• Proceedings of the KIPE Conference
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• 전력전자학회 2008년도 추계학술대회 논문집
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• pp.143-145
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• 2008

최근 각종 전자기기의 슬림화 추세에 따라 PDP PSU(Power Supply Unit) 또한 슬림화가 진행되고 있다. 슬림화를 위해서는 방열판과 벌크(Bulk) 커패시터, 입력단의 필터와 인덕터류, 그리고 변압기의 높이를 줄이는 것이 중요하다. 그 중에서도 변압기의 높이를 줄이는 것이 가장 큰 관건이다. 하나의 변압기를 사용할 경우 슬림화의 한계성을 가지기 때문에 적용된 변압기는 두 개의 LLT 변압기로 구성 하였으며 1차측과 2차측의 결선 방법을 통해 두 LLT변압기간의 전류 불균형 문제를 최소화 할 수 있도록 하였다. 그리고 높이 35mm 시제품을 제작하여 50HD PDP 전원에 적용시켜 검증한 결과를 나타내었다.

• Proceedings of the Korean Vacuum Society Conference
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• 한국진공학회 2013년도 제45회 하계 정기학술대회 초록집
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• pp.103.2-103.2
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• 2013

위성체는 우주공간의 고진공 상태와 태양 복사열에 의한 고온 및 극저온이 반복되는 가혹한 환경으로 인해 주요 부품의 기능장애가 초래되므로 발사전 지상에서 열진공 시험장비를 이용한 열진공시험을 수행한다. 우수한 성능의 위성체 부품의 검증을 위해서 열환경 시험 요구에 따라 균일한 복사열이 매우 중요하나, 시험 조건을 비롯하여 여러 원인으로 인하여 열전달의 불균일성이 발생하게 된다. 이로 인해 시스템에 큰 영향을 미칠 수 있으므로, 시험 조건에 의한 열전달량을 고려하여 적절한 히터파워를 선정하고 챔버 내에 적절한 방열판과 챔버 슈라우드의 열교환이 간섭이 없도록 장비를 운용해야 한다. 본 연구에서는 상용프로그램인 FLUENT를 이용하여 열진공 챔버 내부 벽면의 불균일한 복사열에 따른 비정상 열전달 특성에 대하여 수치해석을 수행한 뒤 시편의 온도 분포 및 열전달 특성에 대해 비교분석하였다.

• Proceedings of the KIPE Conference
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• 전력전자학회 2016년도 추계학술대회 논문집
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• pp.91-92
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• 2016

This paper is studied on optimal selection of heat sink for power electronics devices according to switching conditions. Through thermal analysis of MOSFET and repeated digital simulation, the loss characteristics during both switching and conduction intervals are compared to volume of the heat sinks. As a result, heat sink larger by 25% in volume could radiate more heat about $19^{\circ}C$.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• 제40권2호
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• pp.157-164
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• 2012

The design strategy of the multi-functional structure is that the electrical components and the circuits are directly put on their supporting structural panel in which the radiation shields and the thermal control functions are integrated. Applying the multi-functional structure reduces the total mass and size of the space system and makes it possible to lower launch cost. In present study the performance of thermal radiation for six types of multi-functional structure are investigated by the numerical method. The effect of the rib configuration on heat transfer for the multi-functional-structure is not important alone but is meaningful considering with the structural stiffness, difficulty of manufacturing and mass increase. In heat spreading point of view, the thickness of the outer conductive layer is important rather than the rib configuration and the trade-off study with the mass and thickness is required for optimum design.

• Journal of the Computational Structural Engineering Institute of Korea
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• 제29권1호
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• pp.53-60
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• 2016

This study discusses the thermal insulation capacity of variant of NO96 LNG (liquefied natural gas) cargo containment insulation system. Changing the insulation materials and the insulation layers of conventional GTT NO96 containment system, The thermal resistance and BOR(boil off rate) caused by the heat transfer between cryogenic and environmental temperature is discussed. Therefore, thermal analysis of LNG CCS(cargo containment system) is carried out to determine the insulation capabilities. Also, BOR is evaluated in terms of the total amount of heat invaded into CCS(cargo containment system). Variant of NO96 CCS such as NO96, NO96GW and NO96L3 membrane type during laden voyage is selected for the comparative study. Finite element model for heat transfer analysis is conducted by employing the equivalent thermal resistance model to simplify the complex insulation layers. Finally the results for each variant model are relatively compared and discussed to minimize the BOR.

