Design and optimisation of a hybrid floating wind platform with articulated wave point absorbers

Model testing of hybrid floating wind-wave platforms still lies in low technology levels. Few hybrid configurations have been validated in laboratory, yet the power take-off dynamics and conversion mechanisms affecting the global dynamics of the hybrid systems is hardly simulated, which hinders validation of the models under development. This paper presents a novel physical modelling approach for the design of hybrid floating wind-wave platforms, where the design of wave converters and power take-off for model testing are optimised with the objectives of reducing pitch motion whilst absorbing significant wave power. A hybrid configuration consisting of a 10 MW semi-submersible platform and three wave converters attached via articulating arms and power take-off systems is taken for analysis. The mathematical model based on generalised coordinates for the analysis of floating multi-body systems resolves the nonlinearities of geometric and mechanical constraints and draws the dynamic responses numerically. Then, a two-step systematic analysis is conducted for the best selection of wave converters and power take-off systems: First, a set of hybrid configurations is optimised one-by-one, offering optimal power take-off and location parameters; second, TOPSIS analysis is conducted for the final best selection. Several parameters such as wave converters’ shape, diameter and distance to the platform are systematically compared. The methodology identifies superior geometries for articulated floating wind-wave platforms.