Global wind turbine FTC via T-S fuzzy modelling and control

This paper presents a new approach to active sensor fault-tolerant control (FTC) for offshore wind (OSW) turbine systems operating in the low wind speed region described via Takagi-Sugeno (T-S) multiple models. The FTC strategy is designed in such way that aims to maintaining nominal wind turbine controller without change in both fault and fault-free cases. This is achieved by inserting an observer augmented by a proportional integral feedback to be capable to estimate different generator and rotor speed sensors fault for compensation purposes. Due to the dependency of the FTC strategy on the fault estimation the designed observer has the capability to estimate a wide range of time varying fault signal. Moreover, the robustness of the observer against the difference between the anemometer wind speed measurement and the unmeasurable effective wind speed signal has been taken into account. The corrected measurements fed to a T-S fuzzy dynamic output feedback controller (TSDOFC) designed to track the desired trajectory. The stability proof with H∞ performance and D-stability constraints is formulated as a Linear Matrix Inequality (LMI) problem. The strategy is illustrated using a non-linear wind turbine benchmark system model offered within a competition led by the companies Mathworks and KK-Electronic.