A Rotational Electromagnetic Energy Harvester for The Ultra-low Frequency Vibration

This paper prototypes a rotational electro magnetic energy harvester for the vibrations at ultra-low frequency with potential applications in marine sensor buoys. It mainly contains three sub-systems: the twist-driving system, the pawl-ratchet clutching system, and the magnet-coil transduction system. When the linear motion of the screw is applied at ultra-low frequency, the twist-driving system and pawl-ratchet clutching system can convert it into the high-speed inertial rotation of the rotor. Then the magnet-coil transduction system can help to harvest the electric energy based on Faraday’s law of electromagnetic induction. In our test, an average output power of 112.2 mW can be achieved with the load resistance of 800 Ω at the excitation frequency of 0.25 Hz.