Wave Energy Converters and Hydraulic Power Take-off: analysis of a possible control strategy

Abstract

Wave energy conversion is one of the most promising but untapped worldwide technologies. In fact, wave energy is clean and renewable as the solar and wind ones, but also less mature and utilized. Moreover, several Wave Energy Converters (WECs) patents have been developed in the last decades, as evidence of the great potential beneath these systems. Among the different issues related to this technology, the most challenging is controlling such systems. Maximizing the captured energy is indeed the main goal of a WEC’s control mechanism. As for single-mode oscillating absorbers, it has been proven that a resonance condition between body velocity and excitation force must be achieved. This control solution is generally called phase control. Different phase control strategies have been realized since the 1970s and latching control is one of them. However, how to implement sub-optimal phase control in real seas remains an open problem. A numerical model of the wave energy converter and its power take-off system is proposed in this paper. More precisely, the model simulates the hydrodynamics of a WEC point absorber coupled with a hydraulic Power Take Off in regular waves. Additionally, a parametric latching control strategy is suggested to enhance the converter’s power capture performance.