Low-Resonant-Frequency Micro Electret Generator for Energy Harvesting Application

Abstract

A vibration-driven electret generator has been developed for energy harvesting applications. By using parylene as the spring material, a low-resonant-frequency MEMS generator is realized. Electrostatic levitation is adopted for the gap control. Large in-plane amplitude of 0.5 mm at the resonant frequency as low as 21 Hz has been achieved. We also demonstrate electret-powered operation of LED using a low-power-consumption impedance conversion circuit.

Electrostatic Energy Harvesting Systems: A Better Understanding of Their SustainabilityElectrostatic Energy Harvesting Systems: A Better Understanding of Their Sustainability

“…Edamoto et al [37] developed a vibration-based electret generator for energy harvesting applications. The spring material used was Parylene for low frequency vibrations.…”

Micro harvester using isotropic charging of electrets deposited on vertical sidewalls for conversion of 3D vibrational energy

“…Electrostatic vibration micro-harvesters provide CMOS compatible realization. Electret-based vibration energy harvesters have been reported by Tsutsumino et al (2006) and Edamoto et al (2006Edamoto et al ( , 2009, using high performance electrets to bias comb-like capacitors to realize electrostatic vibration microharvesters, which can harvest energy at a specific frequency and in a specific vibrational direction. These approaches can be expanded to 3D vibrations by bonding separate devices into a 3D arrangement which makes this approach expensive, bulky and not capable of being integrated in a planar CMOS process.…”

Electrostatic energy harvesting using capacitive generators without control circuits

“…It is also possible to exploit the fact that at small distances (tens of lm) greater electric fields are tolerable without sparking than at macroscopic distances, resulting in generators with useful values of energy density (output power per volume) [1]. Most of the recently proposed generators are based on a single variable capacitor [2], possibly using an electret for biasing [3]. Purely electrostatic generators based on a single variable capacitor were described in many works, usually requiring a DC/DC converter to extract energy from the devices, in some cases with the operation depending on carefully synchronized operation of the converter at certain instants of the vibration cycle.…”