By Pradya Prempraneerach, Wirachai Roynarin and Terdkiat Limpeteeprakarn
In the presence of wind turbulence and temperature variation, electrical power produced by wind turbine is very difficult to predict in advance. The uncertainty of captured energy from wind speed fluctuation is investigated to estimate the probability of electrical energy, supplying to the grid. Therefore, this paper presents the stochastic modeling of wind loads and modeling of wind turbine using a permanent magnet generator along with pitch-angle and speed controls. Stochastic wind velocity can be simulated as a gaussian random process according to a specified power spectral density. The model of wind turbine consists of the permanent magnet generator represented in the dq-synchronous rotating reference frame, drive train, variable speed control using a simplified vector control technique, and pitch-angle control. With this control structure, the wind turbine can operate near its optimum tip-speed ratio. The complexity of the proposed wind turbine model, constructed using Matlab/Simulink, is kept to a minimum such that the captured and generated power can be considered from a statistical perspective within a short simulation time.