Experimental Verification and Analytical Study of Influence of Rotor Eccentricity on Electromagnetic Characteristics of Permanent Magnet Machine

Rotor eccentricity occurs during manufacturing, causing the device to vibrate and make noise, thereby shortening its life. Its characteristics can be analyzed via the existing finite element method (FEM); however, analyzing characteristics according to design variables is time-consuming. Therefore, we implemented an analytical method that can rapidly identify the characteristics according to the design variables. We derived the magnetic flux density, the back-electromotive force, and the torque through the analytical method according to rotor eccentricity. The rotor eccentricity was considered to be based on the perturbation and the electromagnetic theories; accordingly, the governing equations and boundary conditions were derived. The analytical method was validated through FEM and experimental result.