Modeling and Analyzing of Surface-Mounted Permanent-Magnet Synchronous Machines With Optimized Magnetic Pole Shape

Two types of eccentric magnetic pole shapes for optimizing conventional surface-mounted permanent-magnet (PM) synchronous machines with radial magnetization are presented in this paper. An analytical method based on an exact subdomain model and discrete idea is proposed for obtaining the air-gap flux density distribution in the improved motor. Cogging torque and back EMF analytical models are further built with the field solution, which provide useful tools for investigating motor performances with unequal thickness magnetic poles. The accuracy and feasibility of the models have been validated by a finite element method. Based on the analytical models, the effects of pole shape parameters on motor performance are investigated. Results show that both pole shapes can perfect magnetic field distribution, decrease harmonic content of back EMF, reduce torque ripples, and improve the utilization of PMs.