Wave energy converter buoy with variable geometry
| DWPI Title: Wave energy converter for extracting energy from waves in body of water i.e. ocean, has shaped buoy in body of water having wave motion, and controller that is configured to vary geometry of buoy in response to wave motion |
| 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. |
| Use: Wave energy converter (WEC) for extracting energy from waves in a body of water i.e. ocean. |
| Advantage: The buoy design can increase power/energy captured by exploiting the nonlinear static coupling between an hourglass (HG) buoy geometry and the potentially wideband frequency spectrum of incoming waves. 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. The steepness angle variation with time can be achieved using an angle servo for the variable design. |
| Novelty: The wave energy converter has a shaped buoy in a body of water having a wave motion, where the waves impacting the buoy exert an excitation force with a set of excitation frequencies on the buoy that causes a buoy motion in a heave direction relative to a reference. The buoy includes 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, thus the reactive power is produced from the wave motion. A controller is used to vary the geometry of the buoy in response to the wave motion. The shaped buoy comprises mirrored hemispheres, pyramids, ellipsoids, paraboloids, or hyperboloids. |
| Filed: 4/19/2022 |
| Application Number: US17723690A |
| Tech ID: SD 15091.3 |
| This invention was made with Government support under Contract No. DE-NA0003525 awarded by the United States Department of Energy/National Nuclear Security Administration. The Government has certain rights in the invention. |
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