매입자석형 동기전동기의 회전자 응력 완화를 위한 설계

Multi-layer magnet IPMSM is often used for high-power motor due to the benefit to increase reluctance torque under the same current condition. But when it is designed for high-speed motor, mechanical condition should be considered. That is because the centrifugal force applied to a rotor increases the mechanical stress as the speed is higher. If maximum mechanical stress of the designed model is over the required specification, it cannot be used as high-speed motor. In this paper, the method for relieving stress concentration is suggested using two-layer magnet IPMSM model. The mechanical stress is analyzed by adjusting various design factors of the rotor such as thickness of Permanent Magnet (PM), position of PM, thickness of bridge. At this time, the shape of stator is not changed. Also, the way to distribute mechanical stress concentration and the analysis condition are suggested. Using this method, the maximum mechanical stress is decreased under the required condition, keeping the target torque. Both electrical characteristics and distribution of mechanical stress are analyzed using 2-D Finite Element Analysis (FEA), and this will be helpful to design the high speed motor.