Large-bandwidth piezoelectric energy harvesting with frequency-tuning synchronized electric charge extraction

Abstract

This paper reports, for the first time, experimental evidence of the effectiveness of the frequency-tuning synchronized electrical charge extraction technique (FTSECE) with a strongly-coupled generator. The ratio between the system bandwidth (7 Hz) and the natural bandwidth of the transducer (0.688 Hz) is 1017 %, surpassing previous demonstrations of synchronized charge extraction methods by a large extent. We prove that the bandwidth of the FTSECE system is only limited by the unideal characteristics of the circuit components and generator. This is a major advantage of FTSECE as opposed to other competitive methods where the bandwidth is intrinsically mathematically limited, even in the hypothetical presence of ideal components. We also propose a new circuit for the implementation of FTSECE, which allows the piezoelectric generator to be connected to the same ground as the control circuit. Our experimental setup based on the combination of a strongly-coupled piezoelectric generator and a FTSECE architecture allows operation at a maximum power plateau on a +/-3.5 % interval around the resonance frequency. The resulting full width at half maximum (FWHM) is +/-10 % around the resonance frequency, which corresponds to +200 % compared to most up-to-date architectures designed for bandwidth enhancement, with the advantage of suppressing local minima in the power responses.