Subdomain Model for Predicting Magnetic Field in Slotted Surface Mounted Permanent-Magnet Machines With Rotor Eccentricity

Abstract

An analytical subdomain model for the prediction of open-circuit magnetic field in slotted surface-mounted permanent-magnet machines is developed in this paper, which considers the effect of rotor eccentricity. The magnetic field domain is divided into three types of simple and regular subdomains, viz. magnet, air gap, and stator slots. The analytical solution is derived by solving the field governing equations in each subdomain and applying the boundary conditions to the interfaces between these subdomains. The perturbation method is used to describe the effect of rotor eccentricity. The model accurately accounts for the effect of stator slots, the mutual influence between slots, and rotor eccentricity. The analytical model is validated by the corresponding finite-element results. The results show that the proposed subdomain model up to the first-order perturbation can accurately predict the open-circuit magnetic field in slotted surface-mounted permanent-magnet machines with rotor eccentricity.