• 전력전자학회논문지
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• 제12권2호
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• pp.174-182
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• 2007

신재생에너지 중에서 태양광 에너지가 중요 에너지원으로서 각광받고 있고 적용이 증대되고 있다. 특히, 미래에는 하이브리드 태양광 발전 시스템이 독립 분산 전원 시스템으로 널리 사용될 것으로 예상되고 있다. 본 논문에서는 DC전력을 기계적인 접촉에 의해 전달하는 것보다는 마그네틱 커플링에 의해 비접촉으로 에너지를 전달 할 수 있는 무접점전원장치를 사용한 직류수용가 서비스 태양광발전시스템을 제안하였다. 제안 적용된 무접점 전원장치는 무접점 변압기와 Half-bridge LLC 공진컨버터, 영 전압 스위칭 Boost컨버터로 구성되어 있다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2005년도 제36회 하계학술대회 논문집 B
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• pp.1401-1403
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• 2005

This paper presents generalized small-signal models for asymmetrically-driven double-ended dc-to-dc converters. The proposed small-signal models include the effects of the parasitic resistances, which have dominant influence on the damping of the secondary power stage double-pole. To confirm the validity of new models, an asymmetrical half-bridge converter with center-taped rectifier and a forward-flyback converter with current doubler rectifier were built, and their performances were compared with the theoretical predictions.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2013년도 추계학술대회 논문집
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• pp.101-102
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• 2013

본 논문은 dual half bridge converter와 full-bridge converter가 결합된 절연형 양방향 컨버터를 제안하였다. 기존의 전류원 컨버터는 스위치가 턴-오프 시 전압 스파이크 문제가 발생한다. 이와 같은 문제를 해결하기 위해 절연형 양방향 컨버터에 공진 커패시터와 공진 인덕터를 추가하였다. 추가된 공진 소자들에 의해 준공진이 발생하고 이를 이용하여 스위치의 zero voltage switching (ZVS)조건을 충족시킬 수 있다. 그 결과 제안된 컨버터의 모든 스위치는 소프트 스위칭을 달성하고 전압 스파이크 문제를 해결 할 수 있다. 이를 이론적인 분석과 시뮬레이션을 통해 검증하였다.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2003년도 추계학술대회 논문집
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• pp.99-103
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• 2003

Recently, a fuel cell with low voltage and high current of electronic output characteristics is remarkable for new generation system. It needs both a dc-dc boost converter and do-ac inverter to be used in domestic power. Therefore, this paper presents do-dc boost converter with ZVS for fuel cell generation system This topology has several advantages, which are ZVS characteristics of all of main and auxiliary switches, reduction of reactor component size because of high frequency switching, and low rated voltage stress of the switches. In this paper, theoretical analysis, operation principle, and design procedures are presented. And simulation results from Pspice are presented to validate the theoretical analysis.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2019년도 전력전자학술대회
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• pp.153-155
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• 2019

This paper proposes a two-phase interleaved bridgeless single-stage ac-dc converter with magnetic integration that can achieve CCM power factor correction without input current sensing. All switches achieve ZVS turn-on and all diodes achieve ZCS turn-on for the whole grid cycle. SDAB-based modulation strategy is applied which results in simple power control and wide range output voltage. A flux cancellation method to integrate the interleaved transformer is firstly proposed in this paper to reduce the core size and loss. Experimental results on a 1.7-kW, 50kHz prototype are given to verify the principle and advantages of the proposed ac-dc converter.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2013년도 전력전자학술대회 논문집
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• pp.102-103
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• 2013

