Disturbance observer-based Takagi-Sugeno fuzzy control of a delay fractional-order hydraulic turbine governing system with elastic water hammer via frequency distributed model

Abstract

The hydraulic turbine governing system (HTGS) is a core part of a hydropower station, and the dynamic characteristics of its transition process and stability under disturbances have been strong concerns for the stable operations of units. In this paper, a disturbance observer-based Takagi-Sugeno (T-S) fuzzy control (DOBFC) method using the frequency distributed model (FDM) is proposed to improve the anti-interference control performance of a delay fractional-order HTGS. First, a more practical mathematical model of a fractional-order HTGS considering both the mechanical time delay and an elastic water hammer is established, and then its fuzzy model is presented on the basis of the generalized T-S fuzzy rules. Second, the disturbance observer is constructed by utilizing the system state and disturbance information, and the output estimated value of the observer is input into the designed fuzzy state feedback controller to compensate for the effect of external disturbances on the system and achieve disturbance suppression. Third, by means of a new FDM transformation and the construction of a novel Lyapunov function, the stability condition and the parameter solving method of the controller are derived using the linear matrix inequality (LMI) technique. Finally, simulation results are given to verify the effectiveness of the proposed algorithm.