Vibration energy harvesting is growing everyday more as an interesting alternative for powering MEMS, NEMS, ultra-low power devices and miniaturized electronics. However it should be noted that, as devices dimensions shrink, the overall size of the harvester has to reduce too. As consequence a reduction in the output voltage from the harvester is expected. In order to have an effective use of the harvester it is mandatory to collect and store the energy scavenged, this in general requires a diode threshold to be overcome by the voltage. However when harvester dimensions reduces, the electric power scavenged is delivered at a voltage that can easily be smaller than the diode threshold. For this reason standard solutions for energy storing based on bridge rectifiers cannot be used. Moreover the situation is even more complicated by the fact that incoming vibrations are very often weak and noisy rather then sinusoidal. To tackle this problem we have already demonstrated, in macro-scale, a novel approach named 'Random Mechanical Switching Harvester on Inductor' (RMSHI) that is a new 'unsynchronized' approach which is able to collect and store energy (typically wasted by using more traditional approaches) thanks to the use of PZT beam and mechanical stoppers that can drive a current to an inductor. In this paper a MEMS release of the RMSHI device is presented together with some preliminary experimental results, the system has been fabricated in piezoMUMPs technology and a hybrid solution has been adopted to realize the mechanical stopper over the piezoelectric MEMS beam. The experimental results shown demonstrate the validity of our approach also a MEMS scale.
|Titolo:||Micromachined 'Random Mechanical Switching Harvester on Inductor' to recovery energy from very low-amplitude vibrations with zero-voltage threshold|
|Data di pubblicazione:||2017|
|Appare nelle tipologie:||4.1 Contributo in Atti di convegno|