Design and Analysis of an Outer-Rotor-Permanent-Magnet Flux-Switching Machine for Electric Vehicle Applications

In this paper, an outer-rotor-permanent-magnet flux-switching (ORPM-FS) machine is proposed. It not only inherits the traditional flux-switching permanent-magnets (FSPM's) flux-switching principle and the high torque density, but also overcomes the FSPM's magnetic saturation and adds the slot area, thus producing favorable output torque capability at rated load and overload condition. By means of finite element method, the ORPM-FS machine is optimized through multi-level process for multi-objectives: the basic variables optimization for high output torque and low torque ripple, the pitch coefficient optimization for favorable torque characteristics and efficiency, the optimal selection for high efficiency at flux-weakening operation. At last, the electromagnetic performances of the optimized ORPM-FS machine are analyzed, which shows that the proposed machine can receive high torque density, low torque ripple, high efficiency, and favorable overload capability.