Optimization of an Energy Harvester Coupled to a Vibrating Membrane

Abstract

Resonant energy harvesters are generally designed for the operating frequency of the host structure. However, when the flexibility and mass parameters of the host structure are comparable to those of the energy harvester, mounting an energy harvester on the host structure may change the vibration characteristics of the host structure considerably. In this study, modeling and optimization of an energy harvester coupled to a vibrating membrane are presented to show the effect of dynamic coupling on maximum voltage output of the energy harvester. First, the optimum design parameters of an energy harvester are calculated to obtain maximum voltage output from piezoelectric material for a given excitation at a specified frequency by considering the dynamics of the energy harvester only. Then, by using the finite element (FE) models of the membrane and the energy harvester, coupled analysis is made and design parameters are optimized to obtain maximum voltage output from piezoelectric material. Finally, the voltage output results from two optimization approaches are compared and it is observed that maximum voltage obtained by considering the coupling effects is several times higher than the voltage output obtained from the energy harvester designed traditionally. The study shows that disregarding the host structure that energy harvesters are mounted in optimization stage may prevent us to find the optimum design parameters.