• Proceedings of the KIEE Conference
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• 2004.04a
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• pp.136-139
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• 2004

This paper presents a buck circuit topology of high-frequency with a single switching element. It solved the problem which arised from hard-switching in high-frequency using a resonant snubber and operating under the principle of ZCS turn-on and ZVS turn-off commutation schemes. In the existing circuit, it has the voltage stress which is twice of input voltage in free-wheeling diode. But in the proposed circuit, it has voltage stress which is lower than input voltage with modifing a location of free-wheeling diode. In this paper, it explained the circuit operation of each mode and confirmed the waveform of each mode with simulation result. Also the experiment result verified the simulation waveform and compared the existing voltage stress of free-wheeling diode with the proposed voltage stress of that. Moreover, it compares and analyzes the proposed circuit's efficiency with the hard-switching circuit's efficiency according to the change of load current.

• Proceedings of the KIEE Conference
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• 1997.11a
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• pp.438-440
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• 1997

This paper proposed a partial resonant switching three-phase high power factor converter using a $PRS^2$(Partial Resonant Soft Switch). The proposed converter has a merit of simple controlled circuit because the input current control DCM(Discontinuous Conduction Mode). And it is improve to input power factor that the snubber capacitor's energy regenerate to the AC source side. This topology is reduced a current/voltage stresses of resonant devices in addition to a partial resonant strategy. The result of simulations with the proposed topology included in this paper.

• Proceedings of the KIEE Conference
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• 2008.07a
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• pp.916-917
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• 2008

In this paper, Switching damage of switches that is used to proposed power conversion system is reduced by soft switching way. dissipation by part resonance and my resonance stress for resonance of resonance circuit are decreased. Is acted by conversion system high effectiveness. Have following characteristic. Design snubber circuit that is used by switch protection in existent hard work rate Topology by resonant circuit for sogt switching, circuit structure was simple and control system is easy. Also, Can generate free output voltage by multi level Tuesday of output that use individuation Power Cell's Phase Shift PWM, and Low-end switching frequency the harmonic is few.

• Proceedings of the KIEE Conference
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• 2015.07a
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• pp.1026-1027
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• 2015

고 승압 플라이백 컨버터를 설계하여 제작, 사용할 때 고주파수의 스위칭시 스위칭 소자의 보호를 위해 스너버 회로를 사용하게 된다. 본 논문에서는 고 승압 플라이백 컨버터의 스위칭 소자에서 R-C 스너버 회로가 미치는 영향에 대해 직접 실험하여 스너버 회로가 스위칭 소자와 스위칭 신호에 미치는 영향을 확인하고 실험을 통해 얻은 스너버 회로 파라미터값과 계산결과를 비교한다.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 2008.05a
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• pp.419-422
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• 2008

This paper presents a novel prototype of ZCS-PFM high frequency series resonant Inverter using IGBT power module for electromagnetic induction eddy current-heated roller in copy and printing machines. The operating principle and unique features of this voltage source half bridge inverter with two additional soft commutation inductor snubber are presented Including the transformer modeling of induction heated rolling drum. This soft switching inverter can achieve stable zero current soft commutation under a discontinuous and continuous resonant load current for a widely specified power regulation processing. The experimental results and computer-aided analysis of this inverter are discussed from a practical point of view.

• Proceedings of the KIPE Conference
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• 2002.07a
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• pp.390-394
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• 2002

전류원 컨버터는 전압원 컨버터에 비해 스위치 차단 시 발생하는 서지에 연루되는 에너지가 커, 무손실 스너버가 필수적인데, 이 스너버는 그 동작 원리가 복잡하고 동작조건이 바뀜에 따라 성능의 변동이 심하여 설계가 어렵고, 적용되는 회로에 따라서도 설계식이 달라진다. 본 논문에서는 0.5 이상의 시비율로 동작하는 전류원 하프-브릿지 컨버터를 위한 무손실 스너버의 동작을 완전히 분석하고 설계사항에 대해 고찰한 뒤 실험을 통해 검증한다.

• Proceedings of the KIPE Conference
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• 2003.11a
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• pp.149-153
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• 2003

In this paper, the design and implementation of a high power(300W) forward converter using a planar transformer is presented. The overall size and volume of the converter is decreased by replacing a planar transformer in stead of using a conventional winding transformer. Due to the decreased size and volume, power density of the applied forward converter is increased. Also, in this paper, the 300W ZVS forward converter with active clamp snubber circuit is compared to the 300W hard switching forward converter.

• Journal of Power Electronics
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• v.9 no.2
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• pp.259-266
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• 2009

In order to increase the power density of power converters, reduction of the switching losses at high-frequency switching conditions is one of the most important issues. This paper presents a new gate drive circuit that enables the reduction of switching losses in both the Power MOSFET and the IGBT. A distinctive feature of this method is that both the turn-on loss and the turn-off loss are decreased simultaneously without using a conventional ZVS circuit, such as the quasi-resonant adjunctive circuit. Experimental results of the switching loss of both the Power MOSFET and the IGBT are shown. In addition, an energy recovery circuit suitable for use in IGBTs that can be realized by modifying the proposed gate drive circuit is also proposed. The effectiveness of both the proposed circuits was confirmed experimentally by the buck-chopper circuit.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2003.07a
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• pp.357-360
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• 2003

In this paper, we designed 4.5kV/1.5kA IGCT devices. GCT thyristor has many superior characteristics compared with GTO thyristor, for examples; snubberless turn-off capability, short storage time, high turn-on capability, small turn-off gate charge and low total power loss of the application system containing device and peripheral parts such as anode reactor and snubber capacitance. In this paper we designed GCT thyristor devices, and analyzed static and dynamic characteristics of GCT thyristor depending on the minority carrier lifetime, n-base thickness and doping concentration of n-base region, respectively. Especially, turn-on and turn-off characteristics are very important characteristics for GCT thyristor devices. So, we considered above characteristic for design and analysis of GCT devices.

• Proceedings of the KIPE Conference
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• 2010.07a
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• pp.142-143
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• 2010

An active-clamped current-fed half-bridge converter for the high step-up application is proposed in this paper. The proposed converter is composed of active clamping snubber circuits and a voltage doubler rectifier. The operational principle, theoretical analysis, and design considerations are presented. To confirm the operation, features, and validity of the proposed circuit, the experimental result for a 200W, 24V input and 400V output prototype are presented.