Fuzzy logic systems for pitch angle controller for smoothing wind power fluctuations during below rated wind incidents

Wind energy has been receiving more acceptance as a reproducible, resourceful and clean energy source since last decade. Wind power is not constant and can fluctuate below the rated wind power when the wind speeds are lower than the rated wind speed. This fact affects the grid the wind generators are connected to, which is becoming more significant with the increasing penetration of wind energy systems. Pitch angle control has been one of the most common methods for smoothing output power fluctuations during below rated wind incidents. In this paper, two methods of fuzzy logic system have been proposed for the pitch angle controller: the determination of the command output power based on Exponential Moving Average (EMA) with a proper selection of correction factor by fuzzy reasoning and the dynamic selections of target output power according to the current wind incident. Simulation results show the effectiveness of the proposed methods in smoothing wind power fluctuations with significantly small drop of output power.