A comparative investigation into the dynamic performance of multiple wind-wave hybrid systems utilizing a full-process analytical model

Abstract

An analytical model is applied to investigate the dynamic performance of a type of hybrid system (PAWT) with a semi-submersible floating offshore wind turbine (FOWT) coupled to an array of point-absorbing wave energy converters (PA). In this process, the linear potential flow theory and eigenfunction matching method are employed to study the wave–structure interactions, and a coupled set of equations is proposed to evaluate the motion response in frequency-domain. To account for the pronounced impact of nonlinear factors inherent in the hybrid system, a constellation of mathematical models has been integrated into Cummins equation framework, including aerodynamic, mooring lines, power take-off (PTO), and viscosity modeling. After running the convergence analysis and model validation, the present model is employed to clarify the effects of PTO damping, WEC radius, layout, and real sea states on the motion response and wave energy capture efficiency. Results demonstrate that integrating Wavestar-type WECs is more beneficial for improving the pitch stability of FOWT than heaving-type. Although augmenting the number of integrated WECs cannot enhance FOWT stability, it does contribute to broadening the bandwidth of the capture width ratio (CWR). Notably, the power take-off (PTO) is simplified as a linear damping to model a linear permanent magnet generator (PMG) in this study. Furthermore, the interest of this work lies in the full-process analytical model itself, which is found to be efficient in modeling the interaction of the wind-wave field and can be used in future hybrid system projects.