of this flux-focusing magnetic gearbox design is that the three rotors are each made of a single lamination stack, and the central modulation structure is retained in place without the use of a resin filler such as epoxy. Ferromagnetic bridges are used to connect individual pole pieces together. It is shown that the use of the ferromagnetic bridges reduces the calculated torque density from 156 Nm/L to 139 Nm/L (a reduction of 11%). The experimentally measured torque density is, however, only 97 Nm/L. The reason for this discrepancy is associated with the demagnetization of the magnets.

1. Martin, T. B., "Magnetic transmission,", USA Patent 3,378,710, 1968.
doi:10.1049/ip-epa:20040224 Google Scholar

2. Atallah, K., S. D. Calverley, et al. "Design, analysis and realisation of a high-performance magnetic gear," IEE Proc.-Electr. Power Appl., Vol. 151, 135-143, 2004.
doi:10.1109/TIA.2005.847319 Google Scholar

3. Rasmussen, P. O., T. O. Andersen, et al. "Development of a high-performance magnetic gear," IEEE Trans. Ind. Appl., Vol. 41, 764-770, 2005.
doi:10.2528/PIER12080808 Google Scholar

4. 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.
doi:10.2528/PIER09032301 Google Scholar

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. Google Scholar

6. Lipo, T. A., Introduction to AC Machine Design, 2nd Ed., Madison, 2004.
doi:10.1109/TIA.2014.2312551

7. Uppalapati, K. K., W. Bomela, et al. "Experimental evaluation of low speed flux focusing magnetic gearboxes," IEEE Trans. on Ind. Appl., Vol. 50, 3637-3643, Nov./Dec. 2014.
doi:10.1109/TIA.2017.2779418 Google Scholar

8. Uppalapati, K. K., J. Z. Bird, et al. "A magnetic gearbox with an active region torque density of 239 Nm/L," IEEE Trans. Ind. Appl., Vol. 54, 1331-1338, Apr. 2018.
doi:10.1109/TMAG.2013.2283018 Google Scholar

9. Uppalapati, K. K. and J. Z. Bird, "An iterative magnetomechanical deflection model for a magnetic gear," IEEE Trans. Mag., Vol. 50, No. 2, 7005904, 2014.
doi:10.2528/PIER11032316 Google Scholar

10. Jian, L., G. Xu, J. Song, H. Xue, D. Zhao, and J. Liang, "Optimum design for improving modulating-effect of coaxial magnetic gear using response surface methodology and genetic algorithm," Progress In Electromagnetics Research, Vol. 116, 297-312, 2011.
doi:10.1109/TIA.2013.2242423 Google Scholar

11. Rasmussen, P. O., T. V. Frandsen, et al. "Experimental evaluation of a motor-integrated permanent-magnet gear," IEEE Trans. Ind. Appl., Vol. 49, 850-859, 2013.
doi:10.1109/TMAG.2014.2351787 Google Scholar

12. Gerber, S. and R. J. Wang, "Design and evaluation of a magnetically geared PM machine," IEEE Trans. Magn., Vol. 51, 1-10, 2015. Google Scholar

13. Frandsen, T. V., P. O. Rasmussen, et al. "Improved motor intergrated permanent magnet gear for traction applications," IEEE 2012 Energy Conv. Cong. Expo., 3332-3339, Raleigh, NC, 2012. Google Scholar

14. Frank, N. W. and H. A. Toliyat, "Analysis of the concentric planetary magnetic gear with strengthened stator and interior permanent magnet inner rotor," IEEE Trans. Ind. Appl., Vol. 47, 1652-1660, Jul. 2011. Google Scholar

15. Gouda, E., "Transmission planetaire magnetique etude, optimisation et realisation,", Ph.D. Disertation, Nancy Universit, France, 2011. Google Scholar

16. Kowol, M., J. Kolodziej, et al. "Impact of modulator designs and materials on efficiency and losses in radial passive magnetic gear," IEEE Trans. Energy Conv., 1-1, 2018. Google Scholar

17. Kim, S.-J., E.-J. Park, et al. "Optimal design of ferromagnetic pole pieces for transmission torque ripple reduction in a magnetic-geared machine," Journal of Electrical Engineering & Technology, Vol. 11, 1628-1633, Nov. 2016. Google Scholar

18. Liu, J., W. Zhao, et al. "A novel flux focusing magnetically geared machine with reduced eddy current loss," Energies, Vol. 9, 904-919, Nov. 2016.
doi:10.1109/TIA.2009.2018974 Google Scholar

19. Jian, L., K. T. Chau, et al. "A magnetic-geared outer-rotor permanent-magnet brushless machine for wind power generation," IEEE Trans. on Ind. Appl., Vol. 45, 954-962, 2009. Google Scholar

20. Uppalapati, K., K. J., et al. "A low assembly cost coaxial magnetic gearbox," South. Power Elec. Conf., Auckland, NZ, Dec. 5-8, 2016.
doi:10.3233/JAE-162072 Google Scholar

21. Nobuhara, S., H. K. Niguchi, et al. "Proposal of new-shaped pole pieces for a magnetic-geared generator," International Journal of Applied Electromagnetics and Mechanics, Vol. 52, 763-769, 2016. Google Scholar

Dr. Kang Li

Dr. Krishna Kiran Uppalapati

Dr. Jason Wright

Dr. Joshua Kadel

Professor Jonathan Bird

Dr. Wesley Willimas