A Chinese lantern-inspired low frequency energy harvester with synchronized multi-branched conversion elements

Quasi-zero-stiffness (QZS) mechanism offers a promising avenue for designing self-powered wearable health monitoring system due to its significant potential for low-frequency vibration energy conversion and harvesting. Nevertheless, designing an efficient and yet compact low-frequency energy harvester remains an open challenge. Inspired by the Chinese lantern, this paper proposes a non-contact QZS piezoelectric energy harvester with synchronized multi-branched conversion elements, in views of improving the efficiency of low-frequency vibration energy harvesting. The operational principles and the basic configuration of the Chinese lantern-inspired low frequency energy harvester (CLI-LF EH) are first presented. Subsequently, a comprehensive analysis is conducted to elucidate the relationship between the deformation of the energy conversion element (composite beam) and the displacement generated by the CLI-LF EH. Based on the static analyses, an electromechanical coupling dynamic model is developed, followed by analyses on system dynamics and electrical output with varying system parameters. Finally, experiments are conducted, including an investigation of the energy harvesting performance in relation with the excitation amplitude. The proposed CLI-LF EH is shown to offer superior energy conversion efficiency when subject to low-frequency and small-amplitude ambient vibration compared with previous designs, thanks to the simultaneous deployment of multiple energy conversion elements.