An Efficient Power Management Circuit Based on Quasi Maximum Power Point Tracking With Bidirectional Intermittent Adjustment for Vibration Energy Harvesting

A power management (PM) circuit based on quasi maximum power point tracking (qMPPT) by maintaining it in maximum power point (MPP) adjacent area is proposed to improve the vibration energy harvesting efficiency. A larger filter capacitor is used to keep the system working in the MPP adjacent area in a long period of time, and the PM circuit can shut down the dc-dc converter for reducing the overall power consumption. When the system deviates from the MPP, a bidirectional buck-boost dc-dc converter turns on to regulate the filter capacitor voltage or extract energy quickly in a short period of time. The experimental results show that the PM circuit can adjust the optimized operating point with the variation of the vibration, the maximum qMPPT efficiency can reach 98.4%, and the maximum end-to-end energy harvesting efficiency can reach 80.6%. The proposed PM circuit can he used in environments permeated with vibration energy to provide energy for the wireless sensor network nodes.