The Mathematical Model of Bearingless Switched Reluctance Motors With Two-Phase Excitation

In view of limitations of mathematical model only suited for the single-phase excitation mode in bearingless switched reluctance motors (BSRM), a novel mathematical model of BSRM with one or two-phase excitation is proposed. The inductance matrix is constructed based on the magnetic equivalent circuits in the two-phase excitation mode. New mathematical formulas of radial force and electromagnetic torque are derived. The operating area of BSRM can be expanded to a great extent. The capability of bearing radial force is enhanced greatly. Computer simulations with magnetic-field analytical-method verify the validity and fine characteristics of the new mathematical model. Two optimizing methods to distribute currents of two-phase windings including main windings and radial force windings for practical applications are also proposed.