Speed-Sensorless DFIG Wind Drive Based on DTC Using Sliding Mode Rotor Flux Observer

In this paper, we present a grid-connected wind turbine equipped with double-fed induction generator directly connected to the grid in the stator side and interconnected via a power converter in the rotor side. The aim of this paper is to control the rotor side power converter via a speed sensorless direct torque control using a rotor flux observer based on the sliding mode method combined with the classical Lyapunov stability theory. The speed sensorless direct torque control seeks to provide a tracking of speed and rotor flux in spite of an unpredictable wind fluctuation. To control the grid side converter, a network voltage vector oriented control strategy is developed. The proposed strategies tested under parametric variations and different scenarios of wind speed disturbances, evaluate the system performances. Simulation results show that the wind variation has influence on the location of system operation mode. The introduction of the SMRFO allows a high fidelity, a good dynamic performance, an easier rotor flux regulation and a robustness against parameter variations.