• Proceedings of the KIEE Conference
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• 2001.04a
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• pp.227-230
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• 2001

This paper deals with a bidirectional ac-dc converter used in ups system application. We propose a Voltage-Source-Charge-Pump-Power-Factor-Correction(VS-CPPFC) ac-dc converters. First of all, we propose a charge pump power-factor-correction converter. Secondly, we derive and analyse a unity power factor condition. The proposed topology is based on a half-bridge for the primary and a current-fed push pull for the secondary side of a high frequency isolation transformer. The advantage of bidirectional flow of power achieved by using the same power components is that the circuit is simple and efficient. And the galvanically isolated topology is specially attractive in battery charge/discharge circuits in ups system. We design equivalent model for the steady-state circuit and analyse operation waveforms for each mode. We show that the proposed model can be applied to ups system by simulation processes.

• Proceedings of the KIEE Conference
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• 2001.10a
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• pp.239-241
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• 2001

Recently the power supply equipments have tendency to take multiple feedback loop paths. In this paper, the state space averaging technique is applied for the analysis of flyback type current mode control circuit. We made real converter for the gurantee of stable output characteristic and proper design of feedback circuit. The validity of proposed method is verified from test results. The improvement of stability is confirmed by sinusoidal signal injection method with isolated transformer. It is known that phase margin is sufficient and gain crossover frequency $f_c$, is nearly 1/5 of switching frequency $f_s$, from the experimental result with frequency response analyzer.

• Journal of Power Electronics
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• v.15 no.1
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• pp.1-9
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• 2015

This study presents a novel transformer isolated parallel connected quasi Z-source (qZ-source) full-bridge DC-DC converter that uses a coupled inductor in both the qZ-source network and output filter inductor. Unlike traditional voltage-fed or current-fed converters, the proposed converter can be open- and short-circuited without damaging switching devices. Therefore, the desired buck and boost functions can be achieved and converter reliability can be significantly improved. All the bulky inductors in the qZ-source network and output filter can also be minimized with the proposed inductor structures. A 4 kW prototype DC-DC converter is built and tested to verify the performance of the proposed converter.

• Proceedings of the KIEE Conference
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• 2000.11b
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• pp.365-367
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• 2000

Recently, the power supply equipments have tendency to take multiple feedback loop paths. In this paper, the state space averaging technique is applied for the analysis of flyback type current mode control circuit. We made real converter for the gurantee of stable output characteristic and proper design of feedback circuit. The validity of proposed method is verified from test results. The improvement of stability is confirmed by sinusoidal signal injection method with isolated transformer. It is known that phase margin is sufficient and gain crossover frequency $f_c$ is nearly 1/5 of switching frequency $f_s$ from the experimental result with frequency response analyzer.

• Proceedings of the KIPE Conference
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• 2014.07a
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• pp.405-406
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• 2014

This paper presents the one direction 3-phase DC-DC converter. The converter employs DC-AC inverter, 3-phase 1:N transformer and 3-phase full wave rectification circuit make low voltage direct current to high voltage direct current. By computer simulation and experiment, the theoretical results can be verified or modified. Finally, the simulation and experiment results are presented. Compared with the general DC converter, has anti-interference ability, high reliability, high output power, range and other characteristics, widely used, fully isolated input and output, the output of the multiplexer is not limited, polar optional.

• Proceedings of the KIPE Conference
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• 2012.07a
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• pp.353-354
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• 2012

본 논문은 동축권선 변압기를 이용한 승압형 플라이백 컨버터에 절연형 스위치드 커패시터 셀을 추가한 새로운 토폴로지를 제안한다. 제안하는 회로는 절연형 스위치드 커패시터 셀의 출력과 플라이백의 출력을 직렬 연결하여 고승압에 유리하고 스위치 온타임과 스위치 오프타임 모두 전력을 전달하여 기존의 플라이백 컨버터보다 향상된 변압기의 이용률을 가진다. 제안된 회로의 동작원리를 설명하고 60W급 하드웨어 프로토 타입을 이용하여 검증하였다.

• Proceedings of the KIPE Conference
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• 2012.07a
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• pp.113-114
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• 2012

최근 전력용반도체 모듈 시장이 발전함에 따라 고전압 제품에 대한 수요가 증가하고 있다. 하지만 1700V급 이상의 고전압용 IGBT 모듈을 구동하기 위한 게이트 드라이버의 경우 해외의 제품은 단가가 매우 높은 것이 현실이다. 이에 따라 1700V급 이상의 전력반도체 모듈용 게이트 드라이버를 손쉽게 구현할 수 있도록 단가 경쟁력과 향상된 성능을 갖춘 게이트 드라이버를 연구하게 되었다. 본 논문에서는 1700V급 이상의 전력용반도체 모듈용 게이트 드라이버를 제작하고 각 부분의 파형을 설명하였다.

• Proceedings of the KIPE Conference
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• 2012.07a
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• pp.9-10
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• 2012

오늘날 산업이 발전 할수록 고효율의 전력변환 시스템이 요구되고, 이를 구현하기 위해서는 스위칭 주파수를 높여야 하지만 스위칭 주파수를 높이면 비례적으로 스위칭 손실은 증가하게 되는 문제점이 있다. 때문에 고효율 전력변환 시스템을 구현하기 위해 스위칭 시 손실저감을 위해 소프트 스위칭 기법이 많이 사용되고 있다. 본 논문에서는 변압기를 사용하여 공진인덕터의 전압을 제한시켜 보조스위치가 영전압/영전류 스위칭을 달성하게 함으로써 보조스위치의 스위칭 손실을 발생시키지 않는 소프트 스위칭 구조를 제안한다.

• Proceedings of the KIPE Conference
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• 2012.07a
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• pp.230-231
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• 2012

This paper describes a gate driver that operates numerous semiconductor switch in the solide-state pulsed power modulator. the proposed gate driver is designed to receive both the isolated drive-power and the on/off pulse signals through the transformer. Moreover, the IGBT-switch can be quickly turned off by adding protection circuit. Therefore it protects the IGBT-switch from the arc condition that frequently occurs in high-voltage pulse application. To comprehend operating characteristic of each IGBT-switch in pulse output condition, the device consisting of a high efficiency soft-switching capacitor charger and two series stacking IGBT-switch is developed. Finally, the relability of the proposed gate driver and the device for its test are proved through PSpice simulation and experiments.

• The Transactions of the Korean Institute of Power Electronics
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• v.25 no.2
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• pp.87-93
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• 2020

This study proposes a gate driver that operates semiconductor switches in the bipolar pulsed power modulator. The proposed gate driver was designed to receive isolated power and synchronized signals through the gate transformer. The gate circuit has a separate delay in the on-and-off operation to prevent a short circuit between the top and bottom switches of each leg. On the basis of the proposed gate circuit, a bipolar pulsed power modulator prototype with a 2.5 kV/100 A rating was developed. Finally, the bipolar pulsed power modulator was tested under resistive load and plasma reactor load conditions. It is verified that the proposed gate driver can be applied to a bipolar pulsed power modulator.