Improvement of Power Factor in Modular Stator Dual-Permanent-Magnet-Excited Vernier Machine

This article aims to propose and analyze a power factor increased modular stator dual-permanent-magnet-excited vernier (DPMEV) machine. Currently, the DPMEV machines suffer from a low power factor due tosignificant amplitude of armature non-working harmonics. With the modular stator design, the magnetic cir-cuit of low-order non-working harmonics is interrupted, effectively reducing its amplitude without compromis-ing working harmonics. Consequently, the proposed DPMEV machine achieves a notable improvement inpower factor, increasing from 0.5 to 0.69 under rated conditions compared to non-modular machines. Firstly,the topology and working principle of proposed machine are introduced. Then, air gap flux density model isestablished for investigating the mechanism of power factor improvement. Furthermore, a comprehensive anal-ysis is conducted using finite element analysis to study the influence of critical dimension parameters on thepower factor, including PM thickness, PM pole arc and modulated pole angle. Lastly, a modular statorDPMEV prototype is manufactured and tested for validation. The experiments results closely align with thefinite element analysis.