Comprehensive analysis of suspending force for improved bearingless switched reluctance motor with permanent magnets in stator yoke

Different from conventional switched reluctance motor(SRM), bearingless SRM not only provides torque but also supplies levitation force for free-friction of rotor. In order to make sure that bearingless SRM can steadily levitates in static and dynamic rotating operation, it is necessary to analyze suspending force. Therefore, suspending force performance of an improved bearingless SRM with permanent magnets in stator yoke is comprehensively investigated in this paper. Basic structure and operation principle with permanent magnets in stator yoke are introduced firstly. Furthermore, mathematical model is built up for design of suspending force. In addition, parametric analysis for levitation performance is implemented. Finally, validity of proposed method is verified by experimental results.