Construction and Performance Evaluation of a Pendulum-Like Low-Frequency Smoothly Plucked Piezoelectric Vibration Energy Harvester

Piezoelectric vibration energy harvester (PVEH), as a significant technology for distributed energy harvesting, provides a promising energy solution for micropower, self-powered environmental monitoring systems. This article presented a pendulum-like, low-frequency, smoothly plucked PVEH (PL-PVEH) that employed a disc cam to limit the maximum deflection of the piezoelectric element, thereby enhancing its durability. This was in contrast to most existing PVEHs, which lack deflection-limiting mechanisms. Theoretical analysis, fabrication, and experimental validation were conducted to verify the proposed principle and evaluate the effects of structural parameters on the dynamic response characteristics and power generation performance of the PL-PVEH. Experimental results showed that structural parameters, such as proof mass, flexible arm length, and rigid arm length, had minimal impact on maximum voltage. In contrast, as the cam lift increased, the maximum voltage correspondingly increased. It implied that the maximum voltage primarily depended on the cam lift. Moreover, the optimal operating bandwidth exhibited an increase as the proof mass, flexible arm length, and rigid arm length were increased. Conversely, an increase in cam lift led to a decrease in the optimal operating bandwidth. Additionally, the PL-PVEH demonstrated a maximum power output of 0.24 mW at 9 Hz under an optimal load resistance of 600 kΩ, sufficient to power 50 LEDs in series.