Position Estimation at Starting and Lower Speed in Three-Phase Switched Reluctance Machines Using Pulse Injection and Two Thresholds

The paper presents a method of accurate indirect position estimation for switched reluctance machines suitable for starting and continuous operation. The position estimation and control of the SRM is accomplished in terms of a few sectors within an electrical cycle. The sector of machine operation is obtained by comparing the injected current amplitude in an idle phase with two thresholds. Each sector is unique and identifies which phase has to be used for sensing and which phase has to be used for powering the SRM. A normalized inductance profile identified from the injected currents helps to develop an algorithm for the application of this method from low power to very high power machines with accurate and reliable estimation and control.