A Critical Study of Pitch Control Techniques used for Horizontal Axis Wind Turbines

In recent times wind energy has emerged as a sustainable source of renewable energy and a substitute to the continuously depleting fossil fuels. Worldwide many countries are promoting the industries involved in harnessing wind energy for electricity production. This expansion in the integration of Wind turbine (WTs) in the power generation system has increased from few kilowatts to many Megawatts. Today wind energy is preferred sources of renewable energy and compels the researchers around the globe to technologically improve its control system designs. The various control methods of wind turbine are proposed for under rated speed regions as well as for above rated wind speed regions, this paper primarily focuses on later part and creates a detailed background of developments in a diverse region of pitch control methodologies combined pitch control or individual pitch control methods involving conventional PI/PID controllers, gain scheduling methods, Sliding mode controllers (SMC), Expert systems like Fuzzy logic controller (FLC), Neural networks (ANN), adaptive control methods and their hybrids to serve as an initial point for new researchers starting to explore in this domain.