An improved analysis of the SSHI interface in piezoelectric energy harvesting

Abstract

This paper provides an analysis for the performance evaluation of a piezoelectric energy harvesting system using the synchronized switch harvesting on inductor (SSHI) electronic interface. In contrast with estimates based on a variety of approximations in the literature, an analytic expression of harvested power is derived explicitly and validated numerically for the SSHI system. It is shown that the electrical response using an ideal SSHI interface is similar to that using the standard interface in a strongly coupled electromechanical system operated at short circuit resonance. On the other hand, if the SSHI circuit is not ideal, the performance degradation is evaluated and classified according to the relative strength of coupling. It is found that the best use of the SSHI harvesting circuit is for systems in the mid-range of electromechanical coupling. The degradation in harvested power due to the non-perfect voltage inversion is not pronounced in this case, and a new finding shows that the reduction in power is much less sensitive to frequency deviations than that using the standard technique.

Nonlinear Conversion Enhancement for Efficient Piezoelectric Electrical Generators

“…Now the basic principles of the nonlinear conversion enhancement exposed, this section proposes the direct application of this concept to energy harvesting, leading to the concept of Synchronized Switch Harvesting on Inductor Lefeuvre et al, 2006a;Shu, Lien and Wu, 2007;Liang and Liao, 2009;Qiu et al, 2009b). Considering the standard energy harvesting interface that consists in connecting the piezoelectric element to a smoothing capacitor C S and load R L (that represents the connected device) through a diode bridge rectifier (Figure 4(a)), the switching element may be placed in two ways: When using the standard interface, it can be demonstrated that the harvested energy under a constant vibration magnitude u M is given in steady state case by : …”

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“…They have claimed that the harvested electrical power may be increased by as much as 900% over the standard technique. Then, Sue et al [29] detailed the analysis for the performance of a piezoelectric energy harvesting system using the synchronized switch harvesting on inductor (SSHI) electronic interface. It shows that the electrical response using an ideal SSHI interface is similar to that using the standard interface in a strongly coupled electromechanical system operated at short circuit resonance.…”

Ferroelectric Materials for Small-Scale Energy Harvesting Devices and Green Energy Products

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