Robust sliding mode control for hydraulic generator regulated system with uncertainty: A comparative study

Hydropower is a clean energy resource, produced by complex, non-linear and time-variant hydraulic-generator regulated system (HGRS). This system is designed with several hydraulic, electrical and mechanical dynamics. Therefore, constructing a proper control technique for such an intricate system is still a challenging problem. Turbine governor works as a controller, whereas, the hydro-generating unit is considered as a controlled device. In this paper, five robust control strategies such as PID-SMC (sliding mode control), Feedback linearization based SMC, Fast Terminal SMC, PID and Fractional order SMC are proposed for speed control of non-linear and uncertain HGRS. Lyapunov's direct analysis reveals the convergence of tracking error with all the proposed methods. Among these, the PID-SMC method also eliminates chattering in HGRS control signal. It allows faster tracking of the desired speed with acceptable overshoots, in the presence of system parametric variations or external disturbances. Comparative analysis with the simulation studies is also carried out for HGRS system with the proposed control schemes.