Modeling of a two-body wave energy converter driven by spectral JONSWAP waves

Abstract

Wave Energy Converter (WEC) design strives to produce as much power as possible across differing wave conditions. It is especially true of autonomous WECs (used, for example, to power an ocean buoy sensing system) because they are smaller and they need to maximize the amount of power produced under minimal wave energy conditions. This is because the electrical power required is considered a constant load. Autonomous WECs (AWECs) also tend to operate near shore where the wave spectral content spans a larger frequency range. This paper describes the type of spectral waves to be used during the design and simulation stage, then presents results from the WEC hydrodynamic finite element analysis (FEA) that uses integrated optimal control with both monochromatic and spectral waves. A comparison is made of these results against a SPICE simulation using a twobody equivalent circuit. Using these results, plus integrating the effects of losses in the power take-off (PTO), conclusions are reached regarding the preferred control method. It was found that damping control may be the preferable control scheme for this application.