A novel mechanical rectifier buoy energy harvester for low-power devices on Over-sea Bridge

Abstract Wave energy, a renewable resource, has attracted global attention with extensive research and applications. This paper proposes an innovative Mechanical Rectification Buoy Energy Harvester (MRBEH) based on piezoelectric generation, designed to power low-power devices on over-sea bridges. Anchored to bridge column bases, the device restricts the buoy to single-degree-of-freedom heave motion. The buoy captures wave motion and converts it into ball-screw rotation. Via a one-way bearing, the ball-screw unidirectionally transmits motion to a planetary gear torque amplifier, which then drives the rotor for unidirectional rotation. Non-contact magnetic repulsion between rotor and PZT unit magnets induces high-frequency mechanical oscillations in piezoelectric sheets, generating electrical output processed by a power management module. This wave energy converter addresses key challenges of low output power and cumbersome installation in existing systems, ensuring stable power supply with easy installation and maintenance. Under 0.4 Hz and 40 mm amplitude, MRBEH achieves an average output power of 1.89 W, outperforming most existing piezoelectric wave energy harvesters for over-sea bridge applications. The generated electricity can power 136 LED lamps, GPS and temperature-humidity sensors, and rapidly charge a large-capacity capacitor from 0 V to 10 V. MRBEH proposes a novel concept for energy harvesting in extreme environments.