Investigation on semi-analytical solution of dynamic characteristics of an anti-pitching generating WEC (AG-WEC)

The Anti-pitching Generating WEC (AG-WEC) combines the floating articulated platform with the wave energy device. The wave energy device is installed between the hinged platform modules to provide damping to reduce the relative pitch while generating electricity at the same time. A semi-analytical solution of the dynamic characteristics of the AG-WEC is developed by the frequency- and time-domain analysis of the device based on the potential flow theory. Based on Eigenfunction Expansion Matching’s potential flow theory, the semi-analytical expressions of wave loads and radiation hydrodynamic coefficients of AG-WEC are derived. By establishing a two-degree-of-freedom vibration system, the analytical solution of frequency-domain dynamic characteristics of the AG-WEC is obtained. Based on the analytical solution of Optimal PTO Damping Coefficient, the analytical optimization of the PTO system is realized, and the mechanism of high-efficiency energy capture of the device is revealed. The time-domain dynamic characteristics of AG-WEC under regular and irregular waves are analyzed by introducing the non-linear Power Take-Off (PTO) system and irregular wave theory with combining the Impose Response Function method.