A Model Predictive Control-Based Power Converter System for Oscillating Water Column Wave Energy Converters
1
Australian Maritime College, University of Tasmania, Newnham, Tasmania 7248, Australia
2
Centre for Renewable Energy and Power Systems, University of Tasmania, Hobart, Tasmania 7001, Australia
*
Author to whom correspondence should be addressed.
Academic Editor: Aristides Kiprakis
Energies 2017, 10(10), 1631; https://doi.org/10.3390/en10101631
Received: 1 September 2017
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Revised: 25 September 2017
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Accepted: 3 October 2017
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Published: 17 October 2017
(This article belongs to the Special Issue Marine Energy)
Despite the predictability and availability at large scale, wave energy conversion (WEC) has still not become a mainstream renewable energy technology. One of the main reasons is the large variations in the extracted power which could lead to instabilities in the power grid. In addition, maintaining the speed of the turbine within optimal range under changing wave conditions is another control challenge, especially in oscillating water column (OWC) type WEC systems. As a solution to the first issue, this paper proposes the direct connection of a battery bank into the dc-link of the back-to-back power converter system, thereby smoothening the power delivered to the grid. For the second issue, model predictive controllers (MPCs) are developed for the rectifier and the inverter of the back-to-back converter system aiming to maintain the turbine speed within its optimum range. In addition, MPC controllers are designed to control the battery current as well, in both charging and discharging conditions. Operations of the proposed battery direct integration scheme and control solutions are verified through computer simulations. Simulation results show that the proposed integrated energy storage and control solutions are capable of delivering smooth power to the grid while maintaining the turbine speed within its optimum range under varying wave conditions.
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Keywords:
active front end rectifier; finite control set-model predictive control (FCS-MPC); two-level voltage source inverter; wave energy conversion (WEC)
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MDPI and ACS Style
Rajapakse, G.; Jayasinghe, S.; Fleming, A.; Negnevitsky, M. A Model Predictive Control-Based Power Converter System for Oscillating Water Column Wave Energy Converters. Energies 2017, 10, 1631. https://doi.org/10.3390/en10101631
AMA Style
Rajapakse G, Jayasinghe S, Fleming A, Negnevitsky M. A Model Predictive Control-Based Power Converter System for Oscillating Water Column Wave Energy Converters. Energies. 2017; 10(10):1631. https://doi.org/10.3390/en10101631
Chicago/Turabian StyleRajapakse, Gimara, Shantha Jayasinghe, Alan Fleming, and Michael Negnevitsky. 2017. "A Model Predictive Control-Based Power Converter System for Oscillating Water Column Wave Energy Converters" Energies 10, no. 10: 1631. https://doi.org/10.3390/en10101631
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