• Proceedings of the KIPE Conference
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• 2011.07a
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• pp.340-341
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• 2011

본 논문에서는 높은 승 강압비를 갖는 양방향 DC-DC 컨버터에 대한 최적의 스위칭 기법을 제안한다. 제안한 컨버터는 CCM에서도 소프트 스위칭이 가능하여 스위칭 손실뿐만 아니라 인덕터의 발열도 줄일 수 있다. 또한 모든 소자의 전압 정격과 수동소자의 부피도 기존 양방향 컨버터 보다 작아 고효율 및 고전력밀도의 달성을 기대 할 수 있다. 1.5kW 시작품의 실험을 통해 본 논문의 타당성을 검증하였다.

• Proceedings of the KIPE Conference
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• 1996.06a
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• pp.117-120
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• 1996

Power conversion system must be increased switching frequency in order to achieve a small size, a light weight and a low noise. However, the switches of converter are subjected to high switching power losses and switching stresses. As a result of those, the power system brings on a low efficiency. In this paper, the authors propose a DC-DC boost converter of high power by partial resonant switch method (PRSM). The switching devices in a proposed circuit are operated with soft switching and the control technique of those is simplified for switch to drive in constant duty cycle. The partial resonant circuit makes use of a inductor using step up and a condenser of loss-less snubber. Also the circuit has a merit which is taken to increase of efficiency, as it makes to a regeneration at input source of accumulated energy in snubber condenser without loss of snubber in conventional circuit. The result is that the switching loss is very low and the efficiency of system is high. The proposed converter is deemed the most suitable for high power applications where the power switching devices are used.

• Proceedings of the KIPE Conference
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• 2009.11a
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• pp.173-175
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• 2009

A dc/dc converter for low voltage of battery application and fuel cell system is required to step up and regulate the low and widely variable voltage. In this paper, we have proposed a soft switching boost converter with high voltage gain using a single switch. Through the theoretical analysis and experimental result, operation modes and characteristics of the proposed topology is verified.

• Proceedings of the KIPE Conference
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• 1999.07a
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• pp.663-666
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• 1999

This paper describes a three-phase converter with high power factor using a scheme of discontinuous current mode(DCM). The proposed system can replace the conventional diode bridge with step-up chopper which is used as a converter for adjustable speed drive. In this system, the current of reactor is zero at turn-on instance because of operation in DCM, while the switch turns off at the instance of maximum current. A soft-switching scheme with lossless snubber was proposed. Therefore, a zero-voltage switching at turn off can be achived by lossless snubber and zero-current switching at turn on can be obtained by operating under DCM. A theoretical analysis and computer simulations with PSpice were done to verify the operation of the proposed system. Also a prototype of hardware system was built and tested for verifying the feasibility of proposed system.

• Proceedings of the KIEE Conference
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• 1993.11a
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• pp.126-128
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• 1993

Rectifiers of power conversion system are widely used condenser at input to be cheap and to be simple construction. But this method is produced harmonics of pulse at peak value of input AC voltage. The main circuit which make input current of a sinusoidal wave and improve power-factor is almost taken step-up converter. This paper is able to obtain high power-factor and efficiency because the input current is made sinusoidal wave in single phase alternating current(AC) source. Also the proposed converter is able to minimize switching loss by ZVCS(zero voltage switching and zero current switching).

• Proceedings of the KIPE Conference
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• 1998.07a
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• pp.20-23
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• 1998

An improved current-fed push-pull PWM converter with integrated magnetics is presented. With this improved topology, the design of magnetic elements such as an inductor and a transformer becomes easier than that using the conventional topology, especially when the converter is suffered from an extremely high input current. Since this gives twice the voltage conversion ratio compared to the conventional one, it is also suited for the high voltage step-up power conversion process. The operation of the proposed converter is thoroughly analyzed. Also, the theoretical analysis and experimental results are taken from the laboratory level prototype.

• Proceedings of the KIPE Conference
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• 2010.07a
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• pp.357-358
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• 2010

An interleaved operation of isolated boost converter system has become a very attractive solution in order to convert from low input voltage (30 ~ 50V) of distributed power sources such as photovoltaic and fuel cells to high output voltage (380V/760V) required in grid-connected power conversion applications. In this paper, we have proposed zero voltage transition(ZVT) interleaved boost converter using a single resonant inductor.

• Journal of the Institute of Electronics Engineers of Korea SC
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• v.43 no.1 s.307
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• pp.45-52
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• 2006

In this paper, authors propose a step-up converter of pulse width modulation (PWM) and power factor correction (PFC) by using a novel loss-less snubber. The proposed converter for a discontinuous conduction mode (DCM) eliminates the complicated circuit control requirement and reduces the size of components. The input current waveform in the proposed converter is got to be a sinusoidal form of discontinuous pulse in proportion to magnitude of ac input voltage under the constant duty cycle switching. Thereupon, the input power factor is nearly unity and the control method is simple. In the general DCM converters, the switching devices are fumed-on with the zero current switching (ZCS), and the switching devices must be switched-off at a maximum reactor current. To achieve a soft switching (ZCS and ZVS) of the switching turn-off, the proposed converter is constructed by using a new loss-less snubber which is operated with a partial resonant circuit. The result is that the switching loss is very low and the efficiency of converter is high. Some simulative results on computer and experimental results are included to confirm the validity of the analytical results.

• The Transactions of the Korean Institute of Power Electronics
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• v.14 no.1
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• pp.72-81
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• 2009

This paper presents quasi-resonant type high power factor ac power supply for atmospheric pressure plasma cleaning system adopting three phase PFC boost converter and it's control method. The presented ac power supply consists of single phase H-bridge inverter, step-up transformer for generating high voltage and three phase PFC boost converter for high power factor on source utility. Unlikely to the traditional LC resonant converter, the propose one has an inductor inside only. A single resonant takes place through the inside inductor and the capacitor from the plasma load modeled into two series capacitor and one resistance. The quasi-resonant can be achieved by cutting the switching signal when the load current decrease to zero. To obtain power control ability, the propose converter controlled by two control schemes. One is the changing output pulse period scheme in the manner of PFM(Pulse Frequency Modulation) control. On the other, to provide more higher power to load, the DC rail voltage is directly controlled by the 3-phase PFC boost converter. The significant merits of the proposed converter are the uniform power providing capability for high quality plasma generation and low reactive power in AC and DC side. The proposed work is verified through digital simulation and experimental implementation.

• The Transactions of the Korean Institute of Power Electronics
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• v.24 no.5
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• pp.379-387
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• 2019

A bidirectional flyback converter is a suitable topology for use in a PV-to-bus differential power processing (DPP) module for PV applications due to its electrical isolation capability, bidirectional power transfer, high step-up ratio, and simple circuit structure. However, the bidirectional flyback converter design should consider the effect of the output-side power switch utilized for bidirectional operation compared with that of the conventional flyback converter. This study presents the structure and design methodology of the bidirectional flyback converter for a PV DPP module. Magnetizing inductance is designed by calculating the power loss of converter components within the rated load range under the discontinuous conduction mode, which is unaffected by the reverse recovery characteristics of the anti-parallel diode of the output-side power switch. The validity of the proposed design methodology is verified using a 25 W bidirectional flyback converter prototype. The operational principles and the performance of the DPP operation are verified using practical DPP modules consisting of bidirectional flyback converters implemented according to the proposed design methodology.