Modelling and experimental verification of more efficient power harvesting by coupled piezoelectric cantilevers

Abstract

A new piezoelectric energy harvester design is proposed in order to achieve a wider bandwidth without compromising energy conversion efficiency. By coupling two cantilevers where the tip of the bottom one is attached to the base of the upper one, the simulated harvester will have a wider bandwidth and higher power output compared with two simulated single tuned single cantilevers. This is a compact design, using only half the area compared to two parallel single cantilevers at the price of a small increase in height. The measured coupled harvester has approximately 1.7 times higher energy output than the combination of two measured tuned single cantilevers achieved by a coupling with less mechanical damping. With an improved coupling the power output is increased to 2.3 times higher than two single tuned cantilevers.