Position controlled synchronous reluctance motor without rotational transducer

This paper presents a position sensorless control scheme of synchronous reluctance motor combining a high frequency current injection in a low speed region and the flux estimation based on the stator voltages in a high speed region. The rotor has inherent saliency and its angle is estimated from d-axis stator current injection and the appropriate signal demodulation in a low speed region. In a high speed region, the rotor angle is estimated by the stator flux from the voltage information. This scheme gives a robust and dynamic estimation of the rotor angle independent of the operating conditions including speed and load conditions. Experimental results of closed loop speed and position control with a 3.75 kW axially laminated synchronous reluctance motor are given to verify the proposed scheme.