• Journal of Power Electronics
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• 제5권4호
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• pp.247-256
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• 2005

In order to harvest power in an efficient manner from a micro piezoelectric (PZT) device for charging the battery of a remote system, a new AC/DC resonant pulse power converter is proposed. The proposed power converter has two stages in the power conversion process. The first stage includes N-type MOSFET full bridge rectifier. The second stage includes a boost converter having an N-type MOSFET and a P-type MOSFET. MOSFETs work in the $1^{st}$ or $3^{rd}$ quadrant region. A small inductor for the boost converter is assigned in order to make the size of the power converter as small as possible, which makes the on-interval of the MOSFET switch of the boost converter ultimately short. Due to this short on-interval, the parasitic junction capacitances of MOSFETs affect the performance of the power converter system. In this paper, the performance of the new converter is analytically and experimentally evaluated with consideration of the parasitic capacitance of switching devices.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2008년도 추계학술대회 논문집 Vol.21
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• pp.220-221
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• 2008

With recent advanced in portable electric devices, wireless sensor, MEMS and bio-Mechanics device, the new typed power supply, not conventional battery but self-powered energy source is needed. Particularly, the system that harvests from their environments are interests for use in self powered devices. For very low powered devices, environmental energy may be enough to use power source. Therefore, in other to made piezoelectric energy harvesting device. The made 31 type triple-morph cantilever was resulted from the conditions of 100k$\Omega$, 0.25g, 154Hz respectively. The thick film was prepared at the condition of $6.57V_{rms}$, and its power was $432.31{\mu}W$ and its thickness was $50{\mu}m$.

• International Journal of Internet, Broadcasting and Communication
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• 제10권2호
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• pp.7-12
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• 2018

The spread of IoT (Internet of Things) technology that connects objects based on wired / wireless networks is accelerating, and IoT-based smart home technology that constitutes a super connected network connecting sensors and home appliances existing inside and outside the home is getting popular. In addition, demand for alternative energy technologies such as photovoltaic power generation is rapidly increasing due to rapid increase of consumption of energy resources. Recently, small solar power systems for general households as well as large solar power systems for installation in large buildings are being introduced, but they are effectively implemented due to limitations of small solar panels and lack of power management technology. In this paper, we have studied smart home structure and IoT / IoL device discovery algorithm for energy harvesting system based on photovoltaic power generation, It is possible to construct an efficient smart home system for device control.

• 한국정보통신학회논문지
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• 제22권4호
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• pp.670-675
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• 2018

센서네트워크의 전력문제를 해결할 수 있는 에너지 수집형 무선 센서네트워크 (EH-WSN)에 대한 관심이 증가하고 있다. EH-WSN에서는 에너지 수집과 소비의 균형을 맞추기 위한 on-off 듀티싸이클링에 관한 연구가 많이 진행되고 있다. 그러나 환경감시를 위한 EH-WSN에서 센싱된 데이터의 긴급성과 에너지 수집율은 네트워크의 성능을 결정하는 중요한 요소가 된다. 따라서 단순히 전력의 균형 상태를 유지하는 것 이외에 센싱된 데이터의 중요도 및 에너지 수집율에 따라 듀티싸이클 주기를 조절할 필요성이 대두된다. 본 논문에서는 환경감시를 위한 EH-WSN에서 기존의 전력만을 고려한 on-off 듀티싸이클링의 문제점을 분석하고, 센싱값의 변화율 및 크기값에 의한 센싱 데이터의 우선순위 및 에너지 수집율 등을 고려하여 적응적으로 on-off 주기를 결정하는 듀티싸이클 스케줄링 기법을 제안한다. 시뮬레이션을 통해 제안된 듀티싸이클 스케줄링의 성능을 분석하였다.

• Journal of electromagnetic engineering and science
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• 제8권1호
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• pp.6-11
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• 2008

Advances in low power design open the possibility to harvest energy from the environment to power electronic circuits. Electrical energy can be harvested from piezoelectric transducer. Piezoelectric materials can be used as mechanisms to transfer mechanical energy usually vibrating system into electrical energy that can be stored and used to power other devices. Micro- to milli-watts power can be generated from vibrating system. We developed definitive and analytical models to predict the power generated from a cantilever beam attached with piezoelectric transducer. Analytical models are pin-force method, enhanced pin-force method and Euler-Bernoulli method. Harmonic oscillations and random noise will be the two different forcing functions used to drive each system. It has been selected the best model for generating electric power based upon the analytical results obtained.

