Design and Analysis of a New Five-Phase Brushless Hybrid-Excitation Fault-Tolerant Motor for Electric Vehicles

High reliability and wide range of speed regulation are key factors for motor drive system in electric vehicles (EVs). To meet the requirement for EV application, this paper proposes and investigates a new five-phase brushless fault-tolerant hybrid-excitation motor. This motor has several advantages over the conventional permanent magnet (PM) motor, such as high fault tolerance and adjustable flux. In addition, to realize flux regulation, based on the utilization of the high-harmonic component of the stator magnetic motive force (MMF), the rotor field winding and the rotor harmonic winding are designed. Unlike the existing hybrid-excitation machines with rotor PM, the proposed motor can achieve the balance between simple structure and no sliding contacts. Moreover, the topology and operation principle of the proposed motor are analyzed. Also, the characteristics of the proposed motor are investigated by using finite-element analysis and experiments with a 2 kW prototype machine. The experimental results are given to be consistent with the theoretical analysis, which validates the correctness of the theory.