• 한국수소및신에너지학회논문집
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• 제21권3호
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• pp.149-157
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• 2010

The electromagnetic characteristics of FCEVs (fuel cell electric vehicles) are much different from the existing combustion engine cars as well as hybrid, plug-in-hybrid, and pure electric vehicles due to the high voltage/current generated by a fuel cell stack which uses a compressed hydrogen gas reacted with oxygen. To operate fuel cell stack efficiently, BOP (Balance of Plant) is essential. BOP systems are used many not only for motors in water pump, air blower, and hydrogen recycling pump but also inverters for these motors. Since these systems or components are connected by high voltage cables, EMC (Electromagnetic compatibility) analysis for high voltage/current cable is the most important element to prevent the possible electric functional safety errors. In this paper, electromagnetic fields of high current/voltage cable for FCEVs is studied. From numerical analysis results, time harmonic magnetic field strength of high current/voltage cable have difference of 20～28 dB according to phase. EMI result considered ground effect of FECV at 10 m shows difference of 14.5 dB at 30 MHz and 2.8 dB at 230 MHz compared with general cable.

• KEPCO Journal on Electric Power and Energy
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• 제2권1호
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• pp.127-131
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• 2016

Polymer electrolyte membrane for unitized regenerative fuel cells requires high proton conductivity, high dimensional stability, low permeability, and low cost. However, DuPont's Nafion which is a commercial polymer electrolyte membrane has high permeability, high cost, and decreasing proton conductivity and dimensional stability over $80^{\circ}C$. To address these problems, sulfonated poly ether ether ketone (sPEEK) which is a low cost hydrocarbon polymer is selected as matrix polymer for the preparation of polymer electrolyte membrane. In addition, composite membrane with improved proton conductivity and dimensional stability is prepared by introducing sulfonated graphene oxide (sGO). The fundamental properties of polymer electrolyte membranes are analyzed by investigating membrane's water content, dimensional stability, proton conductivity, and morphology. The cell test is conducted to consider the possibility of application of sPEEK/sGO composite membrane for an unitized regenerative fuel cell.

• Carbon letters
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• 제22권
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• pp.42-47
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• 2017

In this paper, the in vitro biocompatibility of graphene film (GF) with osteoblasts was evaluated through cell adhesion, viability, alkaline phosphatase activity, F-actin and vinculin expressions, versus graphite paper as a reference material. The results showed that MG-63 cells exhibited stronger cell adhesion, better proliferation and viability on GF, and osteoblasts cultured on GF exhibited vinculin expression throughout the cell body. The rougher and wrinkled surface morphology, higher elastic modulus and easy out-of-plane deformation associated with GF were considered to promote cell adhesion. Also, the biomineralization of GF was assessed by soaking in simulated body fluid, and the GF exhibited enhanced mineralization ability in terms of mineral deposition, which almost pervaded the entire GF surface. Our results suggest that graphene promotes cell adhesion, activity and the formation of bone-like apatite. This research is expected to facilitate a better understanding of graphene-cell interactions and potential applications of graphene as a promising toughening nanofiller in bioceramics used in load-bearing implants.

• 전기학회논문지
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• 제59권12호
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• pp.2250-2255
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• 2010

An fine silver particle has a variety of uses, such as in killing micrograms and as catalysts. Many techniques have been used for the production of the fine particles. Faraday cell, consisting of two silver electrodes in an electrolyte, is unique, but it is hard to get a very fine particle by this method. A finer silver nano-particle producing cell, utilizing a dielectric bed as a lower electric current and higher field controlling means, has been proposed and investigated. The I-V characteristics of the cell and effect of the dielectric bed on the producing finer silver nano-particles have been investigated. The I-V characteristics of the cell with the dielectric bed were different from that of the same system without the bed, due to the increased cell resistance and elevated electric field intensity. It is found that the proposed cell with the dielectric bed can produce finer silver nano-particles effectively, which, however, can be used as one of effective fine silver nano-particle producing means.

