• 한국태양에너지학회 논문집
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• 제40권4호
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• pp.13-22
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• 2020

As the supply of photovoltaic (PV) increases worldwide, the cumulative installations in 2018 were 7.9 and 560 GW in Korea and the world, respectively. Typically, when the ground on commercial PV modules is installed, the area is limited; hence, new designs of PV modules are required to install additional PVs. Among the new design of PV modules, lightweight PV modules can be utilized in PV systems, such as buildings, farmlands, and floating PV. Concerning the investigation of lightweight PV modules, several studies on materials for replacing low-iron tempered glass, which comprises approximately 65% of the PV module weight, have been conducted. However, materials that are used as substitutes for glass should possess similar lightweight properties and reliability as glass. In this study, experimental tests were performed to evaluate the applicability of ethylene tetrafluoroethylene (ETFE) film with excellent resistance to water and aging as a front material of PV modules. The transmittance and ultraviolet properties of the ETFE film were determined and compared with those of glass. A 1-cell module and laboratory-scale 24-cell module were manufactured using the ETFE film and glass, and the electrical output was measured and analyzed. Furthermore, damp heat and thermal cycle tests were conducted to evaluate the reliability of the ETFE film module. Based on the experimental results, the electrical output and reliability of the ETFE film module were similar to those of the glass module, and the ETFE film could be used as the front material of PV modules.

• Transactions on Electrical and Electronic Materials
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• 제18권1호
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• pp.30-34
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• 2017

The building integrated photovoltaic system (BIPV) attracts attention with regard to the future of the photovoltaic (PV) industry. It is because one of the promising national and civilian projects in the country. Since land area is limited, there is considerable interest in BIPV systems with a variety of angles and shapes of PV panels. It is therefore expected to be one of the major fields for the PV industry in the future. Since the irradiation is different from each installation angle, the output can be predicted by the angles. This is critical for a PV system to be operated at maximum power and use an efficient design. The development characteristics of tilted angles based on data results obtained via long-term monitoring need to be analyzed. The ratio of the theoretically available and actual outputs is compared with the installation angles of each PV module to provide a suitable PV system for the user.

• Journal of Power Electronics
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• 제11권2호
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• pp.179-187
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• 2011

This paper proposes a MATLAB Simulink simulator for photovoltaic (PV) systems. The main contribution of this work is the utilization of a two-diode model to represent a PV cell. This model is known to have better accuracy at low irradiance levels which allows for a more accurate prediction of PV system performance. To reduce computational time, the input parameters are reduced to four and the values of $R_p$ and $R_s$ are estimated by an efficient iteration method. Furthermore, all of the inputs to the simulator are information available on a standard PV module datasheet. The simulator supports large array simulations that can be interfaced with MPPT algorithms and power electronic converters. The accuracy of the simulator is verified by applying the model to five PV modules of different types (multi-crystalline, mono-crystalline, and thin-film) from various manufacturers. It is envisaged that the proposed work can be very useful for PV professionals who require a simple, fast and accurate PV simulator to design their systems.

• 한국식품과학회지
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• 제29권2호
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• pp.390-393
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• 1997

2% ${\kappa}-carrageenan$, 0.1% KCl, 0.75%, PEG, 및 0.75% glycerol을 사용하여 제조한 필름을 고등어육의 포장재로 사용 가능성을 시험하기 위하여 포장 후 수분 손실 및 지방 산화의 정도를 측정하였다. 고등어육을 carrageenan 필름으로 포장하여 $20^{\circ}C,\;10^{\circ}C,\;0^{\circ}C$, 및 $-15^{\circ}C$에 저장하였으며, 포장하지 않은 시료도 $0^{\circ}C$에 저장하면서, 무게 감소, PV, TBA가 등을 측정하였다. $20^{\circ}C,\;10^{\circ}C$, 및 $0^{\circ}C$에 저장한 포장 또는 비포장 시료는 저장 후 15일 이내에 60%의 무게 감소 현상을 보였으나, $-15^{\circ}C$에 저장한 시료는 25일 후에도 약 3% 정도만의 무게 감소가 있었다. 포장하지 않은 채 $0^{\circ}C$에 저장한 시료는 지방 산화가 꾸준히 증가하는 현상을 보였는데, PV는 20일만에 23 mequivalent peroxide (PO)/㎏, TBA가는 5일만에 $0.4\;{\mu}mole$ malonaldehyde (MA)/g에 도달한 반면, carrageenan 필름으로 진공 포장한 어육은 28일간의 저장기간 동안 저장 온도에 관계없이 PV 및 TBA가가 각각 2 mequivalent PO/kg 및 $0.4\;{\mu}mole\;MA/g$ 이하를 나타냈다.

