Experimental study on power generation characteristics of a built-in bistable mechanism wave energy converter with broadband capturing performance

Wave energy, as a continuous and reliable power source, has attracted significant attention for powering offshore marine buoys. However, its effective utilization is affected by varying incident wave frequencies, which compromises the overall power generation performance of traditional wave energy converters (WECs). Therefore, a built-in WEC based on a bistable mechanism (BM-WEC) with broadband capture characteristics is proposed to accommodate temporal and spatial fluctuations of waves. The power generation performances were analyzed through numerical simulations and physical experiments, revealing the effects of structural parameters and step changes in spring stiffness and damping coefficient on motion response and electrical output, developing an optimization process to enhance high-power output. Results show that the BM-WEC achieves a captured bandwidth 13.47 % wider than that of a conventional WEC with a single natural frequency under regular wave conditions (ω = 1–4 rad/s), with cumulative output power increased by 57.24 %. Furthermore, this bandwidth advantage increases to 19.05 % under irregular wave condition, demonstrating that it is a practical and feasible solution for self-powered buoy technology.