• Journal of Electrical Engineering and Technology
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• 제10권1호
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• pp.75-82
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• 2015

This paper presents a new technique for enhancing power quality by reducing harmonics in the neutral conductor. Three-Phase Four-Wire (3P4W) system is commonly used where single and three phase loads are connected to Point of Common Coupling (PCC). Due to unbalance loads, the 3P4W distribution system becomes unbalance and current flows in the neutral conductor. If loads are non-linear, then the harmonic content of current will flow in neutral conductor. The neutral current that may flow towards transformer neutral point is compensated by using a series active filter. In order to reduce the harmonic content, the series active filter is connected in series with the neutral conductor by which neutral and phase current harmonics are reduced significantly. In this paper, solar PV based inverter circuit is proposed for compensating neutral current harmonics. The simulation is carried out in MATLAB/SIMULINK and also an experimental setup is developed to verify the effectiveness of the proposed method.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2009년도 제40회 하계학술대회
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• pp.1049_1050
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• 2009

This paper deals with development of a low cost VI(Voltage-Currrent)-tracer for PV(Photovoltaic) system using LabVIEW and DSP(Digital Signal Processor). Although the conventional VI-tracer is a high cost equipment, it can‘t abstract the detailed parameters of solar cell. To overcome above mentioned disadvantages, in this paper, a converter type VI-tracer is developed. The DSP, which controls the buck-boost DC-DC converter, is used to implement the proposed VI-tracer algorithm. The proposed VI-tracer can abstract more detailed parameters of solar cell; A(temperature constant), Rs(series resistance), and Rsh(parallel resistance). The authors emphasize that the proposed VI-tracer can satisfy the users who need to get various parameters. A comparison between the proposed VI-tracer and the conventional VI-tracer is presented to show the effectiveness of the proposed system.

• 전기전자학회논문지
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• 제22권3호
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• pp.664-671
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• 2018

일반적으로 감지식 태양광 추적 시스템은 태양의 위치를 추적하기 위해 광센서를 사용하여, 최대 전력을 생산한다. 광센서 채택은 시스템 제작 가격을 상승시키고, 오동작에 의한 성능 저하를 초래할 수 있다. 본 논문에서는 IoT플랫폼 기반의 원격무선 모니터링이 가능하고, 광센서가 없는 새로운 태양광 추적 시스템을 제안한다. 태양광 발전을 위해 사용되는 여러 개의 태양광 패널의 출력 전류량을 비교하여 태양 위치를 광센서 없이 추적한다. 추적 성능의 검증을 위해서 12[V] 20[W] 태양광 발전 시스템을 제작하여 실험을 수행하였다. 본 논문에서 제안한 시스템은 IoT 플랫폼을 사용하여 원격모니터링이 가능하기 때문에 기존 태양광 추적 시스템에 비해 설치, 유지 보수 및 기능 확장의 장점이 있다.

• 대한영상의학회지
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• 제83권3호
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• pp.538-558
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• 2022

혈관주위공간(perivascular space; 이하 PVS)는 뇌 실질을 관통하는 세동맥 둘러싸고 있는 공간으로, 최근에는 별아교세포의 종족(astrocyte endfoot)에 의해 가장 바깥쪽이 경계지워지는, 체액, 세포, 결합조직으로 구성된 혈관벽내, 혈관벽 주위의 구획을 모두 아우르는 개념으로 이해하고 있다. 정상적으로는 현미경적 해부학 구조물이지만 이 구조물이 늘어나게 되면 MRI T1 혹은 T2 이미지에서 확인할 수 있게 된다. PVS의 명확한 실체나 임상적인 의의에 대해서는 아직 분명치 않은 부분이 많이 있지만 PVS의 확장(enlarged PVS; 이하 EPVS)은 다양한 퇴행성 뇌질환 뿐만 아니라 뇌출혈 및 외상성 뇌손상, 당뇨성 신질환 같은 다양한 질병과의 연관성이 있다는 연구 결과들이 발표되고 있다. 이번 종설에서는 PVS와 EPVS가 가지는 임상적 의의와 병태 생리에 대한 최근 문헌을 고찰하고, MRI를 이용한 정성적 평가 및 최적화에 대해 논의해 보고자 한다.

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2009년도 춘계학술대회 논문집
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• pp.69-72
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• 2009

In this paper, the Stand-alone underground water pumping system was developed that is consist of Submersible Pump (AC type), Photovoltaic Array and Power converter by the application of solar energy. And also wish to introduce system that is possible to supply of drinking water or water for agriculture using solar energy at desertification area or a Off-grid area, interior etc. and operation test results. This system can use in deep tube well of 200m range with common Submersible Pump and maximized to the quantity of pumping through M.P.P.T control. Also system availability raised through apply various driving mode.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2005년도 제36회 하계학술대회 논문집 B
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• pp.1765-1767
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• 2005

This paper proposes central monitoring system(PVCMS) based on a TCP/IP network for effective integrating management about photovoltaic systems. We don't gain confidence the result of production simulation, because the output of PV system have many various environmental change factor. So if we can obtain real operated data about each sites and system types to use PVCMS, we can define the environment change factor to compare with simulation data. And this paper try to access about total management and data analysis methods of renewable energy through results analysis to synthesize of the operation.

