An improved fractional-order nonlinear active disturbance rejection speed control (FO-NADRC) method is proposed for hydraulic turbine regulating systems (HTRSs) with a mechanical delay. First, the mathematical model of an HTRS with a mechanical time delay is established. Based on the principle of coordinate transformation, the state space equation of an HTRS with a time delay is transformed into the controllable normative mathematical model. Second, a new nonlinear function is proposed for the extended state observer (ESO) that improves the observation accuracy and suppresses the high-frequency oscillation of the HTRS. Third, a new fractional-order state error feedback law (FO-SEFL) is proposed by introducing double adjustable parameters. Fourth, according to the improved ESO and the FO-SEFL, a novel FO-NADRC is designed for the HTRS. Furthermore, the Popov-Lyapunov robust stability analysis method is used to analyze the stability of the hydraulic turbine regulating control systems with mechanical delay. Finally, numerical simulation experiments demonstrate the effectiveness and superiority of the proposed control scheme.
This study presents fuzzy decoupling predictive functional control for nonlinear hydro-turbine governing systems with time delay and strong coupling. Here, the Takagi–Sugeno fuzzy approach and fuzzy neural network decoupling algorithm are implemented in the pretreatment of a four-dimensional time delay hydro-turbine governing system model, aiming to solve the nonlinearity and separate coupling variables of the hydro-turbine governing system effectively. Then, a new fuzzy decoupling predictive functional control strategy proposed by combining the simplified hydro-turbine governing system model and predictive function control as well as the robustness and stability of the designed controller are verified by theoretical derivation. Numerical experiment demonstrates effectiveness and superiority of the proposed approach in comparison with fuzzy control under different operation conditions.
In this study, the stability analysis and controller design of a hydropower unit's governing system (HUGS) were studied based on a Takagi-Sugeno (T-S) fuzzy model and constant sampled-data control. First, according to the T-S fuzzy theory, the non-linear Francis hydro-turbine governing system under rigid water hammer is linearised and then the approximate linear system was obtained. Second, a fuzzy sampled-data controller was designed in the case of periodic sampling, and the closed-loop sampling system was discretised. After constructing the Lyapunov function and using the forward difference method, the stabilisation condition was given with less conservatism in a symmetrical linear matrix inequality form. Finally, the numerical simulation results showed that under four different sampling periods, the HUGS can quickly achieve stability and that it has different stability performance. In addition, the superiority of the controller was verified in comparison with traditional proportional-integral-derivative control and fuzzy control techniques.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.