Modifying the control design of DFIG-based wind turbines in order to inhibit power system oscillations

Providing additional damping for system electromechanical oscillations through doubly fed induction generator (DFIG)-based wind turbines is investigated in this study. In this regard, first an objective function is developed to tune the DFIG control gains, aim to maximise the wind farm (WF) contribution to system oscillation damping, but it is shown that it causes a decrease in the damping of DFIG stator mode. In other words, with the current DFIG control design, it is not possible to improve both the small signal stability of the power system and the dynamic stability of WF together. Afterwards, two high-pass filters are suggested to be employed in the control design of DFIG. It is shown that with the modified control design, it is possible to improve the system oscillation without spoiling the dynamic stability of the WF itself. Eigenvalue analysis is performed to validate the effectiveness of the modified control design.