Design of an enhanced wideband energy harvester using a parametrically excited array

A wideband energy harvester has been designed, fabricated, and tested based on an array of four parametrically excited cantilever beams; the cantilever beams carry a tip mass at their free end. Piezoelectric transduction has been used to convert between the mechanical and electrical domains. An array configuration in conjunction with parametric excitation generated an enhanced bandwidth of the device (at low frequencies); furthermore, each piezoelectric beam displayed nonlinear dynamical behaviour due to geometric extensibility at the centreline—this behaviour was used to further increase the bandwidth of the energy harvester. An electrodynamic shaker has been used to parametrically excite the energy harvester, and the corresponding voltage of each piezoelectric beam has been measured. It was observed the energy harvester displayed eight resonance peaks that are within close proximity of each other, particularly, for low frequency applications (below 13 Hz); each piezoelectric beam generated substantial power (in the milli-Watt range).