A Comparison between the Standard and SSHI Interfaces used in Piezoelectric Power Harvesting

摘要

This article provides an analysis for the performance evaluation of a piezoelectric power harvesting system using either the standard or SSHI electronic interfaces. Instead of using the un-coupled and in-phase assumptions, an analytic expression of harvested power is proposed for the SSHI circuit based on the improved analysis. It is shown that the behavior of an ideal SSHI system is similar to that of strongly coupled electromechanical system using the standard interface operated at the short circuit resonance. In addition, the performance evaluation of a SSHI circuit is classified according to the relative magnitudes of electromechanical coupling coefficient and the mechanical damping ratio. It is found that the best use of the SSHI harvesting circuit is for the system with the medium range of electromechanical coupling. The performance degradation due to the non-perfect voltage inversion is not pronounced in this case, and a new finding shows that the average harvested power is much less sensitive in frequency compared to that using the standard interface.