A Position Sensorless Torque Control Strategy for Switched Reluctance Machines with Fewer Current Sensors

To decrease the cost, enhance the torque performance, and improve the system reliability, this article puts forward a novel position sensorless torque control strategy for switched reluctance machines (SRMs) with fewer current sensors. In this article, a developed direct torque control (DTC) strategy is proposed for the torque ripple mitigation, where a hybrid chopping mode is employed and the torque is online compensated according to the torque error. A developed current-sensing scheme with fewer current sensors is presented. The phase current in a whole period can be easily detected for both the torque control and sensorless control. The position sensor is removed from the proposed drive. The real-time rotor position of each phase can be obtained by implementing a flux linkage-current-based method. According to the current and position, the instantaneous phase torque and torque sharing function can be determined for the DTC. Therefore, system reliability can be significantly improved due to the simplified sensor part. With the proposed scheme, a compact, high-reliable, and high-performance SRM drive can be achieved. A three-phase 12/8 SRM prototype is employed for the experiment to verify the feasibility of the proposed system.