The Effect of Non-linear Piezoelectric Coupling on Vibration-based Energy Harvesting

Advances in electronic and consumer technology are increasing the need for smaller, more efficient energy sources. Thus vibration-based energy harvesting, the scavenging of energy from existing ambient vibration sources and its conversion to useful electrical power, is becoming an increasingly attractive alternative to traditional power sources such as batteries. Energy harvesting devices have been developed based on a number of electromechanical coupling mechanisms and their design must be optimized to produce the maximum output for given environmental conditions. While the role of non-linearities in the components has been shown to be significant in terms of the overall device efficiency, few studies have systematically investigated their influence on the system performance. In this work the role of a non-linear piezoelectric relationship is considered on the performance of a vibration-based energy harvester. Using a Poincare-Lindstedt perturbation analysis the response of the harvesting system is approximated, including mechanical damping, stiffness non-linearities, and the above mentioned non-linear piezoelectric constitutive relationship. The predicted behavior is then compared against numerical simulations of the original system, focusing on the relationship between the power generated by the device, the ambient vibration characteristics, and the non-linearities in the system.