A switched reluctance motor with conical magnetic bearings

Abstract

High-speed and high-power-density drives are receiving more and more attention in today's industry. This study presents a switched reluctance motor (SRM) with conical magnetic bearings (CMBs), which is very suitable to operate in high speed and harsh environment such as starter/generator in aircraft. The proposed motor consists of a SRM and two CMBs. There is electric relationship between the SRM and two CMBs, this novel motor's three-phase motoring windings are constructed by connecting each phase biased winding of two CMBs and each phase winding of the SRM in series, respectively, and the three-phase motoring windings are driven by the traditional switched reluctance mode. Thus the rotational torque in SRM and the biased flux used for suspending force generation in two CMBs can be produced by motoring winding currents simultaneously. Initially, the structure and working principle of the proposed SRM with CMBs are demonstrated. Then, the theoretical formulas for computing the suspending force of this novel CMB in the proposed structure are deduced by taking advantage of the magnetic equivalent circuit method and the virtual displacement principle. Furthermore, its suspending force control and basic design method are described. Finally, the characteristics of the proposed SRM with CMBs are deeply analyzed and verified by 3D finite element method.