Control strategies for combining local energy storage with wells turbine oscillating water column devices. (November 2015)

• Record Type: Journal Article
• Authors: Ceballos, Salvador; Rea, Judy; Robles, Eider; Lopez, Iraide; Pou, Josep; O'Sullivan, Dara
• Is Part Of: Renewable energy. Volume 83(2015)
• Page Start: 1097
• Page End: 1109
• Publication Date: 2015-11
• Subjects: Wave energy -- Ocean energy -- Power electronics -- Control of power converters -- Energy storage -- Oscillating water columns -- Control of oscillating water columns; Renewable energy sources -- Periodicals; Power resources -- Periodicals; Énergies renouvelables -- Périodiques; Ressources énergétiques -- Périodiques; 333.794
• DOI: 10.1016/j.renene.2015.05.030
• Languages: English
• ISSNs: 0960-1481

Abstract

Abstract: This paper proposes three generator control strategies for Wells turbine-based floating oscillating water column (OWC) devices comprising electrical or mechanical energy storage systems. The first control strategy is indicated for low inertia turbine OWC devices that include ultracapacitors. This control law optimizes the power take-off efficiency by means of an instantaneous speed controller that allows variation of the turbine rotational speed in a wave-by-wave basis. In addition, the profile of the electrical power injected into the grid is smoothed, so that a high penetration of wave energy does not threaten the grid stability. The second and third control laws are developed for OWC systems comprising a flywheel. Quasi-constant and variable speed controllers are proposed. These control laws do not maximize the system efficiency but allow the use of simpler, smaller and cheaper power electronics. Additionally the power quality is also optimized. The development of the proposed control algorithms is accomplished by means of simulations and verified with an experimental test rig. Highlights: Development of control strategies for Wells turbine-based OWC devices. Development of a methodology to test and develop controllers for OWC devices. Optimum speed controller for Wells turbine-based OWCs combined with ultracapacitors Torque-Speed curve controller for turbines with mechanical storage using flywheel. Efficiency comparison between the controllers.