• Proceedings of the KIEE Conference
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• 2002.06a
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• pp.3-5
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• 2002

This paper proposes a new prototype auxiliary resonant DC link(ARDCL)snubber circuit and deals with its power loss on the basis of actually measured conduction loss characteristic of switching device module. Voltage-type soft switching three phase inverter using proposed ARDCL snubber circuit is presented along with its performance evaluations. And, the power loss analysis of three phase hard and soft switching inverter are carried out from the point of simulation and experimental results.

• Journal of Power Electronics
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• v.9 no.1
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• pp.18-25
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• 2009

Conventional series-resonant pulse frequency modulation controlled DC-DC high power converters with a high-frequency transformer link which is designed for driving the high power microwave generator has the problem of hard switching commutation at turn-on and turn-off of active power switching devices. This problem is due to the influence of the magnetizing current of the high-frequency transformer. This paper presents a novel prototype for a high-frequency transformer using parasitic parameters with a lossless inductive snubber and a series resonant capacitor assisted series-resonant zero current switching pulse frequency modulated DC-DC power converter, which is designed using a high power magnetron for microwave ovens. In order to implement a complete and efficient soft switching commutation, the performance of the new converter topology is practically confirmed and evaluated in the prototype of a power microwave generator.

• Proceedings of the KIPE Conference
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• 2001.07a
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• pp.689-693
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• 2001

The conventional three-level high frequency phase-shifted 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 and RMS current stress, conduction losses of transformer and switching devices increases. To alleviate these problems, we propose an improved three-level Zero Voltage and Zero Current Switching (ZVZCS) dc/dc converter using a tapped inductor, a snubber capacitor and two snubber diodes attached at the secondary side of transformer. The proposed ZVZCS converter is verified on a 10 kW, 30kHz experimental prototype.

• The Transactions of the Korean Institute of Power Electronics
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• v.11 no.6
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• pp.529-534
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• 2006

Nowadays, more than ever before, many researchers take much interest in raising the efficiency of a power converter. In Flyback converter, the resistor of RCD snubber consumes the stored energy in leakage inductor. It plays a role in degrading the overall system efficiency. Thus, in this paper, a novel energy recovery circuit of Flyback converter is proposed to improve the efficiency. The operational principle of the proposed circuit is explained in detail. And, it is vilified through the simulation and experimental results.

• Journal of Electrical Engineering and Technology
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• v.9 no.5
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• pp.1592-1601
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• 2014

In this study, a novel single phase soft switched power factor correction (PFC) converter is developed with active snubber cell. The active snubber cell provides boost switch both to turn on with zero voltage transition (ZVT) and to turn off with zero current transition (ZCT). As the switching losses in the proposed converter are too low, L and C size can be reduced by increasing the operating frequency. Also, all the semiconductor devices operate with soft switching. There is no additional voltage stress in the boost switch and diode. The proposed converter has a simple structure, low cost and ease of control as well. It has a simple control loop to achieve near unity power factor with the aid of the UC3854. In this study, detailed steady state analysis of the proposed converter is presented and this theoretical analysis is verified by a prototype of 100 kHz and 500 W converter. The measured power factor and efficiency are 0.99 and 97.9% at full load.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.17 no.4
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• pp.100-105
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• 2003

This paper proposes a new auxiliary resonant DC link(ARDCL)snubber circuit and deals with its power loss on the basis of actually-measured conduction loss characteristic of switching device module. Voltage-fed soft switching three-phase inverter using proposed ARDCL snubber circuit is presented along with its performance evaluations. And, the power loss analysis of three-phase hard and soft switching inverter are carried out from the point of simulation and experimental results.

• Journal of Power Electronics
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• v.7 no.2
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• pp.124-131
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• 2007

In this paper, a novel type of auxiliary switched capacitor assisted edge resonant soft switching PWM resonant DC-DC converter with two simple auxiliary commutation lossless inductor snubbers is presented. The operation principle of this converter is described using the switching mode equivalent circuits. This newly developed multi resonant DC-DC converter can regulate its DC output AC power under a principle of constant frequency edge-resonant soft switching commutation by an asymmetrical PWM duty cycle control scheme. The high frequency power regulation and actual power characteristics of the proposed soft switching PWM resonant DC-DC converter are evaluated and discussed. The operating performances of the newly proposed soft switching inverter are represented based on simulation results from an applications point of view.

• Proceedings of the KIPE Conference
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• 2012.07a
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• pp.15-16
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• 2012

This paper is study on a novel high efficiency step up-down converter using loss-less snubber capacitor. The proposed converter is accomplished that the turn-on operation of switches is on zero current switching (ZCS) by DCM. The converter is also applicable to a new quasi-resonant circuit to achieve high efficiency converter. The control switches using in the converter are operated with soft switching, that is, ZVS and ZCS by quasi-resonant method. The control 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 efficiency of the converter is high.

• Proceedings of the KIEE Conference
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• 1993.07b
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• pp.777-780
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• 1993

An insulated gate bipolar transistor(IGBT) is a MOS gate turn on/off bipolar transistor which combines the attributes of the MOSFET and bipolar transistor. Because of its limitation of power capability compared to thyristor or GTO, some parallel connection of IGBT has been studied to improve the limitation of current capabillity. In this paper, the switching effects from the unbalance of internal parameters of IGBT and the turn-off snubber characteristics are investigated using SPICE program.

• Proceedings of the KIEE Conference
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• 1995.07a
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• pp.188-190
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• 1995

This paper describes a soft switching using discontinuous inductor current. The soft switching snubber circuit provides ZCS and ZVS for main switch. For high power applications, the input ractifier is fed from a three-phase ac source. The Conventional switching method is hard switching technics, because of the device turn off is ocurred in maximum reactor current. In this time, switching losses are maximised by the hard switching. In generally, soft switching technique has been adjusted with the snubber condenser in order to compensates for this losses. So, it was compared hard switching with soft switching which has proposed in this paper for switching losses, distortion factor by the simulation.