Coupled numerical framework for wind-wave-to-wire energy conversion in floating hybrid wind-wave systems

The integration of floating offshore wind turbines with wave energy converters (WECs) offers a highly promising approach to deep-sea energy exploitation. However, conventional hybrid wind-wave (HWW) systems frequently consider mechanical and electrical subsystems in isolation or with excessive simplification, thereby limiting their relevance to realistic and economically viable designs. To overcome this limitation, the present study introduces a wind-wave-to-wire (WW2W) modelling framework that simultaneously couples fluid, mechanical, and electrical dynamics for comprehensive HWW system simulations. Bidirectional real-time exchange of responses and forces across domains enabled a more accurate and physically representative system model. The proposed framework integrates AeroDyn for aerodynamics, NEMOH and HydroChrono for hydrodynamics, and MoorDyn for non-linear mooring dynamics. A numerical prismatic constraint model was introduced for multi-body interaction, while the hydraulic–electrical subsystems were implemented via AMESim-compiled dynamic link libraries. Following validation, parametric studies were performed to explore the influence of wind speed, wave frequency, and electrical resistive load on system performance, complemented by comparisons with the linear power take-off (PTO) model and experimental data to assess WW2W coupling effects. The results showed that the WW2W framework more closely aligned with experimental motion paths compared with the linear PTO–based framework owing to its consideration of coupling between hydraulic dynamics and platform motion, as well as the cascading influence of electrical loads through hydraulic responses on overall system performance. The proposed method captured WEC resonance in the HWW system near its natural frequencies, thereby broadening the frequency capture bandwidth and enhancing wave energy utilisation. Furthermore, the model predicted that integrating WECs marginally increased the wind power output by 0.18 % at the rated wind speed, although this benefit diminished under resonant conditions. These insights, which remain unobserved when using conventional models, underscore the capability of the framework to capture critical multidisciplinary interactions. Overall, the proposed WW2W framework provides a robust and reliable tool for the design and optimisation of floating HWW systems, thereby supporting their advancement towards commercial deployment.