An Improved Control Strategy for DFIG fed Wind Turbine against Symmetrical Voltage Dip

Abstract

A Doubly Fed Induction Generator (DFIG) based wind energy conversion system is vulnerable to voltage disturbances as the stator winding's direct connection to the grid. An effective approach against the balanced voltage dip presented in this paper. During voltage fluctuation, there arise over current and over voltage in the rotor circuit and the capacitor link of a DFIG. Therefore, a strategy is proposed that combines the use of a DC Chopper circuit and a robust stator current feedback control strategy that considers Low-Voltage Ride Through (LVRT) capability. The aim is to control the dc-link voltage fluctuation for smooth power transfer. To attain controlled performance, the references of the DC capacitor link regulated to adapt the wind energy conversion system to the fault conditions. Moreover, Grid Side Converter (GSC) controlled with unit template based an indirect vector control method to maintain the DC link voltage. Simulation studies performed by Matlab/Simulink are presented.