Genest, Romain and Davidson, Josh and Ringwood, John (2018) Adaptive control of a wave energy converter. IEEE Transactions on Sustainable Energy, 9 (4). pp. 1588-1595. ISSN 1949-3029

Preview

Download (854kB) | Preview

Abstract

Energy maximising controllers (EMCs), for wave energy converters (WECs), based on linear models, are attractive in terms of simplicity and computation. However, such (Cummins equation) models are normally built around the still water level as an equilibrium point and assume small movement, leading to poor model validity for realistic WEC motions, especially for the large amplitude motions obtained by a well controlled WEC. The method proposed here is to use an adaptive algorithm to estimate the control model online, whereby system identification techniques are employed to identify a linear model that is most representative of the actual controlled WEC behaviour. Using exponential forgetting, the linear model can be regularly adapted to remain representative in changing operational conditions. To that end, this paper presents a novel adaptive controller based on a receding horizon pseudospectral formulation. A case study is presented, providing an preliminary evaluation of the adaptive receding horizon pseudospectral control (ARHPC), using simulations based on both linear hydrodynamic modelling and computational fluid dynamics (CFD). The parameter adaptation is shown to behave as expected in both different simulation environments. The ARHPC is observed to perform well in irregular sea states, absorbing more power than its nonadaptive counterpart. The optimal trajectory calculated by the adaptive model is seen to have a smaller motion and power take-off (PTO) forces, compared to those calculated by the nonadaptive linear control model, due to the increased amount of hydrodynamic resistance estimated by the adaptive model, as identified from the nonlinear viscous CFD simulation.

Item Type:	Article
Additional Information:	This is the preprint version of the published article, which is available at https://doi.org/10.1109/TSTE.2018.2798921
Keywords:	Wave energy; adaptive control; system identification; CFD;
Academic Unit:	Faculty of Science and Engineering > Electronic Engineering Faculty of Science and Engineering > Research Institutes > Centre for Ocean Energy Research
Item ID:	12449
Identification Number:	https://doi.org/10.1109/TSTE.2018.2798921
Depositing User:	Professor John Ringwood
Date Deposited:	11 Feb 2020 17:02
Journal or Publication Title:	IEEE Transactions on Sustainable Energy
Publisher:	Institute of Electrical and Electronics Engineers (IEEE)
Refereed:	Yes
Funders:	Science Foundation Ireland (SFI)
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

Repository Staff Only(login required)

Item control page

Downloads

Origin of downloads