Wave energy converter buoy with variable geometry

Patent metadata

Field	Value
Publication number	US-11536243-B2
Application number	US-202217723690-A
Country	US
Kind code	B2
Filing date	Apr 19, 2022
Priority date	Sep 13, 2018
Publication date	Dec 27, 2022
Grant date	Dec 27, 2022

Abstract

A nonlinear control design technique capitalizes on a wave energy converter comprising a shaped buoy having a variable geometry wave energy. For example, the shaped buoy can have an hourglass (HG) geometry having a variable cone or steepness angle. The HG buoy is assumed to operate in the heave motion of the wave. The unique interaction between the HG buoy and the wave creates a nonlinear cubic storage effect that produces actual energy storage or reactive power during operation. A multi-frequency Bretschneider spectrum wave excitation input was simulated for the HG design both with constant and varying steepness angle profiles which demonstrated further increased power generation with changing sea states for the variable design.

First claim

We claim:

1. A wave energy converter, comprising:
a shaped buoy in a body of water having a wave motion, wherein the waves impacting the buoy exert an excitation force with a plurality of excitation frequencies on the buoy that causes a buoy motion in a heave direction relative to a reference and wherein the buoy has a geometry such that a water plane area of the buoy increases with distance away from the water line in the heave direction both above and below the water line, thereby producing reactive power from the wave motion; and
a controller configured to vary the external geometry of the buoy in response to the wave motion.

2. The wave energy converter of claim 1 , wherein the shaped buoy comprises an hourglass geometry.

3. The wave energy converter of claim 2 , wherein the hourglass geometry comprises mirrored right circular cones having a steepness angle.

4. The wave energy converter of claim 3 , wherein the steepness angle is variable from 35 to 75 degrees.

5. The wave energy converter of claim 3 , wherein the steepness angle is varied to harvest maximum energy from the wave motion.

6. The wave energy converter of claim 1 , wherein the shaped buoy comprises opposing geometries that are mirrored about the water line.

7. The wave energy converter of claim 6 , wherein the shaped buoy comprises mirrored hemispheres, pyramids, ellipsoids, paraboloids, or hyperboloids.

8. The wave energy converter of claim 1 , wherein the shaped buoy comprises opposing geometries that are not mirrored about the water line.

9. The wave energy converter of claim 1 , wherein the shaped buoy comprises a geometry of a polynomial spline expansion.

Assignees

• Nat Tech & Eng Solutions Sandia Llc
• Univ Michigan Tech

Inventors

• Wilson David G
• Robinett Iii Rush D
• Weaver Wayne W
• Glover Steven F

Classifications

• F05B2250/232

  conical · CPC title

• F05B2260/821

  Parameter estimation or prediction · CPC title

• F05B2270/404

  active, predictive, or anticipative · CPC title

• F05B2250/02

  variable · CPC title

• F03B13/20 Primary

  wherein both members {, i.e. wom and rem} are movable relative to the sea bed or shore · CPC title