Modeling and direct power control of DFIG for wind energy conversion system with a back to back converter

The variable-speed wind turbines are gaining more prominence due to their ability to generate power for a wide range of wind speeds. This class of turbines requires a fraction of the power be drawn from the grid in order to deliver the promised power when there is a deficiency in wind speed. For this purpose, a Doubly-Fed Induction Generator (DFIG) with a bidirectional converter (AC-DC-AC) on the rotor side is employed. The back-to-back converter controls the flow of energy from the machine to the grid and vice-versa. The Direct Power Control algorithm is used to control the power delivered by the stator to the grid. In this paper, the Space Vector Modulation (SVM) technique using the PI-controllers is used for controlling active and reactive powers. The SVM algorithm triggers the power electronic devices of the converter resulting in improved input current waveform. The paper discusses the simulation results of 1.5 MW DFIG machine connected to the grid via back-to-back converter.