Design of novel bearingless switched reluctance motor

Abstract

This study presents a novel bearingless switched reluctance motor (SRM) with decoupled torque and suspending stator poles. Different from the conventional bearingless SRM, the suspending poles of the proposed bearingless SRM are separated from the phase torque poles. Perpendicularly placed suspending poles are designed to produce a continuous radial force for rotor bearing. Owing to independently placed suspending and torque poles, the produced suspending force has excellent linearity according to rotor position and independent characteristics of the torque current. The control of air gap is easier than the conventional one from the linear and independent characteristics. In order to verify the proposed structure, the mathematic model for the suspending force is derived. Finite element analysis is also employed to compare with expressions for the suspending force. A prototype motor is designed and manufactured to verify the proposed bearingless structure.