Comparison of the iron loss of a flux-reversal machine under four different PWM modes

Flux-reversal machine (FRM) is a new brushless doubly salient permanent magnet machine. It can be driven by 120deg square wave voltage and use PWM pulse patterns in two-phase feeding scheme to control the speed of the machine. This paper introduces four PWM modes used FRM control system, and analyzes the effects of four different PWM modes on the iron loss using a two dimensional time-stepped voltage source finite-element method (FEM). The iron loss is calculated from the time variation of the magnetic field distribution