• 한국추진공학회:학술대회논문집
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• 한국추진공학회 2011년도 제37회 추계학술대회논문집
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• pp.544-547
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• 2011

한국항공우주연구원에서 개발 중인 중형 전기추진 무인기의 추진시스템에 대하여 하드웨어 통합 패시브 전력제어 시뮬레이션을 수행하였다. 이 추진시스템은 태양전지, 연료전지 및 배터리를 통합하여 전력원으로 사용하는 하이브리드 시스템이다. 연료전지는 I-V 커브를 모사하는 모사기를 제작하여 사용하였으며, 나머지 구성품들은 실제 탑재품들을 사용하였다. 시험 결과 각 전력원들은 요구전력 변화에 대해서 고유의 특성을 보이면서 원활히 동작되며, 안정적으로 운전됨을 확인하였다.

• 전기학회논문지
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• 제64권12호
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• pp.1804-1809
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• 2015

The study in railway system to apply a fuel cell system with high efficiency and mobility than other renewable energy is being actively conducted. It is needed a analysis on load characteristics and control method of rolling stock in order to apply to rolling stock. This paper presents study on control small-scale prototype power converter electric railway vehicle using fuel cell generation system. Experiment is conducted through real fuel cell generation system and reference speed applying the driving curve of the actual electric railway vehicle was applied. Also, output voltage of boost converter is controlled considering characteristic of fuel cell. And it was confirmed characteristic according to powering and regeneration of inverter.

• International Journal of Automotive Technology
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• 제8권5호
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• pp.651-658
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• 2007

This paper presents a new type of fuzzy logic-based power control strategy for fuel cell hybrid electric vehicles designed to improve their fuel economy while maintaining the battery's state of charge. Since fuel cell systems have inherent limitations, such as a slow response time and low fuel efficiency, especially in the low power region, a battery system is typically used to assist them. To maximize the advantages of this hybrid type of configuration, a power distribution control strategy is required for the two power sources: the fuel cell system and the battery system. The required fuel cell power is procured using fuzzy rules based on the vehicle driving status and the battery status. In order to show the validity and effectiveness of the proposed power control strategy, simulations are performed using a mid-size vehicle for three types of standard drive cycle. First, the fuzzy logic-based power control strategy is shown to improves the fuel economy compared with the static power control strategy. Second, the robustness of the proposed power control strategy is verified against several variations in system parameters.

• 대한전기학회논문지:전기물성ㆍ응용부문C
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• 제48권2호
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• pp.133-140
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• 1999

The relationships between discharge characteristics and sustain electrode shape are studied in AC PDP by calculating the electric field and measuring discharge voltage, luminance and current. The maximum electric field is obtained for the triangle shape electrode. It is 1.8 times larger than uniform electric field type. It has been shown thatthe firing voltage is largely affected by the degree of electric field concentration. But, as the difference of the maximum and minimum value of electric field in a cell increases, the luminance and luminance efficiency decrease. And, the charge variation during discharge is proportional to the area of electrode.

• 전기전자학회논문지
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• 제13권3호
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• pp.47-54
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• 2009

Design consideration on electric drivetrain(E-D/T), usually referred as electric motor for driving, its compatible reduction gear, and inverter, are performed for developing electric vehicle(EV) with efficient driving performance. Universal mode of driving cycle has been used to make up the actual vehicle performance, and its results are incorporated to the design of E-D/T.

• 전력전자학회논문지
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• 제27권1호
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• pp.26-32
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• 2022

This paper proposes a power system that includes a 120k W fuel cell DC-DC converter (FDC) and 30 kW bidirectional DC-DC converter (BHDC) for a 150 kW fuel-cell vehicle. With a high DC link voltage of 800 V, the efficiency and power density of the power electronic components are improved. Through the modular design of FDC and BHDC, electric components are shared, resulting in reduced mass production costs. The switching frequency of 30 kHz of full SiC devices and optimal design of coupled inductor reduce the volume, achieving a power density of 8.3 kW/L. Furthermore, a synergetic operation strategy using variable limiter control of FDC and BHDC was proposed to efficiently operate the fuel cell vehicle considering the fuel cell stack efficiency according to the load. Finally, the performance of the prototype was verified by Highway Fuel Economy Driving Schedule testing, EMI test, and the linked operation between FDC and BHDC. The full load efficiencies of the FDC and BHDC prototypes are 98.47% and 98.74%, respectively.