• Journal of Power Electronics
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• v.14 no.6
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• pp.1293-1302
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• 2014

A flyback inverter using voltage sensorless maximum power point tracking (MPPT) for photovoltaic (PV) AC modules is presented. PV AC modules for a power rating from 150 W to 300 W are generally required for their small size and low price because of the installation on the back side of PV modules. In the conventional MPPT technique for PV AC modules, sensors for detecting PV voltage and PV current are required to calculate the PV output power. However, system size and cost increase when the voltage sensor and current sensor are used because of the addition of the auxiliary circuit for the sensors. The proposed method uses only the current sensor to track the MPP point. Therefore, the proposed control method overcomes drawbacks of the conventional control method. Theoretical analysis, simulation, and experiment are performed to verify the proposed control method.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2005.11a
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• pp.285-286
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• 2005

Organic photovoltaic properties were studied in ZnPc/$C_{60}$ heterojunction structure by varying the organic layer thicknesses and exiton blocking layer(EBL). Current density-voltage characteristics of organic photovoltaic cells were measured using Keithley 236 source-measure unit, a 500W xenon lamp (ORIEL 66021) for a light source and Agilent 4294A impedance analyzer in the range of 40 Hz $\sim$ 1 MHz. From the analyses of current-voltage characteristics such as short-circuit current density, open-circuit voltage and power conversion efficiency, optimum thickness of the organic layer were obtained and frequency response such as electrical conductance.

• Journal of Electrical Engineering and Technology
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• v.12 no.3
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• pp.1156-1165
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• 2017

A high performance interleaved bridgeless boost power factor correction (PFC) rectifier operating under the critical current conduction mode (CrM) is proposed in this paper to improve the efficiency and system performance of various applications, such as nano-grid systems. By combining the interleaved technique with the bridgeless topology, the circuit contains two independent branches without rectifier diodes. The branches operate in interleaved mode for each respective half-line period. Moreover, when operating in CrM, all the power switches take on soft-switching, thereby reducing switching losses and raising system efficiency. In addition, the input current flows through a minimum amount of power devices. By employing a commercial PFC controller, an effective control scheme is used for the proposed circuit. The operating principle of the proposed circuit is presented, and the design considerations are also demonstrated. Simulations and experiments have been carried out to evaluate theoretical analysis and feasibility of the proposed circuit.

• Current Photovoltaic Research
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• v.8 no.1
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• pp.39-43
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• 2020

In this study, we predict the generation of end-of-life photovoltaic modules when Feed in Tariff applied, in Republic of Korea. Based on the installation of photovoltaic modules, we prepared three different senarios in order to estimate the generation of end-of-life photovoltaic modules. The senarios are i) early worn-out, ii) mid worn-out and iii) late-worn out senario. We selected the mid worn-out senario to estimated the amount of end-of-life photovoltaic modules in this study. Establishment of the end-of-life module generation scenario predicted generation of end-of-life photovoltaic module, and forecasted generation amount of end-of-life module to which Feed in Tariff was applied in consideration of installed photovoltaic modules installed by Feed in Tariff support. The generation of Feed in Tariff-applied end-of-life modules increased from 2021 to 2025 compared to without Feed in Tariff, and since then, the Feed in Tariff-applied end-of-life modules were generated as waste modules during the relevant period (2021 ~ 2025).

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.28 no.11
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• pp.743-747
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• 2015

In this paper, the power generation efficiency of the 4 [kW] fixed-concentrated type photovoltaic power generation system and that of the 4 [kW] single axis trace type photovoltaic power generation system were compared. For that purpose, the two types of photovoltaic power generation systems have been in operation for 1 year on an experimental basis. The amounts of power generated by the two types during the months of January through December and the characteristics of their operating times during the same period have been compared and analyzed. For the study, the type with higher efficiency was selected and the following conclusions have been reached. It was shown that the amount of power generated and the average operation times during the spring months of March through May are higher that those of the summer months of June through August when more sunlight is available. The reason for this phenomenon is thought to be that as the temperatures of the solar panel surface and the surrounding environment go up, the electric current decreases.

