Research on Rotor Eccentricity Compensation Control for Bearingless Surface-Mounted Permanent-Magnet Motors Based on an Exact Analytical Method

An exact analytical model of a surface-mounted bearingless permanent-magnet synchronous motor (BPMSM) with rotor eccentricity by a perturbation method is proposed in this paper and its computational accuracy is verified by the finite-element method. Considering the rotor eccentricity, a compensation control system is implemented based on the mathematical model of levitation force by applying a coefficient of the rotor eccentricity calculated by the exact analytical method (EAM). The experimental results suggest the improvements of the dynamic and the static performances of the stable suspension state for the surface-mounted BPMSM and the feasibility and effectiveness of the EAM.