Study On Performance And Cogging Torque In Flux-Switching Permanent Magnet Motor

Flux-switching permanent magnet(FSPM)motor is a novel doubly salient permanent magnet(DSPM)motor,which has a simple rotor structure without windings,the transverse magnetizing permanent magnets are embedded in the stator tooth,and the magnetization direction of the adjacent permanent magnets are opposite,the concentrated windings are in the stator slots.The PMs of the FSPM motor are in the stator so it is more reliable than the PMs in rotor motors.Moreover,it has the characteristics of high power density,high efficiency and good flux weakening capacity,so the study of FSPM motors has important theoretical significance and good application prospect.The main works of this paper are as follows:The significance and development of the FSPM motor are summarized.The fundamental structure and operational principle are presented based on the three phase 12/10 FSPM motor.The mathematical model based on dqO coordinate is derived by discussing the circuit,magnetic circuit and electromechanical equations,which lay the theoretical foundation for the following research.The static characteristics,loss and efficiency of the FSPM motor are analyzed based on the finite element analysis(FEA)software Maxwell.In addition,the thermal analysis of the FSPM motor is analyzed by AN SYS Workbench based on the theory of thermal transmission.The cogging torque of the FSPM motor is researched intensively in this paper.The magnetic circuit is seriously saturated in the stator teeth of the FSPM motor due to the doubly salient structure,which causes larger cogging torque than the traditional PM motors.In order to reduce the manufacture and assembling complexity,the stator structure simplification is introduced in this paper by adding a magnetic bridge in stator,and the position and thickness of the magnetic bridge is optimized.Four short-magnet(SM)structures are proposed to reduce the cogging torque of the FSPM motor,and the optimal SM structure is chosen by comparing the performance of the cogging torque and output torque under the four schemes based on the FEA.Two prototype motors are manufactured,and then experiments on performance,temperature rise and cogging torque are carricd out.The proposed method and simulation results are verified by the experimental results.