• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.41 no.12
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• pp.1018-1024
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• 2013

On-Board computers (OBC) for LEO & GEO satellites have been developed with their own dedicated architecture so far even though they have many similar functionalities. In this paper, we present a conceptual study results of standard OBC architecture design and propose the domestic development plan for the next generation satellite OBC. Proposed architecture is highly flexible and can be used at LEO/MEO/GEO and Moon Explorer/Deep Space Probe. Also, we introduce current status of standard OBC which is under development.

• Proceedings of the KIPE Conference
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• 2018.11a
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• pp.225-226
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• 2018

전기자동차 배터리팩을 충전하기 위한 장치인 차량용 OBC(On-Board Charger)는 AC/DC 컨버터 기능을 담당하는 PFC(Power Factor Correction)와 DC/DC 전력변환 및 전기적 절연을 담당하는 Phase-Shifted Full Bridge Converter를 포함 한다. 현재 시중에 3.3kW급 OBC를 기준으로 규격화되어 생산되고 있지만 전기자동차의 배터리 용량이 날로 증가하고 전기자동차 보급, 사용률이 증가함에 따라 완속충전에 대한 요구가 높아지고 있다. 여기에 전력 인프라 시설 개선과 더불어 6.6kW급 완속충전이 보편화될 수 있게 된다. 차량용 OBC 공급업체에 있어서는 기존의 3.3kW급과 6.6kW급 OBC의 개발 중 어느 쪽에 중심을 둘지 고민에 대한 대안으로 기존의 3.3kW급을 모듈화하여 병렬운전하는 방법으로 6.6kW급 OBC 시장수요에 대응 할 수 있다. 본 논문에서는 3.3kW급 OBC 및 2병렬운전에 관한 시뮬레이션을 개발하고 분석하였다.

• Proceedings of the KIPE Conference
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• 2020.08a
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• pp.94-96
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• 2020

본 논문은 전 범위 ZVS를 가지는 OBC-LDC 통합형 차량용 충전기를 제안한다. 제안하는 통합형 충전기는 OBC의 절연부인 양방향 LLC 공진형 컨버터의 2차측 스위치 레그와 LDC의 위상천이 풀브릿지 컨버터의 lagging 레그를 공통으로 사용하여 스위치 개수를 2개 줄일 뿐아니라 경부하에서 ZVS 성취가 어려운 lagging 레그의 전 범위 ZVS 턴온을 가능케 한다. 제안하는 통합형 충전기는 OBC와 LDC의 동시동작이 가능하며 OBC와 LDC가 같이 동작할 때 전류 상쇄효과로 인해 도통손실을 저감할 수 있다. 또한 OBC와 LDC가 동일주파수로 동작하므로 고전압측 출력필터와 EMI 필터의 설계가 간단해지는 장점이 있다. 3.6kW급 LLC 공진형 컨버터와 1kW급 위상천이 풀브릿지 컨버터로 구성되는 통합형 충전기의 시작품을 제작하여 본 논문의 타당성을 증명하였다.

• Proceedings of the KIPE Conference
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• 2020.08a
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• pp.401-402
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• 2020

본 논문에서는 차량 탑재형 충전기 (OBC)와 저 전압 배터리 충전기 (LDC)의 각 기능에 대해 분석한다. 또한, 두 배터리 충전기를 통합한 OBC-LDC 통합형 회로의 장·단점과 기능에 대해 분석한다. 또한, OBC-LDC 통합형 회로에 대한 두 토폴로지의 장·단점을 비교 분석하고, PSIM을 사용하여 각 토폴로지에 대한 시뮬레이션을 진행하여 회로의 동작 및 성능을 비교 분석한다.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.12 no.4
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• pp.456-465
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• 2019

PHEV(Plug in Hybrid Electric Vehicle) and BEV(Battery Electric Vehicle) equip high voltage batteries to drive motor and vehicle electric system. Those vehicle require OBC(On-Board Charger) for charging batteries and LDC(Low DC/DC Converter) for converting from high voltage to low voltage. Since the charger and the converter actually separate each other in electrical vehicles, there is a margin to reduce the vehicle weight and area of installation by integration two systems. This paper studies a 1.5kW LDC converter that can be integrated into an OBC using an isolated current-fed converter by simplifying the design of LDC transformers. The proposed LDC can control the final output voltage of the LDC by using a fixed arbitrary output voltage of the bidirectional buck-boost converter, so that Compared to the existing OBC-LDC integrated system, it has the advantage of simplifying the transformer design considering the battery voltage range, converter duty ratio and OBC output turn ratio. Prototype of the proposed LDC was made to confirm normal operation at 200V ~ 400V input voltage and maximum efficiency of 91.885% was achieved at rated load condition. In addition, the OBC-LDC integrated system achieved a volume of about 6.51L and reduced the space by 15.6% compared to the existing independent system.