• 드라이브 ㆍ 컨트롤
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• 제20권3호
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• pp.35-41
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• 2023

Radish and Chinese cabbage are the most produced and consumed vegetables in Korea. The mechanization of harvesting operations is necessary to minimize the need for manual labor. This study to develop and evaluate the performance of a multi-purpose driving platform that can apply modular Radish and Chinese cabbage harvesting devices. The multi-purpose driving platform consisted of driving, device control, engine, hydraulic, harvesting, conveying, and loading part. Radish and Chinese cabbage harvesting conducted using the multi-purpose driving platform each harvesting module. The performance of the multi-purpose driving platform was evaluated the field efficiency and loss rate. The total Radish harvesting operation time 34.3 min., including 28.8 min., of harvesting time, 1.9 min., of turning time, and 3.6 min., of replacement time of bulk bag. During Radish harvesting, the field efficiency and average loss rate of the multi-purpose driving platform were 2.0 hr/10a and 3.1 %. Chinese cabbage harvesting operation 49.3 min., including 26.6 min., of harvesting time, 4.6 min., of turning time, and 18.1 min., of replacement time of bulk bag. During Chinese cabbage harvesting, the field efficiency and average loss rate of the multi-purpose driving platform 2.1 hr/10a and 0.1 %. Performance evaluation of the multi-purpose driving platform that harvesting work was possible by installing Radish and Chinese cabbage harvest modules. Performance analysis through harvest performance evaluation in various Radish and Chinese cabbage cultivation environments is necessary.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2009년도 추계학술대회 논문집
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• pp.277-277
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• 2009

In this paper, PMPG (Piezoelectric Micro Power Generator) was investigated by ANSYS FEA (Finite Element Analysis) to decrease operating frequency and improve out power. The micro power generator was designed to convert ambient vibration energy to electrical power as a ZnO piezoelectric material. To find optimal model in low vibration ambient, the shape of power generator was changed with different membrane width, thickness, length, and proof mass size. Used the ANSYS modal analysis, bending mode and stress distribution of optimal model were analyzed. Also, the displacement with the frequency range was analyzed by harmonic analysis. From the simulation results, the resonance frequency of optimal model is about 373 Hz and confirmed the possibility of ZnO micro power generator for wireless sensor node applications.

• 한국정보통신학회논문지
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• 제20권7호
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• pp.1277-1282
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• 2016

차세대 무선 통신 시스템에서는 RF 에너지 하베스팅 기술을 이용하여 센서의 전원 부족 문제를 해결하고자 한다. 본 논문에서는 채널 추정 오차가 존재하는 에너지 하베스팅 네트워크에서 무선 정보 및 전력 동시 전송을 위한 효율적인 알고리즘을 제안하고자 한다. 먼저, 1차원의 완전 검색을 통해 최적의 채널 추정 주기를 찾은 후, MMSE 채널 추정기를 이용하여 채널을 추정한다. 추정된 채널 값을 기반으로, 최소 필요 획득 에너지 조건을 만족시켜주면서 데이터 전송률을 최대화할 수 있는 파워 할당 및 분할 방안을 제안하였다. 시뮬레이션을 통해 제안 방안은 완벽한 채널 추정을 가정한 최적 방안에 비해 10% 미만의 성능 저하가 있었지만, 기존 방안과 비교할 시에는 데이터 전송률을 20% 이상 향상시킴을 확인 하였다.

• 한국전기전자재료학회논문지
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• 제24권5호
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• pp.422-426
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• 2011

Piezoelectric materials can be used to convert mechanical energy into electrical energy. In this study, we investigated the possibility of harvesting from mechanical vibration force using a high efficient piezoelectric material-polyvinylidene fluoride (PVDF). A piezoelectric energy harvesting system consists of rectifier, filter capacitor, resistance. The experiments were carried out with impacting force to PVDF film with the thickness of 1 ${\mu}m$. The output power was measured with change in the load resistance value from 100 ${\Omega}$ to 2.2 $M{\Omega}$. The highest power was obtained under optimization by selection of suitable resistive load and capacitance. A power of 0.3082 ${\mu}W/mm^2$ was generated at the external vibration force of 5 N (10 Hz) across a 1 $M{\Omega}$ optimal resistor. Also, the maximum power of 0.345 ${\mu}W/mm^2$ was generated at 22 ${\mu}F$ and 1 $M{\Omega}$. The developed system was expected at a solution to overcome the critical problem of making up small size energy harvester.

• 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.