Faedo, Nicolás and Scarciotti, Giordano and Astolfi, Alessandro and Ringwood, John (2018) Energy-maximising control of wave energy converters using a moment-domain representation. Control Engineering Practice, 81. pp. 85-96. ISSN 0967-0661

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Abstract

Wave Energy Converters (WECs) have to be controlled to ensure maximum energy extraction from waves while considering, at the same time, physical constraints on the motion of the real device and actuator characteristics. Since the control objective for WECs deviates significantly from the traditional reference “tracking” problem in classical control, the specification of an optimal control law, that optimises energy absorption under different sea-states, is non-trivial. Different approaches based on optimal control methodologies have been proposed for this energy-maximising objective, with considerable diversity on the optimisation formulation. Recently, a novel mathematical tool to compute the steady-state response of a system has been proposed: the moment-based phasor transform. This mathematical framework is inspired by the theory of model reduction by moment-matching and considers both continuous and discontinuous inputs, depicting an efficient and closed-form method to compute such a steady-state behaviour. This study approaches the design of an energy-maximising optimal controller for a single WEC device by employing the moment-based phasor transform, describing a pioneering application of this novel moment-matching mathematical scheme to an optimal control problem. Under this framework, the energy-maximising optimal control formulation is shown to be a strictly concave quadratic program, allowing the application of well-known efficient real-time algorithms.

Item Type:	Article
Additional Information:	This work was supported by the Science Foundation Ireland under Grant No. SFI/13/IA/1886. This work has been partially supported by the European Union’s Horizon 2020 Research and Innovation Programme, UK under grant agreement No 739551 (KIOS CoE).
Keywords:	Optimal control; Wave energy converter; Phasor transform; Energy maximisation; Moment domain;
Academic Unit:	Faculty of Science and Engineering > Electronic Engineering Faculty of Science and Engineering > Research Institutes > Centre for Ocean Energy Research
Item ID:	12544
Identification Number:	https://doi.org/10.1016/j.conengprac.2018.08.010
Depositing User:	Professor John Ringwood
Date Deposited:	05 Mar 2020 15:23
Journal or Publication Title:	Control Engineering Practice
Publisher:	Elsevier
Refereed:	Yes
Funders:	Science Foundation Ireland (SFI), Horizon 2020 Research and Innovation Programme
URI:	Publisher
Use Licence:	This item is available under a Creative Commons Attribution Non Commercial Share Alike Licence (CC BY-NC-SA). Details of this licence are available here

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