Reduced-order Kaiman filter based sensorless control of permanent magnet synchronous motor

This paper is concerned with design of a speed and position estimator of a permanent magnet synchronous motor (PMSM) controlled by direct torque control (DTC). The designed estimator is based on a reduced-order Kalman filter. The reduced-order Kalman filter is computationally less demanding in comparison with a full model Kalman filter, therefore it is suitable for use in the direct torque control where a short sampling period is needed for its proper function. The designed estimator is implemented in the DTC control algorithms with sampling period of 50 μs. The proper function of the proposed sensorless speed and position estimator was verified by simulations and by experiments in selected transient states on a small scale laboratory drive with rated power of 250 W.