Piezoelectric energy enhancement strategy for active fuzzy harvester with time-varying and intermittent switching

Yushin Hara, Meng Zhou, An Li, Keisuke Otsuka, Kanjuro Makihara

Research output: Contribution to journalArticlepeer-review

9 Citations (Scopus)


This study aims to increase the amount of electrical energy harvested from a piezoelectric vibration energy harvester under unloaded and high-load resistance conditions. Although increased piezoelectric charge due to the synchronized switch harvesting on inductor (SSHI) strategy damps mechanical vibrations, the mechanical vibration amplitude of a mechanical element in a harvester is assumed to be constant for most discussions regarding the active harvester with SSHI strategy. However, this assumption is not valid under excessive switching actions, in which case the performance of the harvester deteriorates. This problem is known as the vibration suppression effect. To address this problem, in this study, two switching strategies for the charge inversion circuit - namely, switching considering vibration suppression-threshold (SCVS-t) and adaptive SCVS-t (ASCVS-t) - are proposed through intermittent switching actions. During the harvesting process, intermittent switching using these strategies is performed based on the output voltage threshold, thus maintaining high mechanical vibration amplitude and excellent harvesting performance by avoiding excess switching. The ASCVS-t adopts a tuning algorithm for the time-varying threshold and can achieve appropriate intermittent switching and effective harvesting under various vibration conditions without pre-tuning. Experimental comparisons with conventional strategies confirm that the proposed strategies achieve 2.9 times and 2.0 times greater harvested energy storages than a standard harvester and conventional switching strategy, respectively.

Original languageEnglish
Article number015038
JournalSmart Materials and Structures
Issue number1
Publication statusPublished - 2021 Jan


  • adaptive control
  • intermittent switching
  • multi-modal vibration
  • semi-active control
  • switching strategy
  • synchronized switch harvesting on inductor (SSHI)

ASJC Scopus subject areas

  • Signal Processing
  • Civil and Structural Engineering
  • Atomic and Molecular Physics, and Optics
  • Materials Science(all)
  • Condensed Matter Physics
  • Mechanics of Materials
  • Electrical and Electronic Engineering


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