• 대한전기학회:학술대회논문집
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• 대한전기학회 1999년도 하계학술대회 논문집 F
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• pp.2695-2697
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• 1999

A new three-phase voltage-fed inverter using partial resonant converter with high power factor and high efficiency is proposed. The proposed Flyback converter is constructed by using a resonant network in parallel with the switch of the conventional converter. The devices are switched zero voltage or zero current eliminating the switching loss. This paper introduces elimination of harmonics compared with conventional SPWM inverter and three-phase voltage-fed inverter using Flyback converter.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2005년도 전력전자학술대회 논문집
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• pp.357-359
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• 2005

In this paper, a new SEPIC-Flyback converter with a single transformer has been proposed, which is suitable for a fuel cell based power generation system. The proposed converter is superposition of sepic and flyback converter mode. It has outstanding high boosting output voltage, component utilization and high efficiency characteristics under the inherently severe low output voltage of the fuel cell generator. The proposed converter for a full cell generator is described and verified by simulation and experimental result that make used of the Polymer Electrolyte Membrane Fuel Cell(PEMFC) Generator.

• 전력전자학회논문지
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• 제17권1호
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• pp.67-76
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• 2012

This paper proposes the aggregated modeling and control of integated boost-flyback converter (IBFC) for understanding of dynamics characteristic and designing of relevant controller. The basic concept of the aggregated modeling is to substitute the boost or the flyback converter with an equivalent current source. Since each converter with equivalent current source corresponds to the basic boost and flyback converters, the overall mathematical process is significantly simplified for the modeling. Afterwards each result is combined to construct the complete model of the IBFC, and the relevant controller is designed through the achieved small-signal model. Simulation and experimental results show excellent agreement with the theoretical expectations.

• 전력전자학회논문지
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• 제11권6호
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• pp.529-534
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• 2006

요즘 많은 연구자들이 전력변환회로의 효율을 올리는데 이전보다 훨씬 많은 관심을 기울이고 있다. 플라이백 컨버터에서 RCD 스너버의 저항은 누설인덕터에 저장된 에너지를 소모한다. 이는 전체 시스템 효율을 감소시키는 역할을 한다. 그래서 이 논문에서는 효율을 향상시키기 위해서 플라이백 컨버터의 새로운 에너지 회복회로를 제안한다. 제안된 회로의 동작원리를 자세히 설명한다. 그리고 이를 모의실험 및 실험을 통해서 확인한다.

• 전기학회논문지P
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• 제65권4호
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• pp.285-291
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• 2016

A light-emitting diode (LED) has been increasingly applied to various industrial fields and general lightings because of its high efficiency, low power consumption, environment-friendly characteristic and long lifetime. To drive the LED lighting, a power converter with the constant output current is needed. Among many power converters, the flyback converter is chosen by many converter designers due to high power density, structural simplicity, and miniaturization. In this converter, an electrolytic capacitor is generally chosen for the stabilization of the DC voltage because of having the large capacitance and the low price. However, the disadvantages are the short expected life time and 120Hz ripple currents on the converter output node. In this paper, a single-stage dimmable PFC DCM flyback converter without the electrolytic capacitor is proposed to prolong the lifetime of the LED driver. For the long lifetime of the converter, the polyester film capacitor with the small capacitance is substituted for the electrolytic capacitor on the output node and an LC resonant filter is added to damp 120Hz ripple current. The proposed converter is verified through the simulation and the experimental works.

• 전기학회논문지P
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• 제65권3호
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• pp.158-164
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• 2016

In this paper, a high frequency flyback type zero voltage soft switching PWM DC-DC converter using IGBTs is proposed. Effective applications for this power converter can be found in auxiliary power supplies of rolling stock transportation and electric vehicles. This power converter is basically composed of active power switches and a flyback high frequency transformer. In addition to these, passive lossless snubbers with power regeneration loops for energy recovery, consisting of a three winding auxiliary high frequency transformer, auxiliary capacitors and diodes are introduced to achieve zero voltage soft switching from light to full load conditions. Furthermore, this power converter has some advantages such as low cost circuit configuration, simple control scheme and high efficiency. Its operating principle is described and to determine circuit parameters, some practical design considerations are discussed. The effectiveness of the proposed power converter is evaluated and compared with the hard switching PWM DC-DC converter from an experimental point of view and the comparative electromagnetic conduction and radiation noise characteristics of both DC-DC power converter circuits are also depicted.

