Quasi Self-Excited DFIG-Based Wind Energy Conversion System

Abstract

This article introduces a new configuration of the doubly-fed induction generator (DFIG) based wind energy conversion system (WECS) employing only a reduced-size rotor side converter (RSC) in tandem with a supercapacitor. In the proposed structure, the grid side converter (GSC) utilized in conventional DFIG-based WECSs is successfully eliminated. This is accomplished by employing the hydraulic transmission system (HTS) as a continuously variable and shaft decoupling transmission unit. This transforms the conventional constant-ratio drives by providing an opportunity to control the power flow through the generator s rotor circuit regardless of the wind turbine s shaft speed. This feature of HTS can be utilized to control the RSC power and ultimately regulate the supercapacitor voltage without a need for GSC. The proposed system is investigated and simulated in MATLAB Simulink at various wind speeds to validate the results and demonstrate the dynamic performance of the system.