Adaptive Optimal Control of Wave Energy Converters

Abstract

This paper proposes a hierarchical adaptive optimal control framework for wave energy converters (WECs) to improve their energy conversion efficiency and reduce the required modeling effort to facilitate the control design. Since the WEC dynamics vary significantly at various operation scenarios with different sea states, an efficient adaptive parameter estimation (APE) algorithm is employed to online update several critical WEC model parameters (e.g. the radiation force and excitation force generation coefficients). Based on the updated model, the predesigned non-causal optimal controller can maintain its efficacy. Thus the proposed method combines the strength of optimal control for generating maximum energy output and APE in coping with model parameter variations. Simulation results demonstrate that the proposed optimal control with APE can cope with the model mismatch and variations effectively.