Initial conceptual demonstration of control co-design for WEC optimization

While some engineering fields have benefited from systematic design optimization studies, wave energy converters have yet to successfully incorporate such analyses into practical engineering workflows. The current iterative approach to wave energy converter design leads to suboptimal solutions. This short paper presents an open-source MATLAB toolbox for performing design optimization studies on wave energy converters where power take-off behavior and realistic constraints can be easily included. This tool incorporates an adaptable control co-design approach, in that a constrained optimal controller is used to simulate device dynamics and populate an arbitrary objective function of the user's choosing. A brief explanation of the tool's structure and underlying theory is presented. In order to demonstrate the capabilities of the tool, verify its functionality, and begin to explore some basic wave energy converter design relationships, three conceptual case studies are presented. In particular, the importance of considering (and constraining) the magnitudes of device motion and forces is shown.

[1]  A. Babarit,et al.  Theoretical and numerical aspects of the open source BEM solver NEMOH , 2015 .

[2]  John Marius Hegseth,et al.  Integrated design optimization of spar floating wind turbines , 2020, Marine Structures.

[3]  L. García-Tabarés,et al.  Dimensioning of Point Absorbers for Wave Energy Conversion by Means of Differential Evolutionary Algorithms , 2019, IEEE Transactions on Sustainable Energy.

[4]  Paula B. Garcia-Rosa,et al.  Control-Informed Geometric Optimization of Wave Energy Converters: The Impact of Device Motion and Force Constraints , 2015 .

[5]  David G. Wilson,et al.  Optimal control of wave energy converters , 2017 .

[6]  Gamal N. Elnagar,et al.  The pseudospectral Legendre method for discretizing optimal control problems , 1995, IEEE Trans. Autom. Control..

[7]  G. Bacelli,et al.  Feedback Resonating Control for a Wave Energy Converter , 2020, IEEE Transactions on Industry Applications.

[8]  Jeffrey T. Scruggs,et al.  Optimal causal control of a wave energy converter in a random sea , 2013 .

[9]  Adi Kurniawan Modelling and geometry optimisation of wave energy converters , 2013 .

[10]  Gordon Lightbody,et al.  Co-design of a wave energy converter using constrained predictive control , 2017 .

[11]  L. C. Iversen,et al.  Numerical method for computing the power absorbed by a phase-controlled point absorber , 1982 .

[12]  Stephen J. Wright,et al.  Numerical Optimization , 2018, Fundamental Statistical Inference.

[13]  Torgeir Moan,et al.  A Comparison of Selected Strategies for Adaptive Control of Wave Energy Converters , 2011 .

[14]  Ron J. Patton,et al.  Enhancement of wave energy absorption efficiency via geometry and power take-off damping tuning , 2019, Energy.

[15]  D. Evans A theory for wave-power absorption by oscillating bodies , 1976, Journal of Fluid Mechanics.

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

[17]  David G. Wilson,et al.  Advanced WEC Dynamics & Controls FY16 Testing Report , 2016 .

[18]  Kalyanmoy Deb,et al.  Finding Knees in Multi-objective Optimization , 2004, PPSN.

[19]  A. P. McCabe Constrained optimization of the shape of a wave energy collector by genetic algorithm , 2013 .

[20]  Paula B. Garcia-Rosa,et al.  On the Sensitivity of Optimal Wave Energy Device Geometry to the Energy Maximizing Control System , 2016, IEEE Transactions on Sustainable Energy.

[21]  K. Haas,et al.  Classification systems for wave energy resources and WEC technologies , 2018, International Marine Energy Journal.

[22]  John V. Ringwood,et al.  Numerical Optimal Control of Wave Energy Converters , 2015, IEEE Transactions on Sustainable Energy.

[23]  J. Falnes,et al.  A resonant point absorber of ocean-wave power , 1975, Nature.

[24]  Ryan G. Coe,et al.  Comments on Control of Wave Energy Converters , 2021, IEEE Transactions on Control Systems Technology.

[25]  Gordon Lightbody,et al.  Maximisation of Energy Capture by a Wave-Energy Point Absorber using Model Predictive Control , 2011 .

[26]  T. Moan,et al.  Optimal Geometries for Wave Absorbers Oscillating About a Fixed Axis , 2013, IEEE Journal of Oceanic Engineering.

[27]  Mario Garcia-Sanz,et al.  Control Co‐Design: An engineering game changer , 2019, Advanced Control for Applications: Engineering and Industrial Systems.

[28]  James T. Allison,et al.  Wave Energy Extraction Maximization in Irregular Ocean Waves Using Pseudospectral Methods , 2013, DAC 2013.