• International Journal of Aeronautical and Space Sciences
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• 제1권2호
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• pp.30-42
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• 2000

On-orbit thermal environment test of KOMPSAT was performed in early 1999. An analysis of the test data are addressed in this paper. For the thermal-environmental simulation of spacecraft bus, an artificial heating through the radiator zones and onto some critical heat-dissipating electronic boxes was made by Absorbed-heat Flux Method. Test data obtained in terms of temperature history were reduced into flight heater duty cycles and converted into the total electrical power required for spacecraft thermal control. Verification result of flight heaters dedicated to the bus thermal control is presented. Additionally, an exhaustive heating-control process for maintaining the spacecraft thermally safe and for realistic simulation of the orbital-thermal environment during the test are graphically shown. Qualitative suggestions to post-test model correlation are given in consequency of the analysis.

• 한국전산유체공학회지
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• 제10권3호
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• pp.63-69
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• 2005

The COMS, the first meteorological geostationary satellite in Korea, is under development by KARI. The radiator size and the heater power for the thermal control of COMS are calculated using an analytic method. The total radiator area of $4.85\;m^2$ and the total heater power of 794.77 W are determined at a conceptual design of COMS. The commercial software, SINDA and TRASYS, are utilized in order to compare and verify the analytic results. The results of on-orbit numerical simulation of cold and hot cases show that the radiator size and heater power obtained from the analytic method are appropriate to maintain COMS equipments within required temperature ranges.

• 한국자동차공학회논문집
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• 제13권2호
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• pp.72-82
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• 2005

The objective of this paper is to describe the optimization of design parameters in a large-sized commercial bus heater system by using CFD(computational fluid dynamics) analysis and Taguchi method. In order to obtain the best combination of each control factor which results in a desired performance of heater system, the parameter design of the Taguchi method is adopted for the robust design considering the dynamic characteristic. The research activity may be divided into four phases. The first one is analyzing the problem, i.e., ascertaining the influential factors. In the second phase the levels were set in such a way that their variation would significantly influence the response. In the third phase the experimental runs were designed. In the final phase the planned runs were carried out numerically to evaluate the optimal combination of factors which is able to provide the best response. In this study, eight factors were considered for the analysis: one with two level and seven with three level combinations comprising the $L_{18}(2^1{\times}3^7)$ orthogonal array. The results of this study can be summarized as follows ; (i)The optimum condition of control factor is a set of <$A_2\;B_1\;C_3\;D_3\;E_1\;F_2\;G_3\;H_2$> where A is shape of the outer fin, B is pitch of the outer fin, C is height of the outer fin, D is the inner fin number, E is the inner fin height, F is length of the flame guide, G is diameter of the heating element and H is clearance between air guide and heating element. (ii)The heat capacity of heated discharge air under the optimum condition satisfies the equation y=0.6M w here M is a signal factor. (iii)The warm-up rate improves about three times, more largely as com pared with the current condition, which results in about 9.2minutes reduction.

• 한국조명전기설비학회:학술대회논문집
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• 한국조명전기설비학회 2005년도 춘계학술대회논문집
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• pp.283-287
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• 2005

In this paper, one general approach is proposed for the design of power system that can be applicable for next generation LEO satellite application. The power system consists of solar panels, battery, and power control and distribution unit(PCDU). The PCDU contains solar array modules, battery interface modules, low-voltage power distribution modules, high-voltage distribution modules, heater power distribution modules, on-board computer interface modules, and internal DC/DC converter modules. The PCDU plays roles of protection of battery against overcharge by active control of solar array generated power, distribution of unregulated electrical power via controlled outlets to bus and instrument units, distribution of regulated electrical power to selected bus and instrument units, and provision of status monitoring and telecommand interface allowing the system and ground operate the power system, evaluate its performance and initiate appropriate countermeasures in case of abnormal conditions. We review the functional schemes of the main constitutes of the PCDU such as the battery interface module, the auxiliary supply module, solar array regulators with maximum power point tracking(MPPT) technology, heater power distribution modules, spacecraft unit power distribution modules, and instrument power distribution module.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2005년도 제36회 하계학술대회 논문집 B
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• pp.1438-1440
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• 2005

A power control and distribution unit(PCDU) plays roles of protection of battery against overcharge by active control of solar array generated power, distribution of unregulated electrical power via controlled outlets to bus and instrument units, distribution of regulated electrical power to selected bus and instrument units, and provision of status monitoring and telecommand interface allowing the system and ground operate the power system, evaluate its performance and initiate appropriate countermeasures in case of abnormal conditions. In this work, we perform the preliminary design of a PCDU scheme for the small LEO Satellite applications. The main constitutes of the PCDU are the battery interface module, the auxiliary supply modules, solar array regulators with maximum power point tracking(MPPT) technology, heater power distribution modules, internal converter modules for regulated bus voltage generation. and instrument power distribution modules.

