A Pull-Out Mooring Wave Energy Converter: Design, Analysis, and Application

Wave energy converters (WEC), as alternative power sources for marine equipment, play a crucial role in promoting the development and utilization of ocean resources. However, the harsh marine environment and the low-frequency nature of ocean waves pose substantial challenges to the lifespan and energy conversion efficiency of WECs. This paper proposes a pull-out mooring wave energy converter (POM-WEC) integrating a high-performance electromagnetic power take-off (EPTO) system. The EPTO system can convert the low-frequency and low-speed wave excitation into high-speed inertial rotational motion of the rotor. Under an excitation velocity of 0.5 m s^-1, the EPTO system achieves an average output power of 9.1 mW. A comprehensive methodology based on response amplitude operators and Cummins equations is developed to analyze and predict the motion response of the POM-WEC under various wave conditions. By comparing the numerical simulation with experimental data, the validity and applicability of the methodology are further verified. The influences of wave height and frequency on both the motion response of the POM-WEC and the output performance of the EPTO system are also systematically tested and evaluated. Furthermore, a self-powered wireless sensing node based on the POM-WEC is successfully developed, featuring non-volatile data storage and three distinct operation modes.