• Journal of Astronomy and Space Sciences
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• v.18 no.2
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• pp.109-118
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• 2001

KITSAT-1, launched in 1992, passes through Inner Van Allen Radiation Belt in which high energy Protons cause single event upsets(SBUs) in the main memory of KITSAT-1 OBC(On-Board Computer) 186. The present paper compares SEU data from the OBC186 with the AP-8 model of NASA/NSSDC using the Chi-Square method to estimate the SEU threshold energy. Shielding effect by the satellite body has been taken into account to model the proton fluxes at the position of OBC186, and SEUs recorded during the high solar activities have been removed to avoid the spurious result. The result shows that the SEU threshold energy of the main memory of KITSAT-1 OBC186 is estimated to be about $110{pm}10MeV$.

• Journal of Astronomy and Space Sciences
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• v.13 no.2
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• pp.41-51
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• 1996

KITSAT-1 and 2 are microsatellites weighting 50kg and all the on-board data are processed by the on-board computer system. Hence, these on-board computers require to be highly reliable and be designed with tight power consumption, mass and size constraints. On-board computer(OBC) systems for KITSAT-1 and 2 are also designed with a simple flexible hardware for reliability and software takes more responsibility than hardware. KITSAT-1 and 2 on-board computer system consist of OBC 186 as the primary OBC and OBC80 as its backup. OBC186 runs spacecraft operating system (SCOS) which has real-time multi-tasking capability. Since their launch, OBC186 and OBC80 have been operating successfully until today. In this paper, we describe the development of OBC186 hardware and software and analyze its in-orbit operation performance.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.12 no.1
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• pp.99-105
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• 2019

OBC for battery charging of electric vehicles mainly consist of two stages including PFC circuit and isolated DC-DC converter circuit. In general, a non-isolated boost converter is used as the PFC circuit, and a resonant converter capable of ZVS (zero voltage switching) is used as the isolated DC-DC converter. In this paper, we propose an OBC composed of isolated current-fed type PFC circuit and buck DC-DC converter. The proposed OBC is easy to configure the circuit and controller, and can cope with a wide output range. In order to verify the validity of the proposed circuit, a prototype 3.3 ㎾ class prototype was fabricated. As a result, the maximum efficiency and the maximum power factor of 99.2% were confirmed under the operational stability and rated load conditions at the output voltage of 150V ~ 400V.

• Proceedings of the KIPE Conference
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• 2016.07a
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• pp.387-388
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• 2016

본 논문은 V2G를 위한 Bidirectional OBC를 제안한다. 상용화 시 적시 적용 가능한 높은 역/전송 효율의 Bidirectional OBC 전력회로를 제안하고 베터리 전력을 입력원으로 분산형 전력공급 장치에서 요구하는 품질을 만족하는 전력 생산을 위해 계통연계 회로 및 제어 기술을 제안한다. Bidirectional OBC의 PFC Type은 양방향 구현을 위해 기존 MOSFET과 Diode로 구현된 구조와 달리 모두 IGBT를 이용하여 Single Phase Inverter를 구현 하였으며, IGBT 이용 시 예측되는 Reverse Recovery Loss 개선을 위하여 Hybrid Switch 구조를 제안 하였다. Bidirectional OBC의 DC/DC Type은 전송 및 역송에 따라 Buck동작과 Boost 동작이 가능하도록 설계 하였고 Secondary LC Resonant Topology 가변구조법을 사용 하였다.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.31 no.4
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• pp.105-111
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• 2003

Qualification Model of On-board Computer (OBC) for KAISTSAT-4 was developed. The OBC of KAISTASAT-4 has some improved features compared with that of KAISTSAT-3: To reduce weight and size of OBC many logics are implemented by FPGAs, and a network controller is included in OBC to access the satellite network with high speed. Also, the developed OBC has an improved tolerance against SEUs and faults. The OBC was fully tested under simulated space environment with no errors.