A low threshold bistable device for energy scavenging from vibrations

In the field of Energy Harvesting, it has been demonstrated that, under the proper conditions, nonlinear configurations of the harvester can provide better performance, compared to linear resonant oscillators. In this paper preliminary results of investigation on a system for energy harvesting from wideband vibrations are shown. The harvester adopts a nonlinear snap-through-buckling (STB) configuration and two piezoelectric transducers, placed near the inflection points of the potential energy function that underpins the dynamics of the system. The device is demonstrated to be capable of scavenging energy from vibration sources in the range 0.5-4 Hz, but could be exploited up to 10 Hz with an acceptable loss of efficiency. The bandwidth of the device is compatible with applications where the vibrations occur at low frequencies e.g. in the case of a running human. Powers about 60μW with root mean square accelerations of 5 m/s² at 4 Hz have been measured.