Digitally Controlled Power Management Circuit With Dual-Functioned Single-Stage Power Converter for Vibration Energy Harvesting

This article proposes a digitally controlled power management circuit (PMC) for vibration energy harvesting in a vehicle suspension system. The PMC is tested with a mechanical motion rectifier (MMR)-based electromagnetic energy harvester that converts from bidirectional vibration to unidirectional rotation, with improved energy harvesting performance and efficiency. The topology of the one-stage dc–dc converter is adapted, and it is digitally controlled while considering the uncertainty of vibration sources. In order to efficiently transfer the harvested power to the electrical load, the algorithm of the digital controller is designed to have four operation modes: the impedance matching mode, the voltage regulation mode, the generator protection mode, and the low power mode, for increasing the PMC efficiency while reducing the power consumption of controller. Experimental results show that the proposed circuit can successfully operate and switch between the four operation modes. In the evaluation of PMC performance with 2-mm and 2-Hz excitation, the efficiency of the proposed one-stage power converter is 86%. The total power consumptions of the controller in the active mode and the low power mode are 109 and 2.52 mW, respectively, while harvesting about 3-W vibration energy.