• The Transactions of the Korean Institute of Power Electronics
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• v.16 no.3
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• pp.293-301
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• 2011

This paper proposes a bridgeless half-bridge AC-DC converter with high-efficiency. The proposed converter integrates the bridgeless power factor correction (PFC) circuit with the asymmetrical pulse-width modulated (APWM) half-bridge DC-DC converter. It provides the isolated DC output voltage from the AC line voltage without using any full-bridge diode rectifier. Conduction losses are lowered with a simple circuit structure. Switching losses are also reduced by achieving zero-voltage switching (ZVS) of the power switches. By using series-connected two transformers, the proposed converter provides a low-profile and high power density for AC-DC converters. The performance of the proposed converter is verified from a 250 W (48 V / 5.2 A) experimental prototype circuit at $90 \;V_{rms}$ line voltage.

• Asia-pacific Journal of Multimedia Services Convergent with Art, Humanities, and Sociology
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• v.8 no.11
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• pp.523-530
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• 2018

It has been studied over the long time for the high efficiency and high power density of the power converter. It is possible to obtain higher power conversion efficiency and small volume by increasing switching frequency, however, the switching loss is also increased. The soft switching technique can overcome of the above deficiency. The design and analysis method for ZVS(Zero Voltage Switching) Phase Shifte Full bridge converter is presented in this paper. The power transfer depends on the phase difference between two legs of the power stage and the maximum power conversion efficiency is achieved by the optimum leakage inductance value. The waveform of the current and voltage of the operational mode is analysed and the corresponding switch status is plotted as on/off status. A ZVS full bridge converter for a communication rectifier with 2kW output power is implemented and its performance are verified through PSIM software simulation and experimental results.

• 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.

• Journal of Power Electronics
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• v.18 no.3
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• pp.802-816
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• 2018

A digital direct phase-shift control (DDPSC) method based on the phase-shifted full-bridge LLC (PSFB-LLC) converter is presented. This work combines DDPSC with the conventional linear control to obtain a hybrid control strategy that has the advantages of linear control and DDPSC control. The strategy is easy to realize and has good dynamic responses. The PSFB-LLC circuit structure is simple and works in the fixed frequency mode, which is beneficial to magnetic component design; it can realize the ZVS of the switch and the ZCS of the rectifier diode in a wide load range. In this work, the PSFB-LLC converter resonator is analyzed in detail, and the concrete realization scheme of the hybrid control strategy is provided by analyzing the state-plane trajectory and the time-domain model. Finally, a 3 kW prototype is developed, and the feasibility and effectiveness of the DDPSC controller and the hybrid strategy are verified by experimental results.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 2009.05a
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• pp.384-387
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• 2009

There is an increasing demand for efficient high power/weight auxiliary power supplies for use on high speed traction application. Many new conversion techniques have been proposed to reduce the voltage and current stress of switching components, and the switching losses in the traditional pulse width modulation (PWM) converter. Especially, the phase shift full bridge zero voltage switching PWM techniques are thought must desirable for many applications because this topology permits all switching devices to operate under zero voltage switching(ZVS) by using circuit parasitic components such as leakage inductance of high frequency transformer and power device junction capacitance. The proposed topology is found to have higher efficiency than conventional soft-switching converter. Also it is easily applicable to phase shift full bridge converter by applying an energy recovery snubber consisted of fast recovery diodes and capacitors.

• Proceedings of the KIPE Conference
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• 2014.07a
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• pp.317-318
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• 2014

This paper is proposed dual full-bridge converter to drive flow battery used battery energy storage system. The system which is proposed has additional legs at each leg to perform stripping algorithm which is necessary to drive flow battery system. The proposed system is verified by simulation.

• Proceedings of the KIPE Conference
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• 2020.08a
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• pp.276-277
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• 2020

본 논문은 Full-bridge converter 2차측 다이오드의 Ringing 전압을 제거하는 방법으로 Active Snubber를 제안한다. 기존 RCD Snubber는 다이오드의 Ringing 에너지를 저항으로 소모하는 방식으로 전압 서지를 줄이는데 한계가 있다. 이러한 문제를 해결하기 위해 Active Snubber가 제안 되었으며, Active Snubber는 다이오드의 Ringing 전압을 회생시킴으로써, 전압스트레스를 줄이고 효율을 개선하는 이점을 보여준다. 본 논문에서는 7KW Full-bridge converter에 제안하는 Active Snubber를 적용하여 그 유도성을 입증하였다.

• The Transactions of the Korean Institute of Power Electronics
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• v.18 no.6
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• pp.515-522
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• 2013

In this paper, a new PCS is proposed which is consisted of high boost dual converter and single phase half-bridge inverter. The proposed PCS is configured in parallel input / serial output, using two interleaved voltage doubler converter. Converter of the proposed PCS is distribute input current by configuring parallel input and reduced turn ratio of transformer by configuring serial output. Also, compositions of the inverter are composed of serial output capacitor of converter and half-bridge inverter. The dual converter and single phase half-bridge inverter is designed and characteristic of the new PCS is analysed. The system of the 1.5[kW] PCS is verified through an experimental about operation and stability.

• The Transactions of the Korean Institute of Electrical Engineers P
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• v.63 no.3
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• pp.125-130
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• 2014

This paper is research result for a development of solar cell silicon ingot glowing(SCSIG) PWM converter system for 120[kW] 3[kA]. The system include 3-phase AC-DC rectifier diode converter of input voltage AC 460[V] and 60[Hz], DC-AC single phase full bridge PWM inverter of high frequency, AC-DC single-phase full wave rectifier using center-tapped of transformer for low voltage 50[V] and large current 3,000[A], carbon resistor load 0.2 [$m{\Omega}$]. PWM switching frequency for IGBT inverter control set 15KHz. The suggested researching contents are designed data sheets of power converter system, PSIM simulation, operating characteristics and analysis results of developed SCSIG system.

• Proceedings of the KIPE Conference
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• 2008.06a
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• pp.502-504
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• 2008

A new output inductor less phase shift full bridge converter with current reduction technique for server power application is proposed in this paper. The proposed converter can reduce the current stress by using the auxiliary circuit. Since the auxiliary circuit causes the additional resonance between the leakage inductor and auxiliary capacitor before the powering period, the proposed converter has lower current stress even no output filter inductor. Small size and circulating energy can be also the merits of the proposed converter. The operational principles and analysis are presented. Experimental results demonstrate that the current stress can be reduced effectively by using the auxiliary circuit without large output filter inductor.