Harnessing ultra-low-frequency vibration energy by a rolling-swing electromagnetic energy harvester with counter-rotations

• Published in: Applied energy Vol. 377; p. 124507
• Main Authors: Yin, Peilun, Tang, Lihua, Li, Zhongjie, Xia, Cuipeng, Li, Zifan, Aw, Kean Chin
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01.01.2025
• Subjects: Counter-rotation; Electromagnetic energy harvesting; Rolling-swing; Ultra-low frequency; Ultra-low frequency; Rolling-swing; Electromagnetic energy harvesting; Counter-rotation
• ISSN: 0306-2619
• DOI: 10.1016/j.apenergy.2024.124507

While ultra-low-frequency vibration is a common energy source, electromagnetic energy harvesting from such vibrations presents a challenge due to the low output performance caused by the slow variation of the magnetic field. In this work, we propose a rolling-swing electromagnetic energy harvester (RS-EMEH) that creates the counter-rotations between magnets and coils, thereby amplifying the magnetic field variation within a single cycle of ultra-low-frequency excitation. Simplified dynamic modeling, rigid-body simulation and finite-element analysis are performed to confirm its working mechanism. A unique alternating pole arrangement of magnets is adopted that enhances the output voltage by 2 times as compared to the traditional uniform pole arrangement. Moreover, the experiment of the RS-EMEH prototype validates the above simulation and demonstrates the positive correlation between electrical output and excitation in terms of both frequency (1.10 Hz to 1.50 Hz) and acceleration amplitude (0.05 g to 0.40 g). Further experiment shows that the harvested energy by the RS-EMEH can sustain the operation of a thermometer and calculator simultaneously for 161.3 s under the excitation at 0.4 g, 1.4 Hz for 92.6 s. Specifically, the RS-EMEH can provide milliwatt-level output at the walking speed ≤3.5 km/h, sufficient to power portable wireless low-power electronic devices. The findings of this work unveil the promising power generation and application potential of the rolling-swing electromagnetic energy harvesters for self-powered systems subject to ultra-low-frequency vibrations. [Display omitted] •A novel rolling-swing structure is proposed to harvest ultra-low-frequency vibration.•Counter-rotation feature of rolling-swing structure enables its excellent performance.•Theoretical model and rigid body simulation confirm its working mechanism.•Output power is doubled by the unique alternating pole arrangement of magnets.•Experiments demonstrate its potential for powering multiple low-power devices.