Analytical Model of Air‐Gap Magnetic Field for Eccentric Harmonic Magnetic Gear with Halbach Array

Abstract

The eccentric harmonic magnetic gear (EHMG) has the characteristics of high torque density, high transmission ratio and high efficiency. The EHMG with Halbach array has better performance than the EHMG with traditional radial magnetization. Accurate calculation of its air‐gap magnetic field is of great significance for design and optimization. Based on the boundary perturbation method, a 2D analytical model of the air‐gap magnetic field of EHMG with Halbach array is established in this paper. The eccentric air‐gap magnetic field is calculated due to the permanent magnets of the eccentric rotor and the stator acting alone, and then the air‐gap magnetic field of the EHMG is obtained according to the superposition principle. The results of the air‐gap magnetic field are compared and evaluated by the regression evaluation indexes. The analytical results are consistent with the finite element results, which verifies the validity and accuracy of the analytical model. Comparing the EHMG with Halbach array and radial magnetization, the maximum static and dynamic electromagnetic torques of EHMG with Halbach array are increased by 59.1% and 55.6% compared with the EHMG with radial magnetization, which verifies the superior performance of EHMG with Halbach array. © 2023 Institute of Electrical Engineer of Japan and Wiley Periodicals LLC.