Experimental study on power matrix and energy capture spectrum of a wind-wave hybrid system under random wave conditions

Power matrices of wind-wave hybrid systems (WWHS) are pivotal for optimizing energy yield predictions, informing device design, and enabling site-specific resource assessments. This study investigates the wave energy capture performance of a WWHS under real sea conditions, employing a configuration comprising a hinged buoy wave energy converter (WEC) array integrated with a WindFloat floating offshore wind turbine. Over 250 experimental cases were conducted to assess the WEC subsystem's power matrices, incorporating variable power take-off (PTO) damping coefficients, random wave parameters, and wind thrust effects. Wave energy capture characteristics were evaluated using the energy capture spectrum (ECS) method, which revealed distinct frequency-dependent performance variations. A novel lagged differencing approach, utilizing Pearson correlation coefficients, was developed to enhance the efficiency of ECS measurements. Findings indicate that optimal PTO damping and wind thrust configurations significantly boost energy extraction efficiency. Lateral buoys outperformed the front buoy by 26.12–49.24 %, due to better high-frequency wave energy absorption. Turbulent winds enhanced energy capture compared to uniform winds, likely from added excitation effects. This study offers detailed experimental data for assessing hybrid wind-wave system resources, highlighting the complex interplay of PTO settings, array interactions, wave parameters, and wind thrusts. Understanding these mechanics is key to optimizing WWHS performance, enhancing efficiency, and promoting its practical use.