• 한국의류산업학회지
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• 제21권3호
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• pp.300-307
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• 2019

This study develops a user centered outdoor jacket capable of energy harvesting based on consumer needs. Jackets are designed for typical outdoor activities such as hiking, trekking, and climbing, integrated with an energy harvesting module that can generate electric power from arm swing in outdoor and daily life walking. Textile based energy generators developed by the previous research of Lee & Roh (2018) were used. A prototype was created based on the arm swing motion experiment for location options and energy harvesting system functions, the simulation by the design sketch, and evaluation of the wearing test by experts. In-depth interviews were later conducted for the prototype with 10 outdoor experts to derive the optimal location of an energy harvesting system in three ways, and the prototype was revised to 5 styles that reflected reviews by experts on function and appearance. Research indicated that the energy harvesting jacket design signifies a user-centered design based on expert interviews and usability evaluation as well as previous research on energy generation and storage device. The jacket is convenient because it combines an energy generator in an optimal position to maximize energy generation with a storage and charging device that can be inserted into various position options for accessibility.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제10권2호
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• pp.504-521
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• 2016

Recently, energy harvesting technology has been integrated into wireless sensor networks to ameliorate the nodes' energy limitation problem. In theory, the wireless sensor node equipped with an energy harvesting module can work permanently until hardware failures happen. However, due to the change of power supply, the traditional hierarchical network routing protocol can not be effectively adopted in energy harvesting wireless sensor networks. In this paper, we improve the Low-Energy Adaptive Clustering Hierarchy (LEACH) protocol to make it suitable for the energy harvesting wireless sensor networks. Specifically, the cluster heads are selected according to the estimation of nodes' harvested energy and consumed energy. Preference is given to the nodes with high harvested energy while taking the energy consumption rate into account. The utilization of harvested energy is mathematically formulated as a max-min optimization problem which maximizes the minimum energy conservation of each node. We have proved that maximizing the minimum energy conservation is an NP-hard problem theoretically. Thus, a polynomial time algorithm has been proposed to derive the near-optimal performance. Extensive simulation results show that our proposed routing scheme outperforms previous works in terms of energy conservation and balanced distribution.

• 한국포장학회지
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• 제29권3호
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• pp.223-228
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• 2023

Sustainable energy supplies without the recharging and replacement of the charge storage device have become increasingly important. Among various energy harvesters, the triboelectric nanogenerator (TENG) has attracted considerable attention due to its high instantaneous output power, broad selection of available materials, eco-friendly and inexpensive fabrication process, and various working modes customized for target applications. In this study, the amount of voltage and current generated was measured by applying the PSD profile random vibration test of the electronic vibration tester and ISTA 3A according to the time of Anodized Aluminum Oxide (AAO) pore widening of the manufactured TENG device Teflon and AAO. The discharge and charging tests of the integrated module during the random simulated transport environment and the recognition distance of RFID were measured while agricultural products (onion) were loaded into the returnable folding plastic box. As a result, it was found that AAO alumina etching processing time to maximize TENG performance was optimal at 31 min in terms of voltage and current generation, and the integrated module applied with the TENG module showed a charging effect even during the continuous use of RFID, so the voltage was kept constant without discharge. In addition, the RFID recognition distance of the integrated module was measured as a maximum of 1.4 m. Therefore, it was found that the surface condition of AAO, a TENG element, has a great influence on the power generation of the integrated module, and due to the characteristics of TENG, the power generation increases as the surface dries, so it is judged that the power generation can be increased if the surface drying treatment (ozone treatment, etc.) of AAO is applied in the future.

• 대한기계학회논문집B
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• 제40권4호
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• pp.255-262
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• 2016

철도차량의 안정성과 신뢰성을 위해 상시 자가진단 시스템의 필요성이 높아지고 있다. 통상적으로 이러한 모니터링 시스템에는 유선 센서가 쓰여 왔는데, 설치 장소의 제약이 적은 무선 센서의 활용과 유지보수의 문제를 위해서는 무선 센서의 전원 문제를 해결하여야 한다. 따라서 본 연구에서는 고속으로 주행하는 차량 주변의 에너지를 활용하여 친환경적이면서 반영구적인 자가 발전의 방편으로 열전 발전의 적용성을 검토하였다. 차량의 주행 조건에 따라 열전 발전 모듈이 설치될 차축 베어링 커버의 온도 차이에 대한 측정이 먼저 이루어졌고, 여기에 상용 열전 소자 모듈을 장착하여 그 성능을 테스트 하였다. 주어진 조건에서 출력을 높이기 위해 부하 저항 및 열전 소자 전용 회로를 적용하여 효과를 분석한 결과, 저온부의 효과적인 냉각 및 열손실의 최소화를 통해 열전 발전을 통한 무선 센서 전원 공급이 가능할 것으로 판단된다.

