• 대한전자공학회논문지SD
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• 제45권2호
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• pp.34-43
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• 2008

평판 디스플레이 인터페이스를 위한 OpenLDI 수신기 IP를 설계하고, $0.18-{\mu}m$ high-voltage CMOS 공정을 사용하여 프로토타입 칩을 제작하였다. 수신기 회로는 크게 DLL과 parallelizer로 구성된다. DLL은 클록을 재생하고, Parallelizer는 데이터를 병렬화하여 재생된 클록에 정렬한다. 회로의 입력은 한 개의 클록 채널과 네 개의 데이터 채널로 구성된다. 측정을 통해 $10Mhz{\sim}65Mhz$ 범위의 입력주파수에서 클록을 재생하는 것을 확인하였으며, 이는 한 개 채널당 $70Mbps{\sim}455Mbps$의 속도에, 네 개의 데이터 채널을 모두 사용할 시 $280Mbps{\sim}1.82Gbps$의 속도에 해당한다. 상용 LCD 모니터를 개조하여 제작된 칩을 사용한 영상데이터 전송을 실험하였다. 이때의 클록 주파수는 49Mhz, 소모되는 전력은 코어가 19mW, 출력버퍼가 82.5mW로 측정되었다.

• 전기학회논문지
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• 제64권1호
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• pp.182-187
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• 2015

In the three-phase power system, when any one-phase or two-phases is open-phase, the unbalanced current flows and the single-phase power supplies to three-phase loads. Specially, motor coil and transformer coil receive over-current. As a result, great damage as well as electrical fire can occur to the power system. In order to improve these problems, this paper proposes that an open-phase detection device is designed by a new algorithm using electric potential difference between the resultant voltage of neutral point and ground, and a control circuit topology of open-phase protector is composed of highly efficient semiconductor devices. It improves response speed and reliability. The control algorithm circuit also operates the cut-off of a conventional residual current protective device (RCD) which flows an enforced leakage current to ground wire at open-phase accident. Furthermore, time delay circuit is added to prevent the incapable operation of open-phase protector about instantaneous open-phase not open-phase fault. The time delay circuit improves more reliability.

• Current Photovoltaic Research
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• 제6권1호
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• pp.12-16
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• 2018

The interest in perovskite solar cells has been skyrocketed owing to their rapid progress in efficiency in recent years. Here, we report the effect of non-stoichiometry in the methylammonium lead trihalide ($MAPbI_3$) precursors used in a solution process with different MAI : $PbI_2$ ratios of 1 : 0.96, 1 : 1.10, 1 : 1.15, and 1:1.20. With an increase in the $PbI_2$ content, the $PbI_2$ secondary phase was found to form at grain boundary region of perovskite thin films, as evidenced by X-ray diffraction (XRD) and scanning electron microscopy (SEM). In terms of device performance, open-circuit voltage in particular is significantly improved with increasing the molar ratio of $PbI_2$, which is possibly ascribed to the reduction in recombination sites at grain boundary of perovskite and hence the prolonged life time of light-generated carriers according to the reported. As a result, the $PbI_2-excess$ devices exhibited a higher power conversion efficiency compared to the MAI-excess ones.

• 설비공학논문집
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• 제22권5호
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• pp.259-267
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• 2010

An experiment has been performed in order to investigate the characteristics of multiple thermoelectric modules (TEMs) with electrical circuits. The open circuit voltage of TEM connected parallel circuit is equal to the sum of individual TEMs. In contrast, the open circuit voltage is equal to the average of that individual TEM for a series circuit. The power output and conversion efficiency of TEM for both parallel and series circuits increase as the operating temperature conditions for individual TEMs becomes identical. Comparing parallel with series circuits, the power generation performance is more excellent for series circuit than parallel circuit. This result is attributed to the power loss from the TEM with better power generation performance.

