A new piezoelectric energy harvester using two beams with tapered cavity for high power and wide broadband

摘要

Designing a wideband vibration based piezoelectric energy harvester is a challenging problem and is currently being investigated by many researchers. In this work, a new piezoelectric energy harvester is proposed to enhance broadband frequency using two beam structures which have variable cross section and tapered cavity. The wider operating frequency range is achieved by bringing the second mode frequency closer to the first mode maintaining the mass ratio between bigger beam and smaller beam. In addition, the enhancement in the magnitude of the generated output voltage is achieved by introducing the tapered cavity. Therefore, the proposed harvester provides enhanced output voltage and power in first mode as well as second mode of the resonance frequency. In order to accomplish this target, the harvester is analytically modeled using Euler Bernoulli beam theory with Bessel functions and the effectiveness is experimentally demonstrated. It is shown the magnitude of the generated voltage is increased as the cavity thickness increases. It is also validated that the generated voltage and harvested power from the analytical model agree well with the measured results in wide frequency.