• Proceedings of the KIPE Conference
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• 2018.07a
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• pp.356-357
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• 2018

Fuel-cell powered Railway Vehicle Propulsion Systems (RVPSs) are highly desirable due to environment friendly characteristics, and high efficiency of fuel cell (FC). Among various types, the faster start-up and optimality to frequent starts and stops of Polymer electrolyte membrane fuel cell (PEMFC) makes it well suited for propulsion systems. A comprehensive model of PEMFC with reflection of multi-physics behavior required to identify and validate its performance in real RVPSs. Thus this paper will model and simulate the PEMFC unit cell model: a detailed reflection of governing laws and account of dynamic conditions.

• Journal of Electrochemical Science and Technology
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• v.1 no.2
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• pp.92-96
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• 2010

A new synthesis method for the preparation of Pt electrocatalysts on carbon nanofibers (CNFs) is reported. In this method, Pt electrocatalysts are loaded onto 2-naphthalenethiol (NT) functionalized CNFs. The noncovalent functionalization of CNFs by NT is the effective way for better distribution of Pt particles and higher electrocatalytic activity in polymer electrolyte membrane fuel cells. It was found that the presence of NT acts as a poison to catalysts. Therefore, it is necessary to remove NT through the heat treatment at $400^{\circ}C$.

• Proceedings of the KIPE Conference
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• 2005.07a
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• pp.357-359
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• 2005

In this paper, a new SEPIC-Flyback converter with a single transformer has been proposed, which is suitable for a fuel cell based power generation system. The proposed converter is superposition of sepic and flyback converter mode. It has outstanding high boosting output voltage, component utilization and high efficiency characteristics under the inherently severe low output voltage of the fuel cell generator. The proposed converter for a full cell generator is described and verified by simulation and experimental result that make used of the Polymer Electrolyte Membrane Fuel Cell(PEMFC) Generator.

• Proceedings of the KSME Conference
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• 2008.11b
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• pp.2589-2593
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• 2008

In a fuel cell vehicle using polymer electrolyte membrane fuel cell(PEMFC), hydrogen is over-supplied to gain higher stack efficiency. So it is needed considering fuel efficiency to re-circulate hydrogen which is not reacted in stack. And to re-circulate hydrogen, a blower or an ejector is used. Ejector re-circulation system has several merits compared with blower system, for example no parasite energy, simple structure and no lubrication system. But the secondary flow of an ejector in fuel cell vehicle, has high humidity because of crossover problem in stack. Therefore in this paper, ejector is designed by 1-D modeling and CFD with the primary and secondary flow of hydrogen. And the ejector which has the primary and secondary flow of air, is designed to have the same Reynolds number and Mach number at the nozzle exit as the hydrogen ejector's. And this air ejector is tested while the humidity of the secondary flow is varied.

• Transactions of the Korean hydrogen and new energy society
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• v.27 no.3
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• pp.264-269
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• 2016

A simple dry chemical approach was developed in order to load palladium (Pd) as a promoter on Pt/gas diffusion electrode (GDE) for polymer electrolyte membrane fuel cell (PEMFC). Palladium(II) bis (acetylacetonate), $Pd(acac)_2$ was sublimed, penetrated into Pt/GDE and then reduced to Pd nanoparticles simultaneously without any reducing agent and any solvent in a glass reactor of $N_2$ atmosphere at $180^{\circ}C$ for 3, 5 and 15 min. Pd distribution was analyzed by scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS), and I-V curve was estimated by using a unit cell with $5{\times}5cm^2$ active area.

• 한국전기화학회:학술대회논문집
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• 2004.06a
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• pp.37-42
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• 2004

To maintain proper operating conditions is important to get optimal output power of a PEMFC stack. The air cooled fuel cell stack is widely used in sub kW PEMFC systems. A 500W air cooled PEMFC stack was experimentally investigated to evaluate the design performance and to get optimal operating conditions for the portable application. The relationship between the operating conditions and the performance was analyzed. The results can be used as design criteria for portable PEMFC under various conditions.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.58 no.9
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• pp.1706-1713
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• 2009

In this paper, a parallel operation algorithm for high power PEMFC generation systems is proposed. According to increasing the capacity of fuel cell systems with several fuel cell stacks, the different dynamic characteristics of each fuel cell stack effect on imbalance of load sharing and current distribution, so that a robust parallel operation algorithm is desired. Therefore, a power-sharing technique is developed and explained in order to design an optimal distributed PEMFC generation system. In addition, an optimal controller design procedure for the proposed parallel operation algorithm is introduced, along with informative simulations and experimental results.

• Proceedings of the KIPE Conference
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• 2017.07a
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• pp.461-462
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• 2017

가장 대표적인 연료전지인 고분자 전해질 연료전지(PEMFC; polymer electrolyte membrane fuel cell)은 두 개의 전극으로 이루어지며, 각 전극(electrode)에 공급되는 수소(anode)와 공기(cathode)의 원활한 반응을 위해 촉매(catalyst)로서 백금(Pt)을 사용한다. 이 때, 촉매의 실험 조건에 따라 연료전지 두 전극의 반응이 달라지므로 촉매의 가변성 즉, 가변적인 전극 조건에 따른 전기화학적 특성이 면밀히 분석되어야 한다. 그러므로, 본 논문에서는 촉매의 변화에 기인한 가변적인 전극 특성에 따른 연료전지의 전기화학적 특성 분석을 실시하였다.

• Journal of Power Electronics
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• v.10 no.6
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• pp.739-748
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• 2010

The increased integration of fuel cells with power electronics, critical loads, and control systems has prompted recent interest in accurate electrical terminal models of the polymer electrolyte membrane (PEM) fuel cell. Advancement in computing technologies, particularly parallel computation techniques and various real-time simulation tools have allowed the prototyping of novel apparatus to be investigated in a virtual system under a wide range of realistic conditions repeatedly, safely, and economically. This paper builds upon both advancements and provides a means of optimized model construction boosting computation speeds for a fuel cell model on a real-time simulator which can be used in a power hardware-in-the-loop (PHIL) application. Significant improvement in computation time has been achieved. The effectiveness of the proposed model developed on Opal RT's RT-Lab Matlab/Simulink based real-time engineering simulator is verified using experimental results from a Ballard Nexa fuel cell system.

• Transactions of the Korean hydrogen and new energy society
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• v.30 no.5
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• pp.411-417
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• 2019

An adsorption chiller is connected to the fuel processing/fuel cell system to increase the energy efficiency of the system. Since, the minimum temperature of $70^{\circ}C$ is needed to operate the adsorption chiller, HT-PEMFC is used as a heating source and $80^{\circ}C$ hot water in the water tank at the system is supplied to the chiller. Experimentally measured COP of the adsorption chiller was between 0.4-0.5 and the total calcuated efficiency of the connected system was between 60% and 70% comparing to 47% without adsorption chilling system.