• 전기학회논문지P
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• 제58권4호
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• pp.609-614
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• 2009

A fuel-cell power system among various alternative power sources has many advantages such as comparatively independable circumstances, high-efficient, and heat-recyclable, thus it is now able to be up to hundreds MWh-scaled through improving feasibility and longevity of it. During the last few decades, numerous research results has been investigated to expand interest in fuel-cell technology. This study presents pressure distribution on the geometrical manifold structures, which are U-type and Z-type, of a planar-type fuel-cell stack by simulated with computational fluid dynamics(CFD). Then, electrical performance of a 200W fuel-cell stack, which is U-type, was diagnosed after pre-conditioning operation. The stack has electrical characteristics ; 22V, 10A, 220W, and current density $200mA/cm^2$.

• 한국자동차공학회논문집
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• 제16권3호
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• pp.87-93
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• 2008

The $CO_2$ air conditioning system installed in fuel cell vehicles could be used either for stack cooling or for cabin cooling, and thus was used for the stack cooling when additional stack heat release was required over a fixed radiator capacity for high power generation. This study investigated the performance of the stack cooling system using $CO_2$ air conditioner at various operating conditions. Also, the heat releasing effectiveness and mutual interference were analyzed for the stack cooling system using an air conditioner and compared with the conventional radiator cooling system with/without cabin cooling. The heat release of the stack cooling system with the aid of $CO_2$ air conditioner increased up to 36% more than that of the conventional radiator cooling system with cabin cooling. Furthermore, the heat release of the stack cooling system using $CO_2$ air conditioner increased more by 7% than that of the conventional radiator cooling system without cabin cooling.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2005년도 추계학술대회 논문집 전력기술부문
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• pp.55-57
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• 2005

This paper presents the development and performance of a power conditioning system (PCS) for application to a 100kw Molten Carbonate Fuel Cell. (MCFC) generation system. The MCFC generation system is a part of a four year government funded research project that began in 2001. This paper presents the results of operation connected to an actual fuel cell stack at a field demonstration site. and this paper shows various tests and performance verification of the 100kW PCS using a simulated DC source.

• 설비공학논문집
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• 제20권2호
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• pp.113-120
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• 2008

Potential application of the scroll type machine to air compressor for fuel cell has been studied. Among the seven configuration factors which determine scroll wrap profile, the wrap thickness and the orbiting radius were chosen as two independent variables to generate various scroll wrap profiles. A conceptual design practice was conducted for scroll air compressor for SOFC with power output of 2 kW. With larger wrap thickness and orbiting radius, base plate area of the orbiting scroll becomes smaller, so is the axial gas force acting on the base plate, resulting in reduced thrust loss in spite of larger friction velocity. Performance analysis on the designed model showed that its total efficiency was 64.4% with the mass flow rate per unit compressor input of 0.00905 kg/(s kW) for the wrap thickness of 3.5 mm and the orbiting radius of 3.0 mm.

• Journal of Power Electronics
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• 제11권1호
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• pp.82-89
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• 2011

Differences in the frequency characteristic applied to a ripple current may shorten fuel cell life span and worsen the fuel efficiency. Therefore, this paper presents an experimental analysis of the ripple current applied variable frequency characteristic in a polymer electrolyte membrane fuel cell (PEMFC). This paper provides the first attempt to examine the impact of ripple current through immediate measurements on a single cell test. After cycling for hours at three frequencies, each polarization and impedance curve is obtained and compared with those of a fuel cell. Through experimental results, it can be absolutely concluded that low frequency ripple current leads to long-term degradation of a fuel cell. Three different PEMFC failures such as membrane dehydration, flooding and carbon monoxide (CO) poisoning that lead to an increase in the impedance magnitude at low frequencies are simply introduced.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2007년도 춘계학술대회 논문집 전기기기 및 에너지변환시스템부문
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• pp.231-233
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• 2007

