• Journal of Power Electronics
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• v.13 no.3
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• pp.339-348
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• 2013

Multiphase dc-dc converters are widely used in modern power electronics applications due to their advantages over single-phase converters. Such advantages include reduced current stress in both the switching devices and passive elements, reduced output current ripple, and so on. Although the output current ripple of a converter can be significantly reduced by virtue of the interleaving effect, the inductor current ripple cannot be reduced even with the interleaving PWM method. One way to solve this problem is to use a coupled inductor. However, care must be taken in designing the coupled inductor to maximize its performances. In this paper, a detailed analysis of a coupled inductor is conducted and the effect of a coupled inductor on current ripple reduction is investigated extensively. From this analysis, a UU core based coupled inductor structure is proposed to maximize the performance of the coupled inductor.

• The KIPS Transactions:PartB
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• v.11B no.2
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• pp.169-176
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• 2004

This paper presents a new color correction method for color reproduction on LCD-based monitor by means of high-order multilayer neural networks. LCD monitors have nonlinear characteristics from various displaying system components. To overcome these nonlinearities and produce quality image, we need a nonlinear transformer for color coordinate transformation between the LCD monitor coordinates and the input color stimulus values. A high-order multilayer neural network is effectively trained to learn a mapping to determine the required color value of monitors for producing a given color stimulus. From the experimental results, the proposed method is effective in reproducing the color images.

• Proceedings of the KIPE Conference
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• 2017.07a
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• pp.231-232
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• 2017

This paper describes the design and implementation of a 2.5kW (500V, 5A) simmer circuit that maintains the ionization of xenon gas inside the lamp. The design is based on a LCC resonant converter in continuous conduction mode (CCM) with above resonant frequency to take advantage of high power density from using parasitic elements such as the leakage inductance in a power transformer. In addition, since the converter has current source output characteristics, it is suitable for maintaining ionization of the lamp having the negative resistance load characteristic. To verify this converter design, PSpice modeling was performed. Finally, the developed simmer circuit is verified by a resistive load of rated performance and the Ionization maintenance operation of the xenon flash lamp.

• Proceedings of the KIPE Conference
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• 2017.07a
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• pp.138-139
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• 2017

This paper describes the design and implementation of a trigger circuit which can be series connected with main pulse circuit for a xenon flash lamp driver. For generating high voltage, the trigger circuit is designed as an inductive energy storage pulsed power modulator with 2 state step-up circuit consisting of a boost converter and a flyback circuit. In order to guarantee pulse width, a resonant capacitor on the output side of the flyback circuit is designed. This capacitor limits the output voltage to protect the flyback switch. In addition, to protect another power supply of xenon flash lamp driver from trigger pulse, the high voltage transformer which can carry the full current of main pulse is designed. To verify the proposed design, the trigger circuit is developed with the specification of maximum 23 kV, 0.6 J/pulse output and tested with a xenon flash lamp driver consisting of a main pulse circuit and a simmer circuit.

• Proceedings of the KIPE Conference
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• 2017.07a
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• pp.18-19
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• 2017

This paper shows the design of the high voltage capacitor charger which using a modified series parallel resonant converter. The used silicon carbide Metal-Oxide Semiconductor Field Effect Transistor (SiC MOSFET) is proper for the few hundred kHz of high switching frequency to overcome the bulk resonant inductor and snubber capacitors. Furthermore, to increase the amount of the charging current, three phase delta transformer is used as well as the secondary sides are connected in parallel. In this paper, the design procedure of the high voltage capacitor charger is suggested and the output power is verified by the experimental results with the rated resistor load.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2006.12a
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• pp.81-86
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• 2006

In this paper, we designed the cylindrical type light source that had a electromagnetic principle of inductively coupled plasma, and measured its electrical-optical properties. Using the principle of transformer, electrically equivalent circuit of cylindrical type light source was analyzed. According to the parameters of electromagnetic induction which were diameter of coil with 0.3~1.2 mm, number of turns with 4~12 turns, distance with 40~120 mm and RF power with 10~150 W, the electrical and optical properties were measured. When diameter of coil was 0.3 mm, number of turns was 8 turns and distance was 40 mm, the highest brightness of 29,730 $cd/m^2$ was shown with RF power 150 W. The relationship between electromagnetic induction and plasma discharges was shown by mode transition from E-mode to H-mode.

