A Single-Stage Dual-Mode AC-DC Converter for Vibration Energy Harvesting with Uninterrupted Output

Abstract

In this paper, a single stage hybrid dual-mode AC-DC circuit for vibration energy harvesting (EH) is presented. The circuit combines a traditional voltage multiplying (VM) circuit and boost regulator, utilizing the winding inductance from the electromagnetic energy harvester. The proposed circuit converts the AC voltage generated from VM to power the load and stores energy in the super-capacitor when external vibration exists. When external vibration disappears, it will continue powering the load using the energy stored in super-capacitor through boost regulator. Traditional two-stage power regulation of energy harvesting based power supply is reduced to one-stage for smaller system size. Furthermore, the start-up transient is expedited through cooperation of VM and boost regulator. A GaN HEMT and Si schottky diodes based prototype is built to demonstrate the performances. Different operation modes are fully verified. The proposed circuit achieves 3.3V/1.089mW output with designed electromagnetic energy harvester under vibration frequency of 85Hz and acceleration of 0.7g. It can maintain stable output for 30s during the disappearance of vibration. The peak output efficiency of the converter reaches to 85.9%.