Comparison of the Iron Loss of a Flux-Reversal Machine Under Four Different PWM Modes

A flux-reversal machine (FRM) is a new doubly salient stator-permanent magnet (PM) machine with flux linkage reversal in the stator concentrated windings. It can be driven by 120deg square-wave voltage and use pulse-width modulation (PWM) patterns in two-phase feeding schemes to control the speed of the machine. This paper introduces four PWM modes that used the FRM control system and analyzes the effects of four different PWM modes on the iron loss using a 2-D time-stepped voltage source finite-element method. The iron loss is calculated from the time variation of the magnetic field distribution