Analysis And Design Of Switching Flux Permanent Magnet Synchronous Motor

Recently, with the progress in permanent magnet materials, power electronic technique, and some other corresponding subjects, permanent magnet machines have gradually become a kind of high performance machines which have been extensively applied in an increasing number of fields. Especially in automobile and aviation fields, the requirement for high power density permanent magnet motor has become larger. Based on switched reluctance machine and doubly salient permanent magnet machine, the switching flux permanent magnet (SFPM) has been developed, which not only has simple and reliable characteristics but also has the advantages of high torque density and high operating efficiency.The primary research of this thesis is around analyzed and designed a 12/10 SFPM machine.Firstly, the structure characteristics and working principle of SFPM machine are introduced. Based on machine EMF star graph, winding connection and fundamental winding factor are determined. The torque and power equations of machine are derived, the initial values of machine sizes have been decided. From conservation of energy, the machine mathematical model is established.The 2-D physical model of machine is established by Ansoft. Based on finite element method (FEM), the machine static characteristics are investigated, including magnetic field and flux density distributions in the air-gap at no-load, armature magnetic field distributions, back-EMF, open circuit flux linkage, cogging torque, winding inductance and static torque. The effect on the inductances of cross-coupling between the permanent magnet field and armature field is taken into account. The analysis results show that both the phase flux linkage and phase back-EMF are sinusoidal, which makes it most appropriate for brushless AC operation. However, the flux density saturation level in teeth is serious and harmonics of air-gap flux density and amplitude of cogging torque are relatively larger.At last, by applying the research tools of FEM, the influences of machine structural sizes on static characteristics are investigated. In this thesis, the investigations are focused on air-gap length, length of permanent magnet magnetization direction and width of rotor teeth. The analysis results provide references for machine design.