Control and current harmonic filtering for grid connected wind turbine energy systems with double-fed induction generator

This paper presents the modelling and simulating of a general wind power system with double-fed induction generator controlled by a back-to-back converter, in order to manage power delivery to or absorbed from the grid through reactive compensation and active filtering of electrical current. The system modelling and the controller design was developed in Matlab®/Simulink® software, where the rotor-side converter control regulates torque and controls active and reactive power. The grid-side converter control maintains the DC link voltage constant and compensates reactive power demanded from the load, besides this converter acts as an active power filter, which improves the total harmonic distortion of the grid current. The main difference of the proposed methodology with respect to others in the literature is the implementation of grid side converter control as an active power filter using proportional integral resonant to mitigate the 5ª, 7ª, 11ª and 13ª harmonics instead of simple Proportional-Integral (PI) controller, which reduces the accomplishment difficulties since the decoupled term is eliminated. The results obtained shows the correction of the power factor and the extraction of the maximum power from the wind. Finally, it is shown harmonic compensation for nonlinear loads and improvement of the total harmonic distortion of the grid current.