Overview of Permanent Magnet Vernier Machines: Topologies, Key Problems and Applications

At present, permanent magnet vernier machines (PMVM) have gained much attention due to their inherent good torque performance. This paper investigates the developments of PMVM, including topologies, key problems, and applications. To start with, the basic working principle is introduced. Then, the developments of the flux modulation theory are overviewed. Moreover, in terms of the technical issues, such as improving the torque density, power factor, reducing the permanent magnet (PM) losses and total cost, various solutions are concluded and synthesized, as well as the utilization of some new materials and topologies. Besides, the present practical applications of PMVM are also concluded. Finally, the future development versions are prospected. Generally, this paper aims at providing a reference for the following researches of PMVM in the future.