A New Incremental Inductance Based Position Estimation Method for SRM with Sliding Mode Observer

This paper proposes a sensorless control scheme for low speed switched reluctance motor (SRM) based on high frequency pulse injection method. The current slope difference method is used to calculate the incremental inductance of idle phase, and the inductance error can be obtained by comparing with the observed inductance, which is used as the input of sliding mode observer (SMO) to realize the position estimation of the whole period. To verify the effectiveness of the proposed method, experiments were carried out on a three-phase 12/8 structure SRM prototype. The experimental results show that the position observation can be realized when the speed changes and the torque changes. Under the condition that the calculation error of incremental inductance is large, the observer can still realize the estimation of position, and has strong robustness.