Proposed and Verification of Torque Equation of IPM-type Magnetic-Geared

A magnetic-geared motor (MGM) consists of a magnetic gear and a permanent magnet (PM) motor, which are shared one inner rotor. Hence, it has high torque density in comparison with conventional PM motors. A structure of interior permanent magnet (IPM) is superior as an inner rotor in terms of efficiency. However, in the IPM-type MGM, magnetic interaction occurs and the torque equation considering the interaction has not been studied. This paper deals with the torque equation of the IPM-type MGM. First, the torque equation considering the magnetic interaction is derived. Next, the parameters of the torque equation are determined by using a two-dimensional finite element method (2D-FEM). Finally, the validity of the torque equation is proved by comparing with 2D-FEM.