Design of fuzzy sliding mode controller for hydraulic turbine regulating system via input state feedback linearization method

• A novel nonlinear hydraulic turbine regulating system (HTRS) model is studied.
• The HTRS model considers unknown bounded uncertainties and external disturbances.
• The input state feedback linearization method is used to construct the relationships.
• Fuzzy sliding mode controller is applied to adjust the orbit output of HTRS system.
• Simulation results demonstrate the robustness of the proposed controller strategy.

The HTRS (hydraulic turbine regulating system) plays an important role in hydropower electricity generating and safe operation of water turbine. In this paper, a novel approach to the LFC (load frequency control) is presented for the HTRS system. This approach combines sliding mode control with fuzzy logic control, where the robustness of the controller is guaranteed by a predefined sliding surface and chattering phenomenon is alleviated by the fuzzy logics. The dynamic model of a hydropower plant is developed with the consideration of inner perturbations and external noises of this system. Based on input state feedback linearization method, the relationship between reference output and control output is established. Simulations of an example HTRS system respect to the dynamical behaviors analysis without controller, fixed point stabilization, periodic orbit tracking and robustness test against random noises have been carried out by using the optimal PID (proportional–integral–derivative) controller, conventional SMC (sliding mode controller) and proposed FSMC (fuzzy sliding mode controller) for evaluating the validity and effectiveness of different controllers. The results indicated that the proposed FSMC controller was excellent from the standpoint of system performance and stability for LFC control of the nonlinear HTRS system with uncertainties.