• 한국태양에너지학회:학술대회논문집
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• 2008.04a
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• pp.257-262
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• 2008

In this paper, we study the electric characteristics of shading effects in photovoltaic module in case of outdoor operation. When fabricating PV module, solar cells are connected serially to obtain the high voltage because of its low open circuit voltage. And total current is determined by lowest current among solar cells. When the shading happens on PV module's surface, the current of shaded solar cell determine the total current flow. Because of this, generally by-pass diode is installed on junction box. The bypass diode operate when revered and shaded solar cell's voltage is over 0.6 voltage. The reverse-biased solar cell gives reduced maximum power of PV module and might give negative effect on durability. So, adequate by-pass installation and selection is needed.

• The Journal of the Korea institute of electronic communication sciences
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• v.17 no.1
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• pp.71-76
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• 2022

Since brightness is proportional to the operating current, a method of connecting several LEDs in series and driving with a constant current source is widely used for driving circuits of LED lights. Because several LEDs are connected in series, if some LEDs open due to a fault, the current path is broken and all other LEDs connected in series are turned off. In this paper, we designed a circuit to solve this problem by connecting a Zener diode having a breakdown voltage of about 0.4V higher than the LED operating voltage in parallel with each LED to create a current bypass in case of LED failure. Through simulations and experiments, it was confirmed that the current of the Zener diode hardly flows when the LED is operating normally, and that the Zener diode stably operates as a current bypass when the LED fails.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2010.06a
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• pp.70-70
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• 2010

Until recently. the study about bypass diode has been limited to theoretical study. but, in this paper, We study on the relationship between structure of PV module and Bypassing point by simulation software(Pspice). We expected the design on the PV module has an effect on bypassing point. So, we designated the two kind of experiment with PV modules. One of the experiment is on the relationship between the number of rows and Bypassing point on the PV modules, the other experiment is on the relationship between the number of groups(two columns) on the PV modules.(around 50Wp, 100Wp, 150Wp, 200WP) As the result, the more increase the number of rows, bypassing point is faster. And the more increase the number of groups in more than 3 groups, bypassing point is faster more than case of increasing the rows.

• Journal of the Semiconductor & Display Technology
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• v.21 no.1
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• pp.114-118
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• 2022

The photovoltaic system is affected by various conditions such as temperature and irradiance. Because non-uniform irradiation and partial shading conditions affect the entire string of cells connected in series, a bypass diode is used to bypass the current flow normally. In order to find the maximum power point in partial shade conditions, it is necessary to estimate various methods of maximum power point tracking. In this paper, the hybrid method of MPPT using Lambert W function and perturbation & observation algorithm is proposed under partial shading conditions. The simulation results are obtained using MATLAB/Simulink and shows the improvement of the accuracy of MPPT.

• Transactions on Electrical and Electronic Materials
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• v.17 no.1
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• pp.21-24
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• 2016

A junction box used in a 3 kW photovoltaic power generation system plays a role in collecting and supplying the direct current voltage produced by photovoltaic modules to an inverter. It is also used for facilitating maintenance checks and protecting the module and inverter by keeping the voltage constant. As for the junction box, using it in a parallel connection creates a difference between the setup modules. In order to compensate, an inverse voltage diode is used. But the high-power created through the solar generator can be delivered to the inverter through the inverter regularly. Therefore, a component can break down due to excess heat. And consequently short circuits and electric leakage occurs. In this study, using a junction box that enabled the bypass of high electric power, it was possible to reduce heat generation by approximately 35℃ when compared to a standard junction box.

• Journal of the Korean Solar Energy Society
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• v.38 no.3
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• pp.21-28
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• 2018

The objects of PV (Photovoltaic) monitoring system is to reduce the loss of system and operation and maintenance costs. In case of PV plants with configured of centralized inverter type, only 1 PV module might be caused a large loss in the PV plant. For this reason, the monitoring technology of PV module-level that find out the location of the fault module and reduce the system losses is interested. In this paper, a fault diagnosis algorithm are proposed using thermal and electrical characteristics of PV modules under failure. In addition, the monitoring system applied with proposed algorithm was constructed. The wireless sensor using LoRa chip was designed to be able to connect with IoT device in the future. The characteristics of PV module by shading is not failure but it is treated as a temporary failure. In the monitoring system, it is possible to diagnose whether or not failure of bypass diode inside the junction box. The fault diagnosis algorithm are developed on considering a situation such as communication error of wireless sensor and empirical performance evaluation are currently conducting.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.25 no.11
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• pp.50-57
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• 2011

This paper proposes a boost type single-phase inverter system to compensate the voltage sag appeared on source side. The proposed system is composed of a boost converter, a PWM inverter, and a bypass diode. If the voltage sag has appeared in input voltage, the boost converter would be operated to compensate it in the proposed system. The boost converter would not be operated when the magnitude of input voltage is more than 0.9 pu. The output voltage is kept constant by a direct-quadrature frame controller in the inverter. A 300 W class boost type inverter system was simulated, and the validity of the proposed system was verified by carrying out experiments.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.5
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• pp.723-730
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• 2016

Solar cells in a PV module are connected in series and parallel to produce a higher voltage and current. The PV module has performance characteristics depending on solar radiation and temperature. In addition, the PV system causes power loss by special situations, including the shadows of the surrounding environment, such as nearby buildings and trees. In other words, an increase in power loss and a decrease in life cycle can occur because of the partial shadow and hot-spot effect. Therefore, this paper proposes the optimal configuration algorithm of a bypass diode to improve the output of a PV module and one of a PV array to minimize the loss of the PV array. In addition, this paper presents a model of a PV module and PV array based on the PSIM S/W. The simulation results confirmed that the proposed optimal configuration algorithms are useful tools for improving the performance of PV system.

• Journal of the Korean Solar Energy Society
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• v.36 no.5
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• pp.91-100
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• 2016

This paper proposes the PV module fault diagnosis sensor which is applied to Zigbee wireless network, and monitoring system using the developed sensor. It is designed with embedded sensor in junction box. The diagnosis elements for algorithm were voltage and temperature. For that reason, It is able to reduce the price and separate the fault of bypass diode from shading differently from other monitoring systems. This fault diagnosis algorithm verified through the Field-installed operations of PV module.

• Journal of Power Electronics
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• v.13 no.3
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• pp.390-399
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• 2013

As a result of the depletion of fossil fuels and environmental contamination, it has become important to use renewable energy. For the stable utilization of renewable energy sources, energy storage devices must be used. In addition, renewable and distributed power sources with energy storage devices must operate stably under grid-connected mode. This paper proposed dynamic response modeling for renewable power generation systems including a charger/discharger with an energy storage device in order to derive a method to guarantee stable operation while fully utilizing the energy from the energy storage device. In this paper, the principle operation and design guidelines of the proposed scheme are presented, along with a performance analysis and simulation results using MATLAB and PSIM. Finally, a hardware prototype of a 1kW power conditioning system with an energy storage device has been implemented for experimental verification of the proposed converter system.