An analytical model using order reduction method for out-of-plane electrostatic sound energy harvesters

J. Li, C. Xu, L. Zhang, G. James, J. Tichy, D.-A. Borca-Tasciuc
Rensselaer Polytechnic Institute,
United States

Keywords: energy harvesting, MEMS, order-reduced modeling


Electrostatic microscale generators able to convert sound energy into electricity for wireless sensors are of interest for deep repository monitoring. Converters using out-of-plane, silicon-based variable capacitors are best suited for this purpose. Such devices employ a membrane with interdigitated electrodes to capture sound force. The power generation efficiency is positive correlated with the relative displacement of the interdigitated electrodes, thus the displacement has to be optimized in the design process. A unique challenge to out-of-plane structure design is the bending of membrane, which makes the standard lumped element modeling highly inaccurate to predict the dynamic response, and more specifically the electrodes’ displacement. This paper presents a method based on order reduction for developing a simplified analytical model for out-of-plane topology, which can accurately predict the electrodes’ displacement for a set of dimension parameters.