PMSM sensorless control using back-EMF based position and speed estimation method

The vector control techniques in AC drives demands exact position and speed feedback information for the current and speed control. This paper presents a position and speed estimation method based on the measurement of phase currents and voltages and a pre-knowledge of the machine model. The object is to elaborate a precise estimator in accordance with some specifications, especially the ability to cancel position error. On the other hand, the method provides satisfactory efficiency when used in sensorless control.