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

作者：Halim M A^*; Rantz R; Zhang Q; Gu L; Yang K; Roundy S

来源：Applied Energy, 2018, 217: 66-74.

DOI：10.1016/j.apenergy.2018.02.093

• Electromagnetic energy harvester
• Pseudo-walking motion
• Eccentric rotor
• Torsional spring
• Magnet pole-pairs
• Mechanical swing-arm

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 mu W average power at +/- 25 degrees 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.

• 出版日期2018-5-1