Model-Free Control for Tidal Current Turbine Generation Systems: A Comparative Study.

During recent years, tidal current turbine systems have been exploited as a promising technology of generating electricity from the sea tides. Traditional PI control may suffer from unpredictable distances or parameter uncertainties. More advanced control strategies such as sliding mode control (SM), active disturbance rejection control (ADRC), and model-free control (MFC) should be applied for improving the system performance. The objective of this work is to carry out a comparative study for the four control strategies. The control structure and the characteristics will be presented for each control strategy, and then controllers based on different strategies are applied in the turbine-generator speed loop to verify the generation system performance under water flow speed changes and turbine torque disturbances. From the simulation comparisons, the ADRC control and MFC based intelligent proportional (iP) controller showed better performance in terms of tracking speed and smooth response under various conditions.