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Analytical Study of Piezoelectric Harvesters With SECE and SSHI Under Variable Excitation | IEEE Journals & Magazine | IEEE Xplore

Analytical Study of Piezoelectric Harvesters With SECE and SSHI Under Variable Excitation


Abstract:

A theoretical analysis aimed at predicting the power extracted from resonant piezoelectric vibration energy harvesters feeding synchronous switching-type electronic inter...Show More

Abstract:

A theoretical analysis aimed at predicting the power extracted from resonant piezoelectric vibration energy harvesters feeding synchronous switching-type electronic interfaces under variable mechanical excitation is proposed. In particular, for the widely used synchronous electric charge extraction (SECE) and synchronized switching harvesting on an inductor (SSHI) switching interfaces, the nonlinear equations describing the circuit behavior are solved under reasonable assumptions, and closed-form expressions of the extracted power are derived as a function of the circuit parameters and of the vibration characteristics, in the case of modulated mechanical vibrations. Numerical and experimental results validate the proposed closed-form expressions and show their usefulness for design purposes.
Published in: IEEE Transactions on Industry Applications ( Volume: 58, Issue: 2, March-April 2022)
Page(s): 2280 - 2290
Date of Publication: 13 January 2022

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I. Introduction

The power extracted from a resonant piezoelectric vibration energy harvester (RPVEH) strongly depends on the power electronic interface used to rectify its ac output voltage when supplying dc loads [1]–[3]. The simplest ac/dc topology in RPVEH applications is the diode bridge rectifier, often followed by a dc/dc converter feeding a battery/dc load [4], [5]. The goal of the latter converter is the proper control of the rectifier output voltage in order to perform the maximum power point tracking (MPPT) [6], [7]. Although its simplicity, the diode bridge rectifier has the disadvantage of not being able to emulate the optimal load impedance of an RPVEH [7]–[9] because passive rectifiers do not allow the control of the reactive power flow. A single-stage active ac/dc converter overcomes the above drawback since it allows the regulation of both active and reactive power flows and, hence, the emulation of the optimal RPVEH load impedance [7], [10]. In [10], the attention has been focused just on the comparison of the power that can be extracted from an RPVEH when using a diode bridge rectifier or an active full-bridge converter. However, from the designer's point of view, the best choice of the ac/dc interface should be based on both the extractable power and on the overall system complexity, which depends on the power stage topology and on the control circuitry. From this point of view, when adopting active interfaces, in order to emulate the optimal load impedance for maximizing the extracted power, both the amplitude and the phase of the converter input voltage should be online regulated. This can lead to a not negligible increase in the overall system complexity. For the above reason, a great number of interfaces and techniques have been proposed in the literature for optimizing the operation of energy harvesters without resorting to active ac/dc converters [12]–[25]. A single inductor could be added to compensate the negative effect of the piezoelectric output capacitance on the extracted power, but the value of the inductance is usually too large and cannot adapt to the environmental variations [11]. To overcome these drawbacks and to increase the extraction of power with respect to a diode bridge rectifier at the same time, switching-type interfaces, operated synchronously with the vibration of the host structure, have been proposed in recent years [5]. The most widely used and continuously improved techniques are the synchronous electric charge extraction (SECE) [12]–[17] and the synchronized switching harvesting on an inductor (SSHI) [18]–[25]. Due to the great practical importance for design purposes, the prediction of the power harvested from an RPVEH connected to the above interfaces has been investigated in a number of articles in the case of purely sinusoidal input vibrations [12]–[25].

References

References is not available for this document.