Wide-speed range control strategy for a 8/6 switched reluctance machine

A control scheme for obtaining low torque ripple and high efficiency for a minimal reduction in average torque as compared to its maximal value is presented for a four-phase switched reluctance motor. At low speed, the torque ripple is minimized by the means of current profiling techniques. As the speed increases the controller switches to optimal firing angle control strategy. The optimal values for the angles are obtained based on minimization routine for different objective functions. Starting from the one variable functions (average torque) step by step, penalties are added for improving the ripple content and eventually the efficiency. The effects of using local and global minimizers are outlined and comparative results are given. Experimental results obtained on a 0.75kW SRM are provided and discussed.