Comparative Study of PM Flux Switching and Surface Mounted PM Synchronous Machines for Direct-drive Vehicle Applications

Abstract

Flux switching machine (FSM) and conventional synchronous machine (SM) locate flux source differently from each other and it directly affects thermal management knowing that both operate with synchronous speed. Meanwhile, FSM operates with double frequency within the half cycle of synchronous machine region. This paper presents the two synchronous machines extension and compares their electromagnetic performances especially the FSM employing segmented rotor rather than salient rotor pole. The differences between the two PM machines type are highlighted, their maximum torque and flux-weakening capabilities are investigated analytically by 2D-FEA method with due account for the same split ratio of 0.85. The JMAG Designer version 14, is used in the simulation to analyze cogging torque, induced back-EMF and electromagnetic torque performance. Performance of FSM machine is seen to be better than conventional synchronous machine due to location of all active materials on the stationary stator. Output average torque of the presented FSM is seen to increase by 2.9 times or 118% higher than conventional synchronous machine of the same design specifications thereby, projecting FSM using segmented rotor as a viable candidate for vehicle application.