Nonlinear controller for nonlinear wave energy converters
| DWPI Title: Nonlinear wave energy converter has actuator that is configured to apply control force in heave direction to buoy, nonlinear feedback controller computes control force to be applied by actuator and controller comprising feedback loop |
| Abstract: The present invention is directed to a nonlinear controller for nonlinear wave energy converters (WECs). As an example of the invention, a nonlinear dynamic model is developed for a geometrically right-circular cylinder WEC design for the heave-only motion, or a single degree-of-freedom (DOF). The linear stiffness term is replaced by a nonlinear cubic hardening spring term to demonstrate the performance of a nonlinear WEC as compared to an optimized linear WEC. By exploiting the nonlinear physics in the nonlinear controller, equivalent power and energy capture, as well as simplified operational performance is observed for the nonlinear cubic hardening spring controller when compared to an optimized linear controller. |
| Use: Nonlinear wave energy converter. |
| Advantage: The large increase in power shows both a reduction in size and weight making the new wave energy conversion designs more efficient, by focusing on multi-resonance. By using nonlinear cubic spring stiffness controller, equivalent power/energy is captured and reactive power requirements is improved. By introducing a cubic spring in the feedback loop, power capture results are significantly increased. |
| Novelty: The converter has a buoy in frame of water having a wave motion. The waves impact the buoy exert an excitation force with several excitation frequencies that cause a buoy motion in a heave direction relative to a reference. An actuator is configured to apply a control force in the heave direction to the buoy. A nonlinear feedback controller computes the control force to be applied by the actuator. The controller comprises a feedback loop comprising a nonlinear cubic spring. |
| Filed: 8/7/2019 |
| Application Number: US16534746A |
| Tech ID: SD 14751.1 |
| 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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