Random Wave Energy Conversion of a Spar-Floater System via the Inerter Pendulum Vibration Absorber Integration

Abstract Due to the vast potential energy of ocean waves, research on ocean wave energy conversion setups is currently receiving significant attention. However, the high costs of installation and maintenance, combined with the relatively low energy conversion efficiency of current research devices, pose considerable challenges. One solution is to integrate wave energy converters (WECs) with existing offshore floating platforms. This paper studies a system integrating a floater WEC with a floating spar platform via the inerter pendulum vibration absorber with a power take-off mechanism (IPVA-PTO). By simulating its energy harvesting performance, considering drag force and under random ocean wave excitation, where ocean waves are generated using the Harmonic Random Amplitude (HRA) method and hydrodynamic coefficients are derived based on linear wave theory and the boundary element method, it is found that the IPVA system, while achieving comparable levels of hydrodynamic response of the spar, can enhance energy conversion by up to 106.37% compared to the optimal system with linear PTO. The simulation results qualitatively correspond with the bifurcation analysis of the system, conducted after solving for a series of Fourier coefficients, including those for drag damping, under regular wave conditions, providing insightful references for analyzing the performance subjected to random wave excitation.