• Solar Energy
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• v.19 no.4
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• pp.63-69
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• 1999

The conventional grid connected PV(Photovoltaic) system has a unstable output pattern due to its dependence on the weather condition, although solar-cell array averagely has a regular output characteristics to have a peak output nearly at noon. Therefore assuming the high density grid connection in the future, this unstable output pattern can be one of the main reasons to generate power disturbance such as voltage variation, frequency variation and harmonic voltage generation in low voltage distribution line. However general grid connected solar-cell system do not have functions to cope with these disturbances. Therefore this study proposed a advanced type grid connected PV system with functions to suppress output power fluctuation due to solar-cell array output variation and showed the levelling effect of fluctuation due to instantaneous array output variation.

• Journal of Energy Engineering
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• v.21 no.1
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• pp.26-32
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• 2012

This study has been performed Thermal Shock test for analyze the cause of Power drop in PV(Photovoltaic) Module. Thermal Shock test condition was performed with temperature range from $-40^{\circ}C{\sim}85^{\circ}C$. One cycle time is 30min. which are consist of low and high temperature 15min. each other. The test was performed with total 500cycles. EL, I-V were conducted every 100cycle up to 500cycles. Mono Cell resulted in 8% Power drop rates in Bare Cell and 9% in Solar Cell. In the case of Multi Cell resulted in 6% Power drop rates in Bare Cell and 13% in Solar Cell. After Thermal Shock test, Solar Cell's Power drop resulted from surface damages, but in the case of Bare Cell's Power drop had no surface damages. Therefore, Bare Cell's Power drop was confirmed as according to leakage current increase by analysis of Fill Factor after Thermal Shock test. Also, Solar Cell's Power drop rates are higher than that of Bare Cell because of surface damages and consuming electric power increase. From now on, it should be considered that analyzed the reasons of Fill Factor decrease and irregular Power drop in PV module and Cell level using cross section, various conditions and test methods.

• Proceedings of the KIEE Conference
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• 2003.07b
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• pp.1347-1349
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• 2003

PV array, which is generally installed in the outside, has the possibility to be damaged by high voltage doc to lightning. Because the surge characteristic of PV array has not been fully identified yet, there is the very important issue whether PV array should be connected with ground or not. In this paper, a basic model of PV array is provided considering solar cell's barrier capacitance and ground capacitance for analysis of surge characteristics.

• 한국태양에너지학회:학술대회논문집
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• 2011.11a
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• pp.239-244
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• 2011

In this paper, we analyzed the electrical characteristics with crack pattern in crystalline solar cell. crystalline solar cells with a thin substrate, even small shocks can be easily damaged. Before the module goes through many processes, because the solar cells are at risk of a crack. That occurred early in the PV module micro-crack is not easily detection by eye test or output test. Because the EL (Electroluminescence) device has been detected using. PV module is made by laminated of a variety of materials. By different properties of each material will affect the crack. For this reason, the crack will grow and affect the output. And We analyzed the three crack patterns in crystalline solar cell. A growth of cracks on crystalline solar cell was interpreted by analysing generated cracks on the PV modules. Based on this interpretation, an electrical output value was calculated by mathematical modeling on electrical output characteristic with each crack patterns.

• Proceedings of the KIPE Conference
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• 1999.07a
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• pp.93-96
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• 1999

Solar cell generate DC power from sunlight whose power is different at any instance according to condition of variables : insolation and temperature. In order to improve the system utility factor and efficiency of energy conversion, it is desirable to operate the PV system at maximum power point of solar cell under different condition. In this paper, Boost chopper is controlled it output voltage with a new discrete control algorithm for MPPT. PWM signal of DC-DC converter are generated with a 89C51 microcontroller. Switching frequency of DC-DC converter is set at 10KHz. Simulation and experimental results show that the PV system studied in this paper is always operated at maximum power point under different maximum power point of solar cells having stabilized output voltage waveform with relatively small ripple component

• Proceedings of the KIEE Conference
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• 2008.07a
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• pp.1110-1111
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• 2008

The life time of PV module is semi-permanent. But, because of installation and module fabrication process, its important part can not be finished. In this paper, we analyze 15 years old modules made from different company. Among the PV modules, the maximum power drop ratio was 12.23% minimum and 80.63% maximum. Also the effect of solar cell's short circuit current difference was analyzed. The PV module exposed about 65days, its the maximum power drop ratio was 1.29% minimum and 23.43% maximum. It is for reduction of current value. And the reason for current reduction was due to reduction of parallel resistance of solar cell. To prevent early degradation, it is need to have attention to fabrication, installation and maintenance.

