• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.21 no.6
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• pp.117-125
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• 2007

Recently, a fuel cell with low voltage and high current output characteristics is remarkable for new generation system. It needs both a DC-DC step-up converter and DC-AC inverter to be used in fuel cell generation system. Therefor, this paper, consists of an isolated DC-DC converter to boost the fuel cell voltage 380[VDC] and a PWM inverter with LC filter to convent the DC voltage to single-phase 220[VAC]. Expressly, The fuel cell system which it proposes DC-DC the efficient converter used PWM the phase transient control law and it depended to portion resonance ZVS switching, loss peek voltage and electric current of realization under make schedule, switching frequency anger and the switch reduction. And mind benevolence it sprouted 2 in stop circuit and it added and a direct current voltage and the electric current where the ingredient is reduced in load side ripple stable under make whom it will be able to supply. Besides the efficiency of 92[%]is obtained over the wide output voltage regulation ranges and load variations. Also, under make over together the result leads simulation and test, the propriety confirmation.

• KIEE International Transactions on Electrophysics and Applications
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• v.5C no.4
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• pp.145-151
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• 2005

The synthetic breaking test method was developed to evaluate the breaking performance of ultra high-voltage circuit breaker and made up of two independent circuits; current source circuit and voltage source circuit. In application of this test method, it is necessary to extend the arc of the test breaker. So, the new re-ignition system using VTGS (Vacuum Triggered Gap-Switch) was constructed to improve the efficiency and reliability of this test. In this re-ignition system, VTGS operates in high vacuum state of $5{\time}10^{17}$torr and control system consists of the triggering device and the air M-G (Motor-Generator). This re-ignition system showed the operating characteristics, such as delay time ($t_d$) and jitter time ($t_j$ not exceeding 5us and 1us respectively, and had the operating voltage of $25\~150kVdc$ at the gap distance of 24mm.

• Journal of Bio-Environment Control
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• v.25 no.1
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• pp.49-56
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• 2016

This study was conducted to develop the disinfection system using electric shock for recycled nutrient solution in recycling soilless culture. Stainless steel (SUS 316) was found as the most appropriate electrode material for electrical disinfection system from the view of high electrical conductivity, low electric resistance, and low price. There were no changes in nutritional elements when the electric shock passed through the nutrient solution by stainless steel electrode. The amount of electric current increased with width than thickness of the electrode. The farther the distance between the electrodes was increased the time to reach out the aimed amount of current. The electric shock was applied to Ralstonia solanacearum and Fusarium oxysporum as representative bacteria and also fungi. Any of those pathogens were killed with the percentage of higher than 97% in the condition of 15VDC or 24VDC.

• Journal of information and communication convergence engineering
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• v.4 no.4
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• pp.170-173
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• 2006

Recently, with increasing efficiency of DSC (photo-electrochemical using a nano-particle), The Performance of DSC solar generation system also needs improvement. The approach consists of a Fly-back DC-DC (transfer ratio 1:10) converter to boost the DSC cell voltage to 300VDC. The four switch (MOSFET) inverter is employed to produce 220V, 60Hz AC outputs. High performance, easy manufacturability, lower component count., safety and cost are addressed. Protection and diagnostic features form an important part of the design. Another highlight of the proposed design is the control strategy, which allows the inverter to adapt to the: requirements of the load as well as the power source. A unique aspect of the design is the use of the DSP TMS320LF2406 to control the inverter by current and voltage feed-back. Efficient and smooth control of the: power drawn from the DSC Cell is achieved by controlling the front end DC-DC converter in current mode.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2009.11a
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• pp.289-289
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• 2009

The series hybrid propulsion system in bimodal tram consists of CNG engine, generator, inverter, motor and battery as main components. Among them, battery is very important thing to make a hybrid bimodal tram more efficient in driving. Battery pack is composed of 168 LPB(lithium polymer battery) cells, 650Vdc-300A. LPB should be treated with a good consideration in both temperature and overvoltage. This paper had analyzed and investigated the thermal flow and distribution of LPB module(l4 LPB cells) and Pack in simulated environments by commercial thermal analysis tool.

