Inertial wave energy converter

Patent metadata

Field	Value
Publication number	US-10473083-B2
Application number	US-201715700118-A
Country	US
Kind code	B2
Filing date	Sep 9, 2017
Priority date	Sep 11, 2016
Publication date	Nov 12, 2019
Grant date	Nov 12, 2019

Abstract

A wave energy converter generates power from a wave-induced separation of a positively buoyant flotation module and a submerged negatively buoyant mass, using a rotating pulley to drive a power-take-off system.

First claim

We claim:

1. An inertial wave energy converter, comprising:
a positively buoyant flotation module adapted to float on a surface of a body of water;
a first pulley journaled at the positively buoyant flotation module;
a first power-take-off system configured to resist rotation of said first pulley;
a submerged negatively buoyant mass enclosing a fluid, said submerged negatively buoyant mass coupled to said positively buoyant flotation module at said first pulley via a flexible connector;
a restoring weight configured to store gravitational potential energy when a separation distance between the positively buoyant flotation module and the submerged negatively buoyant mass increases, the restoring weight reducing slack in the flexible connector when said separation distance decreases;
wherein said submerged negatively buoyant mass is lifted and dynamically suspended by periodic upward impulses applied via said flexible connector when said positively buoyant flotation module moves on waves at the surface of the body of water;
wherein said submerged negatively buoyant mass is configured to gravitationally descend in between said periodic upward impulses;
wherein a torque derived from a momentum of said submerged negatively buoyant mass is applied to said first pulley to drive said first power-take-off system; and
wherein the restoring weight is disposed at a lesser average depth than the submerged negatively buoyant mass.

2. The inertial wave energy converter of claim 1 , wherein said first power-take-off system powers an electrical generator.

3. The inertial wave energy converter of claim 1 , wherein an average separation distance between the positively buoyant flotation module and the submerged negatively buoyant mass is maximal when the inertial wave energy converter is at rest.

4. The inertial wave energy converter of claim 1 , wherein an average separation distance between the positively buoyant flotation module and the submerged negatively buoyant mass decreases when said periodic upward impulses lift said submerged negatively buoyant mass from a resting separation distance to an operational separation distance range.

5. The inertial wave energy converter of claim 4 , wherein an average separation distance between the positively buoyant flotation module and the submerged negatively buoyant mass decreases by more than an average wave height of the body of water when said periodic upward impulses lift said submerged negatively buoyant mass from a resting separation distance to an operational separation distance range.

6. The inertial wave energy converter of claim 1 , wherein the submerged negatively buoyant mass is elevated above a resting depth when said periodic upward impulses dynamically suspend said submerged negatively buoyant mass.

7. The inertial wave energy converter of claim 1 , further comprising a direction rectifying pulley, the direction rectifying pulley pivoting to reduce a fleet angle of the flexible connector.

8. The inertial wave energy converter of claim 7 , further comprising additional direction rectifying pulleys arrayed at a perimeter of said positively buoyant flotation module.

9. The inertial wave energy converter of claim 1 , wherein the positively buoyant flotation module is a direction rectifying flotation module.

10. The inertial wave energy converter of claim 9 , wherein a hydrostatic righting moment of the direction rectifying flotation module is less than a direction rectifying moment applied by the flexible connector.

11. The inertial wave energy converter of claim 1 , wherein the positively buoyant flotation module has a spherical-dome-shaped lower hull to decrease a hydrostatic stability of the positively buoyant flotation module.

12. The inertial wave energy converter of claim 1 , wherein a cross section of a lower hull of the positively buoyant flotation module defines an arc of a circle to decrease a hydrostatic stability of the positively buoyant flotation module with respect to rotational axes normal to the section plane.

13. The inertial wave energy converter of claim 1 , wherein the first pulley is disposed at a bottom region of the positively buoyant flotation module to orient said bottom region toward the submerged negatively buoyant mass when a tension in the flexible connector increases.

14. The inertial wave energy converter of claim 1 , wherein the first pulley is mounted adjacent to a bottom hull of the positively buoyant flotation module to immerse said first pulley in the body of water for cathodic protection.

15. The inertial wave energy converter of claim 1 , wherein the flexible connector comprises a ribbon.

16. The inertial wave energy converter of claim 15 , wherein the ribbon comprises a plurality of flexible connectors arranged side-by-side and engaging the first pulley.

17. The inertial wave energy converter of claim 15 , wherein said ribbon terminates at a rigid ribbon junction body.

18. The inertial wave energy converter of claim 17 , wherein said rigid ribbon junction body further includes a sacrificial anode to protect the ribbon from corrosion.

19. The inertial wave energy converter of claim 1 , wherein the restoring weight has a lesser wet weight than the submerged negatively buoyant mass.

20. The inertial wave energy converter of claim 1 , further comprising a restoring float configured to store buoyant potential energy when a separation distance between the positively buoyant flotation module and the submerged negatively buoyant mass increases, the restoring float reducing slack in the flexible connector when said separation distance decreases.

21. The inertial wave energy converter of claim 1 , wherein the first pulley has a spiral groove to constrain the flexible connector.

22. The inertial wave energy converter of claim 21 , wherein the flexible connector is wound multiple times around the first pulley.

23. The inertial wave energy converter of claim 22 , wherein a part of said flexible connector is fixedly attached to said first pulley.

24. The inertial wave energy converter of claim 1 , further comprising a feedback control system for adjusting a countertorque to the first pulley.

25. The inertial wave energy converter of claim 24 , wherein said feedback control system increases and decreases an average countertorque to stabilize the submerged negatively buoyant mass in an operational separation distance range.

26. The inertial wave energy converter of claim 24 , wherein the feedback control system responds to a separation distance between the submerged negatively buoyant mass and the positively buoyant flotation module to adjust a countertorque to the first pulley.

27. The inertial wave energy converter of claim 24 , wherein the feedback control system responds to a change in an average separation distance between the submerged negatively buoyant mass and the positively buoyant flotation module to adjust a countertorque to the first pulley.

28. The inertial wave energy converter of claim 24 , further comprising a rotary encoder to measure a separation distance between the submerged negatively buoyant mass and the positively buoyant flotation module.

Assignees

• Sheldon Coulson Garth Alexander
• Moffat Brian Lee
• Place Daniel William
• Shalhoub Rabeh Bassam
• Lone Gull Holdings Ltd

Inventors

• Sheldon-Coulson Garth Alexander
• Moffat Brian Lee
• Place Daniel William
• Shalhoub Rabeh Bassam

Classifications

• F03B13/148 Primary

  using the static pressure increase due to the wave · CPC title

• F03B13/14 Primary

  using wave energy · CPC title

• F03B13/1885

  and the wom is tied to the rem · CPC title

• F16H39/00

  Rotary fluid gearing using pumps and motors of the volumetric type, i.e. passing a predetermined volume of fluid per revolution (control of exclusively fluid gearing F16H61/38) · CPC title

• F03B13/12

  characterised by using wave or tide energy · CPC title