Asymmetry stagger array structure ultra-wideband vibration harvester integrating magnetically coupled nonlinear effects

Traditional energy harvesters often have limitations in terms of bandwidth and power output, resulting in poor performance. This study reports a multi-strategy ultra-wideband energy harvesting device that utilizes an asymmetry, stagger array, magnetic coupling, and nonlinearity strategies to achieve high power output over an ultra-wideband frequency range without the need for external power input. The energy harvesting device consists of a base, two elastic beams, and two sets of asymmetric palm-shaped piezoelectric cantilever beam structures, each with a magnet attached at the tip. By reasonably arranging the palm-shaped mechanism and magnets, a magnetic coupling effect is introduced to achieve high power density output at non-resonant frequencies. Numerical analysis is conducted to evaluate the performance of the proposed structure, assess the influence of structural parameters, and establish a dynamic model to analyze the energy harvesting device. Experimental results demonstrate that the structure achieves a maximum power output of 60.49 mW at 19.9 Hz and 0.5 g, with a peak power density of approximately 8.065 × 103 W/m3. Within an ultra-wideband frequency range that spans 6 Hz to 64.2 Hz, the energy harvester maintains an output voltage which is more than 5 V. Furthermore, temperature and humidity monitoring are performed using Bluetooth sensors to adaptively assess the energy harvesting device, eliminating the need for lithium batteries and ensuring stable signal transmission. The device can be utilized for condition monitoring in any unstable vibration environment, contributing to the realization of distributed monitoring in the Internet of Things (IoT).