• Proceedings of the KIPE Conference
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• 전력전자학회 2007년도 하계학술대회 논문집
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• pp.182-184
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• 2007

본 논문에서는 2단 AC/DC 컨버터와 단일단 AC/DC 컨버터가 가지고 있는 단점들을 개선 할 수 있는 새로운 준 단일 전력단 컨버터를 제안한다. DC/DC 단으로는 동적 특성이 좋은 LLC 컨버터를 채용하여 별도의 제어기 없이 고정 주파수 및 고정 Duty(50%) 발생기에 의해 Open Loop로 구동 시킴으로써 저가격화 및 고효율화를 획득 할 수 있다. 또한 역률개선단은 Boost 컨버터를 채용하고 간단한 제어기 1개를 사용하여 역률 개선과 동시에 DC/DC 단의 최종출력을 제어한다. 기존 2단 PFC 컨버터와는 다르게 PFC 링크전압을 Feedback 하지 않고 DC/DC 단의 최종 출력을 Feedback 하여 제어한다. 제안된 회로의 우수성 검증을 위해 600W급 시작품을 이용한 실험 결과를 제시한다.

• The Transactions of the Korean Institute of Power Electronics
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• 제23권1호
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• pp.59-65
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• 2018

A new single-stage flyback power converter with PFC for electrolytic capacitor-less LED driver is proposed in this study. This method minimizes the peak-to-average ratio of the LED driving pulsating current by adding the LED driving current near the LED current valley area, as well as the third harmonic component injection into the input current. The reduced peak current value of the LED drive current minimizes the thermal stress of the LED itself, thereby increasing the reliability of the LED, as well as achieving a long lifetime. Simulation and experimental results show the usefulness of the proposed topology.

• Proceedings of the KIPE Conference
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• 전력전자학회 2016년도 전력전자학술대회 논문집
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• pp.197-198
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• 2016

본 논문에서는 전기자동차용 충전기를 위한 단일단 소프트스위칭 AC-DC 컨버터를 제안한다. 제안하는 컨버터는 두 대의 인터리빙 컨버터에 저손실 스위칭기법을 적용하여 변압기의 저주파 성분을 제거하여 코어부피를 최적화할 수 있을 뿐만 아니라 스위치의 도통손실 및 스위칭 손실을 감소시킬 수 있다. 또한 배터리에 저주파 리플이 허용되는 경우에는 필름 커패시터만을 사용하여 정현파 충전을 함으로써 시스템의 높은 내구성 및 소형화를 달성 할 수 있다. 3.3kW급 시작품을 통해 본 논문의 타당성을 검증하였다.

• Proceedings of the KIPE Conference
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• 전력전자학회 2016년도 추계학술대회 논문집
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• pp.25-26
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• 2016

본 논문에서는 전기자동차용 충전기를 위한 전해커패시터가 없는 단일단 인터리브드 토템폴 소프트스위칭 AC-DC 컨버터를 제안한다. 제안하는 단일단 충전기는 토템폴 구조에 인터리빙 회로를 적용하여 소자의 수를 최소화하였으며 넓은 전압 및 부하영역에서 스위치의 ZVS 턴 온 및 다이오드의 ZCS 턴 오프를 성취하여 고효율을 달성할 수 있다. 또한 CCM 동작으로 인해 입력필터가 작고 스위치의 도통손실을 감소시킬 수 있으며 전해커패시터를 제거하고 필름커패시터를 사용하여 높은 전력밀도와 내구성을 만족한다. 제안하는 전기자동차용 충전기의 동작원리를 제시하고 시작품을 통해 본 논문의 타당성을 검증하였다.

• Proceedings of the KIPE Conference
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• 전력전자학회 2015년도 추계학술대회 논문집
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• pp.87-88
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• 2015

본 논문에서는 전기자동차용 충전기를 위한 전해커패시터가 없는 단일단 브리지리스 AC-DC 컨버터를 제안한다. 제안하는 컨버터는 넓은 동작영역에서 스위치의 ZVS 턴온 및 다이오드의 ZCS 턴오프를 성취한다. 또한 시스템 수명에 장애가 되는 전해커패시터를 사용하지 않고, 필름커패시터를 사용함으로써 높은 내구성을 달성할 수 있으며 또한 제안하는 결선 방식으로 변압기에 저주파리플이 상쇄되어 코어부피를 최적화하여 시스템 소형화를 달성할 수 있다. 본 논문에서는 제안하는 컨버터의 동작원리를 제시하고 시작품을 통해 본 논문의 타당성을 검증하였다.

