On improved active disturbance rejection controller design for a pumped storage hydro unit

The pumped storage hydro unit (PSHU) shows bad dynamic performance because of the frequent switching of working conditions and the S-shaped characteristics of pump turbine. This paper proposes an improved fixed-time active disturbance rejection controller to improve the control performances and counteract the influences of uncertainties including modeling error and friction. A disturbance observer is designed to estimate the total uncertainty by using the information of the states and outputs, compensating the adverse effects of the total uncertainty actively by feed-forward principle as a result. The outstanding benefit of the disturbance observer lies in that it can be designed separately from the original controller and can enhance the performances of the PSHU without changing the original controller. Simulation results show that comparing with the conventional active disturbance rejection controller, the improved active disturbance rejection controller has better adaptability and higher robustness towards the system load disturbance, and the dynamic performance of the system is improved.