Theoretical Analysis And Magnetic Field Calculation On Novel Flux Switching Pm Machine With 3d Magnetic Circuit

Considering the issues of MW level low speed permanent magnet synchronous generator (PMSG) that power density at low speed cases is generally low, winding manufactures and high-voltage insulation are relatively difficult, stator leakage inductances are high especially in concentrated winding structure case. This paper puts forward a new flux switching PM machine with axial concentrated windings and 3D magnetic circuits which can effectively increase power density, reduce armature copper loss and improve efficiency, solve the issues of winding manufactures and high-voltage insulation, at the same time, completely solve the problem of excessive high armature leakage inductance. Theoretical analysis is carried out for this machine with new structure in this paper.Firstly, one single-phase surface mounted pole structure, one single-phase hybrid pole structure, and one multiphase structure are presented based on the new flux switching PM machine. Then 3D parametric finite element modeling and calculation, analysis of flux switching principle are carried out for these three new structures, to varify the feasibility of this new structure and the advantages in high power wind power system.Secondly, 3D magnetostatic and 3D transient calculation using FE method are carried out for these three new structures. And the corresponding operating parameters, magnetic circuit parameters and loss parameters are obtained accordingly. And then the machine parameter optimaization is performed in order to achieve ideal operating performances and working characteristics. Finally the general rules of designing these machines with new structures are summarized.Thirdly, one 3D lumped-parameter magnetic circuit model is built based on the 3D electromagnetic field calculations, and thus the main electric parameters are calculated accordingly. Thus, the optimaization of machine electric parameters can be done easily based on the calculation of 3D lumped-parameter magnetic circuit model.Finally, four methods of suppressing cogging torque are proposed according to the flux switching 3D flux PM machine put forward in this paper: STAW method, SSS method, STCP method and STAP method. And then the principle and effect of suppression are analyzed and compared in 3D electromagnetic field finite element calculations.