Towards a unified formulation of time and frequency-domain models for point absorbers with single and double-body configuration

Point absorbers represent an attractive choice to harness the wave power potential, even if relevant technology is still in a pre-commercial phase and is not competitive enough, as regards other renewable sources. In this respect, in the last decade research activities focused on the design and optimization of the floating buoy, in order to increase the device efficiency and reduce the power production costs. Based on actual state of art, it is still necessary to develop a unified formulation for the hydrodynamic behaviour of point absorbers with single and double-body configuration. Hence, the first aim of current research is to develop a unified time-domain model for point absorbers with single and double-body configurations, focusing on the assessment of power production and the strength check of the tensioned line, connecting the floating buoy to a permanent magnet linear generator, lying on the seabed. Subsequently, a new formula for power production, based on frequency-domain analysis, is outlined to account for the heave motion restraint, exerted by the Power Take-Off unit, as well as for the partial overlapping between translator and stator. Current analysis is performed for a reference point absorber, deployed in the western Mediterranean Sea.