• 전력전자학회:학술대회논문집
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• 전력전자학회 1998년도 Proceedings ICPE 98 1998 International Conference on Power Electronics
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• pp.687-693
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• 1998

An improved zero voltage and zero current switching (ZVZCS) full bridge (FB) PWM converter is proposed to solve the problems of the previously presented ZVACS-FB-PWM converter with secondary active clamp such as narrow ZVS range of leading-leg switches [6]. By adding an auxiliary inductor in between the leading-leg and separated input source voltages, the ZVS of leading leg switches can be extended to the whole line and load ranges, which eliminates unwanted hard switching of clamp switch and simplifies its control. The principle of operation is explained and analyzed. The features and design considerations of the proposed converter are also illustrated and verified on a 3 kW, 100 KHz IGBT based experimental circuit.

• 조명전기설비학회논문지
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• 제29권5호
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• pp.57-64
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• 2015

This paper proposes a new switching algorithm for an controllable clamp snubber to improve the efficiency of a fly-back converter system. This system uses an controllable clamp method for the snubber circuit for the efficiency and reliability of the system. However, the active clamp snubber circuit has the disadvantage that system efficiency is decreased by switch operating time because of heat loss in resonance between the snubber capacitor and leakage inductance. To address this, this paper proposes a new switching algorithm. The proposed algorithm is a technique to reduce power consumption by reducing the resonance of the snubber switch operation time. Also, the snubber switch is operated at zero voltage switching by turning on the snubber switch before main switch turn-off. Experimental results are presented to show the validity of the proposed controllable clamp control algorithm.

• 반도체디스플레이기술학회지
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• 제17권3호
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• pp.21-26
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• 2018

In this paper, the switching characteristics of the active clamp type flyback converter, which is deemed suitable for the miniaturization of the external power supply for home appliance, were analyzed and the process of reducing the switching loss was explained. The active clamp type flyback converter operating in the DCM has confirmed that the surge voltage of the main switch does not occur and the turn-off / on loss of the switch do not occur in principle. Also, in the case of the switch for synchronous rectifier, it was showed that the switch current showed half-wave rectified sinusoidal characteristic, and the switching loss was reduced. The switching characteristics of the experimental results gathered from 120 W class prototype were compared with the theoretical waveform in the steady-state and it was confirmed that the power conversion efficiency of the active clamp type flyback converter was maintained high due to the reduction of the switching loss.

• 전기전자학회논문지
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• 제13권1호
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• pp.87-93
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• 2009

본 논문에서는 높은 홀딩 전압을 갖는 사이리스터(SCR; Silicon Controlled Rectifier)구조에 기반 한 새로운 구조의 ESD(Electro-Static Discharge) 보호 소자를 제안하였다. 홀딩전압은 애노드단을 감싸고 있는 n-well에 p+ 캐소드를 확장시키고, 캐소드단을 n-well로 추가함으로써 홀딩전압을 증가시킬 수 있다. 제안된 소자는 높은 홀딩전압 특성으로 높은 래치업 면역성을 갖는다. 본 연구에서 제안된 소자의 전기적 특성, 온도특성, ESD 감내특성을 확인하기 위하여 TCAD 시뮬레이션 툴을 이용하여 시뮬레이션을 수행하였다. 시뮬레이션 결과 제안된 소자는 10.5V의 트리거 전압과 3.6V의 홀딩전압을 갖는다. 그리고 추가적인 n-well과 확장된 p+의 사이즈 변화로 4V이상의 홀딩전압을 갖는 것을 확인하였다.

• 전기전자학회논문지
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• 제17권2호
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• pp.208-213
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• 2013

본 논문에서는 파워클램프용 높은 홀딩 전압을 갖는 사이리스터(SCR: Silicon Controlled Rectifier)구조에 기반한 새로운 구조의 ESD 보호회로를 제안하였다. 제안된 보호회로는 기존의 SCR 구조의 p-well과 n-well에 floating p+, n+를 삽입하여 홀딩 전압을 증가 시켰다. 제안된 보호회로는 높은 홀딩전압 특성으로 높은 래치업 면역성을 갖는다. 본 연구에서 제안된 보호회로의 전기적 특성 및 ESD 감내특성을 확인하기 위해 Synopsys사의 TCAD Tool을 이용하여 시뮬레이션을 수행하였다. 시뮬레이션 결과 제안된 보호회로는 기존 SCR 기반 ESD 보호회로보다 약 4.98 V의 높은 홀딩전압과 추가적인 floating 영역의 사이즈 변화로 최대 13.26 V의 홀딩전압을 갖는 것을 확인하였다. 또한 기존 SCR 기반 보호회로와 동일한 수준의 감내특성을 갖는 것으로 확인되었다.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2008년도 하계학술대회 논문집
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• pp.400-402
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• 2008

