Power Enhancement in Piezoelectric Energy Harvesting

Abstract: Piezoelectric energy harvesting has been around for almost a decade to generate power from the ambient vibrations. Although the generated power is very small, but there are several ways to increase and enhance the generated power. This project presents different methods of optimizing the output power by changing the structural configuration of the energy harvesters, selection of piezoelectric material and circuit interface of these harvesters. To understand the different steps of the enhancement, the process of energy conversion by piezoelectric material has been first looked at. Different groups of piezoelectric material were studied to see what kind of materials have the ability of increasing the generated power. As mechanical configuration of the energy harvesters has a significant effect on the output voltage, their configuration such as Cantilever beam type, Cymbal type and Circular diaphragms has been described and compared. After the power generated in the piezoelectric crystal , the current is sent to through an interface circuit to get rectified and regulated. This circuit can be modified to increase the power as well. There are several types of circuits that can increase the output voltage significantly. Synchronized Switch Harvesting (SSH) techniques, Synchronous Electric Charge Extraction technique and voltage doubler are such examples. These techniques have been also studied and compared. Because of the outgrowing industry of piezoelectric energy harvesting in Medical field, their function and their progress has also been reviewed.