Modeling and design of V-shaped piezoelectric vibration energy harvester with stopper for low-frequency broadband and shock excitation

Broadband low-frequency vibration and shock energies are ubiquitous such as biomechanical motion, which can be harvested to power wearable electronics. This paper proposes a compact design of V-shaped piezoelectric vibration energy harvester (V-PVEH) with impact stopper. To demonstrate V-PVEH having high power density, Euler beam model is proposed for qualitative comparison between V-PVEH and cantilevered piezoelectric vibration energy harvester (C-PVEH). FEA model in COMSOL for V-PVEH structure design is proposed especially for the stress check. Modal analysis, two bimorphs connection style, tip mass thickness, and acceleration amplitude are discussed in the experimental vibration validation. A peak voltage of 11.5 V at a low resonant frequency of 12 Hz and a maximum power of 0.442 mW are shown in experiments under the excitation of 0.1 g. A lumped parameters model with nonlinearity analysis for impact induced broadband and shock input is discussed comprehensively. The stopper design in V-PVEH can not only limit the vibration amplitude and prevent overload, but also form broadband of 8-15 Hz and generate large voltage output of 5-19 V when impact occurs at an acceleration of 0.4 g. Except for resonating excitation, biomechanical shock energy harvesting with ultra-low frequency of 1 Hz is testified for wearable V-PVEH to charge a 10 mu F capacitor to 10 V in 5 s by stamping feet. Above all, V-PVEH with stopper is believed to show good performance in broadband low-frequency vibration and biomechanical shock energy harvesting. (C) 2020 Elsevier B.V. All rights reserved.