• 전기전자학회논문지
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• 제23권2호
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• pp.407-412
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• 2019

LED 조명은 많은 장점으로 인하여 다양한 분야에서 사용이 점점 증가되고 있다. 특히 플라이백 컨버터는 전력밀도와 구조적 단순성 그리고 소형화가 가능하여 많은 컨버터 설계자들에게 LED 조명용 드라이버로 선택되어지고 있다. 또한 컨버터의 직류출력전압을 안정화하기 위하여 저렴한 가격의 정전용량이 큰 전해커패시터를 사용한다. 전해 커패시터를 갖는 전력변환기를 LED 조명시스템에 적용할 경우에 일반적으로 LED의 수명이 짧아지는 결과를 가져온다. 제안하는 논문은 LED 수명연장과 컨버터 출력리플을 감소시키기 위하여 소용량의 필름 커패시터 LC 필터를 컨버터에 적용하였다.

• Journal of Power Electronics
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• 제19권1호
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• pp.190-200
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• 2019

The flyback converter, which can be regarded as a nonlinear time-varying system, has complex dynamics and nonlinear behaviors. These phenomena can affect the stability of the converter. To simplify the modeling process and retain the information of the output capacitor branch, a special sampled-data model of a peak current-mode (PCM) controlled flyback converter is established in this paper. Based on this, its dynamic behaviors are analyzed, which provides guidance for designing the circuit parameters of the converter. With the critical stability boundary equation derived by a Jacobian matrix, the stable operation range with a varied output capacitor, proportional coefficient of error the amplifier, input voltage, reference voltage and slope of the compensation ramp of a PCM controlled flyback converter are investigated in detail. Research results show that the duty ratio should be less than 0.5 for a PCM controlled flyback converter without ramp compensation to operate in a stable state. The stability regions in the parameter space between the output capacitor and the proportional coefficient of the error amplifier are enlarged by increasing the input voltage or by decreasing the reference voltage. Furthermore, the ramp compensation also can extend to the stable region. Finally, time-domain simulations and experimental results are presented to verify the theoretical analysis results.

• Journal of Power Electronics
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• 제12권5호
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• pp.708-714
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• 2012

This paper presents a new interleaved pulse-width modulation (PWM) boost-flyback converter to achieve power factor correction (PFC) and regulate DC bus voltage. The adopted boost-flyback converter has a high voltage conversion ratio to overcome the limit of conventional boost or buck-boost converter with narrow turn-off period. The proposed converter has wide turn-off period compared with a conventional boost converter. Thus, the higher output voltage can be achieved in the proposed converter. The interleaved PWM can further reduce the input and output ripple currents such that the sizes of inductor and capacitor are reduced. Since boundary conduction mode (BCM) is adopted to achieve power factor correction, power switches are turned on at zero current switching (ZCS) and switching losses are reduced. The circuit configuration, principle operation, system analysis, and design consideration of the proposed converter are presented in detail. Finally, experiments conducted on a laboratory prototype rated at 500W were presented to verify the effectiveness of the converter.

• 전력전자학회논문지
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• 제11권3호
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• pp.258-265
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• 2006

풍력, 태양광, 연료전지와 같은 신 재생 에너지에 관한 연구가 활발해 지면서 컨버터, 인버터와 같은 PCS (Power Conditioning System)의 연구가 활발히 진행되고 있다. 그러나, 부하에 따라 가변되는 저전압, 대전류, 출력특성을 갖는 연료전지 발전 시스템에서는 PCS의 연구 및 개발이 어려운 실정이다. 본 논문에서는 연료전지를 이용한 발전시스템에 알맞은 능동 클램프 sepic-flyback 컨버터를 제안한다. 제안된 컨버터는 중간 탭 변압기를 이용하여 sepic, flyback 컨버터를 결합한 구조를 가진다. 변압기를 이용하는 종래의 토폴로지에 비해 변압기 이용률을 높일 수 있고, 변압기의 변환 비 및 파워 스위치 소자의 수를 줄일 수 있으며, 고효율 운전특성을 갖는다. 본 논문에서는 시뮬레이션과 실험을 통하여 컨버터의 동작특성을 비교 분석하였으며, PEMFC (Proton Exchange Membrane Fuel Cell)을 이용하여 제안된 컨버터의 타당성을 검증하였다.