• 전력전자학회논문지
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• 제26권3호
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• pp.237-240
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• 2021

This research proposes a new rectifier circuit to reduce the circulating current of a phase-shifted full bridge converter. The proposed circuit is a structure in which the output inductor of the secondary rectifier circuit is changed to a coupled inductor in the phase-shifted full bridge with the existing center-tapped rectifier. The parts are rearranged after adding a diode. After applying the proposed circuit, the circulating current to the primary current of the transformer and the voltage stress of the rectifier diode on the secondary side of the transformer are reduced. Accordingly, the snubber loss of the rectifier is improved. By reducing the circulating current and snubber loss, the circuit achieves higher efficiency than conventional circuits. In this research, we present the structure of the proposed circuit, its strengths, and the analysis results from experiments. Furthermore, its effectiveness is verified through the experimental results of a prototype converter with an input of 300-400 V and an output of 50 V/1 kW.

• 전력전자학회논문지
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• 제27권2호
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• pp.165-173
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• 2022

The electrification trend of mobility increases every year due to the development of power semiconductor and battery technology. Accordingly, the development and distribution of fast chargers for electric vehicles (EVs) are in demand. In this study, we propose a design and implementation method of an LLC converter for fast chargers. Two 15 kW LLC converters are configured in parallel to have 30 kW rated output power, and the control algorithm and driving sequence are designed accordingly and verified. In addition, the improved power conversion efficiency is confirmed through zero-voltage switching (ZVS) of the LLC converter and reduction of turn-off loss through snubber capacitors. The implemented 30 kW LLC converters show a wide output voltage range of 200-950 V. Experiments applying various load conditions verify the converter performance.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2013년도 추계학술대회 논문집
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• pp.3-4
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• 2013

본 논문에서는 전류연속 모드로 동작하는 탭인덕터 부스트 컨버터를 위한 무손실 스너버를 제안하고 그 동작을 분석하며, 실험을 통해 그 유효성을 검증한다.

• 전력전자학회:학술대회논문집
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• 전력전자학회 1996년도 창립기념 전력전자학술발표회 논문집
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• pp.67-70
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• 1996

This paper presents SVC which use PAM method and eliminate harmonics. Inverter is connected directly so that SVC improve output voltage waveform into 24 steps. Inverter output waveform THD is reduced to 6.89%. Leading control of reactive power generated in power system is possible. Snubber is added to reduce switching loss.

• 전력전자학회:학술대회논문집
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• 전력전자학회 1997년도 전력전자학술대회 논문집
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• pp.256-260
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• 1997

To achieve high efficiency in high power and high frequency applications, reduction of switching losses and noise is very important. In this paper, an improved soft switching forward converter is proposed. The proposed converter is constructed by using non-dissipative snubbers in parallel with the main switch and output diode of the conventional forward converter. Due to the use of the non-dissipative snubbers in the primary and secondary, the proposed converter achieves zero-voltage and zero-current switching for all switching devices without switching losses and output diode recovery losses. The complete operating principles, theoritical analysis, experimental results will be presented.

• 한국전산유체공학회:학술대회논문집
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• 한국전산유체공학회 2008년도 12th Asian Congress of Fluid Mechanics
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• pp.63.1-63.1
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• 2008

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2002년도 하계학술대회 논문집 Vol.3 No.2
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• pp.1103-1106
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• 2002

This paper presents SVC which use PAM method and eliminate harmonics. Inverter is connected directly so that SVC improve output voltage waveform into 24 steps. Inverter output waveform THD is reduced to 6.89%. Leading control of reactive power generated in power system is possible. Snubber is added to reduce switching loss.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2014년도 추계학술대회 논문집
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• pp.75-76
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• 2014

This study deals with a isolation type MIC(Module Integrated Converter) for AC module with advantages such as DC Wireless, freely selectable installation capacity, minimized shadow effect etc. In this paper, MIC circuit with the function which can remove the ripple voltage of PV module and give the discharging path for charged energy in leakage inductance of isolation transformer. The validity of proposed circuir is verified by the simulation with PSIM.

• 전력전자학회:학술대회논문집
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• 전력전자학회 1999년도 전력전자학술대회 논문집
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• pp.643-645
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• 1999

The conventional high frequency phase-shifted full bridge dc/dc converter has a disadvantage that a circulating current flows through transformer and switching devices during the freewheeling interval. Due to this circulating current, RMS current stress, conduction losses of transformer and switching devices are increased. To alleviate this problem, this paper provides a circulating current free type high frequency soft switching phase-shifted full bridge (FB) dc/dc converter with the modified energy recovery snubber (ERS) attached at the secondary side of transforemr.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2008년도 제39회 하계학술대회
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• pp.2281-2282
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• 2008

전력계통에서 전압을 안정시키고 계통의 안정도를 증진시키기 위해 송전시 발생하는 무효전력을 보상하는 방법으로 SVC(Static Var Compensator, 정지형 무효전력보상기)를 사용한다. SVC를 TCR(Thyristor Controlled Reactor)과 FC(Fixed Capacitor)필터, 그리고 스너버(Snubber)회로를 사용하여 모델링하고 이 모델을 EMTP를 이용하여 시뮬레이션함으로써 그 결과를 통해 SVC가 전력계통의 무효전력을 보상함을 알아본다.