A New Flux-Concentrating Rotor of Double Stator and Single Rotor Axial Flux Permanent Magnet Motor for Electric Vehicle Traction Application

In this paper, a new flux-concentrating rotor with interior permanent magnet (IPM) of double stator and single rotor (DSSR) axial flux permanent magnet (AFPM) motor is proposed for electric vehicle traction application. Compared with the traditional surface-mounted PM rotor and spoke-type IPM rotor, the saliency effect of the proposed IPM rotor can be significantly increased to improve torque performance, as well as reduce rotor losses and increase efficiency. First, the topological structure flux-concentrating principle of the rotor with inserted PMs are introduced and analyzed. The direct-axis or quadrature-axis magnetic path are dissected in depth to explain the contribution rate of reluctance torque. Then, the design and optimization of AFPM motors with traditional surface-mounted rotor, spoke-type IPM rotor and the proposed rotor are carried out to pursue torque density. Finally, the electromagnetic performances of three AFPM motors are compared by finite element analysis (FEA). The results of comparative analysis show that the proposed rotor has some obvious advantages including motor overload capacity, power/torque density and maximum efficiency.