• Journal of Bio-Environment Control
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• v.26 no.4
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• pp.258-267
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• 2017

The price competitiveness of photovoltaic system (PV system) has risen recently due to the growth of industries, however, it is rarely applied to the greenhouse compared to other renewable energy. In order to evaluate the application of PV system in the greenhouse, power generation and optimal installation area of PV panels should be analyzed. For this purpose, the prediction of the heating and cooling loads of the greenhouse is necessary at first. Therefore, periodic and maximum energy loads of a multi-span greenhouse were estimated using Building Energy Simulation(BES) and optimal installation area of PV panels was derived in this study. 5 parameter equivalent circuit model was applied to analyzed power generation of PV system under different installation angle and the optimal installation condition of the PV system was derived. As a result of the energy simulation, the average cooling load and heating load of the greenhouse were 627,516MJ and 1,652,050MJ respectively when the ventilation rate was $60AE{\cdot}hr^{-1}$. The highest electric power production of the PV system was generated when the installation angle was set to $30^{\circ}$. Also, adjustable PV system produced about 6% more electric power than the fixed PV system. Optimal installation area of the PV panels was derived with consideration of the estimated energy loads. As a result, optimal installation area of PV panels for fixed PV system and adjustable PV system were $521m^2$ and $494m^2$ respectively.

• Proceedings of the KIEE Conference
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• 2007.07a
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• pp.1968-1969
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• 2007

In recent years, the research and development for the photovoltaic(PV) energy system are making rapidly progress around the world and specially this country, too due the deregulation law for the renewable energy system seems to be born sooner or later. If we can study PV generation system regardless of weather condition, we will study much more efficiently. This paper introduces the algorithm of PV power generation system simulator and the results of simulation by using PSCAD/EMTDC. In next paper, authors will prove the algorithm of PV simulator proposed in this paper by making real simulator and getting the result of experiment.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.11 no.8
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• pp.2999-3004
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• 2010

In comparison with some other light sources, LED has merits such as long lifetime, pollution free, and high energy efficiency. Lately, due to development of LED with high brightness and capacity, LED, which has been applied in display system only, has applied in the field of lighting system. As power LED for lighting system can be burned out by heat problem, the driving current of power LED has to be controlled below the designed value. In this paper, power LED photovoltaic lighting system, which has the current limitting function, has been described. After photovoltaic power is generated from PV panel. it is charged into a battery. And then, after the charged power is converted to DC24[V] through a boost DC-DC converter, it is supplied to power LED at night. It has been validated by designing and testing of 72[W] power LED lighting system, which includes a PV charger, a boost DC-DC converter and a current limiter for driving power LED.

• Journal of the Korean Solar Energy Society
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• v.29 no.1
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• pp.18-23
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• 2009

We intend to describe a 12kW building-integrated photovoltaic system which was applied into the south wall of a new building. This study showed the results that were appeared from describing the PV module manufacture and installation process, and performing generation performance analysis of BIPV system. From the result we confirmed that the generation performance of the BIPV system was changed by season. The performance ratio(PR) was about 83.6% in winter and it means that performance of this BIPV system was so good in that season. On the other hand, the PR in summer was about 75.0% dropped about 8%. It was believed that the change was influenced by the reduction of solar radiation irradiated into the PV modules by installation position and rainy spell in summer. And we also confirmed that low irradiation condition is cause of the additional loss in the total PV system. In this case, the efficiency ratio of PCS drops significantly at low input loads and the average conversion efficiency of PCS in summer was 76.4% decreased about 10% from 86% in winter.

• Journal of Power Electronics
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• v.8 no.4
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• pp.309-316
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• 2008

In this paper, new topology is proposed that can dramatically reduce the converter power rating and increase the efficiency of total PV system. Since the output voltage of PV module has very wide voltage range, in general, the DC/DC converter is used to get constant high DC voltage. According to analysis of PV characteristics, in proposed topology, only 20% power of total PV system power is needed for DC/DC converter. DC/DC converter used in proposed topology has flat efficiency curve at all load range and very high efficiency characteristics. The total system efficiency is the product of that of converter and that of inverter. In proposed topology, because the converter efficiency curve is flat all load range, the total system efficiency at the low power range is dramatically improved. The proposed topology is implemented for 200kW PCS system. This system has only three DC/DC converters with 20kW power rating each other. It is only one-third of total system power. The experiment results show that the proposed topology has good performance.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.15 no.7
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• pp.4692-4697
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• 2014

