CJEE

Chinese Journal of Electrical Engineering ›› 2019, Vol. 5 ›› Issue (1): 47-52.

• Orginal Article • Previous Articles     Next Articles

扫码分享

Magnetic Field Analytical Model for Magnetic Harmonic Gears Using the Fractional Linear Transformation Method

Yuejin Zhang1, *, Junda Zhang1, Ronghui Liu1, 2   

  1. 1. School of Mechatronics Engineering and Automation, Shanghai University, Shanghai 200444, China;
    2. College of Electric Engineering, Shanghai University of Electric Power, Shanghai 200090, China
  • Online:2019-01-20 Published:2019-01-20
  • About author:Yuejin Zhang received his M.S. degree in electrical engineering from Shanghai University of Technology, Shanghai, China, in 1988, and his Ph.D. degree in electrical engineering from Shanghai University, Shanghai, China, in 2005.
    He is a Professor at Shanghai University, Shanghai. His research interests include magnetic field analysis, design of magnetic gears, and permanent magnet brushless and direct-drive electrical machines.
    Junda Zhang was born in Shanghai, China, in 1986. He received his B.S. degree in automation engineering from Tongji University, Shanghai, China, in 2009, and his M.S. degree in control engineering from Shanghai University, Shanghai, China, in 2015.
    He is currently pursuing his Ph.D. degree in electric machinery at Shanghai University. His research interests include magnetic field analysis, design of electrical machines, and permanent magnet brushless motor control.
    Ronghui Liu received her B.S. degree in computer engineering from Nanjing University of Aeronautics and Astronautics, Nanjing, China, in 2000 and her M.S. degree in electrical engineering from Southeast University, Nanjing, China, in 2003. She is currently pursuing her Ph.D. degree in electrical engineering at Shanghai University, Shanghai, China.
    Since 2014, she has been a Vice Professor at the Electric Engineering College, Shanghai University of Electric Power, Shanghai, China. Her research interests include analytical magnetic field calculation of motors.

PDF

241

Abstract: Magnetic harmonic gears with high gear ratios exhibit high torque densities. However, the revolution and rotation of the eccentric rotor makes the magnetic field analysis complex. In this study, an analytical model of magnetic fields for magnetic harmonic gears is developed by using the fractional linear transformation method. The transformation formula is accurate in theory and suitable for the analysis of magnetic fields with large eccentricity. The rotor eccentricity region in the z-plane is mapped onto a uniform region in the w-plane. The magnetic field solutions are obtained by modulating the magnetic field distributions without rotor eccentricity with the relative permeance function derived from the effect of rotor eccentricity. The torque of magnetic harmonic gears is calculated from the radial and tangential components of the air-gap magnetic fields. Results of the finite element method and prototype test confirm the validity of the analytical prediction.

Key words: Eccentric rotor, electromagnetic torque, fractional linear transformation, magnetic harmonic gears, relative permeance function.