A unified N-SECE strategy for highly coupled piezoelectric energy scavengers

TL;DR

This paper introduces a unified N-SECE strategy for piezoelectric energy harvesters that enhances power output and bandwidth by tuning the energy extraction frequency, validated through experiments showing significant power gains and frequency tuning.

Contribution

It presents a novel N-SECE approach that extends traditional SECE, enabling power maximization and bandwidth enlargement for highly coupled piezoelectric harvesters.

Findings

257% increase in harvested power compared to standard SECE

Resonant frequency can be tuned over 35% of the original frequency

Analytical proof of damping reduction with N adjustments

Abstract

This paper proposes a novel vibration energy harvesting strategy based on an extension of the Synchronous Electric Charge Extraction (SECE) approach, enabling both the maximization of the harvested power and a consequent bandwidth enlargement in the case of highly coupled/lightly damped piezoelectric energy harvesters. The proposed strategy relies on the tuning of the frequency of the energy extraction events, which is either N times greater than the vibration frequency (Multiple SECE case, N > 1) or 1/N times smaller (Regenerative SECE, N < 1). We first prove analytically than increasing or decreasing N both lead to a damping reduction. While N has no impact on the system's resonance frequency in the Regenerative case (N < 1), we show that this resonant frequency becomes a function of N in the Multiple SECE case (N > 1). Experimental results on a highly coupled/lowly damped piezoelectric harvester (k^2= 0.44, Q_m = 20) demonstrates the potential of this strategy, leading to 257% harvested power improvement compared to SECE (N = 1). and the possibility to tune the resonant frequency on a range as large as 35% of the short-circuit resonant frequency of the harvester.