Cantilever-based electret energy harvesters

TL;DR

This paper presents an analytical model and experimental validation of cantilever-based electret energy harvesters, demonstrating their potential to convert ambient vibrations into usable electrical power with state-of-the-art efficiency.

Contribution

It introduces an accurate analytical model for cantilever electret harvesters and validates it with experiments, highlighting their high energy conversion efficiency.

Findings

Theoretically up to 30μW per gram of mass can be harvested.

Experimentally achieved 10μW per gram due to parasitic capacitances.

Results are among the best in the current state of the art.

Abstract

Integration of structures and functions allowed reducing electric consumptions of sensors, actuators and electronic devices. Therefore, it is now possible to imagine low-consumption devices able to harvest their energy in their surrounding environment. One way to proceed is to develop converters able to turn mechanical energy, such as vibrations, into electricity: this paper focuses on electrostatic converters using electrets. We develop an accurate analytical model of a simple but efficient cantilever-based electret energy harvester. Therefore, we prove that with vibrations of 0.1g (~1m/s^{2}), it is theoretically possible to harvest up to 30\muW per gram of mobile mass. This power corresponds to the maximum output power of a resonant energy harvester according to the model of William and Yates. Simulations results are validated by experimental measurements but the issues of parasitic capacitances get a large impact. Therefore, we 'only' managed to harvest 10\muW per gram of mobile mass, but according to our factor of merit, this puts us in the best results of the state of the art. http://iopscience.iop.org/0964-1726/20/10/105013