Sensorless Direct torque control of PMSM

Abstract

Permanent magnet synchronous motor (PMSM) are widely used nowadays due to high power density and low ripple torque at high speed in comparison to other motors. This Thesis presented modelling and analysis of MRAS based speed sensorless for permanent magnet synchronous model (PMSM) with direct torque control (DTC) scheme. Although additional use of PI controller in the MRAS loop will deteriorate the performance of the motor and it will affect the speed transient, torque ripple, current THD and many other parameters as well. However, the proposed speed estimator gives the satisfactory results under full/no load condition in comparison with the sensored model. Preferably this technique will give better dynamic response, fast torque response and precise speed estimation as discussed in this thesis. Sensorless drives reduce the overall cast of drives which the main advantage of Sensorless DTC. The complete implementation of proposed sensorless DTC is discuss thoroughly in this paper and validated through MATLAB simulation.