# Optimal control of wave energy converters

## Abstract

A wave energy converter and method for extracting energy from water waves maximizes the energy extraction per cycle by estimating an excitation force of heave wave motion on the buoy, computing a control force from the estimated excitation force using a dynamic model, and applying the computed control force to the buoy to extract energy from the heave wave motion. Analysis and numerical simulations demonstrate that the optimal control of a heave wave energy converter is, in general, in the form of a bang-singular-bang control; in which the optimal control at a given time can be either in the singular arc mode or in the bang-bang mode. The excitation force and its derivatives at the current time can be obtained through an estimator, for example, using measurements of pressures on the surface of the buoy in addition to measurements of the buoy position. A main advantage of this approximation method is the ease of obtaining accurate measurements for pressure on the buoy surface and for buoy position, compared to wave elevation measurements.

- Inventors:

- Issue Date:

- Research Org.:
- Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

- Sponsoring Org.:
- USDOE

- OSTI Identifier:
- 1502439

- Patent Number(s):
- 10,197,040

- Application Number:
- 15/466,605

- Assignee:
- National Technology & Engineering Solutions of Sandia, LLC (Albuquerque, NM)

- DOE Contract Number:
- AC04-94AL85000

- Resource Type:
- Patent

- Resource Relation:
- Patent File Date: 2017 Mar 22

- Country of Publication:
- United States

- Language:
- English

- Subject:
- 16 TIDAL AND WAVE POWER

### Citation Formats

```
Abdelkhalik, Ossama, Robinett, III, Rush D., Zou, Shangyan, Bacelli, Giorgio, Wilson, David G., and Korde, Umesh.
```*Optimal control of wave energy converters*. United States: N. p., 2019.
Web.

```
Abdelkhalik, Ossama, Robinett, III, Rush D., Zou, Shangyan, Bacelli, Giorgio, Wilson, David G., & Korde, Umesh.
```*Optimal control of wave energy converters*. United States.

```
Abdelkhalik, Ossama, Robinett, III, Rush D., Zou, Shangyan, Bacelli, Giorgio, Wilson, David G., and Korde, Umesh. Tue .
"Optimal control of wave energy converters". United States. https://www.osti.gov/servlets/purl/1502439.
```

```
@article{osti_1502439,
```

title = {Optimal control of wave energy converters},

author = {Abdelkhalik, Ossama and Robinett, III, Rush D. and Zou, Shangyan and Bacelli, Giorgio and Wilson, David G. and Korde, Umesh},

abstractNote = {A wave energy converter and method for extracting energy from water waves maximizes the energy extraction per cycle by estimating an excitation force of heave wave motion on the buoy, computing a control force from the estimated excitation force using a dynamic model, and applying the computed control force to the buoy to extract energy from the heave wave motion. Analysis and numerical simulations demonstrate that the optimal control of a heave wave energy converter is, in general, in the form of a bang-singular-bang control; in which the optimal control at a given time can be either in the singular arc mode or in the bang-bang mode. The excitation force and its derivatives at the current time can be obtained through an estimator, for example, using measurements of pressures on the surface of the buoy in addition to measurements of the buoy position. A main advantage of this approximation method is the ease of obtaining accurate measurements for pressure on the buoy surface and for buoy position, compared to wave elevation measurements.},

doi = {},

journal = {},

number = ,

volume = ,

place = {United States},

year = {2019},

month = {2}

}

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