화석 연료의 고갈과 유가 급등으로 인해 자동차 업체에서는 친환경 차량 개발에 힘쓰고 있다. FCEV는 차량 구동용 전동기에 필요한 에너지를 연료전지를 통해 공급받게 된다. 하지만 연료전지의 특성상 연료전지와 배터리를 같이 사용하게 된다. 본 논문에서는 일반적인 Half-bridge 타입의 양방향 컨버터에 스위치를 추가하여 양방향 buck, boost가 가능한 컨버터를 설계하였다. 전동기 구동용 인버터는 전압형 인버터가 사용되는데 전압형 인버터에서 발생하는 출력은 데드타임과 스위칭 소자의 전압 강하에 의해 왜곡된 전압과 전류를 출력하게 되고 이러한 출력은 토크와 속도에 나쁜 영향을 끼치게 된다. 이러한 문제를 해결하기 위해 전동기의 속도에 따라 DC-link 전압을 가변하여 공급한다.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2018년도 추계학술대회
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• pp.51-53
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• 2018

The Low Voltage DC-DC converters (LDCs) of the Electric Vehicles require high power density and high efficiency operation over the wide range of load and input voltage variations. This paper introduces a novel topology which combines three 1 MHz Half-Bridge (HB) LLC resonant converters and an Inverting Buck-Boost (IBB) converter to adjust the output voltage without frequency modulation. The switching frequency of the proposed converter is fixed at 1MHz to achieve a constant frequency operation for the resonant converter. In the proposed topology GaN FETs and planar transformers are employed to optimize the converter operation at high frequency. A 1 MHz/1.8 kW prototype converter is built to verify the feasibility and the validity of the proposed LDC topology.

• Journal of Electrical Engineering and Technology
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• 제13권4호
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• pp.1528-1538
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• 2018

In this paper, configuration of $1-{\phi}$ seven-level boost DC-link cascade based reversing voltage multilevel inverter (BDCLCRV MLI) is proposed for uninterrupted power supply (UPS) applications. It consists of three level boost converter, level generation unit and full bridge circuit for polarity generation. When compared with conventional boost cascaded H-bridge MLI configurations, the proposed system results in reduction of DC sources, reduced power switches and gate drive requirements. Inverter switching is accomplished by providing appropriate switching angles that is generated by any optimization switching angle techniques. Here, round modulation control (RMC) method is taken as the optimization method and switching angles are derived and the same is compared with various switching angles methods i.e., equal-phase (EP) method, and half-equal-phase (HEP) method which results in improved quality of obtained AC power with lowest total harmonic distortion (THD). Reduction in DC sources and switch count makes the system more cost effective. A simulation and prototype model of $1-{\phi}$ seven-level BDCLCRV MLI system is developed and its performance is analyzed for various operating conditions.

• 전기학회논문지
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• 제56권8호
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• pp.1418-1423
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• 2007

The topology of LLC half bridge resonant converter provides ZVS characteristic. The voltage stress and current stress are smaller than that of the general resonant converters. So the LLC HB resonant converter can be considered as a optimal circuit for the notebook computer adapter. In the adapter design, we should consider the weight, the size and the overheat of the adapter. Thus the higher efficiency is an essential particular. First of all, the optimal design of transformer is the most important facts. Some parameters should be considered in order to get the highest efficiency. The adapter is designed through the considering of these parameters including the PFC circuit as the pre-regulator. It converts AC line input into about DC 390V link voltage of the LLC HB converter input and the converter has 16V/90W ratings. The efficiency measured is about up to 93%.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2003년도 하계학술대회 논문집 C
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• pp.1821-1823
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• 2003

We propose a high voltage dc-dc converter for CW(continuous wave) $CO_2$ laser system using a current resonant half-bridge inverter and a Cockcroft-Walton circuit. This high voltage power supply includes a 2-stage voltage multiplier driven by a regulated half-bridge series resonant inverter. The inverter drives a step-up transformer and the transformer secondary is applied to the voltage multiplier. Thus, it has high efficiency because of the less switching losses by virtue of the current resonant half-bridge inverter, and also compact size, small parasitic capacitance in the transformer stage owing to the low number of a winding turn of the step up transformer secondary by combining with Cockroft-Walton circuit. We could be obtained the maximum laser output power of 44 W and the maximum system efficiency of over 16 %.