• The Journal of the Korea institute of electronic communication sciences
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• v.9 no.7
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• pp.799-804
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• 2014

To combine to the power transmission, photovoltaic inverter is demanded, because the photovoltaic system is generated direct current power. However, photovoltaic inverter is sensitive to high temperature. In the temperature rising such as at noon and on summer, efficiency of machine is decreased due to the loss increment. Because this problem causes national energy loss according to the expanding the photovoltaic industry, countermeasure is demanded. There, in this paper, we installed a cooling system using a thermoelement regardless of the temperature. Also, we analyze the cooling effect according to the position of two fans which improve the effect maximize.

• Current Photovoltaic Research
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• v.5 no.1
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• pp.33-37
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• 2017

Today, photovoltaic power generation mostly uses Si crystalline solar cell modules. The most vulnerable part of the Si solar cell module is that the power generation decreases due to the temperature rise. But, it is widely used because of low installation cost. In the solar market, where Si crystalline solar cell modules are widely used. The CPV (Concentrated Photovoltaic) module appeared in the solar market. The CPV module reduces the manufacturing cost of the solar cell by using non-Si in the solar cell. Also, there is an advantage that a rise in temperature does not cause a drop in power generation. But this requires high technology to install and has a disadvantage that the initial installation cost is expensive compared to normal Si solar cell module. So that we built a testbed to see these characteristics. The testbed was used to measure the amount of power generation in a long-term outdoor environment and compared with the general Si solar cell module.

• Proceedings of the KIEE Conference
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• 2001.07c
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• pp.1427-1429
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• 2001

Polycrystalline silicon(poly-Si) films are deposited on low temperature glass substrate by Hot-Wire CVD(HWCVD). The structural properties of the poly-Si films are strongly dependent on the wire temperature($T_w$). The films deposited at high $T_w$ of 2000$^{\circ}C$ have superior crystalline properties; average lateral grain sizes are larger than $1{\mu}m$ and there at·e no vertical grain boundaries. The surface of the high $T_w$ samples are naturally textured like pyramid shape. These large grain size and textured surface are believed to give high current density when applied to solar cells. However, the poly-si films are structurally porous and contains high defect density, by which high concentration of C and O resulted within the films by air-penetration after removed from chamber.

• Current Photovoltaic Research
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• v.10 no.1
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• pp.1-5
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• 2022

Bifacial photovoltaic (PV) technology has received considerable attention in recent years due to the potential to achieve a higher annual energy yield compared to its monofacial PV systems. In this study, we fabricated the bifacial c-Si PV module with a shingled design using the conventional patterned bifacial solar cells. The shingled design PV module has recently attracted attention as a high-power module. Compared to the conventional module, it can have a much more active area due to the busbar-free structure. We employed the transparent backsheet for a light reception at the rear side of the PV module. Finally, we achieved a conversion power of 453.9 W for a 1300 mm × 2000 mm area. Moreover, we perform reliability tests to verify the durability of our Shingled Design Bifacial c-Si Photovoltaic module.

• Current Photovoltaic Research
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• v.12 no.1
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• pp.17-23
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• 2024

Photovoltaic (PV) power generation is the world's best and largest renewable energy that generates electricity with infinite sunlight. Solar cell modules are a component of photovoltaic power generation and must have a long-term durability of at least 25 years. The development of processes and equipment that can be recovered through the recycling of metals and valuable metals when the solar module's lifespan is over has been completed to the level of commercialization, but few processes have been developed that require repair due to initial defects. This is mainly due to the economic problems caused by remaking. However, if manufacturing processes such as repairing solar cell modules that have been proven to be early defects are established and the technical review of long-term reliability and durability reaches a certain level, it is considered that it will be a recommended process technology for environmental economics. In this paper, assuming that a defective solar cell module occurs artificially, a manufacturing process for replacement of solar cells was developed, and a technical verification of the manufacturing technology was conducted through long-term durability evaluation in accordance with KS C 8561. Through this, it was determined that remanufacturing technology for solar cell replacement of solar cell modules that occurred in a short period of time after installation was possible, and the research results were announced through a journal to commercialize solar modules using manufacturing technology in the solar market in the future.