Theoretical modelling and experimental investigation on a frequency up-converted nonlinear piezoelectric energy harvester

Abstract

Ambient vibration energy harvesting has attracted the great attention of numerous researchers to replace the battery power supply strategy of electronic devices. However, the high natural frequency and narrow broadband operation are still significant shortcomings of the conventional vibration energy harvesters to be widely deployed. This paper presents a novel piezoelectric energy harvester (PEH) based on the traditional impact frequency up-converted PEH to achieve lower and broader operating frequency. Nonlinear magnetic force is adopted to regulate the working frequency of PEH. Distributed-parameter modelling and magnetic force simplified modelling are applied in analyzing the piecewise linear dynamic characteristics of the low-frequency driving beam, and the piezoelectric effect is employed for calculating the output voltage of the high-frequency generating beams. Theoretical results comparison between the traditional impact PEH and the proposed novel PEH shows that the introduced nonlinear magnetic force offers a lower initial frequency and broader operating bandwidth. The comparison experimental study achieves a close match to the theoretical results. Under excitation conditions of 3 m/s 2 excitation acceleration, 3 mm impact distance, and 19 mm magnet distance, the initial frequency decreases by about 9.5 Hz, and the operating bandwidth increases from 9 Hz to 16.5 Hz. The maximum power output value of the proposed PEH is 0.491 mW. The novel proposed PEH in this paper provides promising guidance and understanding for energy harvesting in low and broadband environmental vibration. • A novel frequency up-converted nonlinear piezoelectric energy harvester (PEH) is proposed for lower and wider bandwidth energy harvesting. • Developed the theoretical model and analyzed the performance of the device based on averaging method. • The comparison experimental results achieve a close match to the theoretical research that the novel PEH has lower and wider operating frequency than the conventional impact PEH.