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

Fault tolerance is a key factor for motor driving systems in electric vehicles. To realize the high fault-tolerance under short-circuit, open-circuit, and demagnetization fault, this paper proposes and investigates a new six-phase fault-tolerant hybrid-excitation motor. First, the single concentrated armature winding is adopted to achieve electrical, magnetic, thermal, and physical separations. The unequal teeth width and the asymmetric air-gap length are designed and optimized to reduce torque ripple and distortion of phase back EMF. Furthermore, the field windings are designed to provide magnetization under demagnetization fault. In addition, the motor is designed with the simple structure and no sliding contacts, as well as robust rotor with no windings. Moreover, the topology and operating principles of the proposed motor are analyzed; the characteristics of the proposed motor under healthy and fault conditions are investigated using finite-element analysis. Finally, the calculation results are given to verify the validity of the high fault tolerance for the proposed motor.