Sensorless control of switched reluctance motors based on high frequency signal injection

Sensorless control at low speed is a challenge for Switched Reluctance Motor (SRM). In this paper, a new high frequency signals injection based method is proposed. Since the stator inductance varies with the rotor position θ for its saliency, the responding current contains the position information. With a band pass filter, the high frequency component of current can be acquired then the rotor position can be calculated through series of coordinate transformations and filters. An important feature is that the method doesn´t need to know the parameters of the motor and is easy for implementation. Besides, it doesn´t require external hardware and hence the reliability is guaranteed while not adding to the system cost. Simulations and experiments are carried out and both steady and dynamic performances of sensorless control using this method are verified.