• 한국전산유체공학회:학술대회논문집
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• 2007.10a
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• pp.227-231
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• 2007

COMS (Communication, Ocean and Meteorological Satellite) is a geostationary satellite and has been developing by KARI for communication and 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.

• Journal of Aerospace System Engineering
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• v.16 no.5
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• pp.1-7
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• 2022

Recently, satellites equipped with high-performance electronics have required higher power consumption because of the advancement of satellite missions. For this reason, the size of the solar panel is gradually increasing to meet the required power budget. Increasing the size and weight of the solar panel is one of the factors that induce the elastic vibration of the flexible solar panel during the highly agile maneuvering of the satellite or the mode of vibration coupling to the satellite or the mode of vibration coupling to the micro-jitter from the on-board appendages. Previously, an additional damper system was applied to reduce the elastic vibration of the solar panel, but the increase in size and mass of system was inevitable. In this study, to overcome the abovementioned limitations, we proposed a high -damping yoke structure consisting of a superplastic SMA(Shape Memory Alloy) laminating a thin FR4 layer with viscoelastic tape on both sides. Therefore, this advantage contributes to system simplicity by reducing vibrations with small volume and mass without additional system. The effectiveness of the proposed superelastic SMA multilayer solar panel yoke was validated through free vibration testing and temperature testing using a solar panel dummy.

• Journal of Power Electronics
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• v.18 no.5
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• pp.1479-1488
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• 2018

Power packet (PP) distribution system distributes power to different loads that share the same distribution cable in a packetized form. When compared with conventional power systems, a PP distribution system (PPDS) can reduce standby power, eliminate Point-of-Load (PoL) power conversion, and intelligently control the load demand from the source side. Due to the absence of PoL conversion, when multiple power sources at different voltage levels and conditioning requirements jointly send power to various loads at different voltage ratings, the generated voltage has an irregular shape. A large filter at each of the load sides is required to reduce such a large voltage ripple. In this paper, a single-inductor, multiple-input-single-output converter structure based multiple-energy-source mixer is proposed. It combines PP generation, maximum power point tracking (MPPT) of renewable energy sources (RESs) and filtering at the source side. To demonstrate the possible renewable energy integration, a PV panel is used as a power source together with other constant voltage sources. The PV power is approximately tracked using the constant voltage method and it is used for each of the PP generations. The proposed PP distribution system is experimentally verified and it is shown that a conventional PI controller is sufficient for stable system operation.

• Journal of Biomedical Engineering Research
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• v.17 no.4
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• pp.491-498
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• 1996

The development of a compact two-wavelength Nd:YAG laser for dental and ENT applications is presented. The Nd:YAG resonator generates either 1.06$\mu$m or 1.32$\mu$m. The wavelength selection is made at the control panel. The Nd:YAG laser parameters at 1.06$\mu$m are ; the maximum pulse duration of 150$\mu$s, repetition rates of I-100Hz, and the maximum average power of 25W. At 1.32$\mu$m, the pulse duration is the same where the repetition rates and the maximum average power are I-30Hz and lOW respectively. High voltage power supply consists of a simmer module and two identical high voltage DC converters. In order to make a complete medical laser system, an optical fiber delivery unit, foot pedal and water spray handpiece are also developed. The wavelength selection is reliable since no movement of optical or mechanical components is required. The high voltage power supply is compact, easy to be maintained and applicable for other laser systems due to its modular design.

• Journal of the Korean Society of Industry Convergence
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• v.3 no.3
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• pp.251-256
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• 2000

This report analyzes the Source Qualification Test which is composed of main functional and environmental tests for the localizing avionics(electronic subsystem for aircrafts and spacecraft) and high performance mechanical subsystem. Especially the detail test approaches of integrated servo actuators which is the main part to supply the power to the main and other flying control panel. Nowadays this subsystem works with mechanical and electrical engineering technique. In detail, electrical signal is used as input and transferring tool and mechanical part is the output as a power and manufacture the physical dimensions and functions. Finally in this review, the new test procedure to prove the function by the new manufacturer is established.

