Low-frequency vibration energy harvester using a spherical permanent magnet with controlled mass distribution

Choi, Yunhee; Ju, Suna; Chae, Song Hee; Jun, S.; Ji, Chang-Hyeon

doi:10.1088/0964-1726/24/6/065029

Cited by 27 publications

(13 citation statements)

References 19 publications

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“…At the beginning of the 21 st century, scholars replaced other liquids in tuned liquid dampers with MFs, on account of their controllable flow, to enhance the energy consumption efficiency of tuned MF dampers [8][9][10]. As energy issues attract more and more attention, the combination of MF dampers and energy harvesters has made a remarkable progress in the past decade [11][12][13][14]. Vibration energy harvesters are suitable for energy scarcity environments and are conducive to the development of devices miniaturization.…”

Section: Introductionmentioning

confidence: 99%

Hexagonal Structure Enhancing Damping Efficiency Inspired by Tree Frogs

2022

Preprint

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Magnetic fluid shock absorbers (MFSAs) have been successfully applied in eliminating the micro-vibration of the spacecraft’s flexible structures. The method of enhancing the damping of MFSAs has always been the key issue. The tree frog’s toe pads exhibit the strong adhesion, which inspired us to learn from their surface structure. We got hundreds of scanning electron microscope images of the tree frog’s toe pads surface and used the edge extraction algorithm to obtain the result that the geometric shape with the largest proportion in these images is hexagon. According to this result, hexagonal surface textures were added to the inner surface of the MFSA and a small part of the MFSA was taken for further simulation analysis. The flow distribution of the magnetic fluid (MF) acquired from the simulation clearly illustrates that the surface textures cause vortexes formation in the MF layer. These vortexes increase the shear rate between the MF layers, thereby augmenting the flow resistance. The vibration reduction experiments were carried out and MFSAs employed in these experiments were fabricated by 3D printing technology. Consequently, the bionic textures mimicking the tree frog’s toe pads surface can significantly improve the damping performance of MFSAs.

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Section: Introductionmentioning

confidence: 99%

Hexagonal Structure Enhancing Damping Efficiency Inspired by Tree Frogs

2022

Preprint

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“…Therefore, it possesses the advantages of better generation efficiency and easy design. (9,10) With regard to induction-type lighting equipment, few possess an energy storage feature other than a battery. Therefore, in this work, an ultracapacitor incorporated within a control circuit is developed to constitute a circuit with an uninterruptible power supply (UPS) function.…”

Section: Introductionmentioning

confidence: 99%

An Electromagnetic Energy Harvester and Energy Storage System for Bike Lighting Applications

Chang¹,

Cheng²,

Chan³

et al. 2018

Sensors and Materials

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Keywords: electromagnetic energy harvester, uninterruptible energy storage circuit, lighting applicationsIn this work, we propose an electromagnetic energy harvester and energy storage system for bike lighting applications. On the basis of an energy harvester technique, an electromagnetic mechanism will be designed to drive light-emitting diodes (LEDs). The circuit framework, which comprises an electromagnetic energy harvester, an energy storage capacitor, a boost controller and lighting LEDs, is a kind of wireless sensors network (WSN). This novel design has the following features: (1) the LED is driven via an electromagnetic mechanism without the need for an external power source or battery, (2) an ultracapacitor is used as an energy storage device to deposit induction energy when the bicycle is moving, and (3) power is uninterruptible because electric energy accumulated on the ultracapacitor is supplied to the LED when the bicycle is stopped. In order to verify the feasibility of the proposed bike lighting applications, a prototype electromagnetic energy harvester with the electronic circuit is installed and tested on a bicycle. The experimental results indicate a satisfactory performance. The LED is effectively lit whether the bicycle is moving or at rest.

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“…For miniature and micro scale power generators, rotary turbines supported by miniature bearings, metal balls, and air-bearing have been proposed [ 9 , 10 , 11 ]. In contrast, spherically or cylindrically-shaped permanent magnets or metal structures have been utilized as springless proof mass in vibration energy harvesters to provide smooth motion with less friction and wear [ 12 , 13 , 14 , 15 , 16 , 17 , 18 , 19 ]. Bowers et al utilized a spherical permanent magnet rolling randomly inside the cavity wrapped with coil [ 12 ] and Pillatsch et al developed an impulse-excited harvester where a cylindrical proof mass actuates an array of piezoelectric bimorph beams through magnetic attraction [ 14 ].…”

Section: Introductionmentioning

confidence: 99%

“…Ju et al proposed a magnetoelectric harvester where a spherical permanent magnet actuates the magnetoelectric laminate composite and impact-based piezoelectric harvester using a metal ball [ 17 , 18 ]. Among the previously reported harvesters using rolling motion of springless proof mass, random [ 12 , 13 , 15 ] or linear motion [ 14 , 16 , 17 , 18 ] of the proof mass have been utilized. Utilization of spherically or cylindrically-shaped proof mass provides a simple way of generating frequency-independent large displacement motion in harvesting devices, but effective use of magnetic flux with narrow gap between magnet and coil becomes very challenging for electromagnetic harvesters.…”

Section: Introductionmentioning

confidence: 99%

Electromagnetic Linear Vibration Energy Harvester Using Sliding Permanent Magnet Array and Ferrofluid as a Lubricant

Chae

Choi

et al. 2017

Micromachines

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We present an electromagnetic linear vibration energy harvester with an array of rectangular permanent magnets as a springless proof mass. Instead of supporting the magnet assembly with spring element, ferrofluid has been used as a lubricating material. When external vibration is applied laterally to the harvester, magnet assembly slides back and forth on the channel with reduced friction and wear due to ferrofluid, which significantly improves the long-term reliability of the device. Electric power is generated across an array of copper windings formed at the bottom of the aluminum housing. A proof-of-concept harvester has been fabricated and tested with a vibration exciter at various input frequencies and accelerations. For the device where 5 μL of ferrofluid was used for lubrication, maximum output power of 493 μW has been generated, which was 4.37% higher than that without ferrofluid. Long-term reliability improvement due to ferrofluid lubrication has also been verified. For the device with ferrofluid, 1.02% decrease of output power has been observed, in contrast to 59.73% decrease of output power without ferrofluid after 93,600 cycles.

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Low-frequency vibration energy harvester using a spherical permanent magnet with controlled mass distribution

Cited by 27 publications

References 19 publications

Hexagonal Structure Enhancing Damping Efficiency Inspired by Tree Frogs

Hexagonal Structure Enhancing Damping Efficiency Inspired by Tree Frogs

An Electromagnetic Energy Harvester and Energy Storage System for Bike Lighting Applications

Electromagnetic Linear Vibration Energy Harvester Using Sliding Permanent Magnet Array and Ferrofluid as a Lubricant

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