Calculation of optimal rotor permanent magnet dimensions for RPMFS machine

In this paper, the analytical model for the rotor magnetic circuit of a RPMFS (Rotor Permanent Magnet Flux-Switching) machine is developed. A simple analytical method is proposed for calculating the optimum dimensions of rotor permanent magnets (PMs) with the aim of achieving maximum value of machine electromagnetic torque at constant PM volume and constant dimensions of the stator magnetic circuit. It is shown that the optimum values of PM width and height depend to a large extent on the value of the leakage flux between rotor poles, and the saturation in stator teeth and yoke. The results of the analytical calculation are verified by computer simulations using finite element analysis (FEA).