Comparison of two position and speed estimation techniques used in PMSM sensorless vector control

The paper describes the comparison between two different high-performance techniques used for the sensorless estimation of the motor shaft position in Permanent Magnet Synchronous Motor Sensorless Drives. Rotor position and speed are estimated from measured terminal voltages and currents, and are used as feedback in a sensorless vector control scheme, achieving almost the same high-performance of a sensored drive. The paper point out the differences, by using experimental implementation, between an open-loop flux estimator based on the electrical model of the machine, and a reduced flux observer.