• 한국산학기술학회논문지
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• 제18권9호
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• pp.436-443
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• 2017

최근, 지구온난화 등의 문제로 인해 새로운 에너지 기술의 개발이 화제가 되고 있다. 중규모 이상의 출력을 얻도록 최적화된 태양광 및 태양열, 풍력 발전과 같은 신재생에너지 기술과 다르게 에너지 하베스팅기술은 출력전력이 매우 작아 크게 주목받지 못하고 있다. 하지만 최근 모바일 산업이 활성화 되면서 에너지 하베스팅기술의 활용가치가 재평가 받고 있다. 또한, 최대전력점 추적방식기술 역시 활발히 연구가 이루어지고 있다. 본 논문에서는 일정한 저항부하를 위한 열전모듈의 새로운 최대전력점추적 제어방식을 제안한다. 열전 모듈(이하 TEM: Thermoelectric Module)의 V-I곡선특성과 내부저항을 분석하고. 기존의 MPPT제어방식을 비교하였다. P&O(Perturbation and Observation)제어방식은 전압, 전류를 측정하기위한 센서 2개를 사용해야하기 때문에 CV제어방식보다 경제성이 떨어지지만 보다 정확히 MPP를 찾는다는 장점을 가진다. CV(Constant Voltage)제어방식은 전압센서 1개만 사용하기 때문에 경제적인 측면에서는 P&O제어방식보다 뛰어나지만, MPP가 정확히 못하다는 단점을 가지고 있다. 본 논문에서는 두 제어방식의 장점만을 가지고 TEM의 최대전력점(MPP)을 추적하도록 설계하였다. 제안된 MPPT 제어 방식은 PSIM 프로그램을 이용한 모의실험으로 확인하였으며, 하드웨어제작을 통해 제안된 MPPT제어 방식을 검증하였다.

• 한국전기전자재료학회논문지
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• 제27권12호
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• pp.857-862
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• 2014

In this paper, we designed and fabricated electromagnetic induction based scaffold type energy harvester. For energy harvesting, mechanical energy of vertical motion is transferred to rotational energy using rack gear and multiplying gear was used to maximize energy transfer. To optimize design parameters, physical structure of energy harvester was modeled using finite element method. The effect of multiplying gear ratio and frequency levels of applied mechanical energy on energy generation efficiency are analyzed by computer simulation and experimental test. Experimental results showed that maximum 25.36 W of electric power can be achieved at the frequency of 2 Hz and 1:77 of gear ratio with only 5 mm of vertical changes on scaffold structure.

• 한국전기전자재료학회논문지
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• 제25권12호
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• pp.943-948
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• 2012

A new water energy harvester module, which is composed of piezoelectric bimorph cantilevers, harvesting circuit and a shaft with 16 impellers at a center axis, was fabricated for energy harvesting application. High energy density $Pb(Zr_{0.54}Ti_{0.46})O_3$ + 0.2 wt% $Cr_2O_3$ + 1.0 wt% $Nb_2O_5$ (PZT-CN) thick film obtained by tape casting method was used for the bimorph cantilever. The PZT-CN bimorph cantilever with a proof mass of 49 g exhibited extremely high output power of 22.5 mW (24 $mW//cm^3$) at resonance frequency of 11 Hz. In addition, the fabricated water energy harvester has a cylindrical structure with 48 bimorph cantilevers clamped at inner surface. A significantly high output power of 433 mW was obtained at a rotation speed of 120 rpm with a resistive load of $500{\Omega}$ for the water energy harvester.

• 센서학회지
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• 제31권6호
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• pp.376-382
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• 2022

A triboelectric nanogenerator (TENG) can obtain electrical output due to the reciprocal motion between two objects (i.e., rubbing), in which repetitive contact is made. High reliability, stable output, and high reproducibility are important aspects of the electrical output obtained through a TENG as a sensor or generator, thus enabling its meaningful use. Therefore, many researchers fabricated TENGs into individual parts in the form of one module type to obtain high reproducibility and reliability. Since a TENG manufactured as a module type operates as a single device, it is possible to collect kinetic energy and convert it into electrical energy through the interaction between internally configured elements without the need for a separate structure. In addition, it is relatively easy to apply the size to the body, machine tools, and natural environment by simply adjusting the size suitable for use and surrounding environmental conditions. In this paper, the application cases of module-type TENGs are divided into four areas, and the research progress of module-type TENGs in each area is extensively reviewed.

• Journal of Electrical Engineering and Technology
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• 제11권5호
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• pp.1210-1215
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• 2016

• 융합신호처리학회논문지
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• 제19권3호
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• pp.89-96
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• 2018

본 연구는 915MHz의 UHF (Ultra High Frequency) 대역에서 RF 에너지 하베스팅 기술을 이용하는 풀 패시브 스마트 센서태그 개발을 목표로 한다. 다양한 방사 조건에서 전력수집을 최적화하기 위해, 최대전력점추적(MPPT: maximum power point tracking)을 활용하는 효율적인 에너지 하베스팅 모듈이 사용된다. 특히 제안하는 태그는 에너지 획득과 데이터 전송 능력 향상을 위해 두개의 직교 안테나를 사용한다. 실험 결과 개발된 스마트 센서태그는 4m 거리에서 DC 3.6V 출력을 위해 0.19mW 정도의 낮은 입력 RF 전력을 획득 할 수 있음을 보인다. 더욱이 제안하는 스마트 센서태그는 저전력 센서어레이로 2m 거리에서 무전원 식품 신선도 모니터링을 완벽하게 실현가능하다.