This paper proposes a brushless hybrid excitation motor based on N-S alternating pole (NSAP-BHEM) to meet the requirements of wide speed regulation and high torque output for electric vehicles (EVs). First, permanent magnetic pole and iron core pole of the rotor are arranged alternately on the rotor, which can reduce the usage of permanent magnet. The iron core pole is used as the variable flux pole to provide a parallel excitation path. In addition, the excitation winding and armature winding are placed in the stator to improve the space utilization. The AC excitation winding is used to realize brushless excitation, which can adjust magnetic field flexibly, expand speed regulation range and increase torque output. Moreover, the topology and operating principle of the NSAP-BHEM are described. Furthermore, a 2kW prototype is designed and the electromagnetic characteristics of the NSAP-BHEM are analyzed by finite element analysis (FEA).

Brushless hybrid excitation motor; N-S alternating pole; parallel excitation; AC excitation winding; finite element analysis