More Efficient Wind Energy Conversion System Using Shunt Active Power Filter

Wind energy takes first place in many countries among other renewable energy. However, the power quality problems such as nonlinear and unbalanced loads, unbalanced grid, can increase the mechanical vibrations as well as the risk of overheating in Wind Energy Conversion System (WECS). Therefore, the objective of this work is the use of robust flying capacitor converter in order to enhance the WECS efficiency by minimizing mechanical vibrations and reducing thermal stress with minimum voltage stress of power switches. To this end, this paper proposes a WECS based on doubly fed induction generator (DFIG) with the stator connected directly to non-ideal power grid, grid side converter (GSC) with flying capacitor topology and robust input output linearization control used to regulate the dc side capacitor voltage and also compensate the current harmonics in power grid in order to avoid excessive heating and mechanical vibrations in WECS. Simulation using MATLAB demonstrate that the proposed approach improves the power quality by reducing the total harmonic distortion (THD) of grid current to a value which satisfies the limits of IEEE standard, and allows the 8 KW DFIG to operate with reduced mechanical vibration and minimum heating stress in addition to the generation of power.