Vol. 132

Latest Volume
All Volumes
All Issues

Load Angle of Flux Modulated Magnetic Gears

By Rong-Jie Wang, Stanley Robert Holm, Josh Scheepers, and Stiaan Gerber
Progress In Electromagnetics Research C, Vol. 132, 255-269, 2023


In this paper, the authors address the issue of the flux-modulated magnetic gear (FMMG), which offers many potential advantages over traditional mechanical gears for a wide range of applications. In the proposed FMMG model, two permanent magnet (PM) carriers are of different pole-pairs and rotate asynchronously, and their relative angular position with respect to the pole parts of the flux modulator is not as straightforward and simple as it may seem in conventional electrical machines. Therefore, this paper focuses on the details of the derivation of the FMMG load angle, which attempts to better express the angular relationship between the individual components of an FMMG. Finite element method (FEM) simulations and experiments are used to validate the load angle concept and corresponding results, and are complemented by experimental measurements. It is believed that the concept of loading angle can facilitate the design and simulation of FMMG and magnetically geared machines (MGM) based on the finite element method under different loading conditions.


Rong-Jie Wang, Stanley Robert Holm, Josh Scheepers, and Stiaan Gerber, "Load Angle of Flux Modulated Magnetic Gears," Progress In Electromagnetics Research C, Vol. 132, 255-269, 2023.


    1. Tlali, P. M., R.-J. Wang, and S. Gerber, "Magnetic gear technologies: A review," 2014 International Conference on Electrical Machines (ICEM), 544-550, Berlin, 2014.

    2. Li, K. and J. Z. Bird, "A review of the volumetric torque density of rotary magnetic gear designs," 2018 XIII International Conference on Electrical Machines (ICEM), 2016-2022, Alexandroupoli, 2018.

    3. McGilton, B., R. Crozier, A. McDonald, and M. Mueller, "Review of magnetic gear technologies and their applications in marine energy," IET Renewable Power Generation, Vol. 12, No. 2, 174-181, 2018.

    4. Wang, Y., M. Filippini, N. Bianchi, and P. Alotto, "A review on magnetic gears: Topologies, computational models, and design aspects," IEEE Transactions on Industry Applications, Vol. 55, No. 5, 4557-4566, Sept.-Oct. 2019.

    5. Ruiz-Ponce, G., M. A. Arjona, C. Hernandez, and R. Escarela-Perez, "Review of magnetic gear technologies used in mechanical power transmission," Energies, Vol. 16, No. 4, 1721, 2023.

    6. Rens, J., K. Atallah, S. D. Calverley, and D. Howe, "A novel magnetic harmonic gear," 2007 IEEE International Electric Machines & Drives Conference, 698-703, Antalya, Turkey, 2007.

    7. Huang, C. C., M. C. Tsai, D. G. Dorrell, and B. J. Lin, "Development of a magnetic planetary gearbox," IEEE Transactions on Magnetics, Vol. 44, No. 3, 403-412, Mar. 2008.

    8. Wang, R.-J., A. Matthee, S. Gerber, and P. M. Tlali, "Calculation of torque performance of a novel magnetic planetary gear," IEEE Magnetics Letters, Vol. 7, 1-5, Art. No. 1303805, 2016.

    9. Atallah, K. and D. Howe, "A novel high-performance magnetic gear," IEEE Transactions on Magnetics, Vol. 37, No. 4, 2844-2846, Jul. 2001.

    10. Johnson, M., M. C. Gardner, H. A. Toliyat, S. Englebretson, W. Ouyang, and C. Tschida, "Design, construction, and analysis of a large-scale inner stator radial flux magnetically geared generator for wave energy conversion," IEEE Transactions on Industry Applications, Vol. 54, No. 4, 3305-3314, Jul.-Aug. 2018.

    11. Li, K., S. Modaresahmadi, W. B. Williams, J. D. Wright, D. Som, and J. Z. Bird, "Designing and experimentally testing a magnetic gearbox for a wind turbine demonstrator," IEEE Transactions on Industry Applications, Vol. 55, No. 4, 3522-3533, Jul.-Aug 2019.

    12. Kowol, M., J. Kolodziej, M. Jagiela, and M. Lukaniszyn, "Impact of modulator designs and materials on efficiency and losses in radial passive magnetic gear," IEEE Transactions on Energy Conversion, Vol. 34, No. 1, 147-154, Mar. 2019.

    13. Lee, J., et al., "Design and analysis of the coaxial magnetic gear considering the electromagnetic performance and mechanical stress," IEEE Transactions on Applied Superconductivity, Vol. 30, No. 4, 1-5, Jun. 2020.

    14. Uppalapati, K. K., M. D. Calvin, J. D. Wright, J. Pitchard, W. B. Williams, and J. Z. Bird, "A magnetic gearbox with an active region torque density of 239 N.m/L," IEEE Transactions on Industry Applications, Vol. 54, No. 2, 1331-1338, Mar.-Apr. 2018.

    15. Gardner, M. C., B. E. Jack, M. Johnson, and H. A. Toliyat, "Comparison of surface mounted permanent magnet coaxial radial ux magnetic gears independently optimized for volume, cost, and mass," IEEE Transactions on Industry Applications, Vol. 54, No. 3, 2237-2245, May-Jun. 2018.

    16. Chen, Y., W. N. Fu, S. L. Ho, and H. Liu, "A quantitative comparison analysis of radial-flux, transverse-flux, and axial-flux magnetic gears," IEEE Transactions on Magnetics, Vol. 50, No. 11, 1-4, Nov. 2014.

    17. Johnson, M., A. Shapoury, P. Boghrat, M. Post, and H. A. Toliyat, "Analysis and development of an axial flux magnetic gear," IEEE Energy Conversion Congress and Exposition (ECCE), 5893-5900, 2015.

    18. Misron, N., L. Mohd Saini, I. Aris, C. A. Vaithilingam, and H. Tsuyoshi, "Simplified design of magnetic gear by considering the maximum transmission torque line," Applied Sciences, Vol. 10, No. 23, 8581, 2020.

    19. Filippini, M. and P. Alotto, "Coaxial magnetic gear design and optimization," IEEE Transactions on Industrial Electronics, Vol. 64, No. 12, 9934-9942, Dec. 2017.

    20. Magnetic gear: 2D FEM simulation with EMWorks2D inside SOLIDWORKS, available on-line: https://www.emworks.com/application/magnetic-gear-2d-fem-simulation-with-emworks2d-inside-solidworks (accessed on 20 Feb. 2023).

    21. Gerber, S. and R.-J. Wang, "Design and evaluation of a magnetically geared PM machine," IEEE Transactions on Magnetics, Vol. 51, No. 8, 1-10, Aug. 2015.

    22. Gerber, S. Evaluation and design aspects of magnetic gears and magnetically geared electrical machines, Ph.D. dissertation, Stellenbosch University, Dec. 2015.

    23. Matthee, A., R.-J. Wang, C. J. Agenbach, D. N. J. Els, and M. J. Kamper, "Evaluation of a magnetic gear for air-cooled condenser applications," IET Electric Power Applications, Vol. 12, No. 5, 677-683, 2018.