• 전력전자학회논문지
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• 제14권6호
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• pp.496-503
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• 2009

이 논문은 새로운 인터리브 방식 삼상 절연형 고효율 부스트 컨버터를 제안한다. 이 컨버터는 삼상 전력변환 방식을 채택하여 보다 큰 전력전송 능력을 갖으며 각 상의 rms 전류값이 작으므로 전도손실도 작다. 이에 더하여, 삼상 부스트 컨버터의 인터리브 동작으로 인하여 입력 전류 리플이 줄어들고, 실효 동작 주파수의 증가로 필터소자의 크기가 작아져서 높은 전력밀도를 갖는다. 부스트 컨버터 출력의 각 상 전류는 제안된 3 상 PWM 구동방식에 따라 전류 연속모드로 동작하여 3 상 변압기로 통합된다. 이 컨버터는 전도손실이 작아 96% 이상의 효율로 동작하며 능동클램프의 작용으로 스위칭 손실도 역시 작다. 제안된 컨버터와 PWM 구동방식을 분석 및 시뮬레이션 하고 하드웨어로 제작하였다. 제작된 시제품을 500 W 급으로 실험하여 모든 설계검증 및 해석을 실시하였다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2009년도 제40회 하계학술대회
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• pp.907_908
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• 2009

현재 학계에서는 Soft Switching 방식에 대한 다양한 토폴로지 연구가 활발히 이루어지고 있다. 본 논문에서는 Soft Switching을 이용한 새로운 절연형 DC/DC 컨버터 토폴로지를 제안하였다. 제안된 토폴로지는 입력전압의 거의 모든 영역에 대하여 97% 이상의 효율을 가짐을 검증하였다.

• 전력전자학회논문지
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• 제23권3호
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• pp.161-167
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• 2018

In battery-operated systems, an isolated converter is used to interface the utility grid with the system to increase stability when charging and discharging batteries. Systems such as vehicle-to-grids (V2Gs), on-board chargers, and energy storage systems (ESSs) have recently become popular, and the roles of isolated converters have become important considerations in fabricating such devices. A fixed-frequency LLC converter, which is a type of isolated converter, presents the advantages of high efficiency and high power density by performing zero-voltage switching (ZVS) over wide frequency ranges. However, the magnetizing inductance of the LLC converter should be designed to enable ZVS in all switching devices. Therefore, in this study, the operating characteristics of the LLC circuit are analyzed, and an optimal design method for ZVS operation is established. Moreover, an 8 kW LLC high-efficiency and high-power-density resonant converter is designed and tested for ESS application. The LLC converter achieves 98% efficiency at rated power.

• 전력전자학회:학술대회논문집
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• 전력전자학회 1998년도 Proceedings ICPE 98 1998 International Conference on Power Electronics
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• pp.68-73
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• 1998

This paper presents a novel prototype of active voltage clamped quasi-resonant ZVS-PWM forward DC-DC converter designed for specific low voltage high current application. We establish the soft-switching forward converter with a high frequency isolated link which can efficient operate over wide load ranges under conditions of zero voltage soft-switching and active voltage clamped switching. In addition, we evaluate connection of the soft-switching forward converter with large capacitor which capacitance is over 100[F].

• Journal of Power Electronics
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• 제16권5호
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• pp.1669-1677
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• 2016

A new auxiliary circuit for boost, buck, buck-boost, Cuk, SEPIC, and zeta converters is introduced to provide soft switching for pulse-width modulation converters. In the aforementioned family of DC-DC converters, the main and auxiliary switches turn on under zero current transition (ZCT) and turn off with zero voltage and current transition (ZVZCT). All diodes commutate under soft switching conditions. On the basis of the proposed converter family, the boost topology is analyzed, and its operating modes are presented. The validity of the theoretical analysis is justified by the experimental results of a 100W, 100 kHz prototype. The conducted electromagnetic emissions of the proposed boost converter are measured and found to be lower than those of another ZCT boost converter.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2001년도 춘계학술대회 논문집 전기기기 및 에너지변환시스템부문
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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.

• 전기학회논문지
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• 제58권1호
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• pp.86-92
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• 2009

This paper presents development of 6kw ZVS(Zero Voltage Switching) boost converter by 4-parallel operation. To realize a high capacity converter with 6 kw, 4-parallel operation of 1.5kW unit module is proposed in this paper. To meet high ratio input to output voltage, isolated type booster converter is designed. To achieve ZVS operation of 4-switches of full bridge and protect a voltage overshoot caused by switch turn-off, simple active-clamp circuit is applied to the primary side. For parallel operation of 4-modules, master-slave control method is proposed to achieve input current sharing of 4-unit converter modules accurately. For performance tests, simulation is carried out. Also, load and experimental tests of the developed booster converter, 230Vdc/6kW, are carried out under various conditions. For field tests, the developed converter is applied for boosting a battery power to high DC_link voltage for a VSI inverter which starts a micro-turbine(MT) installed in vehicle and it's performance is verified through high speed motoring a MT up to tens of thousands of rpm.

• Journal of Power Electronics
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• 제13권4호
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• pp.507-515
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• 2013

This paper presents an isolated bidirectional dc/dc converter based on primary parallel isolated boost converter (PPIBC). This topology is an efficient solution in low voltage high power applications due to its ability to handle high currents in the low voltage side. In this paper, the converter has been modeled using non-ideal components and operated without any additional circuitry for startup using a digital soft-start procedure. Simulated and measured loop gains have been compared for the validity of the model. On-the-fly current direction change has been achieved with a prototype interconnecting two battery banks. A second prototype has been constructed and tested for supercapacitor operation in constant power charge mode.

• 전력전자학회논문지
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• 제22권2호
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• pp.102-108
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• 2017

Proper design guides are proposed for a practical dual-active bridge (DAB) converter based on the mathematical model on the steady state. The DAB converter is popular in bidirectional application due to its zero-voltage capability and easy bidirectional operation for seamless control, high efficiency, and performance. Some design considerations are taken to overcome the limitation of the DAB converter. The practical design methodology of power stage is discussed to minimize the conduction and switching losses of the DAB converter. Small-signal model and frequency response are derived and analyzed based on the generalized average method, which considers equivalent series resistance, to improve the dynamics, stability, and reliability with voltage regulation of the practical DAB converter. The design of closed-loop control is discussed by the derived small-signal model to obtain the pertinent gain and phase margin in steady-state operation. Experimental results of a 3.3 kW prototype of DAB converter demonstrate the validity and effectiveness of the proposed methods.

• 전력전자학회논문지
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• 제14권4호
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• pp.315-322
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• 2009

기존의 부스트 컨버터는 출력 전압이 커질수록 스위치와 다이오드의 전압, 전류 스트레스가 커지고 다이오드 역 방향회복에 의한 서지로 인해 실제 사용 가능한 승압비가 제한된다. 본 논문에서는 고승압 응용에 적합한 새로운 비절연 부스트 컨버터를 제안한다. 제안한 컨버터는 듀티비 0.5로 약 6배의 승압비를 가지며 CCM에서도 ZVS 스위칭이 가능하므로 넓은 ZVS 영역을 갖는다. 또한 스위치와 다이오드 전압정격이 출력전압의 1/3로 작고 인터리빙이 가능하여 입출력 수동소자의 정격도 작다. 다이오드도 ZCS 턴오프 동작으로 인해 역방향 회복에 의한 서지가 거의 없다. 제안하는 컨버터의 동작원리를 설명하였고 이론적 해석과 시뮬레이션 및 실험을 통해 타당성을 검증하였다.