• Journal of Digital Contents Society
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• v.14 no.4
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• pp.529-536
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• 2013

Lack of proper amount of sun lights and wind strength which are major factors of solar power and wind power system may cause poor electric power generation and decrease the lifetime of batteries that are major energy saving units. Because the PCS, which is essential in solar and wind power system, for small power generation system has been rarely developed an efficient and stable PCS for small power generation system is highly required. In this paper, we design a new constant current/constant voltage type hybrid PCS by which stand alone/grid connected operation with commercial power system is available and implement the designed PCS as a protype for performance verification.

• The Transactions of the Korean Institute of Power Electronics
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• v.5 no.5
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• pp.475-483
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• 2000

This paper describes designs about the power system of KITSAT-4 satellite. The KITSAT-4 power system is mainly composed of power stage and control stage. The power stage is a 200〔W〕 buck converter and control stages are hardware controller and software controller The hardware controller is PPT(Peak Power Tracker), battery voltage controller and software controller is battery current controller and direct duty controller. So the operation of power system has many advantages in that it can select controller according to reliable control and precise control. The controller design methods are presented and the small signal analyses are performed to verify system stability.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.48 no.4
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• pp.303-310
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• 2020

This paper describes a Power Monitoring Unit (PMU) for Unmanned Aerial Vehicle (UAV) electrical system, It is designed for the PMU which performs data sensing of generator, transformer rectifier unit (TRU), battery and gear box installed in UAV and operate power ON/OFF devices of mission equipment. The PMU measures the voltage and current for the aircraft power source (generators, transformer rectifier unit and battery), measures the pressure and temperature of the gearbox, and performs the mission equipment power command received from the mission computer. The PMU was designed to meet the requirements of the UAV, and was performed through structure/thermal analysis, environmental test, EMI test and ground/flight tests.

• Proceedings of the Korean Information Science Society Conference
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• 2005.11a
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• pp.274-276
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• 2005

유비쿼터스 물류 환경을 위한 능동형 RFID(Radio Frequency IDentfication) 시스템 기술에 대한 필요성이 대두되고 있다. 특히 컨테이너 물류 환경에서 적합한 RFID 기술은 ISO/IEC 18000-7 표준으로 제정되었으나, 현재 이에 대한 연구 개발 사례보고가 드문 실정이다. 본 논문에서는 물류 상황에 적합한 능동형 RFID 시스템에 대한 아키텍쳐 설계 및 저전력 운용 등의 요소기술에 대한 연구 및 시스템 개발 내용을 다루었다. 기본적인 성능평가를 수행한 결과, 1000개의 명령어를 연속으로 요청했을 때 $99\%$이상의 높은 인식률을 보였다. 또한 시스템의 핵심 요소인 저전력 기능을 구현한 결과 배터리는 최장 1년까지 이용 가능한 것으로 나타났다.

• Proceedings of the KIPE Conference
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• 2017.11a
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• pp.163-164
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• 2017

본 논문에서는 KMSL(Korea Microgravity Science Laboratory) 큐브 위성에 대해 설명하고 전력시스템 설계 연구 방법을 제시한다. 1~3리터 사이즈인 초소형 인공위성(큐브위성)의 전력시스템은 태양 전지 패널로부터 큐브 위성의 부하장치 운용을 위한 전력을 공급받고, 남은 잉여 전력은 배터리에 저장하여 식(eclipse) 구간 동안 전력이 공급될 수 있도록 전력계가 구성된다. 본 논문에서는 조선대학교 KMSL팀의 큐브 위성에 대한 전력시스템을 설계하기 위해서 위성 궤도 및 자세에 따른 생산 전력, 소비 전력을 인공위성의 자세 및 궤도에 따라 분석하고, 부하 장치의 전원 및 소모전력을 통해 전력 및 에너지 마진(margin)이 충분하도록 전력계시스템의 구성품 용량을 설계하였다.