• The Transactions of the Korean Institute of Power Electronics
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• 제5권5호
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• pp.508-514
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• 2000

A single-stage power factor correction AC/DC converter with a simple link voltage suppressing circuit (LVSC) for the universal line application is proposed. Using this simple circuit, a low link voltage can be realized without deadbands at line zero-crossings. The proposed converter is analyzed and a prototype converter with 5V, 12A output is implemented to verify the performance. The experimental results show that the link voltage stress and efficiency are about 447V and 81%, respectively.

• The Transactions of the Korean Institute of Power Electronics
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• 제2권3호
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• pp.26-36
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• 1997

An single stage AC/DC converter based on half bridge topology suitable for low power level applications is proposed. The proposed converter has high power factor, low harmonic distortion, and tight output regulations. Asymmetrical control and synchronous rectification are adopted to reduce the switching loss and rectification loss, respectively. The modelling employing average modelling method and detailed analysis are performed to derive the design equations. According to these design equations, a prototype converter has been designed and experimented. This prototype meets the IEC 555-2 regulations with near unity power factor and high efficiency.

• Journal of Power Electronics
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• 제16권1호
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• pp.153-162
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• 2016

Given their structural arrangement, photovoltaic (PV) modules exhibit parasitic capacitance, which creates a path for high-frequency current during zero-state switching of the converter in transformerless systems. This current has to be limited to ensure safety and electromagnetic compatibility. Many solutions that can minimize or completely avoid this phenomenon, are available. However, most of these solutions are patented because they rely on specific and often complex converter topologies. This study aims to solve this problem by introducing a solution based on a classic converter topology with an appropriate modulation technique and passive filtering. A 5.5 kW single-phase residential PV system that consists of DC-DC boost stage and DC-AC H-bridge converter is considered. Control schemes for both converter stages are presented. An overview of existing modulation techniques for H-bridge converter is provided, and a modification of hybrid modulation is proposed. A system prototype is built for the experimental verification. As shown in the study, with simple filtering and proper selection of switching states, achieving low leakage current level is possible while maintaining high converter efficiency and required energy quality.

• Journal of Power Electronics
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• 제16권4호
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• pp.1288-1297
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• 2016

This study proposes a single-stage light-emitting diode (LED) tube lamp driver with input-current shaping for T8/T10-type fluorescent lamp replacements. The proposed AC-DC LED driver integrates a dual-boost converter with coupled inductors and a half-bridge series-resonant converter with a bridge rectifier into a single-stage power conversion topology. This paper presents the operational principles and design considerations for one T8-type 18 W-rated LED tube lamp with line input voltages ranging from 100 V rms to 120 V rms. Experimental results for the prototype driver show that the highest power factor (PF = 0.988), lowest input current total harmonic distortion (THD = 7.22%), and highest circuit efficiency (η = 92.42%) are obtained at an input voltage of 120 V. Hence, the proposed driver is feasible for use in energy-efficient indoor lighting applications.

• The Transactions of The Korean Institute of Electrical Engineers
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• 제61권11호
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• pp.1625-1633
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• 2012

In the lighting industry, a Lighting Emitting Diode (LED) is increasingly used because of many advantages and a eco-friendly product comparing with the conventional lighting. However, the LED lighting has to include various AC/DC converters because the direct current is used for the LED lighting. Among a lot of power converters, the flyback converter is widely used for the LED lighting and includes some electrolytic capacitors for the voltage regulation. But the electrolytic capacitor has shorter lifetime than the LED element. It makes the expected life-time of the converter having the electrolytic capacitor shorter than the LED element. This paper proposes the single-stage PFC flyback converter without electrolytic capacitors. To verify the performance of the proposed converter, simulated and experimental works were carried out.