A three-port power electronic interface to harvest the maximum power in electromagnetic energy harvesting systems

In conventional electromagnetic energy harvesting systems, a two-port pulse-width-modulated ac/dc converter is utilized to process the harvested power. However, it is difficult to achieve voltage regulation and maximum-power-point tracking simultaneously. To resolve this issue, this paper proposes a three-port power-electronic-interface for this specific application. A battery is introduced to buffer the redundant energy in harvest mode. A bidirectional dc/dc converter is utilized to regulate the load side voltage. Thus, the regulations of power and voltage are fully decoupled, which makes it easier to trace the maximum-power-point. Moreover, when the harvester is in idle mode, the battery provides power to the load via the bidirectional dc/dc converter. A 10 mW rated converter 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.