Piezoelectric energy harvesting using a diaphragm structure

Energy harvesting using piezoelectric material is not a new concept, but its small generation capability has not been attractive for mass energy generation. For this reason, little research has been done on the topic. Recently, wearable computer concepts, as well as small portable electrical devices, are a few motivations that have ignited the study of piezoelectric energy harvesting again. The theory behind cantilever type piezoelectric elements is well known, but the transverse moving diaphragm elements, which can be used in pressure type energy generation is not yet fully developed. The power generation in a diaphragm depends on several factors. Among them, the thickness of each layer is important. In this paper, two diaphragm structures, unimorph and regrouped unimorph, were used to calculate energy generation with varying thickness ratio using piezoelectric constitutive equation. The results of this analysis are presented with an eye toward guidelines for design of a useful energy harvesting structure.