FEM analysis of vibration energy harvester with 3D micro-structure for low frequency vibration

Abstract

In recent years, self-powered sensor nodes for wireless sensor networks has been developed by energy harvester. Especially, vibration energy harvester (VEH) has attracted much attention because of the higher energy density, the simplicity of configuration, and the affinity with the micromachining technology. In this paper, we propose a piezoelectric VEH having 3D zigzag micro-structure as an elastic layer of cantilever in order to achieve lower resonance frequency than 10 Hz and improve power generation efficiency. In order to confirm the validity of the proposed piezoelectric VEH, we compared two kinds of VEHs (having 3D zigzag structure and solid flat plate as an elastic layer of a cantilever) by modal analysis and piezoelectric coupling analysis. As a result of modal analysis, the proposed 3D zigzag VEH lowers primary resonance frequency by 59%. Moreover, regarding the coupling analysis, the proposed VEH shows 1.6 times higher output electric power than flat plate one at each resonant condition.