• 한국산학기술학회논문지
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• 제11권11호
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• pp.4483-4488
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• 2010

LED는 다른 광원에 비해 동작수명이 길고, 친환경적이며, 에너지 효율이 높은 장점을 가지고 있다. 최근 LED 기술의 발전으로 인해 고휘도, 고용량의 LED가 개발됨에 따라, 표시장치에만 적용되던 LED를 조명장치에도 적용하는 기술이 확산되고 있다. 파워 LED는 동작의 안정성 및 신뢰성을 확보하기 위해 구동전류를 일정한 값 이하로 유지하는 전류제한기능이 필요한데, 본 논문에서는 전류제한기능을 포함한 하프브리지 LLC 직렬공진형 컨버터를 제안한다. 하프브리지 LLC 직렬공진형 컨버터는 다른 공진형 컨버터에 비해 상대적으로 입력전압 및 출력부하 범위가 광범위한 장점이 있으며, 변압기의 누설인덕턴스를 공진인덕터로 이용할 수 있기 때문에 마그네틱 소자를 줄일 수 있는 장점이 있다. 전류제한기능 및 역률개선기능을 포함하고 있는 출력전압 DC24[V], 200[W]급의 LED 조명장치 구동용 하프브리지 LLC 직렬공진형 컨버터의 설계 및 실험을 통해 타당성을 입증하였다.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2016년도 추계학술대회 논문집
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• pp.15-16
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• 2016

This paper proposes an isolated DCDC converter that consists of unregulated LLC resonant converter and non-isolated synchronous buck converter for battery charger of energy storage systems application. The unregulated converter operates as transformer with fixed duty ratio and switching frequency. The synchronous buck converter is installed in the output of the LLC resonant converter. And the converter charges and discharges the battery by controlling a current of battery. The proposed converter can get the high efficiency by separating function. This paper explains design of an unregulated converter and synchronous converter.

• 전력전자학회논문지
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• 제22권4호
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• pp.305-311
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• 2017

In this paper, the LLC resonant converter battery charger, using adaptive turn ratio scheme, is proposed to achieve high efficiency and wide range output voltage. The LLC converter high frequency transformer has an adaptively changed turn ratio by the auxiliary control circuitry. As a result, the optimal converter design with a large magnetizing inductance is easily achieved to minimize the conduction and the turn-off losses while providing widely regulated voltage gain capability to properly charge the Li-ion battery. The proposed converter operational principle and the optimal design considerations are illustrated in detail. Finally, several simulation results verify the proposed LLC resonant converter's effectiveness.

• 전기학회논문지
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• 제63권7호
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• pp.924-928
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• 2014

LLC resonant converter is used to control laser power density in ruby laser power supply. Zero voltage switching(ZVS) is implemented to minimize the switching loss by the LLC resonant converter. Laser output power is investigated and experimented by changing the output current. That current is controled by the charging voltage of capacitor. From those results, we obtained the maximum laser output of 1.94J at the discharge current of 860A and the pulse repetition rate of 1Hz.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2011년도 전력전자학술대회
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• pp.23-24
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• 2011

In this paper, the 170W LLC half bridge DC-DC converter is designed for the lighting management system. The power conversion circuit consists of PFC and isolated LLC resonant converter. The topology of LLC half bridge resonant converter provides ZVS characteristic. And the stresses of voltage and current is smaller than that of the general resonant converters. So we can expect the higher efficiency. The optimal conditions for high efficiency were investigated through by experiment.

• 전력전자학회논문지
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• 제16권6호
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• pp.627-637
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• 2011

본 논문은 새로운 형상을 가지는 평면 변압기를 적용한 200W급 공진컨버터에 대한 내용이다. 제안된 평면변압기는 기존 누설인덕턴스가 작은 평면변압기와 달리 누설인덕턴스가 조정이 가능하여 원하는 공진 특성을 얻을 수 있는 특징을 가지는 저가형 고집적화에 용이한 변압기이다. 본 논문에서는 제안된 평면변압기를 적용하여 200W급 전원장치에 적용하여 실험하였으며, 실험결과와 이론적인 해석에 대해 서술하였다.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2007년도 하계학술대회 논문집
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• pp.424-427
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• 2007

The LLC series resonant converter with a LLT (Inductor-Inductor-Transformer) transformer for PDP power supply is presented. LLT transformer used to combine the inductor and transformer into one unit has the increased leakage inductance in the primary and secondary due to the winding method and the use of the gaped core. The increased leakage inductance in the primary and secondary of LLT transformer can be impacted on the DC voltage gain characteristics of LLC series resonant converter. In this paper, DC gain characteristics and the experimental results of the LLC series resonant converter with a LLT transformer are verified on the Math-CAD simulation based on the theoretical analysis and the 600W experimental prototype.

• 전력전자학회논문지
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• 제26권1호
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• pp.46-52
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• 2021

This study proposes a feedforward compensation control method to reduce 120 Hz output voltage ripple in a single-phase AC/DC rectifier system composed of PFC and LLC resonant converters. The proposed method compensates for the voltage ripple of the DC-link by using the AC input and DC output power difference, and then reduces the final output voltage ripple component of 120 Hz through feedforward compensation based on the linearized frequency gain curve of the LLC resonant converter. Through simulation and experimental results, the validity of the ripple reduction performance was verified by comparing the conventional PI controller and the proposed feedforward compensation method.

• 전력전자학회논문지
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• 제20권1호
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• pp.51-58
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• 2015

In order to decrease the size of a switch mode power supply, high switching frequency can be an efficient way to reduce the size of passive components in the converter. In this paper, a 500-kHz high-frequency LLC resonant converter is proposed with an accurate design method of magnetizing inductance, as well as the relationship between the switching frequency and the size of the passive components. Simulation and experimental results are presented to verify the proposed methods and equations, including the temperature data of each passive and active device of the converter. Using those results, dominant power losses in the prototype converter under 500-kHz high-frequency operation are investigated, compared with the results from a 100-kHz converter. In addition, operating waveforms and power conversion efficiency will be shown to obtain design considerations for the high switching frequency LLC resonant converter.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2006년도 제37회 하계학술대회 논문집 B
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• pp.1039-1040
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• 2006

The resonant converters cause the high voltage stress according to the input voltage, which increases the conduction loss in converter power switches. The topology of LLC half bridge resonant converter provides ZVS characteristic and also the stress of voltage and current is not higher than that of the general resonant converters. So we can expect the higher efficiency. In this paper, the LLC resonant converter is designed for the notebook computer adapter. In the adapter design, we should consider the weight, the size and 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 of the pre-regulator. It converts AC line input into about $400V_{DC}$ Link voltage of the LLC converter input and the converter has $16V_{DC}/90W$ ratings. The efficiency measured is about up to 92%.