On the optimization and performances of a compact piezoelectric impact MEMS energy harvester

This paper presents the development of a compact energy harvesting configuration to convert low frequency, mechanical oscillations into usable electrical energy using AFM-like MEMS piezoelectric cantilevers coupled to a rotating gear. In this approach, one or several piezoelectric harvesters can be positioned above a rotating gear driven by an oscillating mass. In order to analyze the motion and the electrical power output from the harvester, analytical and finite element models have been developed. The harvester, with an active device volume of 3.5 mm3 (3×5×0.23 mm3), is able to produce an average output power of 12 μW measured across an optimal resistive load of 4.7 kΩ at a rotational speed of 19 rps, demonstrating the potential of the compact MEMS piezoelectric micro-power generator.