Modeling of mutually coupled switched reluctance motors for torque ripple minimization

Abstract

A model of Mutually Coupled Switched Reluctance Machine (MCSRM) which includes the effect of multiple phase current excitations using a single lookup table is developed. The model can predict the MCSRM flux linkage and electromagnetic torque. The current waveform for low torque ripple is determined with the help of this model. The optimum current waveforms vary with the torque and speed levels. This increases the memory requirement of the control system. A memory efficient method for determining the optimum current waveform responsible for low torque ripple is proposed in this paper. With the proposed method Fourier series coefficients of the current shapes at some specific operating points are determined. Parameters for other operating points are determined through bi-cubic spline interpolation. The proposed modeling and torque ripple minimization approach is studied for a 30 kW MCSRM design. Finite Element Analysis (FEA) coupled with circuit simulations are presented along with Matlab/Simulink simulations for verification of the proposed modeling and ripple minimization methods.