Analysis of a PM Vernier Motor With Spoke Structure

In this paper, a vernier motor with a spoke permanent-magnet (PM) structure instead of a surface PM is proposed in order to obtain higher power factor (PF) and flux density. However, upon investigating this structure with a single gap, unique effects that virtually eliminate the vernier effect are analytically identified. To avoid these effects and improve the PF, a spoke PM vernier motor with a double gap is then proposed. Analytic equations for back electromotive force and the PF are then derived for this motor in terms of various geometric factors such as the numbers of magnets and winding poles, the magnet thickness, etc. For a case study, the practical achievable maximum power and PF are calculated and verified with accurate simulations.