Energy-maximising experimental control synthesis via impedance-matching for a multi degree-of-freedom wave energy converter

• Published in: IFAC-PapersOnLine Vol. 55; no. 31; pp. 345 - 350
• Main Authors: Faedo, Nicolás, Pasta, Edoardo, Carapellese, Fabio, Orlando, Vincenzo, Pizzirusso, Domenica, Basile, Dario, Sirigu, Sergej A.
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01.01.2022
• Subjects: Impedance-matching; Optimal control; Wave energy converters; Impedance-matching; Optimal control; Wave energy converters
• ISSN: 2405-8963; 2405-8963
• DOI: 10.1016/j.ifacol.2022.10.453

We present, in this paper, an experimental framework for design and synthesis of impedance-matching-based (IM) controllers capable of maximising energy extraction in inherently multi degree-of-freedom wave energy converter (WEC) systems, and its subsequent application to the Intertial Sea Wave Energy Converter (ISWEC) device, by incorporating recent advances in IM-based theory. In particular, we consider a 1/20th scale prototype of the ISWEC system, tested as part of a larger experimental campaign conducted within the tank facilities available at Università degli Studi di Napoli Federico II, subject to a variety of wave conditions. We adopt two different control structures to realise an approximation of the IM principle, fully tuned based upon interpolation of a particular (experimentally obtained) non-parametric empirical transfer function estimate, which defines the optimal frequency-domain input-output response for energy-maximising behaviour. Furthermore, a performance comparison between controller tuning based upon traditional linear boundary element method models, and the presented experimental approach, is also offered, showing that the latter can consistently outperform the former in realistic scenarios, for the set of analysed sea-states.