Effective Methods of Reducing Cogging Torque in Flux Reversal Machine

For permanent-magnets on the stator and salient structure of both the stator and the rotor, Flux Reversal Machine (FRM) has notable cogging torque inevitably. The cogging torque causes vibration and acoustic noise, which are detrimental to the motor performance, especially in low speed and where need operate smoothly and steadily, even affect normal working. In this paper, two new methods are proposed to reduce the cogging torque of FRM, Segment Rotor method and Pairing Stator poles along with Segment Rotor method. Analyzed by finite element method, it proved that these two methods reduce cogging torque effectively. Moreover, they do not cause inductive electromotive force reduced and reserve the advantages of FRM. These two methods can also be carried out easily in manufacture process. Hence, these are feasible, economical and effective methods and will be applied and generalized in industry in the future.