• Proceedings of the KIPE Conference
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• 2001.07a
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• pp.694-697
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• 2001

A optimal soft switching technique for A/DC full bridge converter is proposed. variable soft switching single stage AC/DC full bridge converter with unit power factor are presented in this paper. Using soft switching, we can reduce a switching losses. As a result, achieving good power factor and achieving a good efficiency. We search a optimal soft switching technique in this paper and to verify the theoretical analysis of the presented AC/DC full bridge converter, a design example is given with its Pspice and Psim simulation and experimental results.

• Proceedings of the KIPE Conference
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• 1997.07a
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• pp.243-246
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• 1997

In this paper, soft switching high power factor buck converter is proposed. This converter is composed of diode rectifier, a input capacitor can be small enough to filter input capacitor can be small enough to filter input current, buck converter with loss less snubber circuit. Converter is operated in discontinous conduction mode, turn of of the switching device is a zero current switching(ZCS) and high power factor input is obtained. In addition, zero voltage switching(ZVS) at turn of is achieved and switching loss is reduced using loss less snubber circuit. The capacitor used in the snubber circuit raised output voltage. Therefore, proposed converter has higher output voltage and higher efficiency than conventional buck type converter at same duty factor in discontious conduction mode operation.

• Proceedings of the KIEE Conference
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• 2008.07a
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• pp.922-923
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• 2008

This paper is proposed to a novel DC-DC buck-boost converter added electric isolation by using a soft switching method. To be achieved of high efficiency system, the proposed converter is constructed by using a partial resonant circuit. The control switches using in the converter are operated with soft switching for a partial resonant method. The controlling switches are operated without increasing their voltage and current stresses by the soft switching technology. The result is that the switching loss is very low and the converter efficiency is high. And the proposed converter is added in a electric isolation. When the power conversion system is required to electric isolation, the proposed converter is adopted with system development of high efficiency. The soft switching operation and the system efficiency of the proposed converter is verified by digital simulation and experimental results.

• Proceedings of the KIPE Conference
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• 1997.07a
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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.

• Journal of Power Electronics
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• v.9 no.5
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• pp.772-780
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• 2009

A novel soft-switching two-switch flyback converter is proposed in this paper. This converter is composed of two active power switches, a flyback transformer, a blocking diode, and two passive regenerative clamping circuits. The proposed converter has the advantages of a low cost circuit configuration, a simple control scheme, a high efficiency, and a wide operating range. The circuit topology, analysis, design considerations, and experimental results of the new flyback converter are presented.

• Proceedings of the KIPE Conference
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• 2008.10a
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• pp.133-136
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• 2008

This paper presents a novel soft switching topology with resonant DC-DC converter and inverter. The resonant DC-DC converter consists of the auxiliary switch, resonant capacitor and inductor. All switches in the proposed topology is turn on at ZCS and turn off at ZVS operation. The proposed soft switching technology can be obtained the reduced switching losses and voltage and current stress of the power devices. Therefore, the resonant converter efficiency is higher than conventional boost converter. Simulation results on a 1kW soft switching converter are presented.

• Journal of Electrical Engineering and Technology
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• v.13 no.4
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• pp.1539-1548
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• 2018

This paper introduces a new soft switched AC-DC boost converter with power factor correction (PFC). In the introduced converter, all devices are turned on and off under soft switching (SS). The main switch is turned on under zero voltage transition (ZVT) and turned off under zero current transition (ZCT). The main diode is turned on under zero voltage switching (ZVS) and turned off under zero current switching (ZCS). Meanwhile, there is not any current or voltage stress on the main devices. Besides, the auxiliary switch is turned on under ZCS and turned off under ZVS. The detailed theoretical analysis of the converter is presented, and also theoretical analysis is verified by a prototype with 100 kHz and 500 W. Also, the proposed converter has 99.8% power factor and 97.5% total efficiency at soft switching operation.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 2005.11a
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• pp.251-255
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• 2005

This paper proposes a new soft switching technique for a phase-shift controlled bi-directional DC-DC converter. The described converter employs a low profile high frequency transformer and two active full-bridge converters for bidirectional power flow capability. A new soft switching technique is proposed, which guarantees soft switching over wide range (no load to full load) without any additional circuit components. In the proposed switching scheme, the switch pairs in the diagonal position of the converter each are turned on/off simultaneously by the switching signals with a variable duty ratio depending on the phase shift amount, and the converter is operated without freewheeling interval.

• Journal of Power Electronics
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• v.4 no.4
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• pp.237-245
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• 2004

In this paper, a two-switch high frequency flyback transformer linked zero voltage soft switching PWM DC-DC power converter implemented for distributed DC- feeding power conditioning supplies is proposed and discussed. This switch mode power converter circuit is mainly based on two main active power semiconductor switches and a main flyback high frequency transformer linked DC-DC converter in which, two passive lossless quasi-resonant snubbers with pulse current regeneration loops for energy recovery to the DC supply voltages composed of a three winding auxiliary high frequency pulse transformer, auxiliary capacitors and auxiliary diodes for inductive energy recovery discharge blocking due to snubber capacitors are introduced to achieve zero voltage soft switching from light to full load conditions. It is clarified that the passive resonant snubber-assisted soft switching PWM DC-DC power converter has some advantages such as simple circuit configuration, low cost, simple control scheme, high efficiency and lowered noises due to the soft switching commutation. Its operating principle is also described using each mode equivalent circuit. To determine the optimum resonant snubber circuit parameters, some practical design considerations are discussed and evaluated in this paper. Moreover, through experimentation the practical effectiveness of the proposed soft switching PWM DC-DC power converter using IGBTs is evaluated and compared with a hard switching PWM DC-DC power converter.

• Proceedings of the KIPE Conference
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• 1998.07a
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• pp.265-268
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• 1998

This paper presents a soft-switching average current control PWM high power factor boost converter. Conventional boost ZVT-PWM converter has a disadvantage of hard-switching for auxiliary switch at turn-off. A soft switched auxiliary switch is proposed to achieve a high performance ZVT-PWM boost rectifier. The simulation and experimental results show that soft switching operation can be maintained for wide line and load range, which in turn improves the converter performance in terms of efficiency, switching noise and circuit reliability.