On the interaction between the harvesting structure and the storage circuit of a piezoelectric energy harvester

The interaction between a harvesting structure and a storage circuit is modeled using a full-bridge rectifier. In order to focus on the challenges associated with modeling the intrinsic nonlinearity of the rectifier, the authors have considered a piezoelectric plate in the thickness-stretch mode of oscillation and have represented the storage circuit by a simple LRC circuit in this first attempt. It is found that the primary performance of such a model energy harvester can be characterized by two non-dimensional parameters, i.e., the non-dimensional aspect ratio of the piezoelectric plate and the non-dimensional inductance of the LRC circuit, and that the power density of this model harvester can be optimized by adjusting these two parameters properly. Specifically, for each fixed non-dimensional aspect ratio there exists an optimal non-dimensional inductance, at which the power density is maximized, and conversely, for each fixed non-dimensional inductance there is an optimal non-dimensional aspect ratio, leading to a maximum of the power density when the volume of the plate is kept constant. The analysis for this simplified model piezoelectric harvester, though not realistic, provides a framework for further development on design guidelines for piezoelectric energy harvesters of optimal performance. © 2008 - IOS Press and the authors. All rights reserved.