• 대한전기학회:학술대회논문집
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• 대한전기학회 2004년도 학술대회 논문집 전문대학교육위원
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• pp.76-79
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• 2004

This paper proposed that the conventional three phase AC-DC converter with bulk LC output filter has been widely used in the industry because of simple circuit, low cost and high power factor (90%). One of the biggest drawback of this three phase AC-DC converter is bulk and heavy. This is serious especially for aerospace applications. To solve this problem a new simple three phase AC-DC converter is presented. Operation of the proposed high power factor three phase AC-DC converter is illustrated and verified by PSpice simulation.

• Journal of Advanced Marine Engineering and Technology
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• 제27권6호
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• pp.767-775
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• 2003

This paper considers the method of elimination harmonics in AC/DC converters, There are few practical methods to reduce the harmonics in AC/DC converters, particularly in filter design and control strategy. In this paper, a harmonic elimination methods are proposed, which includes hybrid PWM control strategy. These methods achieve precise output control along with the optimum performance simultaneously. The control method in this paper is developed to eliminate a fixed number of harmonics in AC to DC converter. The higher order harmonics can be easily eliminated by using filter proposed in this paper. The validity of these methods is confirmed experimentally.

• Journal of Power Electronics
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• 제7권4호
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• pp.318-327
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• 2007

The design and performance analysis of a power factor corrected (PFC), single-phase, single switch flyback buck-boost ac-dc converter is carried out for low power battery charging applications. The proposed configuration of the flyback buck-boost ac-dc converter consists of only one switch and operates in discontinuous current mode (DCM), resulting in simplicity in design and manufacturing and reduction in input current total harmonic distortion (THD). The design procedure of the flyback buck-boost ac-dc converter is presented for the battery charging application. To verify and investigate the design and performance, a simulation study of the flyback buck-boost converter in DCM is performed using the PSIM6.0 platform. A laboratory prototype of the proposed single switch flyback buck-boost ac-dc converter is developed and test results are presented to validate the design and developed model of the system.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1994년도 하계학술대회 논문집 A
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• pp.559-561
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• 1994

In this paper a new AC/DC/AC converter in which Soft-Switched-Inductor Module is used, is proposed. This new converter adopts ZVS(Zero-Voltage-Switching) for main switches. Therefore the switching loss is minimized and high frequency operation is possible. Operations principles, short analyses and computer simulation results are presented.

• 전력전자학회:학술대회논문집
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• 전력전자학회 1997년도 전력전자학술대회 논문집
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• pp.135-140
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• 1997

A highly efficient single-phase/three-phase compatible ac-to-dc converter is proposed and analyzed, which includes three identical single-phase both soft-switched dc-to-dc converter with boost converter as a pre-regulator for input power factor correction (PFC). The proposed converter structure provides a cost reduction and easy implementation of compatibility between single-phase 220V and three-phase 220V/380V with their inputs in delta or wye connections.

• 전력전자학회논문지
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• 제10권3호
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• pp.274-281
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• 2005

압전소자를 에너지원으로 사용하여 자립형 전기전자시스템에 에너지를 공급하는 에너지 획득(Harvesting) 개념의 구현을 위하여, 새로운 AC/DC 공진형 펄스 컨버터를 제안한다. 컨버터는 정류기와 DC 컨버터의 2단계로 구성되었으며, AC/DC 변환을 위한 정류기는 MOSFET의 3상한 동작 특성을 이용하여 구현하고, N형 및 P형 MOSFETs을 사용하여 DC/DC 부스트 컨버터를 구현하였다. 제안된 컨버터 시스템의 동작원리 및 동작모드를 스위칭 소자의 기생캐패시턴스를 고려하여 해석하고, 시뮬레이션을 통하여 해석결과를 검증하였다. CMOS IC 칩으로 제작된 본 시스템의 실험 결과는 수십 uW 용량에서 에너지 획득 개념의 구현 가능성을 제시하였다.

• 전력전자학회논문지
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• 제18권3호
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• pp.247-255
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• 2013

In this paper, a soft switching DC-DC converter for AC module type photovoltaic (PV) module integrated converter is proposed. A push-pull converter is suitable for a low voltage PV AC module system because the step-up ratio of a high frequency transformer is high and the number of primary side switches is relatively small. However, the conventional push-pull converters do not have high efficiency because of high switching losses by hard switching and transformer losses (copper and iron losses) by high turns-ratio of the transformer. In the proposed converter, primary side switches are turned on at zero voltage switching (ZCS) condition and turned off at zero current switching (ZVS) condition through parallel resonance between secondary leakage inductance of the transformer and a resonant capacitor. Therefore the proposed push-pull converter decreases the switching loss using soft switching of the primary switches. Also, the turns-ratio of the transformer can be reduced by half using a voltage-doubler of secondary side. The theoretical analysis of the proposed converter is verified by simulation and experimental results.

• 전력전자학회논문지
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• 제9권2호
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• pp.171-177
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• 2004

일반적으로 압전변압기는 고압을 출력하는 전원장치로 사용되고 있으나, 최근 어댑터와 같은 AC/DC 전원장치에 이를 채용하려는 움직임이 활발히 전개되고 있다. AC/DC 컨버터의 소형 경량화론 위해 기존의 권선형 변압기 대신 압전변압기는 AC/DC 컨버터용이 아닌 LCD 백-라이트구동용으로 제작된 압전변압기(piezoelectric transformer)를 사용하여 AC/DC 컨버터의 기본 특성을 고찰하고자 한다. 압전변압기의 재질, 특성 값으로부터 등가회로의 모델링을 수행하고, 이를 시뮬레이션과 실험을 통하여 검증한다.

• 전력전자학회:학술대회논문집
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• 전력전자학회 1998년도 전력전자학술대회 논문집
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• pp.418-422
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• 1998

A new single stage AC/DC converter based on the forward converter is proposed. The proposed converter offers both the high power factor and the direct conversion from ac line to dc output voltage. Also, the proposed converter reduces the diode conduction loss, so improves the overall efficiency of the converter, compared with other alternatives. The principles of operation and the simulation results of the proposed converter are presented. A 100 W prototype was built and tested to show the potential of applications of the proposed converter.

• 전력전자학회논문지
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• 제3권1호
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• pp.70-76
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• 1998

본 연구에서는 고역률로 동작하면서 입력전류의 고조파성분을 크게 억제시키는 AC/DC 스위치모드 콘버어터의 기본적인 동작을 해석하고, 이를 기초로 수학적모델을 도출하여 전체 회로의 동작을 나타내는 모의실험방법을 제시한다. 제시된 모의실험모델로써 필터나 부스트인덕터 등의 회로구성요소의 정격을 결정하거나 정상 및 고장 운전조건하에서의 동작을 해석할 수 있음으로써 전체회로의 설계기준을 정할 수 있을 것이다. 모의실험결과가 실제 실험결과와 거의 일치함을 보임으로써 제시한 모의실험모델의 타당성을 입증하였다.