Optimal robust first-order frequency controller design for DFIG-based wind farm utilising 16-plant theorem

With increasing the share of wind farms in generation profile, their contribution to frequency regulation has become crucial. This study presents an optimal robust first-order frequency controller in the wind farms, which collectively emulates the inertial response as well as governor droop of synchronous generators. To account for various uncertainties associated with system inertia, damping, and doubly-fed induction generator (DFIG)-based wind turbine's parameters, the robustness of controller is verified through the 16-plant theorem. An analytic method based on the small-signal model of the system is utilised to determine the stability region of the first-order controller. To evaluate the performance of the proposed controller, a DFIG-based wind farm equipped with this controller is added to IEEE 39-bus test system which is updated with wind farms in MATLAB/Simulink environment, and the response of proposed controller is investigated under different conditions. Simulation results verify the robustness as well as the effectiveness of the proposed controller in system frequency regulation.