Comparison of Vernier Machines with Different Rotor PM Configurations

Permanent magnet vernier machines (PMVM) are drawing extensive attention due to its low-speed high-torque output. In this paper, four different PMVM topologies with different permanent magnet configuration are presented, while keeping the stator slot and winding configuration unchanged. The operating principle of the machine, magnet field modulation principle, is discussed by analytic method and their electromagnetic performance is calculated by finite element method (FEM). Comparison results are used to confirm and validate the advantages and disadvantages of the four topologies. Besides, the influence of several structure parameters on performance is analyzed.