• Proceedings of the KIEE Conference
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• 2008.04a
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• pp.41-42
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• 2008

무선방식으로 원격에서의 인식으로 정보교환을 가능하게 하는 RFID(Radio Frequency IDentification) 시스템은 태그 내의 배터리 유무에 따라 수동형과 능동형으로 구분된다. 수동형 태그는 판독기로부터 받은 RF 신호를 에너지로 이용하기 때문에 인식거리가 짧으며, 가격이 싸고 반영구적으로 사용할 수 있는 장점이 있다. 반면에, 능동형 태그는 금속재질에 취약한 수동형의 단점을 극복하는 동시에 인식거리가 길고, 인식률이 좋은 장점이 있다. 따라서 항만물류나 국방 분야에서 능동형 RFID 시스템에 대한 개발이 점차 확대되고 있다. 하지만 동일한 표준으로 개발된 제품의 서로 간에 인식이 불가능한 사례가 보고되고 있으며, 국제적으로 정확한 평가방법 및 장치가 정립되지 않아 개발된 제품들 간의 상호 운용성 및 표준 적합성 평가에 대한 어려움이 존재한다. 본 논문에서는 능동형 RFID 시스템의 적합성 평가를 위한 에뮬레이터의 하드웨어 및 소프트웨어를 설계하고 제작하였다. 설계된 장치는 Matlab의 Simulink를 통한 시뮬레이션으로 성능을 분석하였고, 실제 능동형 RFID 태그의 표준적합성 평가를 통해 에뮬레이터의 적용 가능성을 검증하였다.

• Transactions of the Korean hydrogen and new energy society
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• v.34 no.5
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• pp.490-496
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• 2023

Unmanned aerial vehicles (UAVs) research is recently actively underway. Especially, fuel cell battery hybrid systems are widely used to overcome the limitations of continuous operation. However, fuel cell systems must be operated in combination with a battery due to their low specific output characteristics. Therefore, a hybrid power system model for UAVs is developed. The rule-based strategy is applied to the model to properly distribute power to batteries and fuel cells. As a result, the designed rule-based power distribution control operates UAVs while maintaining battery state of charge(SOC) at an appropriate level.

• Proceedings of the KIEE Conference
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• 2005.10b
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• pp.511-513
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• 2005

The fuel cell system has inherent limitation such as slow response time and low fuel economy especially at the low power region, and thus, the battery system has come to be used to compensate for the fuel cell system. This type of hybrid configuration has many advantages, however, the energy management strategy is essentially required. The work in this paper presents survey on recent power management strategies for fuel cell hybrid electric vehicles. For three power management strategies: basic control method. object function-based control method, and fuzzy logic-based control method. each strategy is reviewed and discussed with other strategy.

• Journal of Korea Multimedia Society
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• v.13 no.1
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• pp.83-92
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• 2010

Sensor networks applications can be employed by a vast range of applications. Environmental information monitoring systems and ecosystem surveillance are representative application using sensor networks. But, limited battery capacity of sensor node is a key feature that determines lifetime of networks and system. It also affects quality of collected data. We recognized factors that affects lifetime of environment sensor nodes through the experiment of environment information system deployed over campus. We will show useful proposals for future construction of sensor network application systems.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.21 no.6
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• pp.662-671
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• 2020

Recently, for the purposes of reducing carbon dioxide(CO₂) emissions in the island area, countermeasures to decrease the operation rate of diesel generator(DG) and to increase one of renewable energy sources(RES) is being studied. In particular, the demonstration and installation of stand-alone micro-grid(MG) system which is composed of DG, RES and energy storage system(ESS) has been implemented in some island areas such as Gapa-do, Gasa-do and Ulleung-do island. However, many power quality(PQ) problems may be occurred due to an intermittent output of RES including photovoltaic(PV) system and wind power(WP) system in a normal operating of constant voltage & constant frequency(CVCF) inverter-based MG system. Therefore, this paper presents a modeling of the 30kW scale MG system using PSCAD/EMTDC, and also implements a 30kW scale CVCF inverter-based MG system as test devices to analyze normal operating characteristics of MG system. From the simulation and test results, it is confirmed that the proposed methods are useful and practical tools to improve PQ problems such as under-voltage, over-voltage and unbalanced load in CVCF inverter-based MG system.