• 한국정보통신설비학회:학술대회논문집
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• 2007.08a
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• pp.390-393
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• 2007

The reliability as well as the power capability of the UPS system can be increased by replacing a single UPS unit with multiple small UPS units in parallel, resulting in a so-called module UPS. This module UPS system allows that a new module can be added or replaced while maintaining power to loads, which is a hot-swappable operation. In addition, it has desirable features such as ease of output power expandability, convenience of maintenance and repair, and high reliability. To realize the module UPS, load sharing without interconnection among parallel connecting modules as well as a small scale and lightweight topology is necessary. The frequency and voltage droop method is applied to parallel operation control to achieve load sharing. 5kVA modules are designed and implemented to confirm the effectiveness of the proposed approaches. Experimental results show that the module UPS system has a high power factor, a low distortion of output voltage and input current, hot-swappable operations and good load sharing characteristics.

• Journal of the Korean Society for Precision Engineering
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• v.23 no.10
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• pp.60-67
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• 2006

This paper presents the temperature control in aluminum plate with Peltier module. From the experimental work, Peltier module is used to control the temperature of small aluminum plate for both heating and cooling with the control of current and fan ON/OFF. And current control of Peltier module was accomplished by PWM method. As a result of experiments, it is proper that operate cooling fan only while cooling duration and there exist a proper cooling current to drop temperature rapidly. It takes about 125sec to control temperature of aluminium plate between $30^{\circ}C$ and $70^{\circ}C$ and about 70sec between $40^{\circ}C$ and $60^{\circ}C$, in ambient temperature $28^{\circ}C{\sim}29^{\circ}C$ while cooling fan is operated only cooling duration. With the cooling current, temperature control of aluminum plate was accomplished more rapidly in comparison without cooling current. Future aim is to realize more rapid temperature control and develop SMHA(special metal hydride actuator) by using Peltier module as a heating and cooling source.

• Journal of the Korean Solar Energy Society
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• v.36 no.4
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• pp.41-47
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• 2016

A bypass diode is connected in parallel to solar cells with opposite polarity. The advantage of using the bypass diode is circumvented a destructive efforts of hot-spot heating in the photovoltaic(PV) module. In addition, it is possible to reduce a energy loss under the partial shading on the PV module. This paper presents a characteristic of photovoltaic module under partial shading condition and with defective bypass diode by using the experimental data. The results of field testing for each photovoltaic modules, when photovoltaic system which is connected power grid is operating, the inner junction-box temperature of shading photovoltaic module is high $5^{\circ}C$ because of difference of flowing current through into bypass diode. And incase of not operating photovoltaic system, the inner junction-box temperature of module with defective bypass diode is greatly higher than partial shading PV module.

• 한국태양에너지학회:학술대회논문집
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• 2008.11a
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• pp.57-62
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• 2008

Building Integrated PV(BIPV) is one of the best fascinating PV application technologies. To apply PV module in building, various factors should be reflected such as installation position, shading, temperature, and so on. Especially the installation condition should be considered, for the generation performance of PV module is changed or the generation loss is appeared according to installation position, method, and etc. This study investigates variation of electrical characteristics of a PV module according to the change of irradiance and temperature. From this experimental study, we confirmed that the irradiance, the temperature variation and the generation performance of a PV module were appeared differently according seasonal variation. Actually the PV module installed in building facade showed high-generation performance in winter.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.17 no.11
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• pp.1093-1101
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• 2007

This study presents the design improvement process for door module. Its objective evades the resonance generated at module plate due to the operation of window regulator motor. For this study, the design improvement process is composed of experimental methods having three steps. First step is modal analysis at door assembly status for acquisition of dynamic characteristics which are modal frequency and damping. Second step is a vibration experiment to get the test mode considered an efficiency of window regulator motor. Last step is a vibration measurement by the form of $6{\times}6$ array on module plate. A vibration measurement of $6{\times}6$ array form can be got to three analysis results which are a transfer path of vibration using cross correlation function, a vibration map using OA level and a contribution by frequency band using coherent output power spectrum on module plate. These results are applied to SDM(structural dynamic modification) for design improvement to get around the resonance on module plate by the excitation of window regulator motor.

