A novel sensorless direct torque control for a doubly fed induction machine

This paper proposes an effective sensorless direct torque control technique (DTC) for a three phase doubly fed induction machine (DFIM) operating in motor mode. A robust approach for sensorless speed estimation based on MRAS observer is presented. At first, the paper presents a detailed description of theoretical basis of the proposed DTC formulation. Then the digital implementation is described. Drive performance is validated by simulation using Matlab/Simulink software and experimentally using a fast control prototyping dSpace1104 board. Results show the feasibility of the proposed technique, obtaining better drive performance over the desired speed range, while overcoming classic DTC drawbacks by a full digital implementation.