• Proceedings of the KIPE Conference
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• 1997.07a
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• pp.393-399
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• 1997

Single-phase and three-phase AC to DC power converters are becoming frequently used for high voltage/high power applications such as telecommunications. They often require input/output transformer isolation for safety, a unity input power factor for minimum reactive power, free input harmonic currents fed back to the AC Power distribution system and, finally, high efficiency and high power density for minimum weight and volume. The proposed boost converter for power factor correction (PFC) provides an unity input power factor, low harmonic distortion and high efficiency along with reduced volume and weight. Single-phase 220VAC input/380VDC 1KW output prototype is constructed and experimental results will be verified with those of PSpice simulation.

• Proceedings of the KIPE Conference
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• 2001.10a
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• pp.790-794
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• 2001

In this paper a soft switching ZVT power factor converter using active snubbers is designed to improve efficiency and reduce voltage spike and parasitic ringing. The main switch achieves ZVT and the auxiliary switch performs with ZCS. A 2KW soft switching ZVT converter is designed with switching frequency 100kHz, output voltage 400VDC. Then the designed system is realized and experimental results show that the measured efficiency and power factor are over $97.45\%$ and 0.997 respectively with an input current THD less than $3\%$.

• Proceedings of the KIPE Conference
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• 2007.11a
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• pp.100-102
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• 2007

본 논문에서는 태양광발전용 소프트 스위칭 부스트 컨버터를 제안하였다. 900W급 어레이 태양전지를 사용하였고, 제안된 컨버터가 최대 전력점에서 발전을 하도록 P&O방식의 MPPT 알고리즘을 적용하였다.[1] 제안된 컨버터의 스위칭 소자 시비율은 MPPT 알고리즘의 수행결과에 따라 제어되며, 그 결과 컨버터에서 태양전지 출력전압(132~260V)을 입력받아 380Vdc로 승압한다. 소프트웨어를 활용하여 태양전지 구성과 MPPT 알고리즘 구현하였고 제안된 컨버터를 시뮬레이션 하였다.

• The Transactions of the Korean Institute of Electrical Engineers P
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• v.58 no.4
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• pp.597-601
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• 2009

Green car such as a hybrid electrical vehicle and fuel cell vehicle is developed as a commercial target. UN/ECE/WP29 is developing GTR of HFCV and establishing the regulation and standard of electrical safety by ELSA. The regulation and standard about Electrical safety of vehicle are prescribed in ISO, UN/ECE, FMVSS, Japanese Attachment and so on, in case of insulation resistance is referred to keep more than 100/Vdc, 500/Vac. However, accurate method to measure insulation resistance agreeable to structure of vehicle does not exist now, it is actually that correctness of measurement drops according to the feature of battery and fuel cell stack. In this paper, the method to measure insulation resistance for protection against electrical shock by direct contact or indirect contact in Green Car will be indicated by making a comparison between the insulation measurement in standard of electrical safety and the experiment results for HEV and HFCV.

• Proceedings of the KIPE Conference
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• 2010.07a
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• pp.259-260
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• 2010

새로운 LLC 직렬 공진 컨버터가 본 논문에서 제안된다. 제안된 컨버트는 1차측에 두 개의 공진 탱크를 가진다. 이 두 개의 공진 탱크로 인하여 컨버터의 입력 전류는 풀 브릿지 LLC 직렬 공진 컨버터에서처럼 연속이고, 하프 브릿지 LLC 직렬 공진 컨버터보다 훨신 낮은 입력 전류 리플을 가진다. 또한, 공진 캐패시터 양단 전압이 하프 브릿지 LLC 직렬 공진 컨버터보다 낮아 낮은 전압 정격을 가진 캐패시터를 사용할 수 있다. 이러한 장점들로 인하여 제안된 컨버터는 fuel cell 시스템과 같이 낮은 source 전류 리플과 넓은 입력/출력 동작 범위가 요구되는 응용에 적합하다. 본 논문에서 제안된 컨버터의 동작 원리를 간단히 설명하고, 380Vdc 입력, 24V/10A 출력 프로토타입 컨버터를 통해 그 동작을 검증한다. 그리고, 제안된 컨버터에서 확장된 두 개의 공진 탱크를 가진 LLC 직렬 공진 컨버터들을 소개한다.