A New Current Control Strategy of Maximizing the Generated Power from a Doubly Fed Induction Generator System

This paper focuses on the development of maximum wind power extraction strategies for variable speed constant frequency (VSCF) grid-connected wind power generation systems with a doubly fed induction generator (DFIG). A new control method is proposed by directly controlling the DFIG rotor current to follow an optimal condition for not only the extracted maximum power of the wind turbine below the base wind speed but also the copper loss minimization. Based on the wind turbine power characteristic and DFIG mathematical models, the relationships between the generator speed and d-q axis rotor current are derived respectively, for maximal mechanical power extraction and copper loss-minimization. Directly control rotor current scheme is simpler than the conventional vector control strategy. Simulation results have shown the proposed control strategy is correct and valid