본 논문은 신 발전방식 중 하나인 용융탄산염형 연료전지(Molten Carbonate Fuel Cell, 이하 MCFC) 발전시스템에서 생성된 전력을 계통에 안정적으로 변환, 주입하기 위한 계통연계형 전력변환기를 설계, 제작하고 성능 시험을 수행한 결과이다. 250kW급 MCFC 시스템의 정격 사양 및 스택의 운전 형태를 기반으로 250kW급 전력변환기 구조 및 단위기기를 설계하였고 전력변환기는 크게 DC/DC 컨버터부와 DC/AC 인버터부로 구성된다. 본 논문은 MCFC 발전 시스템에 적용되는 전력변환기(Power Conditioning System, 이하 PCS)를 제작하고 성능을 확인하는데 목적이 있다.

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2008년도 춘계학술대회 논문집
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• pp.17-20
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• 2008

HYOSUNG manufactured and tested 1kW class PEFC systems to generate electrical and thermal energy for each residential usage. In particular, HYOSUNG developed power conditioning system that performs over 91% electrical conversion ratio specified in 1kW class PEFC systems. Prior to system integration, we tested each performances of components to derive control issues from it. In addition, we have been developing the adequate simulator to describe and predict system performance. In this paper, we verified HYOSUNG's 1kW class PEFC systems are valid for residential energy sources by testing the characteristics of systems and performances of main components.

• 한국태양에너지학회:학술대회논문집
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• 한국태양에너지학회 2008년도 춘계학술발표대회 논문집
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• pp.80-85
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• 2008

A PVIB(Photovoltaic in Building) system is united by a constituent outer covering and can expect dual effects that reduce expenses for the establishment of a PV system. It is a profitable technology because it does not need a building as it is a stand alone PV system. This paper presents design, operational features analysis, and PCS(Power Conditioning System) of grid-connected 30kW PVIB set up on the library of Dongshin University. For a sustainable photovoltaic system in this area, the data of the PVIB system are collected and analyzed by monitoring system using LabView. PCS of the grid-connected PVIB system, also, is designed for optimal operation with characteristics suggested in this paper.

• 전기학회논문지
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• 제58권1호
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• pp.93-99
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• 2009

In this paper, transient voltage response of Polmer Electrolyte Membrane Fuel Cell (PEMFC) stack is analyzed and voltage dynamic characteristic is modeled for optimal design of power conditioning system (PCS). According that the load is changed, the corresponding operating voltage of fuel cell stack is also varied with a certain deep and rising time due to the chemical and mechanical responses. This transient behavior can affect on the operation with respect of PI gain in controller, duty ratio, capacitor of capacitor and so on. So in this paper the detailed theoretical analysis of transient voltage dynamics is explained and the methodology of dynamic modeling is introduced. In addition, the validity and feasibility of the proposed dynamic model is verified by experimental results under various load conditions.

• 전력전자학회논문지
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• 제11권3호
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• pp.258-265
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• 2006

풍력, 태양광, 연료전지와 같은 신 재생 에너지에 관한 연구가 활발해 지면서 컨버터, 인버터와 같은 PCS (Power Conditioning System)의 연구가 활발히 진행되고 있다. 그러나, 부하에 따라 가변되는 저전압, 대전류, 출력특성을 갖는 연료전지 발전 시스템에서는 PCS의 연구 및 개발이 어려운 실정이다. 본 논문에서는 연료전지를 이용한 발전시스템에 알맞은 능동 클램프 sepic-flyback 컨버터를 제안한다. 제안된 컨버터는 중간 탭 변압기를 이용하여 sepic, flyback 컨버터를 결합한 구조를 가진다. 변압기를 이용하는 종래의 토폴로지에 비해 변압기 이용률을 높일 수 있고, 변압기의 변환 비 및 파워 스위치 소자의 수를 줄일 수 있으며, 고효율 운전특성을 갖는다. 본 논문에서는 시뮬레이션과 실험을 통하여 컨버터의 동작특성을 비교 분석하였으며, PEMFC (Proton Exchange Membrane Fuel Cell)을 이용하여 제안된 컨버터의 타당성을 검증하였다.