• 전기전자학회논문지
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• 제14권3호
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• pp.250-255
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• 2010

본 논문에서는 DTMOS(Dynamic Threshold voltage MOSFET) 스위칭 소자를 사용한 인터리브 방식의 전원제어 장치(PMIC)를 제안하였다. 휴대기기에 필요한 높은 출력 전압과 낮은 출력 전압을 제공하기 위하여 벅-부스트 컨버터를 사용하였다. 또한, 높은 출력 전류에서 고 전력 효율을 얻기 위하여 PWM(Pulse Width Modulation) 제어 방식을 사용하였다. 낮은 온-저항을 갖는 DTMOS를 사용하여 도통 손실을 감소시켰으며 인터리브 방식을 사용하여 출력 리플을 감소시켰다. 1mA 이하의 대기모드에서도 높은 효율을 구현하기 위하여 LDO를 설계하였다.

• Journal of Power Electronics
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• 제5권3호
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• pp.233-239
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• 2005

In this paper, a new conceptual circuit configuration of a 3-phase voltage source, soft switching AC-DC-AC converter using an IGBT module, which has one ARCPL circuit and one ARDCL circuit, is presented. In actuality, the ARCPL circuit is applied in the 3-phase voltage source rectifier side, and the ARDCL circuit is in the inverter side. And more, each power semiconductor device has a novel clamp snubber circuit, which can save the power semiconductor device from voltage and current across each power device. The proposed soft switching circuits have only two active power semiconductor devices. These ARCPL and ARDCL circuits consist of fewer parts than the conventional soft switching circuit. Furthermore, the proposed 3-phase voltage source soft switching AC-DC-AC power conversion system needs no additional sensor for complete soft switching as compared with the conventional 3-phase voltage source AC-DC-AC power conversion system. In addition to this, these soft switching circuits operate only once in one sampling term. Therefore, the power conversion efficiency of the proposed AC-DC-AC converter system will get higher than a conventional soft switching converter system because of the reduced ARCPL and ARDCL circuit losses. The operation timing and terms for ARDCL and ARCPL circuits are calculated and controlled by the smoothing DC capacitor voltage and the output AC current. Using this control, the loss of the soft switching circuits are reduced owing to reduced resonant inductor current in ARCPL and ARDCL circuits as compared with the conventional controlled soft switching power conversion system. The operating performances of proposed soft switching AC-DC-AC converter treated here are evaluated on the basis of experimental results in a 50kVA setup in this paper. As a result of experiment on the 50kVA system, it was confirmed that the proposed circuit could reduce conduction noise below 10 MHz and improve the conversion efficiency from 88. 5% to 90.5%, when compared with the hard switching circuit.

• Journal of Power Electronics
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• 제15권3호
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• pp.610-620
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• 2015

An inherent zero-voltage and zero-current-switching phase-shifted full-bridge converter with reverse-blocking insulated-gate bipolar transistor (IGBT) or non-punch-through IGBT is proposed in this paper. This converter not only ensures that the switches in the lagging leg works at zero-current switching, but also minimizes circulating conduction loss without any additional auxiliary circuits. A 1.2 kW hardware prototype is designed, fabricated, and tested to verify the proposed topology. The control loop design procedures with small-signal models are also presented. A simple, low-cost, and robust democratic current-sharing circuit is also introduced and verified in this study. The proposed converter is a suitable alternative for compact, cost-effective applications with high-voltage input.

• Journal of Power Electronics
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• 제9권6호
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• pp.823-834
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• 2009

This paper proposes a high-efficiency single-stage ac/dc converter. The proposed converter features low voltage stresses and reduced switching losses. It operates at the boundary of discontinuous- and continuous-conduction modes by employing variable switching frequency control. The turn-on switching loss of the switch can be reduced by turning it on when the voltage across it is at a minimum. The voltage across the bulk capacitor is independent of the output loads and maintained within the practical range for the universal line input, so the problem of high voltage stress across the bulk capacitor is alleviated. Moreover, the voltage stress of the output diodes is clamped to the output voltage, and the output diodes are turned off at zero-current. Thus, the reverse-recovery related losses of the output diodes are eliminated. The operational principles and circuit analysis are presented. A prototype circuit was built and tested for a 150 W (50V/3A) output power. The experimental results verify the performance of the proposed converter.

