Title: 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:

Abdelkhalik, Ossama; Robinett, III, Rush D.; Zou, Shangyan; Bacelli, Giorgio; Wilson, David G.; Korde, Umesh

Issue Date:

2019-02-05

Research Org.:

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

Sponsoring Org.:

USDOE

OSTI Identifier:

1502439

Patent Number(s):

10197040

Application Number:

15/466,605

Assignee:

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

Patent Classifications (CPCs):

F - MECHANICAL ENGINEERING F03 - MACHINES OR ENGINES FOR LIQUIDS F03B - MACHINES OR ENGINES FOR LIQUIDS

F - MECHANICAL ENGINEERING F05 - INDEXING SCHEMES RELATING TO ENGINES OR PUMPS IN VARIOUS SUBCLASSES OF CLASSES F01-F04 F05B - INDEXING SCHEME RELATING TO MACHINES OR ENGINES OTHER THAN NON-POSITIVE-DISPLACEMENT MACHINES OR ENGINES, TO WIND MOTORS, TO NON-POSITIVE DISPLACEMENT PUMPS, AND TO GENERATING COMBUSTION PRODUCTS OF HIGH PRESSURE OR HIGH VELOCITY

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F - MECHANICAL ENGINEERING F03 - MACHINES OR ENGINES FOR LIQUIDS F03B - MACHINES OR ENGINES FOR LIQUIDS

F03B13/16 - using the relative movement between a wave-operated member, {i.e. a "wom"} and another member, {i.e. a reaction member or "rem"}
F03B15/00 - Controlling

F - MECHANICAL ENGINEERING F05 - INDEXING SCHEMES RELATING TO ENGINES OR PUMPS IN VARIOUS SUBCLASSES OF CLASSES F01-F04 F05B - INDEXING SCHEME RELATING TO MACHINES OR ENGINES OTHER THAN NON-POSITIVE-DISPLACEMENT MACHINES OR ENGINES, TO WIND MOTORS, TO NON-POSITIVE DISPLACEMENT PUMPS, AND TO GENERATING COMBUSTION PRODUCTS OF HIGH PRESSURE OR HIGH VELOCITY

F05B2220/706 - an electrical generator
F05B2260/84 - Modelling or simulation
F05B2270/20 - to optimise the performance of a machine

G - PHYSICS G05 - CONTROLLING G05B - CONTROL OR REGULATING SYSTEMS IN GENERAL

G05B19/406 - characterised by monitoring or safety
G05B2219/39218 - Force tracking

Y - NEW / CROSS SECTIONAL TECHNOLOGIES Y02 - TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE Y02E - REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION

Y02E10/30 - Energy from the sea

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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