Energies (Jul 2020)

Improved Interface Circuit for Enhancing the Power Output of a Vibration-Threshold-Triggered Piezoelectric Energy Harvester

  • Jiqiang Liu,
  • Junjie Yang,
  • Ruofeng Han,
  • Qisheng He,
  • Dacheng Xu,
  • Xinxin Li

DOI
https://doi.org/10.3390/en13153830
Journal volume & issue
Vol. 13, no. 15
p. 3830

Abstract

Read online

The vibration-threshold-triggered piezoelectric energy harvester is a new type of piezoelectric energy harvester with a two-stage structure, which can generate electricity in a low frequency environment and recognize vibration intensity at the same time. In this study, a theoretical model of a vibration-threshold-triggered energy harvester was examined, and an equivalent circuit model of the energy harvester was obtained. Then, an interface circuit was proposed that can significantly improve the output power of the energy harvester. The interface circuit achieved impedance matching with the piezoelectric material to maximize the energy collected from the energy harvester. First, we calculated and analyzed the impedance characteristics of the energy harvester, based on the equivalent circuit model. It was found that because the piezoelectric material is in resonance as the energy harvester is in operation, the corresponding impedance is almost resistance. Therefore, a resistance-matching strategy was proposed. Last, we proposed an interface circuit with adjustable input impedance to achieve resistance matching. The experimental results show that the proposed interface circuit can increase the output power of the energy harvester by 48.1–55.7% over that achieved with the standard interface circuit.

Keywords