Design and analysis of open-slot fault-tolerant permanent-magnet motors

This paper proposes a new open-slot fault-tolerant permanent-magnet (FTPM) motor for electric vehicles. The key of the proposed motor is to introduce the open-slot stator design method into the FTPM motors, in which the halbach permanent-magnet array rotor is adopted. The proposed FTPM motor not only retains the merits of high power/torque density and high fault-tolerant capability, but also offers more sinusoidal back-EMF and lower cogging torque than the existing one. Especially, by adopting open-slot, coil space factor is significantly improved. Also, the impact of the open-slot on the rotor losses is investigated. By using the time-stepping finite element method, electromagnetic performances and the efficiency of the proposed motor are analyzed and predicted, verifying the effectiveness of the theoretical analysis.