• Journal of the Institute of Convergence Signal Processing
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• v.12 no.3
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• pp.222-227
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• 2011

2-axis tracking solar PV system applying a fixed-type unit than in the same area as the panel's power output to more than 140% can be obtained that have been identified. However, this approach compared with fixed or 1-axis control system and control the complexity of trekking equipment power the cursor comes to a relatively small output PV unit is called. In this paper, a small PV power units as a way to improve the economics of the small output of multiple PV units in the central control unit in enclosed places an intermittent manner by a remote control for each unit of the trek at the same time to simplify the control mechanism to reduce power that will be introduced. also the construction of large-scale PV development plans in difficult environments can be utilized in a manner appropriate to introduce.

• Proceedings of the Korean Nuclear Society Conference
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• 1995.05a
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• pp.602-607
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• 1995

This article presents safety review experience of microprocessor-based Interposing Logic System(ILS) of Engineering Safety Feature Actuation System(ESFAS). The ILS is the first application of computerized logic design to safety system in Korean nuclear power plants without verification of the system reliability by proven technology concept. As a result of evaluation for the ILS, Korea Institute of Nuclear Safety(KINS) concluded that the microprocessor-based ILS is not acceptable in some features detailed enough to defend against software common mode failures(CMF). Therefore, we required licensee to install hardwired interlock signal configuration and a Hardwired Backup Panel to control safety-related equipment. We believe that the microprocessor-based ILS with the hardwired backup panel and inter-connection of interlock signal by hardwired configuration will improve the plant safety.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.28 no.1
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• pp.36-44
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• 2014

The conventional central photo voltaic inverters have several problems. First, shadow problem in each solar panel, and high DC voltage problem from each panel because of concentration to one central inverter. Therefore, module integrated inverter is proposed to solve these problems. The inverter should be small and cost effective. The cost and size in the inverter depend on the inductor. So the switching frequency should be increased to reduce the inductor and total size, but there is a problem in efficiency because of the losses in turn-on and turn-off. In the paper, the critical conduction mode(CRM) switching method is adopted to reduce the switching loss and interleaving method is proposed to increase the efficiency in Flyback converter. Finally, the validity of the proposed scheme is investigated with simulated and experimental results for a prototype system rated at 200W.

• Proceedings of the KIPE Conference
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• 2018.07a
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• pp.123-125
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• 2018

태양광발전시스템은 낮은 효율의 PV 패널을 사용하여 최대의 전력을 생산하기 위해 PV 패널의 최대전력점에서 운전하는 MPPT(Maximum Power Point Tracking) 제어가 반드시 필요하다. 기존의 MPPT 알고리즘은 대부분 경사법에 기초하고 있으며 그 중 대표적인 방법이 P&O(Perturb and Observe) 알고리즘이다. P&O 알고리즘의 MPPT 성능을 좌우하는 두 가지 인수는 MPPT 제어주기와 변량전압의 크기이다. MPPT 제어기의 빠른 동특성과 극대화된 효율을 위한 최적의 MPPT 제어주기와 변량전압의 크기를 결정하기 위해서는 실제 날씨 환경에서 다양한 일사량 프로파일 패턴에 대한 MPPT 제어기의 성능분석이 필수적이다. 본 논문에서는 대한민국 중부지역의 전형적인 맑은 날씨와 흐린 날씨에서 실제 일사량을 측정하고, 취득한 일사량데이터를 기초로 저자가 개발한 다이오드 등가모델을 적용하여 시뮬레이션을 수행하였다. 이를 기반으로 MPPT 제어주기의 설정값에 따른 PV 패널의 전력생산량을 예측하여 MPPT 목표 효율을 극대화할 수 있는 최적의 MPPT 제어주기를 제시한다.

• Proceedings of the Korean Society of Computer Information Conference
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• 2011.01a
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• pp.299-300
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• 2011

태양에너지를 에너지 공급원으로 하고 LED 램프를 조명용 광원으로 사용하여 적은 전력 소모와 연장된 램프의 수명으로 에너지 소모를 크게 줄이고, 유지 보수 관리 비용을 획기적으로 줄일 수 있는 LED 조명제어시스템을 개발하였다. 점등 회로, 구동회로 등의 최적화된 설계와 구성으로 광 변환 효율을 높여 소형화, 경량화 되도록 하고, 환경 친화적인 조명 광원으로서 효율적인 성능을 얻을 수 있도록 한다.