• 한국산업융합학회 논문집
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• 제26권4_2호
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• pp.715-724
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• 2023

Solar energy forecasting is essential for (1) power system planning, management, and operation, requiring accurate predictions. It is crucial for (2) ensuring a continuous and sustainable power supply to customers and (3) optimizing the operation and control of renewable energy systems and the electricity market. Recently, research has been focusing on developing solar energy forecasting models that can provide daily plans for power usage and production and be verified in the electricity market. In these prediction models, various data, including solar energy generation and climate data, are chosen to be utilized in the forecasting process. The most commonly used climate data (such as temperature, relative humidity, precipitation, solar radiation, and wind speed) significantly influence the fluctuations in solar energy generation based on weather conditions. Therefore, this paper proposes a hybrid forecasting model by combining the strengths of the Prophet model and the GRU model, which exhibits excellent predictive performance. The forecasting periods for solar energy generation are tested in short-term (2 days, 7 days) and medium-term (15 days, 30 days) scenarios. The experimental results demonstrate that the proposed approach outperforms the conventional Prophet model by more than twice in terms of Root Mean Square Error (RMSE) and surpasses the modified GRU model by more than 1.5 times, showcasing superior performance.

• Current Photovoltaic Research
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• 제11권1호
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• pp.34-37
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• 2023

Solar energy had become the main energy industry of renewable energy along with hydroelectric power generation. One of the technologies that contributed to the popularization of photovoltaic power and the decrease in the unit price of photovoltaic modules was the large-area solar cell. However, as the area increased, the light receiving area increased and the current value increased accordingly. Since power loss occurs when the current value was large, the number of busbar was increased to increase the current collection rate, and a technology to lower the current value through half-cutting was developed. The bus bar of the solar cell served as a passage through which the generated current was transmitted. This was because when the number of busbar decreases, the moving distance of electrons increased, so the amount of power generation decreases and when it increases, shadows occured. An important aspect of the electrode design was the optimal balance of these busbars and number of fingers. Therefore, in this study, the characteristics of the solar cell according to the number of front bus bars of the large-area solar cell were simulated using Griddler 2,5 pro. After selecting the number of busbar with the best characteristics, the difference was compared by varying the number of fingers and a better direction for the number of cutting was presented.

• 한국태양에너지학회 논문집
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• 제39권1호
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• pp.21-32
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• 2019

Solar hot water system produces hot water using solar energy. If it is not used effectively, overheating occurs during the summer. Therefore, a lot of research is being done to solve this. This study develops thermoelectric power module applicable to solar hot water system. A thermoelectric material can directly convert thermal energy into electrical energy without additional power generation devices. If there is a temperature difference between high and low temperature, it generate power by Seebeck effect. The thermoelectric module generates electricity using temperature differences through the heat exchange of hot and cold water. The water used for cooling is heated and stored as hot water as it passes through the module. It can prevent overheating of Solar hot water system while producing power. The thermoelectric module consists of one absorption and two radiation part. There path is designed in the form of a water jacket. As a result, a temperature of the absorption part was $134.2^{\circ}C$ and the radiation part was $48.6^{\circ}C$. The temperature difference between the absorption and radiation was $85.6^{\circ}C$. Also, The Thermoelectric module produced about 122 W of irradiation at $708W/m^2$. At this time, power generation efficiency was 2.62% and hot water conversion efficiency was 62.46%.

• Journal of Power Electronics
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• 제17권2호
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• pp.514-521
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• 2017

This paper proposes a shadowing compensation method for the solar modules of grid-connected photovoltaic generation systems. The shadowing compensator (SC) implemented by the proposed shadowing compensation method is used only for the solar modules that can be shaded by predictable sources of shading. The proposed SC can simplify both the power circuit and the control circuit as well as improve power efficiency and utilizes a voltage equalizer configured by a modified multi-winding fly-back converter. The proposed SC harvests energy from the entire solar cell array to compensate for the shaded sub-modules of the solar cell array, producing near-identical voltages of all shaded and un-shaded sub-modules in the solar cell array. This setup prevents the formation of multiple peaks in the P-V curve under shaded conditions. Hardware prototypes are developed for the SCs implemented by the conventional and modified multi-winding fly-back converters, and their performance is verified through testing. The experimental results show that both SCs can overcome the multiple peaks in the P-V curve. The proposed SC is superior to the SC implemented by the conventional multi-winding fly-back converter.

