ASSESSMENT OF LATCHING CONTROL FOR THE HEMISPHERIC HEAVING BUOY TYPE POINT ABSORBER WITH AND WITHOUT NONLINEAR FROUDE-KRYLOV FORCE ACTING ON THE BUOY

摘要

In this study, a latching control strategy was utilized to increase the efficiency of a heaving buoy-type point absorber with a hydraulic Power take-off(PTO) system. For this purpose, the hydrodynamic performance of a floating buoy was analyzed based on the potential flow theory and Cummins equation. Nonlinear Froude-Krylov(FK) force according to instantaneous wetted surface of a buoy was calculated by a theoretical solution. The effect of the latching control on a point absorber was evaluated by considering PTO performance with hydrodynamic coefficients including nonlinear FK force. The hydraulic PTO system was modeled as an approximate coulomb damping force.