• Proceedings of the KIEE Conference
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• 1997.07f
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• pp.1999-2001
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• 1997

The main two drawbacks of the Sin91e Stage PFC (SS-PFC) converters employing a DCM Boost PFC cell are relatively high voltage stress on the bulk capacitor and the input current harmonic distortion. The high voltage stress on bulk capacitor makes the SS-PFC converter impractical in a universal input application and the input current harmonic distortion lowers power factor. In this paper a selective variable frequency control that reduces the voltage stress on the bulk capacitor and the input current harmonic distortion is proposed. Computer simulation results of the proposed control method are presented.

• Proceedings of the KIPE Conference
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• 2007.11a
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• pp.127-129
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• 2007

절연이 필요하지 않은 응용에서 낮은 전압을 높은 전압으로 승압시키기 위해 무변압기형 고승압 부스트 컨버터가 제안되었다.[1] 이 컨버터는 변압기 없이 6~8배의 실제 승압비를 가지며, 인터리빙 동작으로 입력전류 및 출력전압 리플이 작아지는 장점이 있어 연료전지 응용에 적합하다. 본 논문에서는 기존에 제안된 고승압 무변압기형 부스트 컨버터에 DCM 방식의 영 전압 스위칭을 적용하여 인덕터의 부피를 줄이고 스위치의 턴 온손실과 EMI를 저감하여 고주파의 응용에 적합하도록 하였다. 제안된 컨버터의 영 전압 스위칭의 동작모드 분석을 통해 원리분석을 행하였으며, 실험 및 기존 컨버터와 효율비교를 통하여 타당성을 검증하였다.

• Proceedings of the KIPE Conference
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• 2012.11a
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• pp.81-82
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• 2012

본 논문은 고효율 획득 및 입력전류 리플 저감을 위한 3상 부스트 컨버터의 동작 알고리즘을 제안한다. 입력전압별로 인덕터 전류에 따른 투자율 감소를 고려하여 DCM 및 BCM 동작시의 효율과 입력 전류 리플을 수식적으로 분석한다. 이에 따라 3상 부스트 컨버터를 경계 도통 모드+불연속 도통 모드의 혼합 모드에서 동작시키고 타당성을 실험을 통해 검증한다.

• Proceedings of the KIPE Conference
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• 1999.07a
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• pp.639-642
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• 1999

An integrated zero current switching(ZCS) quasi-resonant converter(QRC) for power factor correction and high efficiency with single switch is proposed in this thesis. Boost integrated circuit operating discontinuous conduction mode(DCM) and QRC are used for power factor correction and reducing switching loss, respectively. A prototype converter has been designed and experimented. At rated condition, the THD in the input current waveform of this prototype has approximately 18%. The efficiency is obtained about 70%, the power factor is about 0.985 as well. Therefore, the proposed converter is suitable for a low power level converter with operating switching frequency above several hundred KHz.

• Proceedings of the KIEE Conference
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• 1997.11a
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• pp.438-440
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• 1997

This paper proposed a partial resonant switching three-phase high power factor converter using a $PRS^2$(Partial Resonant Soft Switch). The proposed converter has a merit of simple controlled circuit because the input current control DCM(Discontinuous Conduction Mode). And it is improve to input power factor that the snubber capacitor's energy regenerate to the AC source side. This topology is reduced a current/voltage stresses of resonant devices in addition to a partial resonant strategy. The result of simulations with the proposed topology included in this paper.

• Proceedings of the KIPE Conference
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• 2006.06a
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• pp.62-64
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• 2006

본 논문에서는 하나의 인덕터만을 사용하여 동작하는 벅부스트 방식의 새로운 배터리 이퀄라이저를 제안하고, 그 동작을 살펴본다. 제안된 배터리 이퀄라이저는 배터리 전압을 센싱할 필요 없이, 벅부스트의 DCM(전류 불연속) 모드를 이용하여 배터리 간의 에너지를 순차적으로 순환시키고 이 과정을 반복하여 배터리 간의 전압을 균등화한다. 즉, 제안된 회로는 전압 센싱을 필요로 하지 않으므로 제어 회로를 단순화 시킬 수 있고, 인덕터를 하나만 사용함으로써 회로 자체의 크기와 가격을 줄일 수 있는 장점을 가진다.

• Proceedings of the KIPE Conference
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• 2012.11a
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• pp.88-90
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• 2012

A study on an integrated single stage AC/DC converter is presented in this paper. The input current can be controlled by the auxiliary winding($L_{aux}$), auxiliary primary winding($N_3$), and the boost inductor($L_B$) which are designed to operate in discontinuous conduction mode(DCM) to reduced the total harmonic distortion(THD) of input current. The auxiliary primary winding($N_3$) is critically selected in order to compress the input capacitor voltage($V_{in}$) as well as to reduce the current stress of the switch(Q). Low total harmonic distortion(THD), low input voltage($V_{in}$) in universal input voltage($V_{AC}$), low current stress at the switching device and high efficiency are the main consideration keys in this design to achieve high performance system with low cost of single stage AC/DC converter. A 30W single stage AC/DC prototype converter is under study.

• Journal of Power Electronics
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• v.15 no.2
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• pp.356-365
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• 2015

This paper presents a new single phase front-end ac-dc bridgeless power factor correction (PFC) rectifier topology. The proposed converter achieves a high efficiency over a wide range of input and output voltages, a high power factor, low line current harmonics and both step up and step down voltage conversions. This topology is based on a non-inverting buck-boost (Zeta) converter. In this approach, the input diode bridge is removed and a maximum of one diode conducts in a complete switching period. This reduces the conduction losses and the thermal stresses on the switches when compare to existing PFC topologies. Inherent power factor correction is achieved by operating the converter in the discontinuous conduction mode (DCM) which leads to a simplified control circuit. The characteristics of the proposed design, principles of operation, steady state operation analysis, and control structure are described in this paper. An experimental prototype has been built to demonstrate the feasibility of the new converter. Simulation and experimental results are provided to verify the improved power quality at the AC mains and the lower conduction losses of the converter.