Analysis of multi-direction low-frequency vibration energy harvester using diamagnetic levitation

2015 ◽  
Vol 47 (3) ◽  
pp. 847-860 ◽  
Author(s):  
Zhitong Ye ◽  
Zhiyong Duan ◽  
Liushuai Su ◽  
Kenichi Takahata ◽  
Yufeng Su
2016 ◽  
Vol 28 (5) ◽  
pp. 578-594 ◽  
Author(s):  
Sri Vikram Palagummi ◽  
Fuh-Gwo Yuan

This article identifies and studies key parameters that characterize a horizontal diamagnetic levitation mechanism–based low frequency vibration energy harvester with the aim of enhancing performance metrics such as efficiency and volume figure of merit. The horizontal diamagnetic levitation mechanism comprises three permanent magnets and two diamagnetic plates. Two of the magnets, lifting magnets, are placed co-axially at a distance such that each attracts a centrally located magnet, floating magnet, to balance its weight. This floating magnet is flanked closely by two diamagnetic plates which stabilize the levitation in the axial direction. The influence of the geometry of the floating magnet, the lifting magnet, and the diamagnetic plate is parametrically studied to quantify their effects on the size, stability of the levitation mechanism, and the resonant frequency of the floating magnet. For vibration energy harvesting using the horizontal diamagnetic levitation mechanism, a coil geometry and eddy current damping are critically discussed. Based on the analysis, an efficient experimental system is setup which showed a softening frequency response with an average system efficiency of 25.8% and a volume figure of merit of 0.23% when excited at a root mean square acceleration of 0.0546 m/s2 and at a frequency of 1.9 Hz.


2013 ◽  
Vol 22 (11) ◽  
pp. 115037 ◽  
Author(s):  
Suna Ju ◽  
Song Hee Chae ◽  
Yunhee Choi ◽  
Seungjun Lee ◽  
Hyang Woon Lee ◽  
...  

2015 ◽  
Vol 137 (6) ◽  
Author(s):  
S. Palagummi ◽  
J. Zou ◽  
F. G. Yuan

This paper investigates a horizontal diamagnetic levitation (HDL) system for vibration energy harvesting in contrast to the vertical diamagnetic levitation (VDL) system recently proposed by Wang et al. (2013, “A Magnetically Levitated Vibration Energy Harvester,” Smart Mater. Struct., 22(5), p. 055016). In this configuration, two large magnets, alias lifting magnets (LMs), are arranged co-axially at a distance such that in between them a magnet, alias floating magnet (FM), is passively levitated at a laterally offset equilibrium position. The levitation is stabilized in the horizontal direction by two diamagnetic plates (DPs) made of pyrolytic graphite placed on each side of the FM. This HDL configuration mitigates the limitation on the amplitude of the FM imposed in the VDL configuration and exploits the ability to tailor the geometry to meet specific applications due to its frequency tuning capability. A simple circular coil geometry is designed to replace a portion of the pyrolytic graphite plate without sacrificing the stability of the levitation for transduction. An experimental setup exhibits a weak softening frequency response and validates the theoretical findings; at an input root mean square (RMS) acceleration of 0.0434 m/s2 and at a resonant frequency of 1.2 Hz, the prototype generated a RMS power of 3.6 μW with an average system efficiency of 1.93%.


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