Experimentally verified model of electrostatic energy harvester with internal impacts

Abstract

This paper presents experimentally verified progress on modeling of MEMS electrostatic energy harvesters with internal impacts on transducing end-stops. The two-mechanical-degrees-of-freedom device dynamics are described by a set of ordinary differential equations which can be represented by an equivalent circuit and solved numerically in the time domain using a circuit simulator. The model accounts for the electromechanical nonlinearities, nonlinear damping upon impact at strong accelerations and the nonlinear squeezed-film damping force of the in-plane gap-closing transducer functioning as end-stop. The comparison between simulation and experimental results shows that these effects are crucial and gives good agreement for phenomenological damping parameters. This is a significant step towards accurate modeling of this complex system and is an important prerequisite to improve performance under displacement-limited operation.