Contents I. Introduction
In recent years, permanent magnet vernier (PMV) machine is gaining much interest in direct-drive applications due to its potential to overcome the bulkiness that most high-power direct-drive machines are subjected to. With superior torque density, compact mechanical structure, high reliability, and inherent magnetic gear effect, PMV machines are promising alternatives in low-speed, high-torque applications, such as wind power, electric propulsion, and robotic servo system. In two decades since PMV machine was first presented in 1995 [1] , research works about this kind of machine have been conducted on proposing novel topologies [2]–[7], establishing analytical theories [8]– [10], and modeling approaches [11], [12], as well as comparison with commercial machines [13], [14].
