• Proceedings of the KIPE Conference
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• 2015.07a
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• pp.243-244
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• 2015

본 논문에서는 새로운 방식의 무손실 스너버를 적용한 역률 개선회로를 제안한다. 기존 역률 개선회로의 경우 구동 주파수에 비례하여 스위칭 손실이 증가하고, 연속전류모드 구동 시 출력 다이오드의 역회복 특성 문제가 존재하였다. 하지만 제안된 방식 경우 소프트 스위칭이 가능하기 때문에 고주파수 구동에 유리하며, 출력 다이오드의 역회복 특성 문제를 해결할 수 있다. 이러한 장점으로 인하여 스위칭 주파수 상향에 유리하며 스위칭 주파수 증가 시 리액티브 소자의 부피를 대폭 저감할 수 있기 때문에 고밀도 전원회로 구현 시 유리한 장점을 갖는다. 본 논문에서 제안한 방식을 250W급 시제품 제작을 통해 실험적 결과를 제시하여 이론적 타당성을 검증한다.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.9 no.2
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• pp.295-300
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• 2005

In this paper we have designed a two-stage Class I power amplifier operated at 2.4CHz for Class-1 Bluetooth application. The power amplifier employs class-I topology to exploit its soft-switching property for high efficiency. The latch-structured pre-amplifier with amplifiers makes its output signal as sharp as possible for soft switching of the next power amplifier. It improves the overall efficiency of the proposed power amplifier. It shows 65.8$\%$ PAE, 20dB power gain and 20dBm output power.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.19 no.8
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• pp.102-108
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• 2005

In this paper, authors propose novel boost AC-DC converter of high power factor and analyze for waveform and harmonics component of input current. The input current waveform in the proposed converter is got to be a sinusoidal form of discontinuous pulse in proportion to magnitude of at input voltage under the constant duty cycle switching. Therefore, input power factor is nearly unity. Particularly, the stored energy of loss-less snubber capacitor is recovered with input side and increases input current from resonant operation. The result is that input power factor of the proposed converter is higher than that of conventional converter of high power factor. Some simulative results on computer and experimental results are included to confirm the validity of the analytical results.

• Proceedings of the KIPE Conference
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• 2008.10a
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• pp.25-28
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• 2008

본연구는 부스트형 대기압 플라즈마 전원장치에 대한 연구로서 부스트형 전원장치는 플라즈마의 발생을 원활하게 하기위해 커패시터로 모델링되는 부하단에 인가되는 전압을 직접 제어하는 방식을 의미한다. 기존의 정현파 공진형 전원장치는 PWM기법을 이용하여 펄스의 폭을 증감하는 방식으로 전압의 크기를 제어하지만 이 방식은 별도의 공진회로를 이용하여 공진을 일으킨 다음 이를 부하에 인가하는 방식으로 구성되기 때문에 속응성이 떨어지고 균일한 플라즈마를 발생시키기 어렵다. 부스트형 전원장치는 별도의 부스트 컨버터로 직류전압을 제어하여 부하단에 입력되는 전압을 직접 제어하므로 매우 균일한 플라즈마를 발생시킬 수 있는 이점이 있으나 별도의 부스트용 스위치가 필요하고 이로 인한 효율의 감소 및 사이즈의 증가가 되는 문제점이 생긴다. 본 연구에서는 커패시터로 모델링되는 부하를 이용하여 직접 공진을 일으키고 공진된 부하 전압을 직접 부스트 스위치에 인가시키는 방식으로 부스트용 스위치의 소프트 스위칭이 가능한 새로운 방식을 개발하였다. 개발된 방식에서는 부스트용 스위치가 ZCS형태로 켜지고 ZVS형태로 꺼지는 특성을 갖게 되므로 별도의 추가 회로 없이도 획기적인 효율 증가와 방열판 사이즈의 감소로 인한 제품의 경량화가 가능한 장점이 있다. 또한, DC링크 커패시터의 최소화로 인하여 부하단의 아크 문제가 자동적으로 해결되는 장점도 있다. 제안된 제어 방식은 시뮬레이션과 실험으로 그 타당성을 입증하였다.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.43 no.8 s.350
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• pp.69-76
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• 2006

In this paper, we propose blind adaptation strategies for decision feedback equalizer (DFE) optimizing the operation mode between acquisitionand tracking modes based on adjustable soft decision devices. The proposed schemes select an optimal soft decision device to generate feedback samples for the DFE at a given noise to signal ratio, and apply corresponding adaptation rules which combine a blind infinite impulse response (IIR) filtering adaptation and the decision-directed least mean squared (DD-LMS) DFE adaptation. These adaptation approaches attempt to achieve not only smooth transition between acquisition and tracking of DFE but also mitigation of error propagation.

