Ekf- Based Sensorless Direct Torque Control of Permanent Magnet Synchronous Motor: Comparison between Two Different Selection Tables

In this paper a sensorless direct torque control (DTC) scheme of permanent magnet synchronous motor (PMSM) is proposed. To improve the performance of the classical DTC a modified control scheme based on twelve sectors instead of six is presented and a comparison between the two methods is carried out. The high performance of the DTC is related to the accuracy of the flux estimation witch is affected by parameter variation especially the stator resistance due changes in temperature or frequency. Therefore, it is adequate to compensate this parameter variation using an online adaptation of the control scheme by the estimated stator resistance using the Extended Kalman Filter (EKF). The EKF is designed to estimate the rotor speed and stator flux and resistance. Estimated parameters are used for the closed loop speed sensorless control operation of the PMSM. It has been demonstrated that the EKF estimation and sensorless DTC perform quite well in spite of the parameters and load variations that handled by the system. The simulation results are presented to validate the effectiveness of the overall control scheme.