Analysis of a PM vernier motor with spoke structure

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