High torque density design of a new outer-rotor hybrid excitation flux switching machine for in-wheel drive electric vehicle

In this paper, a new 12-slot 14-pole outer-rotor hybrid excitation flux switching machine (ORHEFSM) that consist of two flux sources namely PM and DC field excitation coil (FEC) is proposed to overcome the problems. The flux paths caused by PMs only of the initial design machine are illustrated. Based on 2-D finite element analysis (FEA), the initial performances of the proposed machine is still far from the target value, then design refinement and parameter optimization are conducted until the target performances are achieve. In addition, the torque and power versus speed characteristics, PM demagnetization analysis, the loss and efficiency of final designed machine are also investigated.