• Journal of the Korean Solar Energy Society
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• v.29 no.6
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• pp.88-93
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• 2009

This study was conducted to improve the power of PV module using a surface cooling system One of the unique characteristics of PV module is power drop as a module surface temperature increases due to the characteristics of crystalline silicon used in a solar cell. To overcome the output power reduction by temperature effect, module surface cooling using water circulation was performed. By cooling effect, module surface temperature drops maximally $20.3^{\circ}C$ predicting more than 10% power enhancement. Maximum deviation of voltage and current between a control and cooled module differed by 5.1 V and O.9A respectively. The maximum power enhancement by cooling system was 12.4% compared with a control module. In addition, cooling system can wash the module surface by water circulation so that extra power up of PV module can be achieved by removing particles on the surface which interfere solar radiation on the cells. Cooling system, besides, can reduce the maintenance cost and prevent accidents as a safety precaution while cleaning works. This system can be applied to the existing photovoltaic power generation facilities without any difficulties as well.

• Proceedings of the KIEE Conference
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• 2008.07a
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• pp.1100-1101
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• 2008

After lamination process, Isc is increased by sheet reflection. This paper presents the electrical output characteristics by back sheet reflection. The experiments was conducted by using single crystalline and multi crystalline PV module. The reflection area of single crystalline PV module is larger than multi one due to the difference of solar cell manufacturing. The experiments show that the increased performance ratio of single crystalline PV module output power is 1.55% rather than that of multi crystalline PV module output power is 1.13%. In addition, it is expected that the output power of single one rather than multi-one is increased by the lower temperature when the PV module is installed outside. The results can be reconsidered by the test material and test process. Back sheet used for humidity prevention makes PV module output power increasing.

• 한국태양에너지학회:학술대회논문집
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• 2009.11a
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• pp.309-313
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• 2009

This study was conducted to improve the power of PV module using a surface cooling system. One of the unique characteristics of PV module is power drop as a module surface temperature increases due to the characteristics of crystalline silicon used in a solar cell. To overcome the output power reduction by temperature effect, module surface cooling using water circulation was performed. By cooling effect, module surface temperature drops maximally $20.3^{\circ}C$ predicting more than 10% power enhancement. Maximum deviation of voltage and current between a control and cooled module differed by 5.1V and 0.9A respectively. The maximum power enhancement by cooling system was 12.4% compared with a control module. In addition, cooling system can wash the module surface by water circulation so that extra power up of PV module can be achieved by removing particles on the surface which interfere solar radiation on the cells. Cooling system, besides, can reduce the maintenance cost and prevent accidents as a safety precaution while cleaning works. This system can be applied to the existing photovoltaic power generation facilities without any difficulties as well.

• Proceedings of the KIEE Conference
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• 2006.04b
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• pp.386-389
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• 2006

BIPV(Building Integrated PV) system can expect dual effects that reduce expenses for establishment of PV system by adding new function as outer covering material of building expect producing the electricity. In case of PV(photovoltaic system) there are many generation differences according to the exterior environmental facts(solar cell array, design and installation condition of interactive inverter system). In this paper, we compared constitute factors of 3kW BIPV(solar cell module, inverter), operating characteristic and total system characteristic(utilization, generation efficiency, loss fact) and found out long time operating data using a watch instrumentations. By use of long time operating result, compare a totally operating characteristics, and we proposed a next building application of BIPV. BIPV system that is proposed in this paper, was established in Solar Energy research center of Chosun University, composed with system. The objective of this paper, is to provide a efficient BIPV design method through the considerations for the integration of PV system.