Grid and rotor sides of doubly-fed induction generator-based wind energy conversion system using sliding mode control approach

Abstract

This thesis deals with the analysis, modeling, and control of a Doubly-Fed Induction machine used as a wind turbine generator. A sliding mode control scheme is applied to control the power and Dc-link voltage. Two back-to-back converters are used at rotor and stator sides. At the rotor side, power control is achieved by controlling the rotor current, while at the grid side, an active power transfer is used to model the dc-link voltage. Overall robustness and tracking performance are enhanced to deal with uncertainties due to the structure of the sliding mode control law, compensation combinations, sliding and integral terms. An experimental 2-kw DFIG wind turbine system was used to validate the proposed control system. Based on the results obtained, the proposed system showed good capabilities in tracking and control under various operating conditions as well as robustness to uncertainties.