Robust fixed-time sliding mode control for fractional-order nonlinear hydro-turbine governing system. (August 2019)

• Record Type: Journal Article
• Authors: Huang, Sunhua; Zhou, Bin; Bu, Siqi; Li, Canbing; Zhang, Cong; Wang, Huaizhi; Wang, Tao
• Is Part Of: Renewable energy. Volume 139(2019)
• Page Start: 447
• Page End: 458
• Publication Date: 2019-08
• Subjects: Hydraulic energy -- Hydro turbine -- Fractional-order modelling -- Fixed-time stability -- Renewable energy; Renewable energy sources -- Periodicals; Power resources -- Periodicals; Énergies renouvelables -- Périodiques; Ressources énergétiques -- Périodiques; 333.794
• DOI: 10.1016/j.renene.2019.02.095
• Languages: English
• ISSNs: 0960-1481

Abstract

Abstract: This paper proposes a nonlinear sliding mode controller for effective fixed-time stabilization of a hydro-turbine governing system (HTGS). The HTGS is a highly nonlinear, multi-variable coupled and non-minimum phase system to maintain frequency stability by regulating the generation output in response to load variations. The state trajectories of HTGS under random load disturbances exhibit unstable behaviours on the rotor angle, rotor speed, and guide vane opening, which would affect the stable operation of hydroelectric stations. In the proposed approach, the fractional calculus technique is adopted to model the nonlinear dynamics of fractional-order hydro-turbine governing system (FOHTGS). In order to validate the system stabilization and convergence within a bounded time, a robust sliding mode controller is proposed to force the FOHTGS to reach the equilibrium point based on the fixed-time stability and Lyapunov stability theories. The proposed controller can guarantee the superior stabilization of FOHTGS with the bounded and quantifiable convergence time, and thus overcome the drawback of finite-time controllers whose convergence characteristics are heavily dependent on the initial conditions. Finally, numerical simulations have been implemented to confirm the effectiveness and superior performance of the fixed-time controller compared with the existing finite-time control methods. Highlights: A fixed-time sliding mode controller is proposed for stabilization and suppression of FOHTGS. The nonlinear behaviours of FOHTGS are investigated by numerical simulations. The Proof is presented for the fixed-time stability of FOHTGS with the proposed control scheme. The system convergence time can be exactly estimated and is independent of initial conditions.