Fault Tolerant Control of Variable-Speed Variable-Pitch Wind Turbines: a Subspace Predictive Control Approach

Grid integration of wind power, especially using offshore wind farms, is dramatically increasing all over the world. Consequently, the reliability and robustness of wind turbines against faults are becoming important issues these days. In this paper, a new wind turbine Fault Tolerant Control (FTC) strategy based on adaptive Subspace Predictive Control (SPC) is proposed. The proposed strategy uses a model predictive control algorithm with its predictor matrices continuously updated using recursive subspace identification techniques. In contrast with SPC algorithms previously proposed in the literature, the proposed strategy includes integral action, and consequently, offers better disturbance rejection and better performance. The effectiveness of the proposed strategy is illustrated using detailed simulations of a 1.5 MW variable-speed variable-pitch wind turbine model with a fault in the hydraulic pitch system.