A piezoelectric vibration energy harvester using multiple nonlinear techniques

This article presents a compact piezoelectric vibration energy harvester (VEH) using multiple nonlinear techniques. Spring-plate and a manually tunable stopper-plate was used to tune the resonance frequency and broaden the bandwidth of VEH. Experimentally, the VEH can be operated in three kinds of work modes according to the gap distance between the spring-plate and the stopper-plate. The simulation results based on mathematic model agree well with the experimental results, indicating that the air elastic effect and initial tensile stress introduced by the pre-deflection have a significant impact on shift in resonance frequency, whereas the increase of bandwidth is attributed to the piecewise-linear stiffness caused by the impact effect and the bistable nonlinear spring caused by the pre-deflection.