Robust sliding mode observer/controller of wind energy conversion system based on DFIG

We develop in this paper a sliding mode control of the stator powers of the doubly fed induction generator (DFIG), which is used within a wind energy conversion system (WECS). The elements of the state vector, used for control, are assumed available via measurements except the components of the rotor flux, which are estimated by a sliding mode observer. No rotor current sensor is required. The controller and the observer are involved from the DFIG nonlinear and coupled model. The global stability of the sliding mode observer/controller (SMOC) is treated. Our approach is tested in the case of 1.5 MW WECS rating based on DFIG. The stator active power reference is given to extract the maximum of the wind power available. The stator reactive power reference is given to impose the reactive power at the point of the common coupling (PCC). The robustness and the performances analysis were done for the case of an unbalanced grid, within the presence of disturbance and parameter variations. The proposed method keeps the steady-state harmonic spectra at the same level as the vector control (VC) strategy. The satisfying obtained results have allowed validating the proposed method.