• 조명전기설비학회논문지
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• 제22권6호
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• pp.34-43
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• 2008

상태 공간 평균화 모델은 강압형, 승압형 및 승 강압형 DC/DC 컨버터에 적용이 가능하며, 특별한 계산이 필요 없는 높은 정밀도가 증명된 모델이다. 이러한 모델은 전류연속모드(CCM) DC/DC 컨버터에서 확립되었으며, 본 논문에서는 컨버터의 전류연속모드(CCM) 모델로부터 의미 있는 결론을 유도하고자 한다. 본 논문에서는 스위치 평균모델을 이용한 DC/ DC 컨버터의 전류불연속모드(DCM) 모델링 및 임계특성에 관하여 논하였다. 스위치 평균 모델은 전류연속모드(CCM)와 전류불연속모드(DCM) 사이의 DC/DC 컨버터의 경계 조건에 대한 모델로부터 유추할 수 있으며, 시뮬레이션과 실험에 의해서 스위치의 평균 모델의 주파수 응답 특성을 예측할 수 있었다. 본 연구에서는 MOSFET를 사용하여 입력전압 15[V], 출력전압 24[V], 출력전력 24[W]급 시스템을 제작하여 실험하였다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2005년도 춘계학술대회 논문집 전기기기 및 에너지변환시스템부문
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• pp.129-133
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• 2005

This paper discusses DC/DC converter modeling using average model of switch and critical characterist. Average model of switch approach is expended to the modeling of boundary conduction mode DC/DC converters that operate at the boundary between Continuous Conduction Mode(CCM) and Discontinuous Conduction Mode(DCM). Frequency responses predicted by the average model of switch are verified by simulation and experiment.

• 전력전자학회논문지
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• 제10권2호
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• pp.169-176
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• 2005

본 논문에서는 능동 클램프 풀브릿지 Boost 컨버터에 관한 DC 모델링과 AC 모델링 과정에 대하여 기술한다. 동작 원리로부터 이 컨버터의 교류 부분을 등가의 직류 부분으로 바꾸고 반도체 스위치를 재배치하여 개념적인 등가 회로가 유도된다. 유도된 등가회로는 CCM(Continuous conduction mode) Boost 컨버터와 DCM(Discontinuous conduction mode) Buck 컨버터로 표현된다. 유도된 등가회로의 각 스위치 부분을 PWM 스위치 모델로 대체하여 DC 모델 및 AC 모델이 완성된다. 이론적인 DC 및 AC 모델링 결과는 실험이나 SIMPLIS 시뮬레이션을 통해 검증된다.

• 전력전자학회논문지
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• 제24권3호
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• pp.207-214
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• 2019

In this study, discrete-time domain analysis is proposed to investigate the input current of a buck AC/DC light-emitting diode (LED) driver. The buck power factor correction converter can operate in both discontinuous conduction mode (DCM) and continuous conduction mode (CCM). Two discontinuous and two continuous conduction operating modes are possible depending on which event terminates the conduction of the main switch in a switching cycle. All four operating modes are considered in the discrete-time domain analysis. The peak current-mode control with slope compensation is used to design a low-cost AC/DC LED driver. A slope compensation design of the buck AC/DC LED driver is described on the basis of a discrete-time domain analysis. Experimental results are presented to confirm the usefulness of the proposed analysis.

• Journal of Electrical Engineering and Technology
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• 제1권1호
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• pp.63-72
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• 2006

The purpose of this raper is to address the negative impedance instability in DC/DC converters. We present the negative impedance instability of PWM DC/DC converters loaded by constant power loads (CPLs). An approach to design digital controllers for DC/DC converters Is presented. The proposed method, called Power Alignment control technique, is applied to DC/DC step-down choppers operating in continuous conduction or discontinuous conduction modes with CPLs. This approach uses two predefined state variables instead of conventional pulse width modulation (PWM) to regulate the output voltage. A comparator compares actual output voltage with the reference and then switches between the appropriate states. It needs few logic gates and comparators to be implemented thus, making it extremely simple and easy to develop using a low-cost application specific integrated circuit (ASIC) for converters with CPLs. Furthermore, stability of the proposed controllers using the small signal analysis as well as the second theorem of Lyapunov is verified. Finally, simulation and analytical results are presented to describe and verify the proposed technique.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1999년도 하계학술대회 논문집 F
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• pp.2665-2667
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• 1999

This Paper proposes a new toplogy snubber circuit of Full-Bridge DC-DC Converter for reducing conduction losses and snubber circuit heating loss. Using Partial Resonent Soft Switching Method and Clamping, studying on a new snubber circuit for reducing losses that a snubber circuit heating loss in the secondly diode rectification side, a switching losses in the primary side of IGBT inverter and conduction losses in the high frequency insulation transformer. In this paper, we present FB DC-DC converter included a new lossless snubber circuit, and then be analyzed and simulated.

• 한국초전도ㆍ저온공학회논문지
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• 제5권2호
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• pp.30-35
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• 2003

The inductive superconducting fault current limiter (SFCLJ limits the fault current with its dc reactor. To fabricate the optimal dc reactor for inductive SFCL, several design and manufacturing technologies are necessary. In this paper, the manufacturing technology for dc reactor and cryogenic cooling method are described in detail. GM-cryocooler was used enlarge the critical current of dc reactor by cooling down the temperature of dc reactor about 20 K. Moreover, the results of short circuit test were described. Finally, the thermal characteristics of conduction-cooled system were discussed and then, sub-cooled nitrogen system was proposed to enhance the thermal stability of dc reactor.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2018년도 전력전자학술대회
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• pp.430-431
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• 2018

DC-DC 위상천이 풀브릿지 컨버터는 경부하 운용시에 영전압 스위칭이 발생하지 않아 큰 스위칭손실이 발생한다. 경부하에서 위상천이 풀브릿지 컨버터의 낮은 효율을 개선하기 위해 DCM (Discontinuous Conduction Mode) 동작을 이용한다. 본 논문은 경부하에서 위상천이 컨버터의 DCM과 CCM (Continuous Conduction Mode) 동작의 특성 및 도통 손실 절감을 위한 동기 정류기의 제어 방법을 이론적으로 분석하고, 시뮬레이션을 통해 검증하였다.

• 조명전기설비학회논문지
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• 제29권1호
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• pp.80-85
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• 2015

In the issues of interleaved topology which have been in limelight as high power converter, various soft-switching methods are studied to reduce switching losses in high power application. The interleaved ZCT converter has an additional filter inductor to reduce losses of diodes during reverse recovery process. However, additional current conduction modes are occurred by the inductor, we need to analyze switching losses with inductor values on each mode. In this paper, current conduction modes and boundary conditions of interleaved ZCT converter are analyzed. In the conclusion, the minimum of switching losses in converter operation modes is analyzed by calculating switching losses.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2001년도 전력전자학술대회 논문집
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• pp.608-611
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• 2001

This paper is indicating the problems, which are the conduction loss on the high frequency transformer, the protection of rectification diode as the snubber loss and the stress of switching main devices, as be made high current and high speed in the phase-shift switching full-bridge DC-DC converter is used the power supply's main circuit of high capacity. In this paper, to improve those problems, it is proposed that is the resonant circuit auxiliary can be reduced conduction losses and stabilized output control. And, it is constructed prototype of the power supply as the result of computer simulations.