There are several methods in order to reduce the torque pulsations forsynchronous permanent magnet (PM) motors in literature [1]. These methods include design modifications both at rotor and stator sides such as using different slot/pole combinations, skewing rotor or stator, magnet grouping and adding auxiliary slots. One of the most common methods used in practice is step skew rotor. In general, adding one slot pitch step skew with several equal rotor segments increase torque quality and also decrease both cogging and ripple torque components for integer slot PM motors [2-7]. However, the skew angle and the step skew length could be optimized to get better torque quality. In this study, a new step skew technique is proposed with different segment lengths and skew angles between the segment pieces. Optimization comprising both parameters are carried out and the results compared with traditional step skew approach. 2D FEA results are obtained for conventional step skew motor for a reference motor. Rotor optimization with varying rotor segment lengths and skew angles are attained and the optimized results are compared with the reference PM motor.
展开▼
