A pulse injection based sensorless position estimation method for a switched reluctance machine over a wide speed range

In this paper, a pulse injection based method for determining the rotor position of a switched reluctance motor (SRM) over its entire speed range is presented. A single high-frequency pulse is injected in an idle phase and the rotor position is estimated through analysis of the resultant current after the voltage pulse injection. Low speed sensorless method developed previously based on pulse injection has also been extended to improve robustness against varying operating conditions. The developed variable pulse injection duty ratio provided uniform sensing thresholds over varying DC bus voltages. The low speed and high speed methods can be integrated together to provide a robust wide speed range rotor position estimator for SRM.