• 한국정보전자통신기술학회논문지
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• 제2권4호
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• pp.29-36
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• 2009

본 논문은 버스에 사용되는 연소식 프리히터(Fuel Fired Heater) 퍼지 제어기(Fuzzy controller)를 설계하였다. 프리 히터는 얼마나 빠른 시간 안에 설정한 온도에 다다르는지와 공간내의 온도 편차가 얼마나 작게 발생하는지의 두 가지가 가장 중요한 요소이다. 기존의 연소식 프리히터의 온도 제어 방식으로 사용된 PI 제어기의 온도편차를 줄임과 동시에 응답특성을 개선한 퍼지 제어기를 설계하여 그 성능을 평가하였다. 설계된 퍼지 제어기에서 온도를 설정하면 기존의 PI 제어방식에서는 $25^{\circ}C$의 도달시간이 12분 소요되었으나 퍼지 제어방식에서는 9분 20초 소요되어 기존의 제어기보다 퍼지제어기가 2분 40초의 빠른 응답 성능으로 향상됨을 확인하였다. 난방의 온도 편차에서도 기존의 PI 제어 방식에서는 $2.4^{\circ}C$의 편차를 보인 반면 설계된 퍼지 제어기에서는 $1.6^{\circ}C$로 온도 편차 또한 개선되었음을 확인하였다.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2007년도 하계학술대회 논문집
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• pp.55-57
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• 2007

A Power control and Distribution Unit (PCDU) plays roles of protection of battery against overcharge by active control of solar array generated power, distribution of unregulated electrical power via controlled outlets to bus and instrument units, distribution of regulated electrical power to selected bus and instrument units, and provision of status monitoring and telecommand interface allowing the system and ground operate the power system, evaluate its performance and initiate appropriate countermeasures in case of abnormal conditions. In this work, we perform the preliminary design of a PCDU for the small Low Earth Orbit (LEO) Satellite applications. The main constitutes of the PCDU are the battery interface module, solar array regulators with maximum power point tracking (MPPT) technology, heater power distribution modules, internal converter modules for regulated bus voltage generation, power distribution modules of unregulated and regulated primary bus, and instrument power distribution modules.

• 항공우주기술
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• 제10권2호
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• pp.20-28
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• 2011

저궤도 관측위성의 광학탑재체는 궤도에서 임무수행을 뒷받침하는 위성 본체와 열적으로 분리되어 각각 독립된 열제어를 할 수 있도록 개발된다. 광학탑재체는 내부에 작동하는 동안에 높은 발열량으로 순간적으로 온도가 상승하는 부품 박스인 FPA(Focal Plane Assembly)의 열을 외부로 방출하기 위한 히트파이프, 방열판으로 구성된 냉각 장치(Cooling Unit)를 가지고 있다. 이러한 냉각 장치는 고온 조건에서 내부 발열을 빠르게 외부로 방출할 수 있는 히트파이프의 성능과 충분한 면적의 방열판 면적을 확보하도록 설계되어야 하고, 동시에 저온 조건에서 최저 온도 이상을 유지하는 위한 히터설계도 포함해야 한다. 본 연구에서는 먼저 FPA 냉각 장치의 열제어 요구조건과 현재 열설계 기준의 열해석 결과를 통하여 히터설계에 대한 검토와 설계 제한 조건을 분석을 하였다. 또한 열해석을 이용한 효율적이고 경제적인 위성 히터설계 방식을 제시하고, 이것을 FPA 냉각 장치의 히터설계에 적용하여 개선된 히터설계 요소를 찾았다.

• 항공우주기술
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• 제10권1호
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• pp.141-148
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• 2011

저궤도 관측위성에는 버스 히터, 탑재체 히터, 배터리 내부 히터 등 다양한 히터들이 각각의 해당 영역에 대한 열제어를 위해 존재한다. 이러한 히터들의 제어는 서미스터에 의해 수행되거나 비행소프트웨어에 의해 제어될 수 있다. 각 히터들은 설치된 위치, 텔레메트리로 전송하기 위한 분류, 사용되는 서브시스템 등에 따라서 여러 형태의 그룹으로 나눌 수 있으며, 비행소프트웨어에서는 히터제어를 위한 정보들을 다양한 배열에 저장하는데 각 히터마다 고유의 인덱스를 부여하여 구분하는 방법을 사용할 수 있다. 각 히터들이 분류하는 방식에 따라 서로 다른 그룹에 속하기도 하고 비행소프트웨어 로직에서 사용되는 히터정보가 어느 히터, 또는 어느 그룹의 정보인지를 판별하는데 어려움이 있을 수 있다. 본 문서에서는 저궤도 관측위성의 일반적인 히터 제어를 위한 비행소프트웨어의 설계에 대해 기술하고, 히터들의 그룹 및 배열의 활용과 특별한 관리가 필요한 히터들의 제어방식에 대하여 설명한다.

• 한국전산유체공학회지
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• 제13권2호
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• pp.48-54
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• 2008

COMS (Communication, Ocean and Meteorological Satellite) is a geostationary satellite and has been developing by KARI for communication, ocean and meteorological observations. It will be launched by ARIANE 5. Ka-band components are installed on South panel, where single solar array wing is mounted. Radiators, embedded heat pipes, external heat pipe, insulation blankets and heaters are utilized for the thermal control of the satellite. The Ka-band payload section is divided several areas based on unit operating temperature in order to optimize radiator area and maximize heat rejection capability. Other equipment for sensors and bus are installed on North panel. The ocean and meteorological sensors are installed on optical benches on the top floor to decouple thermally from the satellite. During the transfer orbit operation, satellite will be under severe thermal environments due to low dissipation of components, satellite attitudes and LAE(Liquid Apogee Engine) firing. This paper presents temperature and heater power prediction and validation of thermal control design during transfer orbit operation.