A broadband E-shaped piezoelectric energy harvester based on vortex-shedding induced vibration from low velocity liquid flow

This letter presents an E-shaped piezoelectric energy harvester (PEH) based on vortex-shedding induced vibration (VSIV) for achieving broadband and enhanced energy capture from the liquid flow with low velocities. The PEH is realized by introducing two symmetrical vice piezoelectric beams to a traditional structure consisting of a drive sheet and a main piezoelectric beam. By changing the mass blocks on the sheet and vice beams, the first two order resonance frequencies can be tuned to be close enough to obtain a wide bidirectional tunable operating bandwidth. Experimental results demonstrate that the proposed harvester can adapt to a wider fluid velocity spectrum and bring out higher output performances than the conventional PEH. Under the excitation of vortexes from the liquid flow with low velocities (0.15m/s–0.7m/s), the maximum increase in power, efficiency and velocity spectrum over 20μW can be 70%, 326% and 60%, respectively, compared to its conventional counterpart. The total size of the E-shaped harvester is L×W×H = 90 mm×70 mm×5 mm.