• 전력전자학회논문지
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• 제7권2호
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• pp.171-177
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• 2002

계통연계형 태양광 발전시스템은 계절별 전력수요의 변동이 많은 경우에 첨두전력 삭감의 한 방안으로 고려된다. 본 시스템의 발전효율을 증가시킬 수 있는 방법으로는 근본적으로 태양전지 자체의 변환효율을 증가시키는 방법과 제어관점에서 일사량과 태양전지 표면온도에 따라 시시각각 변하는 태양전지의 최대출력 점에 시스템의 동작점을 추종하게 하는 최대 전력점추적 (Maximum Power point Tracking, 이하 MPPT) 기법을 들 수 있고 발전 효율을 높이기 위하여 자주 사용되어 왔다. 초기 투자비용을 줄이기 위해 후에 등장한 직류초퍼를 사용하지 않고 MPPT 기능을 구현하는 태양광 발전시스템의 경우에 MPPT 알고리즘은 기존의 방법들을 사용하였고 직류초퍼를 사용하지 않은 태양광발전시스템에 적합한 MPPT 알고리즘의 연구는 없었다. 따라서 직류초퍼를 사용하지 않은 태양광 발전시스템에 적합한 MPPT 알고리즘의 연구가 요구되며 본 논문에서는 초퍼 없는 계통연계형 태양광발전 시스템을 대상으로 기존 MPPT 알고리즘의 문제점을 밝히고 이를 해결할 수 있는 새로운 MPPT 알고리즘을 연구하였다.

• 한국태양에너지학회 논문집
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• 제30권6호
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• pp.131-136
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• 2010

The purpose of this study is to provide foundational data for expansion of solar generation in building application, a clean energy, by introducing applicability of solar power generation system on roofs of industrial buildings and computing expected amounts of power and carbon dioxides reduction. As methodologies of this study, after reviewing 120,000 domestic factories to verify the BIPV feasibility for industrial building sthrough theoretical considerations of solar generation system, we calculated BIPV application methods and subsequent expected power generation quantity and carbon dioxide reductions through roof type analysis. we analyzed four cases of expected power generation amounts of solar batteries according to application methods, and when considering that the main type of roofs are slant roofs according to the investigation result about roof forms of domestic industrial complexes, we believe that the module angle of a slant roof around $17^{\circ}$(case3) is most suitable for the application. Finally, we came up with 517,944[TOE] as the corresponding petroleum tonnage based on this computed expected power generation amount and the amount of 1,214,836[$tCO_2$] carbon dioxide reductions by calculating them by energy sources.

• Journal of Microbiology and Biotechnology
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• 제29권12호
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• pp.1975-1981
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• 2019

Recently, outbreaks of food-borne diseases linked to fresh produce have been an emerging public health concern worldwide. Previous research has shown that when human pathogens co-exist with plant pathogens, they have improved growth and survival rates. In this study, we have assessed whether Escherichia coli O157:H7 benefits from the existence of a phytopathogenic bacterium and the underlying mechanisms were further investigated. When Pseudomonas syringae pv. tomato DC3000 (Pst DC3000) and E. coli O157:H7 were co-inoculated by either dipping or infiltration methods, the populations of E. coli O157:H7 increased; however, no effect was observed when type three secretion system (T3SS) mutants were used instead, suggesting that E. coli O157:H7 benefits from the presence of Pst DC3000. In addition, this study confirmed that the E. coli O157:H7 populations increased when they occupied the tomato leaf intercellular space; this colonization of the interior of the leaves was possible due to the suppression of the PAMP-triggered immunity (PTI) by Pst DC3000, in particular with the AvrPto effector. In conclusion, our data support a plausible model that E. coli O157:H7 benefits from the presence of Pst DC3000 via AvrPto suppression of the PTI resistance.

• 반도체디스플레이기술학회지
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• 제13권4호
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• pp.43-48
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• 2014

Two-level inverter has some disadvantages like high harmonics contained in the output current, efficiency limit and stress to switching device as IGBT and FET. Many researches have reported multi-level inverter to complement two-level inverter of problems. In this paper, we suggest MPPT algorithm of multi-string three-level solar inverter that considered nowadays. We added midpoint controller in order to implement the MPPT algorithm because the three-level inverter has to need midpoint controller and procured the stability of direct current link. We verify the superiority of multi-string T-Type inverter and the algorithm we suggested with solar irradiance variation experiment and MPPT efficiency measurement. The MPPT efficiency was confirmed with a high efficiency more than 99.97%.