Analytical Calculation of Electromagnetic Performance in Dual-winding Bearingless Flux-Switching Permanent Magnet Machines Considering Rotor Eccentricity

Dual-winding bearingless flux switching permanent magnet motors (BFSPMM) are doubly salient, the magnetic field distribution of the motor will be more complicated when the rotor is eccentric. A subdomain model method considering the rotor eccentricity of dual-winding BFSPMM is proposed in this paper to analyze the electromagnetic characteristics of the rotor eccentricity with slots on both sides of stator and rotor. Based on retaining the original polar coordinates at the geometric center of the stator, a new polar coordinate system is established at the geometric center of the rotor. The Laplace and Poisson equations of each subdomain are established in two different coordinate systems respectively. In the developed model, the entire air gap area is divided into the non-uniform and uniform air gap area. The electromagnetic parameters under the condition of rotor eccentricity are analyzed, such as flux density, back-EMF, and suspension forces. The analytical model are verified through the finite element method (FEM) and prototype experiment.