Hybrid position sensorless vector control of a reluctance synchronous machine through the entire speed range

In this paper a new hybrid position sensorless control scheme for reluctance synchronous machine drives is introduced. The scheme combines a simplified alternating high frequency injection position sensorless control method with a relatively new fundamental saliency based position sensorless control method. Separate phase locked loops and current controllers are designed and implemented for each method, thus ensuring optimum performance of each method. The synchronisation of the two phase locked loops, combined with a hysteresis changeover threshold, ensures seamless transition between the two estimation methods. Current- and speed control is shown to be possible through the entire speed range at high loads.