Design and Analysis of Piezoelectric Energy Harvesting Systems

Abstract

This Paper presents a new technique of electrical energy generation using mechanically excited piezoelectric materials and a nonlinear process. This technique, called double synchronized switch harvesting (DSSH), is derived from the synchronized switch damping (SSD), which is a nonlinear technique previously developed to address the problem of vibration damping on mechanical structures. This technique results in a significant increase of the electromechanical conversion capability of piezoelectric materials. An optimized method of harvesting vibrational energy with a piezoelectric element using a dc–dc converter is presented. In this configuration, the converter regulates the power flow from the piezoelectric element to the desired electronic load. Analysis of the converter in discontinuous current conduction mode results in an expression for the duty cycle-power relationship. Using parameters of the mechanical system, the piezoelectric element, and the converter; the “optimal” duty cycle can be determined where the harvested power is maximized for the level of mechanical excitation. A circuit is proposed which implements this relationship, and experimental results show that the converter increases the harvested power by approximately 365% as compared to when the dc–dc converter is not used.