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

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.