40 research outputs found
Electret-based cantilever energy harvester: design and optimization
We report in this paper the design, the optimization and the fabrication of
an electret-based cantilever energy harvester. We develop the mechanical and
the electrostatic equations of such a device and its implementation using
Finite Elements (FEM) and Matlab in order to get an accurate model. This model
is then used in an optimization process. A macroscopic prototype (3.2cm^{2})
was built with a silicon cantilever and a Teflon\textregistered electret.
Thanks to this prototype, we manage to harvest 17\muW with ambient-type
vibrations of 0.2g on a load of 210M{\Omega}. The experimental results are
consistent with simulation results
Adjustable Nonlinear Springs to Improve Efficiency of Vibration Energy Harvesters
Vibration Energy Harvesting is an emerging technology aimed at turning
mechanical energy from vibrations into electricity to power microsystems of the
future. Most of present vibration energy harvesters are based on a mass spring
structure introducing a resonance phenomenon that allows to increase the output
power compared to non-resonant systems, but limits the working frequency
bandwidth. Therefore, they are not able to harvest energy when ambient
vibrations' frequencies shift. To follow shifts of ambient vibration
frequencies and to increase the frequency band where energy can be harvested,
one solution consists in using nonlinear springs. We present in this paper a
model of adjustable nonlinear springs (H-shaped springs) and their benefits to
improve velocity-damped vibration energy harvesters' (VEH) output powers. A
simulation on a real vibration source proves that the output power can be
higher in nonlinear devices compared to linear systems (up to +48%).Comment: Please refer to paper "Nonlinear H-Shaped Springs to Improve
Efficiency of Vibration Energy Harvesters", Journal of Applied Mechanics |
Volume 80 | Issue 6, 2013 -- Paper No: JAM-12-1470; doi: 10.1115/1.4023961 --
for the published version of this articl
Electrostatic Conversion for Vibration Energy Harvesting
This chapter focuses on vibration energy harvesting using electrostatic
converters. It synthesizes the various works carried out on electrostatic
devices, from concepts, models and up to prototypes, and covers both standard
(electret-free) and electret-based electrostatic vibration energy harvesters
(VEH).Comment: This is an author-created, un-copyedited version of a chapter
accepted for publication in Small-Scale Energy Harvesting, Intech. The
definitive version is available online at: http://dx.doi.org/10.5772/51360
Please cite as: S. Boisseau, G. Despesse and B. Ahmed Seddik, Electrostatic
Conversion for Vibration Energy Harvesting, Small-Scale Energy Harvesting,
Intech, 201
Cantilever-based electret energy harvesters
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/0964-1726/20/10/105013Comment: This is an author-created, un-copyedited version of an article
accepted for publication in Smart Materials and Structures. IOP Publishing
Ltd is not responsible for any errors or omissions in this version of the
manuscript or any version derived from it. The definitive
publisher-authenticated version is available online at
doi:10.1088/0964-1726/20/10/105013;
http://iopscience.iop.org/0964-1726/20/10/10501
New DRIE-Patterned Electrets for Vibration Energy Harvesting
This paper is about a new manufacturing process aimed at developing stable
SiO2/Si3N4 patterned electrets using a Deep Reactive Ion Etching (DRIE) step
for an application in electret-based Vibration Energy Harvesters (e-VEH). This
process consists in forming continuous layers of SiO2/Si3N4 electrets in order
to limit surface conduction phenomena and is a new way to see the problem of
electret patterning. Experimental results prove that patterned electrets
charged by a positive corona discharge show excellent stability with high
surface charge densities that may reach 5mC/m^2 on 1.1\mu m-thick layers, even
with fine patterning and harsh temperature conditions (up to 250{\deg}C). This
paves the way to new e-VEH designs and manufacturing processes.Comment: Proc. European Energy Conference, 201