• Journal of Power Electronics
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• 제18권4호
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• pp.997-1006
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• 2018

This paper proposes a transformerless photovoltaic (PV) power converter system based on the DC/AC boost inverter, which can solve the leakage current and second-order ripple power issues in single-phase grid-connected PV inverters. In the proposed topology, the leakage current can be decreased remarkably since most of the common-mode currents flow through the output capacitor, by-passing parasitic capacitors, and grounding resistors. In addition, the inherent ripple power component in the single-phase grid inverter can be suppressed without adding any extra components. Therefore, bulky electrolytic capacitors can be replaced by small film capacitors. The effectiveness of the proposed topology has been verified by simulation and experimental results for a 1-kW PV PCS.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2009년도 제40회 하계학술대회
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• pp.1061_1061
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• 2009

Running low of fossil fuel energy forces the industry to find a new way to overcome this energy crisis. One of the solutions is using the unlimited and everlasting energy sources like wind, sun, water, and so on. Especially, sun energy becomes the hottest issue in recent years because of its merit in installation, operation and abundant material source of silicon. In 2008, about 5.5GW photovoltaic (PV) system has been installed all around world. Many professional renewable energy organizations expect that the total PV system installation will be 30GW. To sustain the long-term stability of the PV system, several institutes perform the test based on IEC standards like IEC 61215 for silicon crystalline PV module and IEC 61646 for thin film PV module. Also in South Korea, Korea Institute of Energy Research (KIER) performs the certificate test according to IEC 61215 standards. In this paper, we want to summarize and inform the 3 years‘ test results of domestic and foreign PV modules. The specific and technical explanation will be shown in the following paper in detail.

• Advances in Energy Research
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• 제1권2호
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• pp.97-106
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• 2013

This study designs and tests a photovoltaic system with distributed maximum power point tracking (DMPPT) methodology using a field programmable gate array (FPGA) controller. Each solar panel in the distributed PV system is equipped with a newly designed DC/DC converter and the panel's voltage output is regulated by a FPGA controller using PI control. Power from each solar panel on the system is optimized by another controller where the quadratic maximization MPPT algorithm is used to ensure the panel's output power is always maximized. Experiments are carried out at atmospheric insolation with partial shading conditions using 4 amorphous silicon thin film solar panels of 2 different grades fabricated by Chi-Mei Energy. It is found that distributed MPPT requires only 100ms to find the maximum power point of the system. Compared with the traditional centralized PV (CPV) system, the distributed PV (DPV) system harvests more than 4% of solar energy in atmospheric weather condition, and 22% in average under 19% partial shading of one solar panel in the system. Test results for a 1.84 kW rated system composed by 8 poly-Si PV panels using another DC/DC converter design also confirm that the proposed system can be easily implemented into a larger PV power system. Additionally, the use of NI sbRIO-9642 FPGA-based controller is capable of controlling over 16 sets of PV modules, and a number of controllers can cooperate via the network if needed.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2009년도 제38회 동계학술대회 초록집
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• pp.141-141
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• 2010