• Electronics and Telecommunications Trends
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• v.16 no.5 s.71
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• pp.1-11
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• 2001

본 논문은 대형 ATM 스위칭 시스템인 HANbit ACE2000 시스템의 소프트웨어를 개발하고 시스템 개발 시 필요한 각종 소프트웨어 컴포넌트들을 효율적으로 개발 및 등록, 관리하기 위해 도입된 미들웨어와 객체지향 설계 개념을 이용한 UML을 적용하여 프로그램의 에러를 줄이고 개발자와 관리자간의 규약에 의한 체계적인 종합개발 및 관리 방안에 대한 특성과 각 기능에 대해 살펴본다. 또 이것을 활용하여 ACE2000 시스템에서 개발, 등록 관리되고 있는 소프트웨어에 대해 소개함으로써 대형 시스템 개발에 유용하게 이용되도록 한다. 특히, 대형 시스템 개발에 적용된 개발체계 및 개발환경을 언급함으로써 유사 프로젝트 수행 시 추가 개선사항이나 개발환경 개선에 참고가 되도록 하였다.

• Journal of Energy Engineering
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• v.15 no.3 s.47
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• pp.181-187
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• 2006

This paper is proposed to a solar cell power system used in fire emergency equipment. Also it is designed with a high efficiency power converter in order to increase efficiency of power system. The controlling switches used in DC-DC booster chopper and DC-AC inverter are operated with soft switching, which is applied to resonant circuit method to reduce switching loss. The result is that the system gets to high efficiency. In this paper, A detection circuit of maximum power point of solar cell is described in this paper. And the performance evaluations for the photovoltaic power system of high efficiency are examined by the analysis of a new tracking controller with a maximum power $P_{max}$ detection of solar cell.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.27 no.11C
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• pp.1152-1157
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• 2002

In this paper, a detailed procedure of development for an AAL2 processor widely used in voice gateway application is introduced. The processor supports CPS and SSCS with voice service and framed mode data service. It provides 4 ATM virtual connections, which include 1020 AAL2 channels. The processor has one UTOPIA Level 1 interface for an ATM cell interface and 4 TDM ports for a voice channel interface. The TDM ports carry PCM/ADPCM voice streams. Most AAL2 processors are implemented as software, or hardware and software, so its latency is large. But this processor has very low latency as to CPS and SSCS because all of them are implemented in hardware. Also, it allows not only loopback and switching of CPS packets, but loopback and switching of TDM channels. The key feature is that the internal structure of the CPS and SSCS in this processor seems like as each software function, so they are called whenever they are required. In addition, they are reusable for another design and are scalable for more channels.

• The Journal of the Korea Contents Association
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• v.9 no.6
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• pp.256-265
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• 2009

Laser output becomes output adjustment from 20 w to 100 w consecutively and time of exposure is available adjustment through water plant in 0.01 seconds. Pulse action can intercept laser beam periodically and supermarket pulse 0.1 $\sim$ between 1ms discharge consist and momentary laser output is increased to 5 $\sim$ 10. Specially, that must remove malignancy cell in womb nine escarps in the case of uterine cancer first of all stability of tube output about pulse by weight very, stable soft switching action area is defined without high frequency transformer leakage inductance ($L_1$) increase and additional series inductor insertion to converter the first main circuit securing zero voltage and marks of switching action in this research specially, because circulation current path of inductor ($L_f$) current is intercepted, converter the first main circuit switching component and spiritual enlightenment damage of high frequency transformer take decreasing greatly and high frequency the second stoppage department ($D_5,\;D_6$) becomes soft switching, and also, switching damage absorption quantity characteristic that can come to life again as subordinate have, and to become tube stabilization design and result that manufacture and experiment, brought result that improve of 10% than existing equipment, and if supplement as systematic late, it becomes thought to get into superior result.

• The Transactions of the Korean Institute of Power Electronics
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• v.11 no.2
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• pp.149-158
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• 2006

A soft-switching scheme for the PWM boost converter, ZCT (Zero current transition : ZCT) boost converter Is newly proposed to obtain the desirable features of both the conventional BWM boost and resonant converters such as easy of control, reduced switching losses and stresses, an4 low EMI. In order to achieve the soft-switching action, the proposed scheme employs an auxiliary circuit, which is added to the conventional boost converter and used to achieve soft-switching for both the main switch and the output diode while not incurring any additional losses due to auxiliary circuit itself. The basic operations, in this paper, we discussed and design guidelines are presented. Through a 100kHz, 60-W prototype, the usefulness of the proposed scheme is verified.