Electromagnetic Modeling and Investigation for Bearingless Switched Reluctance Motor Considering Magnetic Saturation

For 12/4 bearingless switched reluctance motors (BSRMs), the levitation forces are generated in the maximum-inductance flat region of each phase. The magnetic saturation can be reached with the increase in ampere turns. In this paper, the mathematical model considering magnetic saturation is proposed to overcome the problem associated with the nonlinear characteristic. Three regions are divided in the $B$ - $H$ loop according to the change of relative permeability with magnetic field intensity. In addition, the single-valued expression between the flux density and the magnetic flux density is defined. The different parameters, i.e., air gaps, lamination, and rotor angle, influencing the performance of BSRM are analyzed. In the control process, the lookup tables (LUTs) of the electromagnetic forces based on the mathematical model are obtained. Finally, the experimental results for the 12/4 BSRM verify the feasibility of the proposed model.