• The Transactions of the Korean Institute of Power Electronics
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• v.20 no.2
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• pp.167-174
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• 2015

This study describes how digital time delay deteriorates control performance in zero voltage switching (ZVS) phase-shifted full bridge (PSFB) converter. The small-signal model of the ZVS PSFB converter is derived from the buck-converter small-signal model. Digital time delay effects have been considered according to the digital sampling methods. The analysis verifies that digital time delays reduce the stability margin of the converter, and the double sampling technique exhibits better performance than the single sampling technique. Both simulation and experimental results based on 250 W ZVS PSFB confirm the validity of the analyses performed in the study.

• The Transactions of the Korean Institute of Power Electronics
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• v.15 no.2
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• pp.119-126
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• 2010

An integrated magnetic (IM) transformer is proposed for a phase shifted full bridge (PSFB) converter with zero voltage switching (ZVS). In a proposed IM transformer, the transformer is located on the center leg of E-core and the output inductor is wound on two outer legs with air gap. The proposed IM transformer is analyzed by using the magnetic capacitor model. For reducing the core size, EE core is redesigned. The proposed IM transformer is experimentally verified on a 1.2 kW prototype converter. The converter efficiency with the proposed IM transformer is about 93 % at full load and its volume size can be reduced. It can be expected that the power density can be largely increased with the proposed IM transformer.

• Journal of Power Electronics
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• v.15 no.3
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• pp.610-620
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• 2015

An inherent zero-voltage and zero-current-switching phase-shifted full-bridge converter with reverse-blocking insulated-gate bipolar transistor (IGBT) or non-punch-through IGBT is proposed in this paper. This converter not only ensures that the switches in the lagging leg works at zero-current switching, but also minimizes circulating conduction loss without any additional auxiliary circuits. A 1.2 kW hardware prototype is designed, fabricated, and tested to verify the proposed topology. The control loop design procedures with small-signal models are also presented. A simple, low-cost, and robust democratic current-sharing circuit is also introduced and verified in this study. The proposed converter is a suitable alternative for compact, cost-effective applications with high-voltage input.

• Proceedings of the KIEE Conference
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• 1996.07a
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• pp.392-394
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• 1996

This paper is to describe how to apply the Phase-shifted Full Bridge 100kHz high frequency soft-switching PWM method to 48[V], 200[A] DC/DC converter. The soft-switching is achieved from light load to full load by using phase-shifted zero voltage switching method with additional capacitors besides the MOSPET's of the right leg even though the leakage inductance of high frequency transformer is designed small. This method can reduce the switching tosses, EMI problems, and increase the effective duty. Also, this paper includes the simulation, analysis, and experiment results of the DC/DC converter unit.

• Proceedings of the KIPE Conference
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• 2019.07a
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• pp.346-347
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• 2019

본 논문에서는 3.3 [kW] on-board charger (OBC) 용 phasw-shifted full-bridge (PSFB) 컨버터의 고효율 및 고전력 밀도 달성을 위한 스위칭 주파수 설계 방안을 제안한다. 스위칭 주파수에 따라 달라지는 손실 양상 및 전력 밀도에 대해 분석하기 위해 각 스위칭 주파수 별 반도체 소자 손실과 수동 소자 손실을 계산하고, 수동 소자의 부피 변화에 따른 전력밀도 변화를 분석한다. 분석 결과를 바탕으로 고효율 및 고전력밀도 달성을 위한 시스템 설계 포인트를 선정하고 시뮬레이션을 통하여 설계 결과를 검증한다.

• Proceedings of the KIPE Conference
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• 1997.07a
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• pp.251-255
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• 1997

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 energy recovery snubber (ERS) attached at the secondary side of transformer. The energy recovery snubber (ERS) adopted in this study is consisted of three fast recovery diode(Ds1, DS2, Ds3), two resonant capacitor (Cs1, Cs2)

• Journal of Power Electronics
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• v.16 no.3
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• pp.883-893
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• 2016

This paper presents a comprehensive analysis of the spurious turn-on phenomena in phase-shifted full-bridge (PSFB) converters. The conventional analysis of the spurious turn-on phenomenon does not establish in the PSFB converter as realizing zero voltage switching (ZVS). Firstly, a circuit model is proposed taking into account the parasitic capacitors and inductors of the transistors, as well as the parasitic elements of the power circuit loop. Second, an exhaustive investigation into the impact of all these parasitic elements on the spurious turn-on is conducted. It has been found that the spurious turn-on phenomenon is mainly attributed to the parasitic inductors of the power circuit loop, while the parasitic inductors of the transistors have a weak impact on this phenomenon. In addition, the operation principle of the PSFB converter makes the leading and lagging legs have distinguished differences with respect to the spurious turn-on problems. Design guidelines are given based on the theoretical analysis. Finally, detailed simulation and experimental results obtained with a 1.5 kW PSFB converter are given to validate proposed analysis.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 2000.11a
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• pp.188-192
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• 2000

This paper presents a novel prototype of soft-switching PWM Full-bridge converter which incorporates active power switches in series with each rectifier diode in transformer secondary side. Switching and conduction losses of all the switches and devices are reduced as well as commutating current and circulating current flowing through transformer as compared with conventional converter. And duty ratio of primary switches is constant for maximum voltage conversion ratio. But this converter can be varied output by duty ratio of secondary switches. Operation principles basically the same as that of the PWM Full-bridge converter published previously. The operating characteristics of this converter are illustrate and discussed including the simulated analysis.

• Proceedings of the KIPE Conference
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• 2003.07a
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• pp.231-234
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• 2003

This paper presents a novel high frequency transformer linked full-bridge type soft-switching phase-shift PWM control scheme DC-DC power converter, which can be used as power conditioner fur small-scale fuel cell power generation system. Using full-bridge soft-switching DC-DC converter topology makes possible to use low voltage high performance MOSFETs to achieve high efficiency of the power conditioner. A tapped inductor filter is implemented in the proposed soft-switching converter topology to achieve soft-switching PWM constant high frequency operation for a wide load variation range. to minimize circulating and idling currents without using additional resonant circuit and auxiliary power switching devices. The practical effectiveness of the proposed soft-switching DC-DC converter is verified in laboratory level experiment with 1 kW 100kHz breadboard setup using power MOSFETs. Actual efficiency of 94-96$\%$ is obtained for the wide load range

• Proceedings of the KIPE Conference
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• 2001.10a
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• pp.140-145
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• 2001

This paper proposes to use a 20[kHz] phase­shifted Full-Bridge (FB) Zero-Voltage-Switched (ZVS) PWM converter in order to drive a 600[W] magnetron, and analyzes the operational modes in a switching period. Additionally, the controller of the average anode current is designed. Simulation studies and experiments verify that the proposed converter and the average anode current controller shows good performance to drive the magnetron.