H∞ robust control design for wind driven doubly-fed induction generator

In this paper a robust control method of a doubly fed induction generator driven by wind turbine (WT-DFIG) is proposed. The rotor of the induction generator is connected to the power grid using two back to back power convertors. Two controllers, rotor side controller and grid side controller, are deployed for proper tracking of power captured by the wind turbine. Traditionally PI controller is used for this application. Due to stochastic nature of the wind and use of variable speed drive systems make the operating condition of the WT-DFIG system to vary over a wide range. Therefore a robust tracking control design could be a better solution to overcome the problem of varying operating conditions and the same time any kind of parametric uncertainly present in the system. A mixed sensitivity based robust controller is synthesized using linear matrix inequality (LMI) technique. Simulations are carried out to validate the robustness and high performance of the designed controller.