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2009년도 춘계학술대회 논문집
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• pp.139-142
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• 2009

The worldwide energy market is enlarging rapidly according to current issues like globalization, deregulation, global warming and strengthening for environmental regulation as well as the energy technology is developing speedily by the add of information and communication techniques. In spite of these advanced techniques in the field of the renewable energy, solar power depends on the governmental aid largely in comparison with other renewable energy sources because of the high initial investment cost. Therefore it is important to investigate scrupulously for the expected erection site of solar power plant from the planning stage. This paper shows actual measurement data of solar radiation of scheduled solar power locations in the waterworks site with consideration of waterworks facilities and regional specialties and presents the data which was analyzed comparably with the radiation data of adjacent locations served by national authorities. In addition, these data were analyzed using RETScreen and used for making decision on the business validity.

• 조명전기설비학회논문지
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• 제28권10호
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• pp.95-100
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• 2014

To solve the problem of conventional fossil energy, utilization of renewable energy is growing rapidly. Solar energy as an energy source is infinite, and a variety of research is being conducted into its utilization. To change solar energy into electrical energy, we need to build a solar power plant. The efficiency of such a plant is strongly influenced by meteorological factors; that is, its efficiency is determined by solar radiation. However, when analyzing observed generation data, it is clear that the generated amount is changed by various factors such as weather, location and plant efficiency. In this paper, we proposed a solar power generation prediction algorithm using geographical factors such as latitude and elevation. Hence, changes in generated amount caused by the installation environment are calculated by curve fitting. Through applying the method to calculate this generation amount, the difference between real generated amount is analyzed.

• 한국태양에너지학회:학술대회논문집
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• 한국태양에너지학회 2011년도 추계학술발표대회 논문집
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• pp.45-50
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• 2011

The efficiency of solar cell was about 4[%] in initial stage of photovoltaic industry, but it has quite a lot of efficiency through technology advances. Today, the efficiency of c-Si solar cells is about 17 to 19[%] and the efficiency of PV modules is about 14 to 15 [%]. We called that electrical losses occurred in the Conversion of solar cells to PV modules are CTM loss(Cell To Module loss), the CTM loss typically has a value of about3~5[%]. The more efficiency of solar cell increase, differences are larger because the efficiency decrease owing to physical or technical problems occurred in the Conversion of solar cells to PV modules. In this study, the power loss factors occurred in the Conversion of solar cells to PV modules are analyzed and it is proposed that how to reduce losses of the PV module. The types of power loss factor are (1)losses of front glass and encapsulant(generally EVA sheet), (2)losses by sorting miss, (3)losses by interconnection, (4)losses by the field aging of PV modules. In further study, experimental and evaluation will be conducted to make demonstrate for proposed solutions.

• 통합자연과학논문집
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• 제15권2호
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• pp.89-97
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• 2022

This paper presents the comprehensive feasibility study of solar mini-grid project located in Bajhang District, Sudur Paschim Province, Nepal. The study has been conducted with the aim of developing a suitable size solar mini-grid system to meet electricity demand of proposed settlements of the village people. The study forecasts that the estimated average daily peak power consumption of load is about 20kW and average daily energy demand of load is about 100-150kWh/day in the base year 2022. The shared ratio of productive end uses is about 25% of the total power consumption and about 27% of the total energy demand, which will be used for small business/income generation activities and required 45kWp size solar power generation mini-grid system. The estimated project cost for the proposed 45kW solar mini-grid system technology, including 3 years of operation & maintenance, as well as power distribution network up to end user's premises is about 0.24 million USD. It is concluded that 45kWp photovoltaic mini-grid is feasible for the location.

• 전력전자학회:학술대회논문집
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• 전력전자학회 1997년도 전력전자학술대회 논문집
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• pp.365-369
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• 1997

In this paper, solar array of KOMPSAT was modeled and analyzed. The modeling results of solar array was achieved by neural algorithm, which is powerful of nonlinear system with a few data sets. The algorithm was analyzed and verified by simulation considering on solar cell data of KOMPSAT. The characteristics VI curves and power generation of solar array are analyzed by using the modeling.

• Journal of Astronomy and Space Sciences
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• 제28권2호
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• pp.133-141
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• 2011

A satellite power system should generate and supply sufficient electric power to perform the satellite mission successfully during the satellite mission period, and it should be developed to be strong to the failure caused by the severe space environment. A satellite power system must have a high reliability with respect to failure. Since it cannot be repaired after launching, different from a ground system, the failures that may happen in space as well as the effect of the failures on the system should be considered in advance. However, it is difficult to use all the hardware to test the performance of the satellite power system to be developed in order to consider the failure mechanism of the electrical power system. Therefore, it is necessary to develop an accurate model for the main components of a power system and, based on that, to develop an accurate model for the entire power system. Through the power system modeling, the overall effect of failure on the main components of the power system can be considered and the protective design can be devised against the failure. In this study, to analyze the failure mode of the power system and the effects of the failure on the power system, we carried out modeling of the main power system components including the solar array regulator, and constituted the entire power system based on the modeling. Additionally, we investigated the effects of representative failures in the solar array regulator on the power system using the power system model.