Three-Port Power Electronic Interface With Decoupled Voltage Regulation and MPPT in Electromagnetic Energy Harvesting Systems

Abstract

In conventional electromagnetic energy harvesting systems, a two-port ac–dc rectifier is utilized to process the harvested power. However, it is difficult to achieve voltage regulation and maximum-power-point-tracking (MPPT) simultaneously. To resolve this issue, this article proposes a three-port power-electronic-interface (PEI) dedicated to this application. A battery port is introduced to buffer the redundant energy. A bidirectional dc–dc converter is utilized to tightly regulate the load side voltage. To capture the maximum power for the harvester, a simple MPPT method is proposed for this PEI. The power tracking of ac source can be simplified by dealing with the power of the battery port. The regulations of power and output voltage are fully decoupled with different control degree-of-freedoms. Moreover, when the harvester is in idle mode, the load can be powered by the battery via the bidirectional dc–dc converter independently. A 24-mW rated laboratory prototype, which processes the power flow among a 0.6 V, 100 Hz ac source, a 1.2 V battery, and a 3.3 V constant voltage load is developed and tested. The proposed concept is validated by experimental results.