# Modeling and Optimization of an Electrostatic Energy Harvesting Device

Andrea Crovetto, Fei Wang, Ole Hansen

Research output: Contribution to journalJournal articleResearchpeer-review

### Abstract

Modeling of energy harvesting devices is complicated by the coupling between electrical and mechanical domains. In this paper, we present a coupled electromechanical model for electret-based resonant energy harvesters where the two output pads are placed on the same device side (single-sided). An analytical analysis is complemented by 2-D finite element method simulations, where the fringing field effect on a plane capacitor is studied and accounted for by an effective area that is well fitted by a sinusoidal function of the displacement of the proof mass. From analytical calculations, we prove that the electrostatic transducer force is related to the voltage output and cannot be approximated by viscous damping or a Coulomb force as reported previously. The coupled model with two simultaneous differential equations is numerically solved for the voltage output and transduction force with given parameters. The model was verified both by practical measurements from our own fabricated device and results from a reference. An optimization study is carried out using this model to achieve the maximum output power by tuning the allowable movement (XM) of the proof mass. Finally, the effect of a standard power-conditioning circuit is investigated for both continuous and burst power supply applications.
Original language English I E E E Journal of Microelectromechanical Systems 23 5 1141-1155 1057-7157 https://doi.org/10.1109/JMEMS.2014.2306963 Published - 2014

### Keywords

• Energy harvesting
• MEMS
• Electret
• Modelling

### Cite this

@article{f7890e27632d40ecb2e99ea9b7db0824,
title = "Modeling and Optimization of an Electrostatic Energy Harvesting Device",
abstract = "Modeling of energy harvesting devices is complicated by the coupling between electrical and mechanical domains. In this paper, we present a coupled electromechanical model for electret-based resonant energy harvesters where the two output pads are placed on the same device side (single-sided). An analytical analysis is complemented by 2-D finite element method simulations, where the fringing field effect on a plane capacitor is studied and accounted for by an effective area that is well fitted by a sinusoidal function of the displacement of the proof mass. From analytical calculations, we prove that the electrostatic transducer force is related to the voltage output and cannot be approximated by viscous damping or a Coulomb force as reported previously. The coupled model with two simultaneous differential equations is numerically solved for the voltage output and transduction force with given parameters. The model was verified both by practical measurements from our own fabricated device and results from a reference. An optimization study is carried out using this model to achieve the maximum output power by tuning the allowable movement (XM) of the proof mass. Finally, the effect of a standard power-conditioning circuit is investigated for both continuous and burst power supply applications.",
keywords = "Energy harvesting, MEMS, Electret, Modelling",
author = "Andrea Crovetto and Fei Wang and Ole Hansen",
year = "2014",
doi = "10.1109/JMEMS.2014.2306963",
language = "English",
volume = "23",
pages = "1141--1155",
journal = "I E E E Journal of Microelectromechanical Systems",
issn = "1057-7157",
publisher = "Institute of Electrical and Electronics Engineers",
number = "5",

}

Modeling and Optimization of an Electrostatic Energy Harvesting Device. / Crovetto, Andrea; Wang, Fei; Hansen, Ole.

In: I E E E Journal of Microelectromechanical Systems, Vol. 23, No. 5, 2014, p. 1141-1155.

Research output: Contribution to journalJournal articleResearchpeer-review

TY - JOUR

T1 - Modeling and Optimization of an Electrostatic Energy Harvesting Device

AU - Crovetto, Andrea

AU - Wang, Fei

AU - Hansen, Ole

PY - 2014

Y1 - 2014

N2 - Modeling of energy harvesting devices is complicated by the coupling between electrical and mechanical domains. In this paper, we present a coupled electromechanical model for electret-based resonant energy harvesters where the two output pads are placed on the same device side (single-sided). An analytical analysis is complemented by 2-D finite element method simulations, where the fringing field effect on a plane capacitor is studied and accounted for by an effective area that is well fitted by a sinusoidal function of the displacement of the proof mass. From analytical calculations, we prove that the electrostatic transducer force is related to the voltage output and cannot be approximated by viscous damping or a Coulomb force as reported previously. The coupled model with two simultaneous differential equations is numerically solved for the voltage output and transduction force with given parameters. The model was verified both by practical measurements from our own fabricated device and results from a reference. An optimization study is carried out using this model to achieve the maximum output power by tuning the allowable movement (XM) of the proof mass. Finally, the effect of a standard power-conditioning circuit is investigated for both continuous and burst power supply applications.

AB - Modeling of energy harvesting devices is complicated by the coupling between electrical and mechanical domains. In this paper, we present a coupled electromechanical model for electret-based resonant energy harvesters where the two output pads are placed on the same device side (single-sided). An analytical analysis is complemented by 2-D finite element method simulations, where the fringing field effect on a plane capacitor is studied and accounted for by an effective area that is well fitted by a sinusoidal function of the displacement of the proof mass. From analytical calculations, we prove that the electrostatic transducer force is related to the voltage output and cannot be approximated by viscous damping or a Coulomb force as reported previously. The coupled model with two simultaneous differential equations is numerically solved for the voltage output and transduction force with given parameters. The model was verified both by practical measurements from our own fabricated device and results from a reference. An optimization study is carried out using this model to achieve the maximum output power by tuning the allowable movement (XM) of the proof mass. Finally, the effect of a standard power-conditioning circuit is investigated for both continuous and burst power supply applications.

KW - Energy harvesting

KW - MEMS

KW - Electret

KW - Modelling

U2 - 10.1109/JMEMS.2014.2306963

DO - 10.1109/JMEMS.2014.2306963

M3 - Journal article

VL - 23

SP - 1141

EP - 1155

JO - I E E E Journal of Microelectromechanical Systems

JF - I E E E Journal of Microelectromechanical Systems

SN - 1057-7157

IS - 5

ER -