Investigation of mechanical nonlinear effect in piezoelectric MEMS vibration energy harvesters

摘要

Nonlinear resonance in piezoelectric vibration energy harvesters (pVEHs) has a large effect on the characteristics of power generation. In this study, the origin of nonlinearity was investigated on MEMS pVEHs using a 3-mu m-thick-Pb(Zr,Ti)O-3 film. The resonant frequency and mass of the pVEHs were 180.6 Hz and 3.63 mg, respectively. From the resonance curves of the output voltage and tip displacement measured at a low acceleration, where linear resonance was obtained, the electromechanical coupling and mechanical quality factors of the pVEHs were determined to be 0.3% and 430, respectively. Although the high output power density of 4.1 mu W mg(-1).G%(-2) was obtained at the acceleration of 0.024 G, the effect of nonlinear resonance appeared and suppressed the output power density at the acceleration of 0.07G and more (G is the gravitational acceleration). The comparison between the results of experiment and numerical analysis using an equivalent circuit model revealed that the nonlinear damping effect has a larger contribution than a nonlinear spring on the suppression of the output power density at a high acceleration. (C) 2018 The Japan Society of Applied Physics