Mathematical model of single-winding bearingless switched reluctance motor considering two-phase coupling

In order to avoid the limitation of the mathematical model of single-winding bearingless switched reluctance motor (SWBSRM) in the single-phase excitation mode, a new model considering two-phase coupling is proposed in this paper which is suitable for both single- and two-phase excitation. Firstly, the inductance matrix is developed based on the magnetic equivalent circuit considering two-phase coupling. Then, the radial force and torque are derived using virtual-work method based on the stored magnetic energy which is calculated from the inductance matrix. In addition, the developed models of the radial force and torque are verified by the finite element method (FEM). Any current combination is available for the single-phase excitation mode based on the proposed model which eases the design of control strategy in the single-phase excitation mode. Furthermore, the proposed mathematical model can facilitate the development of further advanced control strategy for SWBSRMs.