• Proceedings of the KIPE Conference
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• 2019.11a
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• pp.170-171
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• 2019

본 논문은 건물일체형 태양광 발전(Building Integrated PV:BIPV)의 에너지 수급에 대한 특징과 보다 효율적인 시스템 설계 및 최대 에너지 수급기법에 대해 기술한다.

• Proceedings of the KIPE Conference
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• 2017.07a
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• pp.371-372
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• 2017

본 논문에서는 태양광 발전 전력을 스위칭 손실 없이 승압하여 밸런싱 회로를 통해 균일하게 전압을 양극성 직류배전망으로 전달하는 시스템을 제안한다. 제안하는 시스템에 대한 컨버터 설계와 제어를 수행하고 이를 PSIM 시뮬레이션을 통해 검증하였다.

• Proceedings of the KIEE Conference
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• 2011.07a
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• pp.53-54
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• 2011

태양광 발전 시스템은 환경오염을 최소화하고 배전선에 손실을 줄이는 등 여러 가지 이점으로 최근 전력계통 분야에서 계통 연계형 태양광 발전이 각광 받고 있다. 따라서 실제 태양광 발전을 전력계통에 연계하였을 경우의 영향을 분석하기 위해 이를 모델링하고 분석하는 것이 필요하다. 본 논문에서는 EMTP를 이용하여 태양광(Photovoltaic, PV) 발전을 모델링한 후, 태양광 발전의 연계 위치 및 용량을 변화시켜 전력품질을 분석하였다.

• Clinical and Experimental Pediatrics
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• v.48 no.12
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• pp.1330-1336
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• 2005

Purpose : It has been suggested that changes in cerebral blood flow by ventilator care could be a risk factor in periventricular leukomalacia(PVL) and severe periventricular-intraventricular hemorrhage(PV-IVH). The study aims to assess the relationship between perinatal clinical events, including ventilator care, and the development of PVL and severe PV-IVH; especially, whether ventilator care could be causers of PVL and severe PV-IVH as an individual risk factor. Methods : Among 255 very low birth weight infants who survived in the Fatima neonatal intensive care unit from January 1999 to December 2003, 15 infants with PVL and eight infants with severe PV-IVH were classified as a study group, while 231 infants were enrolled as a control group. The analysis was performed retrospectively with medical records. Results : Twenty four infants were diagnosed with PVL or severe PV-IVH. Asphyxia, recurrent apnea, sepsis, acidosis and ventilator care were significantly increased in the PVL goup. Asphyxia, recurrent apnea, RDS, acidosis and ventilator care were significantly increased in the severe PV-IVH group. Conclusion : Infants with PVL or severe PV-IVH may have multiple perinatal risk factors including asphyxia, recurrent apnea, sepsis, acidosis, RDS and ventilator care. Because most patients with ventilator care have multiple perinatal risk factors, ventilator care does not cause PVL and severe PV-IVH independently. Therefore, incidences of PVL and severe PV-IVH can be decreased by not only gentle ventilation, but also more professional antenatal care.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2013.05a
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• pp.999-1000
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• 2013

• 한국신재생에너지학회:학술대회논문집
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• 2007.11a
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• pp.259-259
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• 2007

• Journal of the Institute of Electronics and Information Engineers
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• v.50 no.6
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• pp.105-113
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• 2013

In this paper a micro solar energy harvesting system with MPPT(Maximum Power Point Tracking) control using a miniature PV(photovoltaic) cell of which the output is less than 0.5V is proposed. The MPPT control is implemented using linear relationship between the open-circuit voltage of a PV cell and its MPP(Maximum Power Point) voltage such that a pilot PV cell can track the MPP of the main PV cell in real time. The proposed circuit is designed in 0.18um CMOS process. The designed chip area is $900um{\times}1370um$ including a load charge pump and pads. Measured results show that the designed system can track the MPP voltage changes with variations of light intensity. The designed circuit with MPPT control delivers MPP voltages to load even though the load is heavy such that it can supply more power when the MPPT control is applied. The proposed circuit does not require any precharged battery resulting in more suitability for miniaturized self-powered systems compared to the existing works.

• Current Photovoltaic Research
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• v.5 no.3
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• pp.89-94
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• 2017

We have examined the issues on the measurement of bifacial photovoltaic(PV) devices that should be considered in order to ensure a measurement accuracy beyond a certain level and the comparability between the bifacial PV devices. Based on the results of various experiments and previous studies, solutions for these measurement issues are suggested. The most significant technical issues in the performance measurement of the bifacial PV devices are 1) elimination of the effect due to the light reflection on the sample holder surface and 2) the measurement of the expected power generation gain in outdoor operation. The effect due to the light reflection on the sample holder surface can be eliminated by using an anti-reflective sample holder. In case of a reflective sample holder, if the bifacial device have a linear characteristic with respect to the irradiance of incident light, it has been confirmed (through some previous studies and additional experiment) that exact measurement results can be obtained by the correction of the measurement data. In addition, it was also confirmed that the expected power generation gain in the outdoor operation can be obtained by three different methods along with the basic concepts of the bifaciality coefficient, the albedo, and the effective front irradiance.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.22 no.5
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• pp.22-33
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• 2021

In the case of open phase faults caused by the disconnection of distribution feeders interconnected to a PV system, many problems can occur depending on the core type and wiring method of the grid-connected transformers. Moreover, open phase faults are difficult to detect because the open phase voltage of the existing protection relay (Open Phase Relay (47)) can be maintained, even though a disconnection fault occurred, depending on the wiring method and the iron core type of the grid-connected transformer for a PV system. Therefore, this paper proposes a novel algorithm to detect open phase faults by comparing the currents and phases between the primary and secondary sides of a grid-connected transformer. In addition, this paper presents the modeling of a distribution system and protection devices for detecting open phase faults using PSCAD/EMTDC S/W, and implements a test protection device for detecting open phase faults based on the above-mentioned modeling. The simulation and test results confirmed that the proposed algorithm is useful for detecting open phase faults according to the wiring method and iron core type of grid-connected transformer for a PV system because operation slope and unbalance rate of the primary current exceed the setting value (30[%]) of the protection device.

• The Transactions of the Korean Institute of Power Electronics
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• v.14 no.2
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• pp.89-95
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• 2009

Tracking the Maximum Power Point(MPP) of a photovoltaic(PV) array is usually an essential part of a PV system. The problem considered by MPPT techniques is to find the voltage $V_{MPP}$ or current $I_{MPP}$ at which a PV array should operate to generate the maximum power output PMPP under a given temperature and irradiance. The MPPT control methods, such as the perturb and observe method and the incremental conductance method require microprocessor or DSP to determine if the duty cycle should be increased or not. This paper proposes a simple and fast analog MPPT method. The proposed control scheme will track the MPP very fast and its hardware implementation is so simple, compared with the conventional techniques. The new algorithm has successfully tracked the MPP, even in case of rapidly changing atmospheric conditions, and Has higher efficiency than ordinary algorithms.