Impact energy harvesting system using mechanical vibration frequency stabilizer

Abstract

Scavenging irregular energy from various environmental impacts has gained great attentions. In this paper, an impact energy harvesting system with a mechanical vibration frequency stabilizer (MVFS) is proposed and evaluated. The MVFS, constructed with a spiral spring and a series of gear sets, can store the short-duration irregular energy, and then stably release it to excite a piezoelectric cantilever with a regular frequency. Torque equations are constructed to analyze the energy transmitting process, and the parameters correlating with the vibration frequency of cantilever. A lab-scale prototype with a dimension of 6.0 × 3.0 × 5.2 cm3 is fabricated and tested. The experimental results demonstrate that the proposed MVFS can realize a frequency stabilization within 33% for the output voltage when the frequency of impact input changes by 436%. This system concept features good compatibility for powering wireless sensor nodes with the impact energy from roads, railways, offices and sports fields.