Integrated control strategy for DFIG wind turbine power regulation

The conventional control method used for wind turbine, PI control, is still the most common method adopted by industry. This requires several cascaded control loops decoupled and tuned carefully in order to make the control system stable and independent to each other. This may restrict the bandwidth of each controller. Using an advanced control strategy as an alternative has been studied for years. In this field, sliding mode control attracts high attention due to its advantages of fast convergence and robustness to the system´s uncertainties. This paper integrates a sliding mode control method together with PI control on a doubly-fed induction generator wind turbine system, which has been developed in PSCAD/EMTDC. Equipped with a pitch controller, this model can achieve both targets of power maximization at low speed and power limitation at higher speeds. The proposed strategy improves the system response with little effort of increasing the structure complexity.