Torque analytical model of switched reluctance motor considering magnetic saturation

Flux saturation of switched reluctance motors (SRMs) and severe non-linear relationship between current, position angles and electromagnetic torque lead to the difficulty of torque modelling and analysis. Specifically, the permeability of ferromagnetic material varies with the magnetic field strength H, and the core saturation effect increases with H. In this study, piecewise curve fitting method is adopted for analysing the relationship between the permeability and the stator winding current. The magnetic equivalent circuit method is adopted to build an analytical model for a SRM where the saturation of ferromagnetic material is expressed in the form of variable permeance. The comparison between computation results of analytical model and finite-element method simulation results verifies the correctness of the proposed model. Simulation and experimental research of a SRM speed control system verify the practicability of the model.