A robust parametrically excited piezoelectric energy harvester with resonant attachment

Drawing inspiration from the enhancement of sensing capabilities in Micro-electro-Mechanical Systems (MEMS), the utilization of parametric resonance with nonlinear amplification features shows promise in vibration energy harvesting. However, harnessing parametric resonance for vibration energy harvesting presents several challenges. Initiating the resonant regime under low-energy conditions can be challenging, and the periodic modulation of system parameters requires additional time to accumulate the vibration amplitude. The range of modulation frequencies needs to trigger parametric resonance is notably narrow, especially when employing piezoelectric transducers for energy harvesting. To address these concerns, a parametrically excited piezoelectric energy harvester incorporating with a movable resonant attachment is proposed. The governing equations of this system were derived using the extended Hamilton principle and then numerically solved. Experimental testing was performed based on the design, and it displayed good agreement with numerical predictions. System parametric studies were carried out, revealing the mutual influence among critical system parameters. The findings demonstrate that the proposed device exhibited hardening dynamic responses and achieved more than a fivefold increase in overall bandwidth compared to a conventional parametrically excited counterpart.