Observer-based adaptive torque-ripple minimization in switched reluctance machines using backstepping

The paper addresses torque ripple reduction in current-fed switched reluctance motors (SRMs). Ripple-free torque production in SRMs requires an accurate model that is often too complex for practical implementation. The algorithm proposed here combines the use of a simplified model with adaptation. Explicitly, it includes dynamic estimation of low harmonics of the combined unknown load torque and the ripple in the produced torque (due to model simplification), and adds appropriate terms to the commanded current to cancel these harmonics. The control is based only on the position signal and the speed related information is obtained by an observer. Simulations suggest that our method is indeed effective for constant speed reference commands. Finally, experimental results are included to demonstrate that the algorithm performs well in reducing the torque ripple.