토크 성능 향상을 위한 표면부착형 영구자석 전동기의 레벨셋 기반 영구자석 형상 최적설계

Abstract

This paper presents the optimal shape of a permanent magnet in the surface-mounted permanent magnet motor using the level set based optimization method. In this method, the material property of the permanent magnet is expressed by level set function with Heaviside function. Since back electromotive force profile is the differential of the flux linkage with respect to the time, flux linkage profile is optimized to be a sinusoidal form to improve the torque performance. The optimization problem is formulated to minimize the difference of the target flux linkage and the flux linkage analyzed by magnetostatic finite element method. The time evolution equation is solved to obtain the optimal shape using the sensitivity of the objective function with respect to level set function. To confirm this method, 4 poles 6 slots surface-mounted permanent magnet motor is optimized and torque performance is improved.