Improving Power Quality in Grid-Connected Wind Energy Conversion Systems Using Supercapacitors

Stochastic and periodic power fluctuations generated by phenomena such as turbulence, wind shear, and tower shadow effects in grid-connected wind energy conversion systems (WECSs) can be mitigated by using supercapacitors. An appropriate design method for the sizing of supercapacitors is highly desirable as overdesign results in extra cost and size and underdesign results in inappropriate performance. In this study, a design method for supercapacitors in WECSs that is based on the decomposition of output power frequency components using discrete Fourier transformation (DFT) and that results in an appropriate design is proposed to mitigate power fluctuations in WECSs. The proposed design method is discussed in the paper in detail and is validated with a fixed-speed grid-connected WECS using MATLAB/Simulink software.