Analyzing Flux-Switching and Vernier Permanent Magnet Machines Through Field Harmonic Theory: A Comparative Study

This is the authors' abstract. We don't add key points for this paper.

Flux-switching permanent magnet (FSPM) and permanent magnet Vernier (PMV) machines have several similarities, such as the utilization of the modulation flux to obtain the back electromotive force (back-EMF), high torque at low speed and negligible reluctance torque. The arrangement of the magnets in the PMV machine further classifies these machines into the surface type and the spoke type. The aim of this paper is to compare the performance of three different flux modulation (FM) machines: 1) the FSPM machine, 2) the surface PMV (SPMV) machine, and 3) the spoke-type PMV (STPMV) machine. The comparison is developed through an analytical approach. The air-gap field harmonics are first analyzed, and differences in their working harmonics are determined. Furthermore, the role of each working harmonic in the production of modulation flux and back-EMF is identified in all the machines. Next, each machine is designed and analyzed by a unified criterion to make a fair comparison. The performance of the three machines is evaluated using both analytical modeling and finite element analysis (FEA). The results show that the FSPM machine achieves the highest back-EMF and a low reactance, leading to an improved power factor.