A wideband vibration energy harvester based on a folded asymmetric gapped cantilever

This paper reports a wideband multi-mass multi-spring piezoelectric vibration energy harvester (VEH) based on a folded asymmetric gapped cantilever, which enables multiple resonant modes formed by pure bending of every stage. Moreover, the heaviest proof mass is placed at the last stage of the cantilever to increase the harvested power. The VEH's energy conversion efficiency is further increased using the asymmetric gapped structure. A prototype has been developed and characterized. The experimental results match with finite element simulation well. The prototype was tested on an air conditioning unit to demonstrate its energy harvesting capability with a realistic broadband vibration source.