Modeling and characterization of capacitor storage circuit for piezoelectric vibration energy harvester

Abstract

Purpose This paper aims to study a power management circuit for a piezoelectric vibration energy harvester. It presents how to accumulate energy and provide regulated DC voltage for practical applications. Design/methodology/approach Energy storage and extraction circuit are proposed. While the storage stage consists of a full wave rectifier and a storage capacitor, the extraction stage includes a voltage comparator and regulator, which may provide the load steady DC voltage when the voltage of the storage capacitor is higher than the threshold. Findings The numerical analysis and experimental results indicate that it takes a longer time to charge to a specified voltage for the greater storage capacitor and the net charge flowing into the storage capacitor during each period decreases when the voltage of the storage capacitor is higher. The higher threshold voltage of the capacitor has lower harvesting efficiency owing to the rate of charging of the storage capacitor slowing down over time. Research limitations/implications Because of the chosen research method, the power management circuit is only suitable for the piezoelectric vibration energy harvester under resonant conditions. Practical implications This study includes practically useful applications for users to build a power management circuit for piezoelectric energy harvester. Originality/value This study presents results that the charging efficiency of the storage circuit is relative to the storage capacitor and the threshold voltage.