An electromagnetic rotational energy harvester using sprung eccentric rotor, driven by pseudo-walking motion

M.A. Halim, R. Rantz, Q. Zhang, L. Gu, K. Yang and S. Roundy

Applied Energy, 2018, vol. 217, issue C, 66-74

Abstract: In this work, an electromagnetic energy harvesting device using a sprung eccentric rotor has been designed, optimized and characterized to harvest power from pseudo-walking signals (a single frequency sinusoidal signal derived from motion of a driven pendulum that approximates the swing of a human-arm during walking). Our analysis shows that a rotor with an eccentric mass suspended by a torsional spring enhances the mechanical energy captured from low-frequency excitations (e.g., those produced during human walking, running/jogging). An electromagnetic transducer in the sprung eccentric rotor structure converts the captured mechanical energy into electrical energy. An electromechanical dynamic model of a sprung eccentric rotor has been developed and an optimization routine was performed to maximize output power under pseudo-walking excitation. The structure of the electromagnetic transducer was refined using Finite Element Analysis (FEA) simulations. A prototype energy harvester was fabricated and tested in a pseudo wrist-worn situation (by mounting on a mechanical swing-arm) to mimic the low-frequency excitation produced during human walking. A series of pseudo-walking motions was created by varying the swing profile (angle and frequency). The prototype with optimal spring stiffness generates a maximum 61.3 μW average power at ±25° rotational amplitude and 1 Hz frequency which is about 6-times higher than its unsprung counterpart under same excitation condition. The experimental results are in good agreement with the simulation results.

Keywords: Electromagnetic energy harvester; Pseudo-walking motion; Eccentric rotor; Torsional spring; Magnet pole-pairs; Mechanical swing-arm (search for similar items in EconPapers)
Date: 2018
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Citations: View citations in EconPapers (27)

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Persistent link: https://EconPapers.repec.org/RePEc:eee:appene:v:217:y:2018:i:c:p:66-74

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DOI: 10.1016/j.apenergy.2018.02.093

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