• 조명전기설비학회논문지
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• 제21권3호
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• pp.44-49
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• 2007

본 논문은 기존 컨버터에 보조 스위치와 공진 인덕터, 공진 커패시터, 두개의 다이오드를 추가하여 새로운 소프트 스위칭 액티브 스너버회로가 부가된 컨버터를 제안하였다. 제안한 컨버터는 공진 에너지 회생율을 최대화함으로써 전체적인 효율을 증가시켰으며, 모든 스위칭 소자들이 소프트 스위칭 조건에서 턴-온/턴-오프하여 스위칭 손실을 최소화하였다. 그리고 공진 에너지를 완전히 입력으로 회생시켜 전도손실을 저감시켰다. 이러한 결과는 시뮬레이션과 실험을 통하여 증명하였다.

• Journal of Power Electronics
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• 제15권2호
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• pp.299-308
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• 2015

This study proposes four novel pulse width modulation (PWM) shoot-through control methods for impedance source (IS) galvanically isolated DC-DC converters. These methods are derived from a PWM control method with shifted shoot-through introduced by the authors in 2012. In contrast to the baseline solution, where the shoot-through states are generated by the simultaneous conduction of all transistors in the inverter bridge, our new approach is based on the shoot-through generation by one inverter leg. The idea is to increase the number of soft-switched transients and, therefore, decrease the dynamic losses of the front-end inverter. All the proposed approaches are experimentally verified through an insulated-gate bipolar transistor-based IS DC-DC converter. Conclusions are drawn in accordance with the results of the switching loss analysis.

• Journal of Electrical Engineering and Technology
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• 제7권4호
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• pp.601-605
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• 2012

Insulated Gate Bipolar Transistors(IGBTs) have received wide attention because of their high current conduction and good switching characteristics. To reduce the power loss of IGBT, the onstate voltage drop should be lowered and the switching time should be shortened. However, there is trade-off between the breakdown voltage and the on-state voltage drop. The FLoatingIsland(FLI) structure can lower the on-state voltage drop without reducing breakdown voltage. In this paper, The FLI IGBT shows an on-state voltage drop that is 22.5% lower than the conventional IGBT, even though the breakdown voltages of each IGBT are almost identical.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2011년도 전력전자학술대회
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• pp.394-395
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• 2011

In order to increase the power conversion efficiency and improve the power factor, a modified forward converter is proposed, which adopts a capacitive output filter instead of the inductive output filter of the conventional forward converter. Therefore, the proposed converter has wide input voltage range in opposite to that of the conventional forward converters. Moreover, the proposed converter uses the critical conduction mode for automatic current shaping to improve the power factor. As a result, the proposed converter can achieve quasi-resonant zero-voltage-switching, which can minimize the switching loss of main MOSFET. In addition, the operational principle of the proposed converter is analyzed and the characteristic of the proposed converter is investigated in this paper. To validate the effectiveness of the proposed converter, a prototype of 13W is implemented and the experimental results are discussed in more detail.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2001년도 하계학술대회 논문집 B
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• pp.950-952
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• 2001

This paper proposes a new zero-current transition (ZCT) pulse-width modulation (PWM) switch cell that overcomes the limitations of the conventional ZCT converters. The proposed ZCT cell provides zero-current-switching (ZCS) condition for the main switch and the auxiliary switch. The conduction loss and current stress of the main switch are minimized, since the circulating current for the soft switching does not flow through the main switch. The proposed ZCT PWM switch cell is suitable for the high power applications employing IGBTs. Design guidelines with a design example are described and verified by experimental results from the 1 kW prototype boost converter operating at 70kHz.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1999년도 하계학술대회 논문집 F
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• pp.2691-2694
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• 1999

The multi-resonant converter(MRC) can reduce the switching losses exiting in a converter, so it is capable of operating at a high frequency. Such a few MHz high frequency application provides a high power density [$W/inch^{3}$]. But the high voltage stress across a switch of the resonant circuit is about 4$\sim$5 times the input voltage, it causes increasing of the conduction loss in MRC. In this paper, the mode analysis for the suggested AT Forward MRC with low voltage stress is discussed. The operational modes of the AT Forward MRC are divided to 8 equivalent modes according to the two switching sequences, Each mode is analyzed over all of the paper.