INDIRECT CURRENT CONTROLLED DOUBLY-FED INDUCTION GENERATOR FOR WIND ENERGY APPLICATIONS

Abstract

This thesis deals with the analysis, modeling, and current control of the doubly-fed induction generator (DFIG) for wind turbines. This report presents a new technique to control the stator voltage and frequency by controlling the rotor current in quadrature frame synchronized at rotor frequency. Another technique has been explored for extracting the maximum power from the generator. A single unit of wind energy system under investigation was doubly-fed induction generator (DFIG) controlled through two voltage source converters (VSCs) one in the rotor circuit dealing with slip power and the other on grid to control the flow of reactive power and for maintaining the THD of the generator currents under control. Grid side converter also responsible to regulate the dc bus voltage this controls the real power exchange only, whereas, rotor-side converter keep an eye over the stator voltage and frequency. The rotor circuit converters are operated to the extract the maximum power from the wind...