Position Sensorless Control of Switched Reluctance Motors Using Reference and Virtual Flux Linkage With One-Phase Current Sensor in Medium and High Speed

This paper presents a novel position sensorless control for 6/4 switched reluctance motors (SRMs) using only one-phase current sensor in medium and high speed. In order to eliminate phase voltage sensors, a virtual phase voltage is established to replace the real-time phase voltage in the whole conduction cycle, so as to calculate the phase flux linkage which is called virtual flux linkage. A nonlinear model is utilized to estimate the reference flux linkage-curve of any rotor position. With only one-phase current sensor, the determination of turn off angle position and phase commutation position is achieved by the comparison of reference flux linkage and virtual flux linkage. The speed estimation is performed by two reference flux linkage-current curves at particular rotor positions. Based on the obtained turn off pulse of the present phase and the turn on pulse of next phase, the remaining trigger pulse signals of three phases are derived from a delay-time strategy. The proposed scheme requires only one-phase current sensor, without any pulse injection or complicated decoupling algorithm, achieving a simple and cost-effective drive. Simulations and experiments are carried out on a 6/4-pole prototype SRM drive system to verify the correctness and effectiveness of the proposed sensorless control scheme.