Investigating the vibration-based energy harvester characteristics to obtain maximum efficiency for an electrical interface

This work presents an electrical interface design for a vibration-based energy harvester which is aimed for low power electronics applications. The electrical interface circuits consist of two distinct components: a voltage doubler and a voltage booster circuits. The voltage doubler and voltage booster circuits were simulated in the LTSpice IV simulator to determine the output response when the magnitude of the input voltage or the oscillating frequency was changed. The sensitivity study carried out in simulation was later validated through experimental studies. An AC power supply and a resistive loading R were used to simulate the energy harvester and the battery management circuit, respectively. In this study, the maximum efficiency for the combined voltage doubler and booster circuits was found to be approximately 40% for an input voltage of 4 Vp-p, input frequency of 100 Hz at 50 kΩ loading. The overall efficiency was found to decrease with increasing of loading resistance.