The connection of a wind generator to an electrical grid depends essentially on its ability to respond to changes in wind speed and the quality of the energy produced. This paper presents an analysis of the control techniques of a wind energy conversion system (WECS) based on a doubly-fed induction generator (DFIG). To do this, and in order to realize independent control of the statoric active and reactive powers of the DFIG, a control law is synthesized using three controllers: proportional-integral (PI), polynomial RST and sliding mode controller (SMC). Their performances in terms of power reference tracking, robustness to the parametric variations of the generator, sensitivity to perturbations and reaction to speed variations are compared and evaluated by simulation results.

Keywords: Wind energy, Doubly-fed induction generator (DFIG), Vector control, Power control, Proportional-integral (PI) controller, RST controller, Sliding mode controller (SMC)