A quad-stable piezoelectric energy harvester for enhancing energy harvesting from rotational motion: Theoretical model and experiments

Recently, different nonlinear energy harvesters were designed to harvest energy from various rotational motions, which aim to provide power to self-powered wireless sensors. In this paper, a quad-stable piezoelectric energy harvester, comprising of a piezoelectric beam and magnets, is designed to enhance energy harvesting efficiency in rotational motion. In addition, a theoretical model is derived to describe the dynamic performance and the output voltage of the harvester. Furthermore, experimental results demonstrate that the presented harvester in rotational motion exhibits a wider working frequency range compared with that of the bi-stable one. Most importantly, for the rotational speed range of 60 - 420 rpm (1 - 7 HZ), the inter-well oscillation for the harvester can be achieved and corresponding peak voltage is higher than 10 V, which can be used to power wireless sensors. Overall, the quad-stable piezoelectric energy harvester is experimentally verified to be suitable for the low-frequency rotational environment.