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

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, ) or times smaller (Regenerative SECE, ). We first prove analytically than increasing or decreasing both lead to a damping reduction. While has no impact on the system’s resonance frequency in the Regenerative case we show that this resonant frequency becomes a function of in the Multiple SECE case (). Experimental results on a highly coupled/lowly damped piezoelectric harvester demonstrates the potential of this strategy, leading to 257% harvested power improvement compared to SECE (). and the possibility to tune the resonant frequency on a range as large as 35% of the short-circuit resonant frequency of the harvester.