• Journal of Advanced Navigation Technology
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• 제23권5호
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• pp.460-465
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• 2019

In this study, we aim to derive a solution from the structural analysis for electrical failure of single board computers for computing navigation information. By analyzing the characteristic factor, we identify that crack occur on the central processing unit board due to a certain structural problem, and that the physical effect by the crack make communication function be impossible to perform, which it causes booting error. In order to find the location of excessive stress causing the crack, structural analysis for the single board computer is done. From the structural analysis, the areas where stress concentration occurs are identified, and improvement methods changing the structures are developed. As a result, we shows that stresses are reduced entirely on the stress distribution for the improved structure. In addition, heat analysis shows that changing the structure to reduce stresses is not affect to the heat radiation, and the thermal resistance of the actual equipment is verified by measuring the temperature of the heat sink applied with the improved structure.

• Journal of the Korea Academia-Industrial cooperation Society
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• 제18권7호
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• pp.17-25
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• 2017

To resolve the problem of the temperature rise in LED or OLED lighting, until now a thick metal film has been used as a heat-sink. Conventionally, this thick metal film is made by the electroplating method and used as the heat-dissipating plate of the electronic devices. However, nowadays there is increasing need for a Cu metal film with a thickness of several hundred micrometers that can be formed by the dry deposition method. In this work, we designed and fabricated a Cu film deposition system where the heating element is separated from the ceramic crucible, which makes ultra-rapid deposition possible by preventing heat loss. In addition, the resulting induction heating also contributes to the high deposition rate. By tuning the various parameters, we obtained a $100-{\mu}m$ thick Cu film whose heat conductivity is high and whose thickness uniformity is better than 2%, while the deposition rate is as high as $1000{\AA}/s$.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• 제37권6호
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• pp.580-585
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• 2009

Thermal analysis and design of FPA(Focal Plane Assembly)-CU(Cooling Unit) for Earth observation camera is performed. FPA-CU is the first cooling device for a spacecraft which is designed and manufactured by its own technology in Korea. FPA-CU has a special feature, TBM(Thermal Buffer Mass) which is discriminated from typical cooling devices using heat pipes and radiator. TBM can be regarded as a thermal energy reservoir and it shows thermally transient characteristics, which make it difficult to design the size and shape of TBM. In current study, a method to determine the volume and the size of TBM is proposed and validated. The transient thermal analysis for FPA-CU for 5 operational scenarios is performed and validates the final design of FPA-CU (Radiator,TBM, Heat pipe I/F). In case of an abnormal operation of a heat pipe among three radiator heat pipes, the temperature of FPA can be increased $3{\sim}4^{\circ}C$ according to the numerical simulation.

• Journal of the Korean Institute of Gas
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• 제21권1호
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• pp.87-93
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• 2017

This study was conducted to analyze thermal effects for the structure of portable butane gas stoves in accordance with the introduction of safety standard to protect gas accidents that were caused by using oversized grills. The temperatures of oversized grill, cartridge and cover of cartridge coupling part were measured with stoves that heat sink was installed the inside of cover of cartridge coupling part and had different height of tripods. The trend of measured temperatures affected by thermal effects of grill and flame was analyzed. The condition of using portable butane gas stove safely is that the distance between grill and cover of cartridge coupling part should be about 28 mm and over. In contrast, when the distance between grill and cover of cartridge coupling part would be shorter, thermal effects of not only grill but also flame could affect the cartridge directly. In this case, the danger that could cause gas accident would be higher. When heat sink was installed the inside of cover of cartridge coupling part, it was effective on reducing of thermal effects. However, it still had the danger of explosive gas accident of cartridge due to overheating.

• Journal of the Korea Academia-Industrial cooperation Society
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• 제22권2호
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• pp.810-818
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• 2021

A leakage current of ESS is classified mainly by the occurrence from a PCS(Power Conditioning System) section and an unbalanced grid current. The reason for the leakage current from the PCS section is a voltage change by IGBT (Insulated Gate Bipolar Transistor) switching and stray capacitance between the IGBT and heatsink. The leakage current caused by the grid unbalanced current flows to the ESS through the neutral line of grid-connected transformer for the ESS with a three limb iron type of Yg-wire connection. This paper proposes a mechanism for the occurrence of leakage current caused by stray capacitance, which is calculated using the heatsink formula, from the aspect of the PCS section and grid unbalance current. Based on the proposed mechanisms, this study presents the modeling of the leakage current occurrence using PSCAD/EMTDC S/W and evaluates the characteristics of leakage currents from the PCS section and grid unbalanced current. From the simulation result, the leakage current has a large influence on the battery side by confirming that the leakage current from the PCS is increased from 7[mA] to 34[mA], and the leakage current from an unbalanced load to battery housing is increased from 3.96[mA] to 10.76[mA] according to the resistance of the housings and the magnitude of the ground resistance.