Multi-phase fault-tolerant switched-flux permanent magnet motors having odd rotor pole number

This paper proposes and analyze a new five-phase fault-tolerant switched-flux permanent magnet (FT-SFPM) motor having odd rotor pole number. The key of this new motor topology is to incorporate the concept of fault-tolerant teeth (FTT) to provide the desired decoupling among phases. The electromagnetic performances of the newly designed FT-SFPM motor having 19 rotor poles are analyzed including the flux, back-EMF as well as cogging torque. The finite-element analysis (FEA) results show that the proposed FT-SFPM motor not only retains the merits of stator-PM brushless motors and multi-phase motors, but also offers lower cost and higher fault-tolerant capability. Especially, the proposed 10/19-pole topology incorporates the merits of symmetric back-EMF and reduced cogging torque. An experimental FT-SFPM machine is designed and built for exemplification. Experimental results of the prototype are given to confirm the validity of the proposed machines.