The rotor speed and position sensorless control of SRM using the binary observer

The speed and position control of a SRM (switched reluctance motor) needs the encoder or resolver to obtain the rotor position information. Speed sensors occasionally malfunction under hostile environments such as EMI, dust, and high temperature and humidity. Therefore the speed and position sensorless control has been studied widely. In this paper, the binary observer is suggested to control the SRM without the rotor speed and position sensors. The proposed observer consists of two feedback compensation loops. One directly reduces the estimation error like the sliding mode observer, and the other indirectly removes the estimation error chattering occurring in the sliding mode observer. The proposed observer is constructed based on the variable structure control theory and has inertial terms to exclude chattering. The proposed observer increases the estimation performance without the chattering of the estimation error in the rotor speed and position and the robustness for parameter variations and disturbances. The proposed methods are proved by experiments.