Design and performance analysis of sliding-mode observers for sensorless operation of switched reluctance motors

This paper presents an analytical and experimental evaluation of the sliding-mode observer (SMO) for eliminating position and speed sensors in switched reluctance motor (SRM) drives. Design guidelines are derived for the SMO to guarantee an upper bound on the observer error for all time. An analysis is presented to demonstrate that the SMO also possesses an automatic adaptation property with respect to the intensity of the measurement noise. The SMO approach is shown, in simulations and in experiments, to provide accurate position and speed estimates under various operating conditions. The resolution and reliability of the scheme are shown to be superior to those obtained using standard state observers. The results demonstrate the applicability of the SMO-based sensorless controllers for SRM drives.