A wave energy converter based on a zero-pressure-angle mechanism for self-powered applications in near-zero energy sea-crossing bridges

The concept of near-zero energy conversion from ocean waves is an emerging topic that can be applied to supply power to self-powered applications in sea-crossing bridges. In this paper, a point-absorbing wave energy converter (WEC) with a novel zero-pressure-angle mechanism structure was proposed and investigated. The system includes a wave energy capture module, power take-off module (PTO), generator module, and energy storage module. The proposed PTO structure consists of a pair of guide rods, zero-pressure-angle rockers, gearbox, and flywheel, which convert the oscillation of the buoy into unidirectional continuous rotation of the generator, and electricity is stored in the supercapacitor. For accurate prediction, kinematic and dynamic approaches were employed for the non-constant damping PTO. The mechanical test and sensing system experiments achieved the highest mechanical efficiency of 81.87%, the maximum output power of 5.49 W, and the 53.44% average efficiency. It was found that the PTO with a flywheel can effectively improve the output performance compared to without a flywheel. In addition, the experiments of the actual WEC were performed and recorded an output power ranging from 0.964 W to 3.218 W, proving that the proposed structure meets the power requirements for self-powered sea-crossing bridge applications.