Simultaneous Suppression of Torque Pulsation and Electromagnetic Vibration of a Spoke-Type PM Motor by Space-Time Flux Density Harmonics Optimization

This article presents an effective method to suppress torque pulsation and electromagnetic vibration. The key is to identify and suppress the space-time flux density harmonics that have a significant contribution to both torque pulsation and electromagnetic vibration. First, the mechanism of torque pulsation and electromagnetic vibration is investigated. Then, the contributions of different flux density harmonics are quantified considering the amplitude, phase, and space-time order. Meanwhile, the most critical flux density harmonics can be identified. Finally, a multiobjective optimization method combined with a symmetrically shaped rotor is used to optimize space-time flux density harmonic distribution. With the proposed method, a great improvement in torque and vibration performance of a 40-slot, eight-pole spoke-type permanent magnet (STPM) motor is achieved. Furthermore, the method does not bring additional burden to manufacturing and does not increase material costs. Both the finite element model (FEM) and prototype results verify the effectiveness of the proposed method.