Fault-Tolerant Flux-Switching Permanent Magnet Brushless AC Machines

Flux-switching permanent magnet (FSPM) brushless machines have emerged as an attractive machine type by virtue of their high torque densities, simple and robust rotor structure and the fact that permanent magnets and coils are both located on the stator. Both 2D and 3D finite element analyses (FEA) are employed to compare the performance of a standard topology with three modular, fault-tolerant designs in terms of output torque, flux-linkage, back-EMF and inductances. It is shown that the FSPM machine can be designed to be fault-tolerant without incurring a significant performance penalty, but that some degree of rotor skewing may be required in order to maintain a sinusoidal back-EMF waveform and reduce the torque ripple. Experimental validation is reported for both standard and fault-tolerant FSPM machine topologies.