Title: Pseudo-spectral method to control three-degree-of-freedom wave energy converters

Abstract

The invention provides optimal control of a three-degree-of-freedom wave energy converter using a pseudo-spectral control method. The three modes are the heave, pitch and surge. A dynamic model is characterized by a coupling between the pitch and surge modes, while the heave is decoupled. The heave, however, excites the pitch motion through nonlinear parametric excitation in the pitch mode. The invention can use a Fourier series as basis functions to approximate the states and the control. For the parametric excited case, a sequential quadratic programming approach can be implemented to numerically solve for the optimal control. The numerical results show that the harvested energy from three modes is greater than three times the harvested energy from the heave mode alone. Moreover, the harvested energy using a control that accounts for the parametric excitation is significantly higher than the energy harvested when neglecting this nonlinear parametric excitation term.

Inventors:

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

Issue Date:

Tue Jul 09 00:00:00 EDT 2019

Research Org.:

National Technology & Engineering Solution of Sandia, LLC, Albuquerque, NM (United States); Michigan Technological Univ., Houghton, MI (United States)

Sponsoring Org.:

USDOE

OSTI Identifier:

1568571

Patent Number(s):

10344736

Application Number:

15/837,853

Assignee:

National Technology & Engineering Solution of Sandia, LLC (Albuquerque, NM); Michigan Technological University (Houghton, MI)

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"}
F03B13/183 - {of a turbine-like wom}
F03B15/00 - Controlling
F03B15/20 - specially adapted for turbines with jets of high-velocity liquid impinging on bladed or like rotors

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

F05B2250/43 - with three degrees of freedom
F05B2270/20 - to optimise the performance of a machine

G - PHYSICS G02 - OPTICS G02F - DEVICES OR ARRANGEMENTS, THE OPTICAL OPERATION OF WHICH IS MODIFIED BY CHANGING THE OPTICAL PROPERTIES OF THE MEDIUM OF THE DEVICES OR ARRANGEMENTS FOR THE CONTROL OF THE INTENSITY, COLOUR, PHASE, POLARISATION OR DIRECTION OF LIGHT, e.g. SWITCHING, GATING, MODULATING OR DEMODULATING

G02F1/39 - for parametric generation or amplification of light, infra-red, or ultra-violet waves {

G - PHYSICS G06 - COMPUTING G06F - ELECTRIC DIGITAL DATA PROCESSING

G06F1/02 - Digital function generators {
G06F1/022 - {Waveform generators, i.e. devices for generating periodical functions of time, e.g. direct digital synthesizers

H - ELECTRICITY H01 - BASIC ELECTRIC ELEMENTS H01J - ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS

H01J49/4275 - {Applying a non-resonant auxiliary oscillating voltage, e.g. parametric excitation}

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:  

NA0003525

Resource Type:

Patent

Resource Relation:

Patent File Date: 12/11/2017

Country of Publication:

United States

Language:

English