• 대한전자공학회논문지
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• 제11권2호
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• pp.33-39
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• 1974

VNIC를 구성하는 방법으로서, 공통베이스접속회로의 베이스단자에 제어전압을 인가하는 방법을 제안하고 이것을 모델화한다. 단낙안정형은 제어압력을 입력전력에 종속하도록 함으로써 실현가능하며, 개방안정형은 입력전류에 종속인 출력전력에 비례하도록 함으로써 가능하다. 제안한 회로모델에 의하여, 회로를 구성하오 해석하여, 회로모델의 횡성기법의 타당성을 찾고, VNIC의 구성이론을 평이화하고자 한다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1999년도 하계학술대회 논문집 C
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• pp.1242-1244
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• 1999

AVR parameter tuning for voltage control of power system generators has generally been done with the open-circuit model of the synchronous generator. When the generator is connected on-line and operating at rated load conditions, the AVR operates in an entirely different environment from the open-circuit conditions. This paper describes a new method for AVR parameter tuning using optimization technique with on-line linearized system model. As this method considers not only the on-line models but also the off-line open-circuit models, AVR parameters tuned by this method can give the sufficiently stable performance at the open-circuit commissioning phase and give the desired performance at the operating conditions. Also this method estimates the optimum parameters for desired performance indices that are chosen for satisfying requirements in some practical applications, the performance of the AVR can satisfy the various requirements.

• Journal of Power Electronics
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• 제16권5호
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• pp.1950-1963
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• 2016

A novel open-circuit fault diagnosis method for 3-phase 4-wire 3-level active power filters based on voltage error correlation is proposed in this paper. This method is based on observing the output pole voltage error of the active power filter through two kinds of algorithms. One algorithm is a voltage error analytical algorithm, which derives four output voltage error analytic expressions through the pulse state, current value and dc bus voltage, respectively, assuming that all of the IGBTs of a certain phase come to an OC fault. The other algorithm is a current circuit equation algorithm, which calculates the real-time output voltage error through basic circuit theory. A correlation is introduced to measure the similarity of the output voltage errors between the two algorithms, and OC faults are located by the maximum of the correlations. A FPGA has been chosen to implement the proposed method due to its fast prototyping. Simulation and experimental results are presented to show the performance of the proposed OC fault diagnosis method.

• 한국위성정보통신학회논문지
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• 제11권3호
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• pp.114-118
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• 2016

인공위성은 다양한 제작사에서 공급하는 전장품들로 구성되는 시스템이다. 각 제작사에서는 각 제작사에서 사용하는 제작 이력 및 제작하는 위성 요구조건에 따라 다양한 내부전원을 사용하게 된다. 따라서 전장품마다 사용하는 내부전원이 다르기 때문에 전장품 사이의 접속요건에 대한 분석이 필수적이다. 접속요건에 대한 검증을 완화시키기 위해서 사용되는 회로가 Open Collector회로로, Open collector는 내부전원 차이에서 발생하는 문제를 완화시킬 수 있지만, 정전류에 의한 전력소모 증가 및 상승시간의 증가와 offset 전압 문제를 발생시킬 수 있다. 따라서 본 논문에서는 전력소모를 감소시키면서 빠른 반응시간을 얻기 위한 접속회로를 제안하고, 감소되는 전력 및 상승시간 감소를 분석한다.

• 대한전자공학회논문지
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• 제11권6호
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• pp.16-24
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• 1974

본 논문은 종래의 NIC회로의 구성방법을 종합하여 일반화하는 방법으로써 파라미터 제어회로와 전압 또는 전류제어회로에 의한 NIC구성방법을 제시하였다. 그리고 FET에 의해 개방 및 단락안정형 NIC회로를 구성하고 회로해석에 의한 임피던스와 실험치를 비교하여 NIC특성을 확인하고 회로해석이 타당함을 검토 확인하였다. 또한 병렬 LC를 NIC와 직렬로 연결하여 발진상태를 실험으로 확인하고 NR에 의한 발진상태와 비교 검토하였다.

• Current Photovoltaic Research
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• 제2권4호
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• pp.168-172
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• 2014

Under concentrated illuminations, the solar cells show higher efficiencies mainly due to an increase of the open circuit voltage. In this study, InGaP/InGaAs/Ge triple-junction solar cells have been grown by a low pressure metalorganic chemical vapor deposition. Photovoltaic characteristics of the fabricated solar cells are investigated with a class A solar simulator under concentrated illuminations from 1 to 100 suns. Ideally, the open circuit voltage should increase with the current level when maintained at the same temperature. However, the fabricated solar cells show degraded open circuit voltages under high concentrations around 100 suns. This means that the heat sink design is not optimized to keep the cell temperature at $25^{\circ}C$. To demonstrate the thermal degradation, changes of the device performance are investigated with different bonding conditions and heat sink materials.