Influence of Fault-Tolerant Stator Structure on Performance of Permanent Magnet Bearingless Slice Machines

Fault-tolerant capability is a vital requirement for bearingless slice machine which is used in safety critical application field. This paper compares two bearingless slice machines, conventional permanent magnet bearingless slice machine and fault-tolerant permanent magnet bearingless slice machine, from fault-tolerant capability, suspension and drive performance points of view. Due to introduction of fault-tolerant stator structure, a optimization method for reduction of total harmonic distortion(THD) of back-EMF and electromagnetic coupling between different phases is proposed. Then, some relevant performance comparison, such as fault-tolerant performance, suspension performance as well as drive torque performance, is analyzed by finite element analysis. Finally, several design considerations are presented as guideline for design of bearingless slice machines with fault-tolerant stator structure.