A new modelling approach for switched reluctance motors

This paper presents a new modelling approach for the nonlinear flux-linkage/current characteristics of the switched reluctance motors at different rotor positions. In this modelling approach, the experimentally obtained flux-linkage characteristics are divided into two regions such as the unsaturated and the saturated region so that each one of them can be represented by a simple analytical expression. Numerical curve fitting technique has shown that the flux-linkage values in each of these regions can be defined by a polynomial equation in phase current. Effort has been made to minimize the powers of the polynomial equations. The coefficients of the polynomial equations vary at different rotor positions and are expressed by a Fourier cosine series. The Fourier cosine series is restricted only up to the second harmonic component and here lies the uniqueness of this modelling approach. The modelling has been verified by the simulation and the experimental results of the instantaneous current waveforms and the average torque values in both single pulse and multiple pulse operation of the motor.