Fuzzy-logic control system of a variable-speed variable-pitch wind-turbine and a double-fed induction generator

The utilization of variable-speed variable-pitch wind, or aeolic, turbines jointly with double-fed induction generator (DFIG) is one of several strategies on the aeolic energy capture and the aeolic-electrical energy conversion, according to local power system standards. The aeolic energy captured must be controlled, such as to be maximized for weak winds and to be limited for strong winds to avoid damages and overvoltages in the DFIG. In this work the energy capture control is made applying a fuzzy-logic controller directly on the turbine pitch-angle and the speed control is made by a field-oriented fuzzy-logic controller, that acts on DFIG electromotive torque so that to follow the reference value generated by an optimum angular speed estimator. The simulation results of the whole aeolic-electrical energy conversion system show a stable and smooth dynamic behavior for three different real conditions of wind, even though under strong and turbulent winds.