Self-Powered Collaborative Energy Harvesting Interface Circuit for Stacked Multiple Piezoelectric Elements

To hold promise for the high-power demands of wireless sensor networks nodes, energy harvesting from discrete multiple piezoelectric elements (multi-PEs) has started to be of research interest. However, few interface circuits are developed for stacked multi-PEs. This article proposes a self-powered collaborative energy harvesting (CEH) interface circuit for stacked multi-PEs. It regards one PE as an auxiliary energy source and transfers accumulated energy from this PE to the other to enhance the total output power. Theory and experiments are carried out to demonstrate the advantages of the CEH circuit. It achieves a 10.3% gain in terms of peak output power, compared to the sum of each individual peak output power, and the peak power of every PE reaches 3.1 times that of the full-bridge rectifier circuit. In addition, the output power of the CEH circuit is load-independent (or at least weakly dependent), the changes in load have a relatively minor impact on the output power.