The effect of thermal anneal on the characteristics of structural properties and the enhancement of luminescence and photovoltaic (PV) characteristics of silicon-rich silicon-nitride films were investigated. By using an ultra high vacuum ion beam sputtering deposition, B-doped silicon-rich silicon-nitride (SRSN) thin films, with excess silicon content of 15 at. %, on P-doped (n-type) Si substrate was fabricated, sputtering a highly B doped Si wafer with a BN chip by N plasma. In order to examine the influence of thermal anneal, films were then annealed at different temperature up to $1100^{\circ}C$ under $N_2$ environment. Raman, X-ray diffraction, and X-ray photoemission spectroscopy did not show any reliable evidence of amorphous or crystalline Si clusters allowing us concluding that nearly no Si nano-cluster could be formed through the precipitation of excess Si from SRSN matrix during thermal anneal. Instead, results of Fourier transform infrared and X-ray photoemission spectroscopy clearly indicated that defective, amorphous Si-N matrix of films was changed to be well-ordered thanks to high temperature anneal. The measurement of spectral ellipsometry in UV-visible range was carried out and we found that the optical absorption edge of film was shifted to higher energy as the anneal temperature increased as the results of thermal anneal induced formation of $Si_3N_4$-like matrix. These are consistent with the observation that higher visible photoluminescence, which is likely due to the presence of Si-N bonds, from anneals at higher temperature. Based on these films, PV cells were fabricated by the formation of front/back metal electrodes. For all cells, typical I-V characteristic of p-n diode junction was observed. We also tried to measure PV properties using a solar-simulator and confirmed successful operation of PV devices. Carrier transport mechanism depending on anneal temperature and the implication of PV cells based on SRSN films were also discussed.

• 마이크로전자및패키징학회지
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• 제27권4호
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• pp.55-60
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• 2020

태양광 발전소에 설치된PERC 태양광 모듈 스트링-어레이는 고전압의 전위차로 인해 여전히 potential-induced degradation(PID) 열화 현상이 여전히 보고되고 있다. 이는 태양전지 모듈 커버글라스의 Na+ 이온이 태양전지 봉지재(EVA)를 투과하여 셀 표면으로 전이되고 결함이 많이 분포되어 있는 ARC(SiOx/SiNx) 계면에 양전하가 축적됨으로써 shunt-Resistance(Rsh)가 감소되고 누설전류량이 증가되어 태양전지 출력이 저하되는 현상이다. 본 연구에서는 이를 방지하기 위해 나노임프린트 리소그래피(nano-imprint lithography, NIL) 방식을 이용하여 모스아이(Moth-eye) 나노 구조를 광학 필름 후면에 증착 하였고, 이를 커버글라스와 EVA 사이에 삽입하여 태양광 미니 모듈을 구성하였다. PID 열화 현상을 확인하기 위해 IEC 62804-1 규격에 기반한 셀 단위 PID 열화가속시험을 진행하였고, Light I-V, Dark I-V 분석을 통해 출력(Pmax), 효율(Efficiency), 병렬 저항(shunt resistance)을 확인하였다. 그 결과 기존의 태양전지는 초기 효율 19.76%에서 6.3% 감소하였으나 모스아이 나노 구조 광학 필름(Moth-eye film)이 적용된 태양전지는 0.6% 만 감소하여 PID 열화 현상이 방지되는 것을 확인하였고, 모스아이 나노구조를 통해 투과도가 4% 향상되어 미니 모듈 출력이 2.5% 향상되었다.

• 멤브레인
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• 제25권3호
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• pp.287-294
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• 2015

태양전지는 태양복사에너지를 반도체의 광전효과를 통해 전기에너지로 변환시키는 친환경 에너지변환장치를 의미한다. 수분을 포함하는 다양한 화학물질들에 대한 높은 차단성을 갖는 다층형 필름인 백시트는 태양전지의 중요한 요소이다. 대표적인 백시트는 polyvinyl fluoride (PVF)와 poly(ethylene terephthalate) (PET)의 다층필름으로 구성된다. PVF는 높은 내후성을 가지는 반면, 가격이 상대적으로 비싼 단점을 보인다. 따라서, 백시트의 제조가격을 낮출 수 있으면서, 동시에 실제 태양전지모듈에 적용할만한 수명특성을 만족시킬 수 있는 대체소재의 개발이 필수적이다. 본 연구에서는 일정수준의 결정성을 갖는 PET 필름을 PVF 필름 대신 사용하였다. 그러나, PET 소재는 다양한 pH 조건에서 trans-esterification 및 가수분해에 의해 분해될 수 있기 때문에, 태양전지의 구동조건에서 PET의 분해거동을 이해할 필요가 있다. 단시간 내 화학적 분해거동을 평가하기 위해서, 가속화된 PET 분해실험 프로토콜이 개발되었다. 마지막으로, 제안 개념의 효용성은 태양전지모듈의 장기운전성능 평가를 통해 확인하였다.