A micro-grid including photovoltaic source and Li battery has been installed and operated for several years at the campus of USF and been used as a test bed. Photovoltaic power source has been strongly influenced by the location, weather and climate of the installed area. To compensate for the uncertainty of photovoltaic source's power output, a Li battery is connected directly to the photovoltaic source and supplies electric power to the grid. The Li battery is operated to supply power output to the grid according to the charging or discharging mode of the battery based on the average power output of the photovoltaic source, which is calculated from the monitored data for several years. The grid of the photovoltaic and Li battery system is operated as a severe loading condition and the operating characteristics of PV source and Li battery cells are analyzed in detail.

• New & Renewable Energy
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• v.16 no.1
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• pp.47-57
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• 2020

In Floating PV (Photovoltaic) systems, PV modules are installed on water by utilizing the surface of idle water such as a reservoir and multipurpose dam. A floating PV system, therefore, has the advantage of efficiency in national land use and improved energy yield owing to cooling effect compared to on-land PV systems. Owing to the limitation of installation environment for a floating PV system, the system, however, has the disadvantage of an increase in transmission distance of DC (Direct current) cables. A longer transmission distance of a DC cable results in greater power loss due to a voltage drop. This leads to a decline in economic feasibility for the floating PV system. In this paper, the economic analysis for 10 floating PV systems installed in a reservoir has been conducted in terms of a change in annual power sales according to the variation of transmission losses depending on the factors affecting the voltage drop, such as transmission distance, cross-section area of underwater cable, the presence of joint box, and PV capacity.

• Proceedings of the KIEE Conference
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• 2004.04a
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• pp.201-204
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• 2004

Consider the optimal design for PV system, it is apply to 3kW interconnected electric power PV system, that is a point of reference for 3kW PV the spread residential section system. Through the driving various practical system, we look into that for efficiency of generation and stability of interconnected system. Using obtained data acquisition, It can be suggest that installation and management for system parameter to optimal design maximum generation electric power. PV system have some losses that are variation radiation, shadow, change temperature, unbalanced grid connection, serial circuit loss, MPP deference loss, PCS loss and so forth. Using obtained various performance characteristic result, we can make database in the future, through the this study, we can get the reliance and have regard to spread PV system.

• Proceedings of the KIPE Conference
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• 2005.07a
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• pp.591-594
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• 2005

Islanding of PV systems occurs when the uitilty grid is removed but local sources continue to operate and provide power to local loads. Islanding Is one of the serious problems in an electric power system connected with dispersed power sources. Also, this scan present safety hazards and the possibility of damage to other electric equipments. If the real and reactive power of RLC load and PV system are closely matched, islanding phenomena can't be detected by the passive methods. Several active methods were proposed to detect islanding phenomena. The most effective method is SFS method which was suggested by Sandia National Laboratory. In this paper, a new anti-islanding algorithm is proposed and its validity is verified through simulation and experimental results for utility interconnection of PV system.

• KIEAE Journal
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• v.14 no.6
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• pp.53-58
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• 2014

Residental photovoltaic power system achieved remarkable results in distribution and activation through 'One Million Green Homes Program' led by the government. However, system maintenance and management after installation are relative unsatisfactory. Thus, problems, such as malfunctioning, decrease in efficiency, breakage, etc, are occurring in succession which means that expensive facilities are not used effectively. This study attempted to propose a more preferred alternative to the photovoltaic power system currently applied and installed to the housing by investigating and analyzing the said system, identifying management practices, and deriving problems. For this study, 48 houses equipped with photovoltaic systems in J City were chosen and they were analyzed after preliminary research and field investigation. The results revealed that most of the surveyed systems in J City are still in fairly good conditions. But the instruction and information regarding the appropriate operational management of those surveyed systems have not been delivered to the owner. Therefore, promotion education and related manual deployment should be done by the contractor. In terms of installation, inadequate system location and some warranty services are required to be improved, which are usually caused by a lack of careful planning and construction. In addition, the follow-up management needs to be provided about five years later after installation considering system deterioration.