Arbitrary Vibration Driven Piezoelectric Energy Harvester Using Hair-Cell Structured Cantilever
A piezoelectric vibration energy harvester of hair-cell structured cantilever was developed to effectively scavenge three-dimensional ambient (or arbitrary) vibration energies. Most of the piezoelectric vibration energy harvesters are comprised of a flat cantilever with mass at its end. The conventional flat cantilever structure oscillates and is operated by d 31 mode or d 33 mode only in one direction of vibration (vertical direction) resulting in power generation while extremely poor response (almost none) to the other directions. Our proposed hair-cell structured cantilever, made in curled and elongated shape, can perform significantly to scavenge energy not only from vertical direction but also from longitudinal and horizontal directions (d 15 mode) of vibration. The fabricated device generated a peak to peak output voltage of 15 mV under vertically induced vibrations with an acceleration of 0.5 g at its resonance frequency of 116 Hz. In addition, it also generated 33 mV peak to peak output voltage and 10 mV under longitudinally and horizontally induced vibrations, respectively.