• The Transactions of the Korean Institute of Electrical Engineers P
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• v.63 no.4
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• pp.345-350
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• 2014

DC electrolytic capacitor is widely used in the power converter including PWM inverter, switching power supply and PFC Boost converter system because of its large capacitance, small size and low cost. In this paper, basic characteristics of DC electrolytic capacitor vs. frequency is presented and the real-time estimation scheme of ESR and capacitance based on the bandpass filtering is adopted to the single phase boost converter of uninterruptible power supply to diagnose its split dc-link capacitors. The feasibility of this real-time failure prediction monitoring system is verified by the computer simulation of the 5[kW] singe phase PFC half-bridge boost converter.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.18 no.8
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• pp.904-912
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• 2007

In this paper, a broadband 4-way power divider which can be used from 20 MHz to 500 MHz in the V/UHF band is designed using transmission-line transformer and ferrite toroid. A 4:1 impedance transformer is realized and this 4:1 transformer is connected with bridge-type 2-way dividers to form a 4-way rower divider, Insertion loss of about 6.8dB, isolation of less than -20dB, and return loss of less than -15dB in most band of interest are measured.

• The Journal of the Korea institute of electronic communication sciences
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• v.12 no.5
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• pp.845-850
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• 2017

In this thesis, various solutions through four different cases have been sought for an efficiency improvement of the bidirectional LDC for vehicles. For example, it analyzed the reduction factor of the channel resistance and applied the optimum MOSFET applied to the system, and found and improved the efficiency reduction factor of the transformer. As a result, the average efficiency of the developed LDC could be improved from 85% to 94.7%.

• Textile Coloration and Finishing
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• v.18 no.3 s.88
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• pp.1-9
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• 2006

In order to dye polyester/cotton blend fabric by one-bath dyeing process with single disperse dye, a novel hetero-bifunctional bridge compound(DBDCBS) was synthesized and utilized. The DBDCBS was designed to contain two different reactive groups such as ${\alpha},{\beta}$-dibromopropionylamido and dichloro-s-triazinyl groups. The ${\alpha},{\beta}$-dibromopropionylamido group shows considerable reactivity towards amines or amino groups at acidic condition and high temperature. In contrast, the dichloro-s-triazinyl group has reactivity towards hydroxyl groups at alkaline condition and room temperature. In order to examine whether as a bridge the compound could combine dyes containing amino groups with cellulosic substrates, disperse dyes containing amino group were tried to dye the cotton fibers pretreated with the DBDCBS compound. By the results, polyester/cotton blends were dyed by one-bath dyeing process with single disperse dye,1,4-diaminoanthraquinone.

• Journal of KSNVE
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• v.7 no.4
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• pp.589-596
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• 1997

A energy equation for a thin plate and surrounding fluid is derived. The equation essentially determines the relation between internal loss of thin plate, energy of acoustic radiation, and structure intensity. We attempted to use this relation to measure internal loss of thin plate. The significance of this approach is that internal loss at any point of a thin plate can be measured. The quality of this measure is dicated by the accuracy of associated measurement systems such as structure and acoustic intensity measurements. A strain gauge bridge system has been developed to measure structure intensity of thin plate. Its performance is tested by experiments.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.58 no.4
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• pp.756-762
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• 2009

This paper proposes a high efficient Dual Buck Inverter design with a zero voltage switching (ZVS) control technique. The ZVS control is realized by adding a feedback loop circuit which is implemented by simple RS latch and TTL gate. The used load was 200W -Ceramic Metal Halide Lamp. The experimental results show that the proposed Inverter system could avoid the acoustic resonance and achieve high efficiency by Zero Voltage Switching.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.25 no.7
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• pp.32-39
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• 2011

FPS(Filament Power Supply), one of the KSTAR NBI(Neutral Beam Injections) is implemented by full-bridge DC/DC converter. NBI heating device for KSTAR(1.5MW) is developed for heating an ion source of plasma in KSTAR tokmak. The full-bridge DC/DC converter is applied to FPS for isolation with input and output. And FPS is operated with PWM control method which is the most usual method. In this paper, NBI FPS of 4.8kW is simulated by using the PSIM 6.0. And the full-bridge DC/DC converter using IGBTs is fabricated to demonstrate it. The processor DSP 28335 is implemented for digital control.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2001.07a
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• pp.1050-1053
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• 2001

There is great interest in developing magnetoresistance(MR) sensor, using ferromagnetic, electrically non-magnetic conducting and antiferromagnetic films, especially for the use in weak magnetic fields. Here, we report single and Wheatstone-bridge type of MR sensors made in Si(001)/HiO(300$\AA$)/NiFe bilayers. Angular dependence of MR profiles was measured in Si(001)/NiO(300$\AA$)/NiFe(450$\AA$) films as a function of an angle between current and applied field direction, also, linearity was determined. AMR characteristics of single MR sensors was well explained with single domain model. Good linearity in 45$^{\circ}$Wheatstone-bridge type of MR sensors consisting of 4 single MR sensors made in Si(001)/NiO(300$\AA$)/NiFe(450$\AA$) was shown in the range of about $\pm$50 Oe.

• Proceedings of the KIEE Conference
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• 2006.11a
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• pp.66-68
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• 2006

본 논문은 펄스 삽입 보조 회로를 갖고 있는 12-펄스 브리지 4대를 사용한 36-펄스 back-to-back 전압원 컨버터를 제안한다. 제안된 back-to-back 전압원 컨버터는 교류 연계점에서 유효전력과 무효전력의 독립적인 제어가 가능하다. 펄스 수를 증가하는 원리는 이론적 접근을 사용하여 분석되었다. 제안된 시스템의 동작 타당성은 PSCAD/EMTDC 소프트웨어의 시뮬레이션을 통해 검증되었다. 하드웨어 구현 타당성을 검증하기 위해 축소모형을 제작하고 실험에 의해 분석하였다. 제안된 back-to-back 전압원 컨버터는 HVDC와 FACTS 장치로 널리 사용될 수 있다.

• Proceedings of the KIEE Conference
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• 2005.11b
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• pp.6-8
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• 2005

본 논문은 펄스 삽입 보조 회로를 갖고 있는 12-펄스 브리지 4대를 사용한 36-펄스 back-to-back 전압원 컨버터를 제안한다. 제안된 back-to-back 전압원 컨버터는 교류 연계점에서 유효전력과 무효전력의 독립적인 제어가 가능하다. 펄스 수를 증가하는 원리는 이론적 접근을 사용하여 분석되었다. 제안된 시스템의 동작 타당성은 PSCAD/EMTDC 소프트웨어의 시뮬레이션을 통해 검증되었다. 제안된 back-to-back 전압원 컨버터는 HVDC와 FACTS 장치로 널리 사용될 수 있다.