• Journal of the Korean Solar Energy Society
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• v.30 no.6
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• pp.102-107
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• 2010

a-Si solar cell has relatively dominant drift current when compared with crystalline solar cell due to the high internal electric field. Such drift current make an impact on the PV module in the local shading. In this paper, the a-Si PV module output characteristics of shading effects was approached in terms of process condition, because of the different deposition layer of thin film lead to rising the resistance. We suggested design condition to ensure the long-term durability of the module with regard to the degradation factors such as hot spot by analyzing the module specification. The result shows a remarkable difference on module uniformity for each shading position. In addition, the unbalanced power loss due to power mismatch of each module could intensify the degradation.

• Current Photovoltaic Research
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• v.8 no.4
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• pp.120-123
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• 2020

Transparent photovoltaics (PV) are used in various applications such as building-integrated photovoltaics (BIPV). However, crystalline silicon (c-Si) is not used for developing transparent PV due to its opaque nature. Here. we fabficate the three holes in 6-inch c-Si solar cells using laser scribing process with an opening area ratio of about 6.8% for transparent c-Si solar modules. Moreover, we make the shingled strings using the perforated cells. Our 7 interconnected shingled string PV cells with 21 holes show a solar to power conversion of 5.721 W. In next work, we will fabricate a transparent c-Si PV module with perforated strings.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.29 no.12
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• pp.847-852
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• 2016

Using both EVA and POE encapsulants, we fabricated polycrystalline Si PV modules and performed a set of reliability tests of PID, DH, TC, and Complex prior to outdoor installation. The power output with temperatures and insolation as well as I-V characteristics had been monitored under outdoor environments for 18 months. In the entire period, the total power of 3,576 kWh from POE PV modules was observed larger than 3,449 kWh from EVA PV modules by 3.5%. All the PV modules showed a 5.6~9.2% drop in the conversion efficiency. As for the solar power generation, the PV modules performed through PID, TC test revealed distinct difference in between EVA and POE for which the POE PV module produced more power by +11.4% and +6.6%, respectively, as measured in the 18th month. In addition, POE was proved to protect better the solar cells under PID influence.

• Current Photovoltaic Research
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• v.10 no.4
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• pp.107-110
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• 2022

Lightweight and flexible photovoltaic (PV) modules are attractive for building-integrated photovoltaic (BIPV) applications because of their easy construction and applicability. In this study, we fabricated lightweight and flexible c-Si PV modules using ethylene tetrafluoroethylene (ETFE) front cover and shingled design string cells. The ETFE front cover instead of glass made the PV modules lighter in weight, and the shingled design string cells increased the flexibility. Finally, we fabricated a PV module with a conversion power of 240.08 W at an area of 1.25 m² and weighed only 2 kg/m². Moreover, to check the PV module's flexibility, we conducted a bending test. The difference of conversion power between the modules before and after bending shown was only 1.7 W, which showed a power reduction rate of about 0.7%.

• Journal of the Korean Solar Energy Society
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• v.32 no.spc3
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• pp.179-184
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• 2012

This research on building Integrated Photovoltaic System replacing windows and doors with amorphous silicon thin film PV windows and doors installing same exact mount on Mock-up. The windows and doors should be installed in different angle and bearing so that we can analyse the amount of electricity from them. The objective of the research is to evaluate and investigate the relationship between factors(intensity of solar radiation, PV window surface temperature, incidence angle, and sky conditions) that affects performance of PV window and performance. The range and method of this research is to establish monitoring system and analysis the data from the monitoring system to evaluate the performance of PV windows that have thin film of solar battery. We should evaluate the insolation according to the position of PV window, output, and surface temperature according to months and seasons so that we can figure out the relationship between these. And we should investigate the relationship between performance and efficiency according to incidence angle and sky condition so that we can figure out the correlation between factors and performance.

• Korean Journal of Optics and Photonics
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• v.27 no.3
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• pp.106-113
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• 2016

In this paper, we deal with the wavefront compensation capability of a silicon carbide (SiC) deformable mirror (DM) with 37 actuators for adaptive optics. The wavefront compensation capability of the SiC DM is predicted by computer simulation and examined by actual experiments with a closed-loop adaptive optics system consistsing of a light source, a phase plate, a SiC DM, a high speed Shack-Hartmann sensor, and a control computer. Distortion of wavefront is caused by the phase plate in the closed-loop adaptive optics system. The distorted wavefront has a peak-to-valley (PV) wavefront error of $0.3{\mu}m{\sim}0.9{\mu}m$ and root-mean-square (RMS) error of $0.06{\mu}m{\sim}0.25{\mu}m$. The high-speed Shack-Hartmann sensor measures the wavefront error of the distortion caused by the phase plate, and the SiC DM compensates for the distorted wavefront. The compensated wavefront has residual errors lower than $0.1{\mu}m$ PV and $0.03{\mu}m$ RMS. Consequently, we conclude that we can compensate for the distorted wavefront using the SiC DM in the closed-loop adaptive optics system with an operating frequency speed of 500 Hz.

• Transactions on Electrical and Electronic Materials
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• v.15 no.5
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• pp.279-283
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• 2014

In this paper, we present an economical and practical standard to install a bypass diode in a thin-film PV module. This method helps to reduce heat generation and to prevent module degradation due to excess current from reverse bias. The experimental results confirm that for different numbers of solar cells, there is a relation between the excess reverse current and the degradation of solar cells in a-Si:H modules. The optimal number of solar cells that can be connected per bypass diode could be obtained through an analysis of the results to effectively suppress the degradation and to reduce the heat generated by the module. This technique could be expanded for use in high power crystalline Si PV modules.

• 한국태양에너지학회:학술대회논문집
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• 2011.11a
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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.

• Proceedings of the KIEE Conference
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• 2011.07a
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• pp.1316-1317
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• 2011

This paper presents analysis of temperature and light intensity characteristics of PV modules with solar cell type. Taking the effect of sunlight irradiance on the cell temperature, the first experiment takes ambient temperature as reference input and uses the solar insolation as a unique varying parameter. Then taking the effect of the cell temperature on sunlight irradiance, the second experiment takes 1000W/$m^2$ as reference input and uses the cell temperature as a unique varying parameter. As a result, varying sunlight irradiance, the Cell-Type with the smallest change in output is HIT and the Cell-Type with the biggest change in output is a-Si. Varying the cell temperature, the Cell-Type with the smallest change in output is a-Si and the Cell-Type with the biggest change in output is Single-Si. And considering both temperature and light intensity characteristics, the Cell-Type with the smallest change in output is HIT.

• The Transactions of the Korean Institute of Power Electronics
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• v.19 no.1
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• pp.51-56
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• 2014

PV cell modeling is necessary both for software and hardware simulators in analyzing and testing the performance of PV generation systems. Unique I-V curve of a PV cell identifies its own characteristics by electrical equivalent model that is composed of diode constants ($I_o$, $v_t$), photo-generated current ($I_{ph}$), series resistance ($R_s$), and shunt resistance ($R_{sh}$). Photo-generated current can be easily estimated since it is proportional to irradiation level. However, other electrical parameters should be solved from the manufacturer's data sheet that is consisted with three remarkable operating points such as open circuit voltage ($V_{oc}$), short circuit current ($I_{sc}$), and maximum power voltage/current ($V_{MPP}/I_{MPP}$). This paper explains and analyzes mathematical process of a novel PV cell modeling algorithm that was proposed by the authors with the name of "K-algorithm".