• Proceedings of the KIEE Conference
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• 2005.07c
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• pp.2129-2131
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• 2005

최근 건축물의 대형화로 인해 대용량의 전기설비가 건물의 지하에 설치되고 있지만 전기설비에 대한 특별한 안전 대책 마련이 미비한 실정이다. 본 논문은 지하 구내에 설치된 몰드 변압기가 침수되었을 경우 발생될 수 있는 1차 재해와 2차 재해에 대한 피해를 최소화하기 위한 연구의 기초 단계로 실제 지하구내에 설치된 몰드 변압기를 실험 시편으로 선택하여 거리에 따른 연면 파괴 전압과 전류파형 등을 분석하였다. 분석결과 전극간 간격이 커질수록 연면방전전압이 증가하는 것으로 나타났으며, 방전전류의 피크치도 높아짐을 알 수 있다. 또한, 전극간의 간격이 커질수록 방전시간이 증가하였으며 방전시간의 증가로 인해 절연물의 손상도 증대되었을 것으로 생각된다.

• Proceedings of the KIEE Conference
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• 2005.07c
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• pp.1903-1905
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• 2005

다중 코어를 이용한 대전류용 고효율 변압기 개발을 위해 고주파 손실이 작고, 전기 비저항이 큰 자성재료와 최적의 코어 형상 및 권선 방법에 대한 연구개발과 최종적으로 고효율 다중 코어를 이용한 변압기를 개발하고 전원장치에 적용하여 동작특성을 평가하였다. 최소 손실 온도를 $90^{\circ}C$ 이하로 감소시켜 100 kHz에서 250kW/m3의 낮은 전력손실을 갖는 다중 코어를 이용하여 변압기를 제조하고, 제조된 변압기가 채용된 컨버터의 50A 출력 전류에서 측정된 변압기의 발열특성은 30분 이후 약 $58^{\circ}C$까지 증가하였으며, $30{\sim}80A$의 출력 전류에서 85% 이상의 고효율을 얻었다.

• Proceedings of the KIEE Conference
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• 2004.11a
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• pp.281-284
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• 2004

In Recent, it became necessary to envelope the technology about electrodeless fluorescent lamp according to demand of the electrodeless fluorescent lamp system that used higher efficiency and advantage of long-lifetime. Especially, in the electrodeless fluorescent lamp which used H-mode, efficiency of lamp is decided from matching parameter of antena and inverter So it is of the utmost importance to design antena and inverter. Therefore, this paper used a transformer principle for efficiency rising of electrodeless fluorescent lamp and interpreted an equivalent circuit, used an impedance analyzer in order to confirm a performance enhancement of lamp along design of antenna, and confirmed parameter characteristic of R, L, C, Z, Phase, Q-factor along a change of magnetic flux density. Also, this paper confirmed a luminance characteristic of electrodeless lamp along parameter change with measuring optical characteristic along a change of magnetic flux density.

• Proceedings of the KIEE Conference
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• 2003.07b
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• pp.840-842
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• 2003

저 주파수에서 인덕턴스 단위(H, Henry)는 전기용량의 단위(F, Farad)로부터 Maxwell bridge 또는 LC를 이용한 resonance 방법으로써 유도가 된다. 이중 Maxwell bridge 방법은 국가의 단위표준을 유지하는 연구소 또는 기관에서 가장 많이 사용되는 "product arm" 형의 bridge로 잘 알려져 있다. 개발된 bridge는 ratio-transformer를 전압공급 쪽(source)과 신호검출 쪽(detector)에 사용하여 종래의 Maxwell bridge 평형조절 시 main balance와 Wagner balance의 2개 과정을 진행하던 것과는 달리 main balance, source balance, detector balance의 과정을 진행함으로서 기존 bridge의 불안정한 ground admittance들의 영향에 의해 나타나는 불확도를 완전히 제거하였다. 한편 개발된 bridge는 10 mH, 100 mH를 10 nF의 전기용량표준기와 $1\;k{\Omega}$, $10\;k{\Omega}$의 저항표준기로부터 유도 되도록 제작되었으며. 10 mH의 경우 $400\;Hz{\sim}5\;kHz$의 주파수 영역에서 약 $2.2{\times}10^{-6}$(k=1)의 불확도로 인덕턴스 단위를 유도할 수가 있게 되었다.