Control Performance Assessment and Design of Optimal Control to Harvest Ocean Energy

Different approaches exist to design the optimal control strategy to harvest ocean energy with a point absorber. However, the control paradigm changes if the efficiency of the power takeoff (PTO) is taken into account. The motivation of this paper is twofold. The first objective is to develop a framework that includes the PTO efficiency to determine the optimal control strategy. The second objective is to assess the performance of any control strategy given the PTO efficiency. The performance assessment is based on the upper bound of the deliverable electrical energy of the optimal control strategy. As an example, different PTO efficiencies were considered for a given point absorber model, and extensive simulation results show the annual electrical energy delivered to the grid by the optimal control strategy. The performance of a nonoptimal control strategy is assessed with respect to the optimal control strategy.

[1]  Alexandra A E Price,et al.  New Perspectives on Wave Energy Converter Control , 2009 .

[2]  Duarte Valério,et al.  Reactive control and phase and amplitude control applied to the Archimedes Wave Swing , 2007 .

[3]  J. Sneddon.  Sequential simplex optimization , 1992 .

[4]  W. Cummins.  THE IMPULSE RESPONSE FUNCTION AND SHIP MOTIONS , 2010 .

[5]  W. Pierson,et al.  A proposed spectral form for fully developed wind seas based on the similarity theory of S , 1964 .

[6]  J. Falnes.  Ocean Waves and Oscillating Systems , 2002 .

[7]  Ted K.A. Brekken,et al.  Wave Energy Converter with wideband power absorption , 2011, 2011 IEEE Energy Conversion Congress and Exposition.

[8]  Paula B. Garcia-Rosa,et al.  Efficiency optimization in a wave energy hyperbaric converter , 2009, 2009 International Conference on Clean Electrical Power.

[9]  Jonathan Shek.  Control of Linear Electrical Generators for Direct Drive Wave Energy Conversion , 2006 .

[10]  G. De Backer.  Hydrodynamic design optimization of wave energy converters consisting of heaving point absorbers , 2009 .

[11]  P. Frigaard,et al.  Performance Evaluation of the Wavestar Prototype , 2011 .

[12]  Rico Hjerm Hansen,et al.  Early Performance Assessment of the Electrical Output of Wavestar's prototype , 2012 .

[13]  M. Molinas,et al.  Impact of control strategies on the rating of electric power take off for Wave Energy conversion , 2010, 2010 IEEE International Symposium on Industrial Electronics.

[14]  S H Salter,et al.  Power conversion mechanisms for wave energy , 2002 .

[15]  Jonathan Shek,et al.  Phase and amplitude control of a linear generator for wave energy conversion , 2008 .

[16]  Rico Hjerm Hansen,et al.  Modelling and Control of the Wavestar Prototype , 2011 .

[17]  Aurélien Babarit,et al.  Assessment of the influence of the distance between two wave energy converters on energy production , 2010 .

[18]  Pierpaolo Ricci,et al.  Control strategies for a wave energy converter connected to a hydraulic power take-off , 2011 .

[19]  Thomas Lykke.  Lecture Notes for the Course in Water Wave Mechanics , 2015 .

[20]  Paolo Mattavelli,et al.  Effect of Control Strategies and Power Take-Off Efficiency on the Power Capture From Sea Waves , 2011, IEEE Transactions on Energy Conversion.