Coupled analysis of a compact autoparametric vibration energy harvester with synchronized switch circuits

Abstract

We previously developed a high-performance autoparametric vibration energy harvester (VEH) with a self-powered synchronized switch circuit, which can realize miniaturization, a low acceleration threshold for triggering the autoparametric resonance, and milliwatt-level power output. However, the mechanical and electrical nonlinearities considering nonlinear stiffness hardening and electrical switching complicate the performance analysis. We established a simpler analysis technique for the autoparametric vibration energy harvester with a synchronized switch circuit. We first derived governing equations and then introduced an equivalent impedance model to simplify the analysis coupled with a synchronized switch circuit. The simulation replicated experimental results well at an acceleration sufficiently higher than the acceleration threshold but not around the acceleration threshold because the acceleration dependency of the inversion coefficient and the switching delay were ignored in the analysis. The analysis technique revealed a complex coupling interaction of the upper and lower oscillators (i.e., the piezoelectric cantilever and the microfabricated oscillator with a seismic mass) and the synchronized switch circuits. The analysis technique is a useful tool for predicting the performance or designing the structure of a compact autoparametric VEH connecting to switch circuits.