Design of hydraulic power take-off systems unit parameters for multi-point absorbers wave energy converter

Abstract

Ocean waves represent a substantial renewable energy source, prompting this study's exploration of harnessing this potential via multi-point floating absorbers equipped with hydraulic Power Take-Off (PTO) systems. The study's primary motivation is to comprehensively model a Wave Energy Converter (WEC), including the hydraulic PTO system's control mechanism and protection system. To optimize the WEC design, we first investigate the hydrodynamic parameters of the floating absorber, employing potential flow theories and assessing the effects of varying the diameter-to-draft ratio. Our research involves analyzing Response Amplitude Operators (RAOs) and hydrodynamic forces for different ratios to identify the most effective design, followed by using computed wave forces as inputs for PTO simulations in MATLAB/SimScape to determine the unit parameters. The analysis of RAOs and wave-exciting forces reveals that diameter-to-draft ratios between 0.67 and 1.0 yield the best WEC performance, offering promising recommendations. In the final step, we compare the performance of single and multi-point absorber system simulations, assessing factors such as pressure drop, flow rate, and power output at the hydraulic motor. This comparison concludes that multi-point absorbers generate a more stable power output than their single-absorber counterparts.

Keywords

• Multi-point absorbers
• Wave energy converter
• Hydraulic PTO
• Hydrodynamic parameters
• Control strategy
• Pressure drop