ESTIMATION OF ROTOR POSITION AND SPEED OF A SYNCHRONOUS RELUCTANCE MOTOR FOR SERVODRIVES

The main advantage of synchronous reluctance motors is their structura l ruggedness. To retain this advantage in a drive system using such a motor, no position sensor should be used. Instead, it is advantageous to use a software estimator. An effective algorithm is proposed for po sition and speed estimation based on the motor terminal voltages and c urrents. In a VSI-fed drive system, the terminal voltages are determin ed by the DC-link voltage and the switching pattern. Therefore only cu rrent sensors are needed. In the proposed method, the position and spe ed are estimated independently, and the estimation depends only on the measured currents without dependency on any estimated variable. No it eration is involved in the estimation process. Digital simulation demo nstrates that the proposed method is suitable for both transient and s teady-state operation of the drive system, with any initial position.