A Simulation Study on Sensorless Control of Permanent Magnet Synchronous Motor Drives

This paper presents simple methods for controlling permanent-magnet synchronous motors (PMSM) over a wide speed range without using a shaft position and speed sensor. In classical estimation methods the voltage and current vectors are the input to the estimator, while the rotor position and speed are the output of the estimator. To avoid the drawback of differential and integral operations in conventional sensorless PMSM drives a recursive approach for estimation of the rotor speed and angle is proposed and investigated. The position and speed estimations are based on the back electromotive force (BEMF) method in the alphabeta-stator reference frame. Two estimation strategies, one using the steady-state equations and the other using the dynamic equations, are compared. Extensive simulation results are given and discussed.