A new interleaved forward converter, adopting series-input parallel-output structure with a common transformer reset circuit, is proposed in this paper. Series-input structure distributes the voltage stress on switches, which makes it suitable for high input voltage application. Paralleling output stage with an interleaving technique enables the circuit handle large output current and reduces filter size. In addition, since two forward converters share one active-clamp circuit for the transformer reset, its primary structure is simplified. All these features make the proposed converter promising for high input voltage applications with high efficiency and simple structure.

• 대한전기학회논문지:전기기기및에너지변환시스템부문B
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• 제49권8호
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• pp.551-556
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• 2000

A zero-voltage-switching(ZVS) programmable power supply employing the ZVS active clamp forward converter is suggested. Through the analysis on operation region of the supply, the constant power region and the maximum current limit region are clearly identified. Furthermore, the duty ratio range corresponding to the variation range of the output voltages and the control scheme at the minimum duty ration region are presented. Finally, in order to vefity the validity of the operation for the proposed power supply, experimental evaluation results obtained on an 1kW prototype power supply for the 198~242VAC input voltage range(220VAC$\pm$10%), the 0~25V output voltage range, and the 100kHz switching frequency are presented.

• 전력전자학회논문지
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• 제18권5호
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• pp.477-484
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• 2013

This paper proposes a novel switching method of active clamp snubber for efficiency improvement of PV module integrated converter(MIC) system. Recently, MIC solar system is researched about the efficiency and safety. PV MIC system is used active clamp method of snubber circuit for the price and reliability of the system. But active clamp snubber circuit has the disadvantage that system efficiency is decreased for switch operating time because of heat loss of resonant between snubber capacitor and leakage inductance. To solve this problem, this paper proposes a novel switching method of the active clamp. The proposed method is a technique to reduce power consumption by reducing the resonance of the snubber switch operation time and through simulations and experiments proved the validity.

• The Korean Journal of Physiology
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• 제18권1호
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• pp.9-17
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• 1984

The second inward current $(i_{si})$ was studied by the two microelectrode voltage clamp technique in the sino-atrial node of the rabbit. The slow component $(i_{si,2})$ of the second inward current was sometimes identified and $i_{si}$ behaved as if it were a mixture of two currents. We analysed the $(i_{si,2})$ in relation to membrane potential and frequency of voltage clamp pulses. 1) Membrane was held at -40mV which was usually found to be zero current level. When depolarizing pulses were applied, the slow inward current $(i_{si})$ was activated. 2) It was shown that there are three categories of the $i_{si}$ activation by the low level of depolarizing clamp pulses. Moderately fast inward current with single component was developed in most cases in the presence of tetrodotoxin(TTX). But sometimes there was two separate components of $i_{si}$ activation in the peak level and the time course. Thirdly the only slow component of $i_{si}$ was found in rare cases. 3) The activation of $(i_{si,2})$ was dependent upon membrane potential. The $i_{si}$ shows two separate peaks during clamp depolarizations and higher clamp pulses lead to fusion of the peaks. 4) The $i_{si,2}$ activation showed that it decreased with repetitive clamp pulses and it was more evident in higher frequencies(2Hz)(negative staircase).

• 전력전자학회논문지
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• 제19권1호
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• pp.23-30
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• 2014

This paper proposes a single power-conversion ac-dc converter with a dc-link capacitor-less and high power factor. The proposed converter is derived by integrating a full-bridge diode rectifier and a series-resonant active-clamp dc-dc converter. To obtain a high power factor without a power factor correction circuit, this paper proposes a suitable control algorithm for the proposed converter. The proposed converter provides single power-conversion by using the proposed control algorithm for both power factor correction and output control. Also, the active-clamp circuit clamps the surge voltage of switches and recycles the energy stored in the leakage inductance of the transformer. Moreover, it provides zero-voltage turn-on switching of the switches. Also, a series-resonant circuit of the output-voltage doubler removes the reverse-recovery problem of the output diodes. The proposed converter provides maximum power factor of 0.995 and maximum efficiency of 95.1% at the full-load. The operation principle of the converter is analyzed and verified. Experimental results for a 400W ac-dc converter at a constant switching frequency of 50kHz are obtained to show the performance of the proposed converter.