A Hybrid Piezoelectric and Inductive Rotational Energy Harvester

This paper presents the development of a rotational energy harvester that generates a power based on a combination of piezoelectric and electromagnetic methods. The device utilizes two piezoelectric beams and two inductors and potentially multiple elements on a stationary plate to maximize the harvested energy. The piezoelectric beams generate voltages when deflected with a rotating magnet. In addition, the inductors generate voltages when a magnet passes over them. In order to maximize the harvested energy and frequency, sixteen magnets were embedded in the rotating plate to excite the elements with a higher frequency. A 3D printer was used to make the enclosure, and stationary and rotating components of the device. An assembly of Arduino microcontroller, DC motor, IR sensor and LCD screen was used to test the device. The harvester utilized a closed loop feedback system to monitor rotational speed. The device was tested at various rotational speeds from 130 rpm to 510 rpm. Voltage output versus time graphs were analyzed for each speed. It was determined that raising the number of moving magnets and rotational speed increase not only the frequency but also the voltage amplitude in both piezoelectric beams and inductors. The developed energy harvesting device can be used in any existing rotational system such as vehicle tires, bicycles, rotating machines and exercise equipment. (paper)