• Journal of the Korean Solar Energy Society
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• v.36 no.5
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• pp.63-71
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• 2016

Installed PV module in field is affected by shading caused by various field environmental factors. Bypass diodes are installed in PV module for preventing a power loss and degradation of PV module by shading. But, Bypass diode is easily damaged by surge voltage and has often initial a defect. This paper propose the electric characteristic variation and the power prediction of PV module with damaged bypass diode. Firstly, the resistance for normal bypass diode and damaged bypass diode of resistance was measured by changing the current. When the current increases, the resistance of normal bypass diode is almost constant but the resistance of damaged bypass diode increases. Next, To estimate power of PV module by damaged bypass diode, the equation for the current is derived using solar cell equivalent circuit. Finally, the derived equation was simulated by using MatLab tools, was verified by comparing experimental data.

• 한국태양에너지학회:학술대회논문집
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• 2011.11a
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• pp.93-98
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• 2011

A photovoltaic/thermal(PVT)collector produces both thermal energy and electricity simultaneously. The heat from PV modules should be removed for better electrical performance, and can be converted into useful thermal energy. A PVT module is a combination of PV module with a solar thermal collector which forms one device that converts solar radiation into electricity and heat. In general, there are two different types of PVT module: glazed PVT module and unglazed PVT module. On the other hand, two types of the PVT module can be distinguished according to absorber on PV module rear side: the sheet-and-tube absorber PVT module and the fully wetted absorber PVT module. The absorber collector plays an important function in PVT system. It cools down the PV module, while collecting the thermal energy produced in the form of hot water. The aim of this study is to compare the electrical and thermal performance of two different PVT collectors, one with the rectangular tube and the other with fully wetted absorber PVT collectors. For this paper, the PVT collectors with two different types of thermal absorber were made, and both the thermal and electrical performance of them were measured in outdoor, and the results were compared. The experimental results were analyzed that the thermal efficiency of the fully wetted absorber PVT collector is about 8.7% higher than the sheet-and-tube absorber PVT collector, and for the electrical efficiency, the fully wetted absorber PVT collector had about 7% higher than the rectangular tube absorber.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.17 no.1
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• pp.138-143
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• 2018

In general, the operating temperature of electronic equipment is closely related to product life and reliability, and it is recognized that effectively cooling the parts is an important problem. In this paper, an experimental study on the cooling characteristic according to the pin array of the heat sink is conducted. The experiment on the heat sink was based on the natural convection and temperature distribution changes. The experimental results indicate that the pin array of the heat sink has an effect on the thermoelectric module's cooling characteristic.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.24 no.10
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• pp.130-135
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• 2010

In this paper, the shading ratio about to output the minimum critical power of a photovoltaic panel was determined by experiment and simulation. A 2.475[kW] poly-crystalline photovoltaic panel consisting of 11 modules was used in the experiment and its surface was covered with shading curtains, thus the amount of light incident to the modules were controlled. In order to compare with the experimental results, the experimental circuits were modelled with the CASPOC (power electronics electrical drives simulator) and module parameters were applied to it, by which the minimum critical power was calculated. As a result, the photovoltaic panel was about to generate the power when the 5th shading curtains were removed from the module surface, after then the output power linearly increased by removing the shading curtains. In addition, the CASPOC simulation results were similar to the experimental results in the abrupt decreasing pattern of power.

• 한국지구과학회:학술대회논문집
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• 2005.09a
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• pp.304-314
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• 2005

The present study aims to develop animation module-based teaching-learning materials for a unit of middle school 3rd grade science, which contains the movement of the solar system, through the utilization of various forms of multimedia elements. The developed materials consist of 12 in total flash animation modules covering ‘movement of the Earth,’ ‘movement of the Moon,’ movement of the Planets,‘ etc. To analyze the student responses to the science classes to which the developed animation modules were to be applied, the researcher selected for subjects two third-grade classes that were made up of 60 students and later divided for an experimental group and a control group in a middle school located in Jeonju. The experimental group was treated with the animation module-based lessons developed in the present study while the control group was taught in the traditional teacher-centered ways. Tests for the science-related attitudes of the two groups were administered and the results showed that the mean score of the experimental group was significantly higher than the mean score of the control group (p<0.05) in the categories of ‘interest’ and ‘scientific attitude’. It was thus believed that the animation module-based teaching has a positive effect on the categories of ‘interest’ and ‘scientific attitude’. To assess the qualitative dimension of the developed materials, the researcher subjected them to the utilization of the 30 local science teachers and afterwards a survey was done with the 8 crucial items taken from the WBI evaluation test developed by Multimedia Education Support Center in 1998. The result was broadly positive in terms of lesson design and from a technological point of view.