• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.3
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• pp.491-499
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• 2019

Recently, there has been increasing demand for power quality in power supply devices. The IEC 61000-3-2 standard requires that the AC / DC power supply for lighting meet the specifications for the power factor (PF) and total waveform distortion (THD). In addition, advanced countries in Europe are regulating the ripple rate as 15 ~ 30% for the flicker phenomenon caused by the change in the amount of foot energy due to the change in current of the output terminal. Therefore, domestic standards and regulations are being updated. This study adopted the Flyback converter to satisfy the PFC standard, and has the circuit first and second insulation function. To reduce the low frequency ripple of the LED current, Flyback, Coupled Inductor, LC parallel resonance filter, LLC resonance filter, and Cuk were simulated by PSIM to mimic each LED driving circuit. A coupled LC resonant circuit with a coupled inductor on the primary side and LC resonance on the secondary side was also proposed for output side ripple reduction.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 1992.11a
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• pp.51-55
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• 1992

By using the state plane approach, the steady state analysis and design of a half bridge parallel-series (LLC-type) resonant converter (HBPSRC) operating in the continous conduction made is presented. The state-plane diagram representation of the converter response gives good insight into the converter operation. Based on this analysis, a set of steady state characteristic waves for HBPSRC is presented. A simple design procedure is given and design example for a 100watts, 30KHz HBPSRC is presented for illustrative purposes.

• Proceedings of the KIPE Conference
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• 2012.11a
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• pp.95-96
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• 2012

본 논문에서는 조명용 LED 구동 장치를 위한 새로운 방식의 단일전력단을 갖는 LED 구동회로를 제안한다. 제안 회로는 임계모드에서 동작하는 부스트 컨버터를 역률 개선 회로로 사용하였고, LED 구동회로로 LLC 고주파 공진 회로를 채택하였다. 또한, 기존의 역률 개선 회로와 LED 구동회로의 2단 회로를 단일전력단을 갖는 회로로 구성함으로 고역률, 고효율, 경량 및 소형의 LED 구동회로를 구성하였다. 본 논문에서는 제안한 회로의 동작 원리를 설명하였고, 시뮬레이션과 실험을 통하여 제안 회로의 타당성을 입증하였다.

• Proceedings of the KIPE Conference
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• 2012.11a
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• pp.39-41
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• 2012

• Proceedings of the KIPE Conference
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• 2014.07a
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• pp.183-184
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• 2014

• Journal of Power Electronics
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• v.15 no.5
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• pp.1158-1167
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• 2015

In this paper, a new hybrid DC-DC converter is proposed for electric vehicle 3.3 kW on-board battery charger applications, which can be modulated in a phase-shift manner under a fixed frequency or frequency variation. By integrating a half-bridge (HB) LLC series resonant converter (SRC) into the conventional phase-shift full-bridge (PSFB) converter with a full-bridge rectifier, the proposed converter has many advantages such as a full soft-switching range without duty-cycle loss, zero-current-switching operation of the rectifier diodes, minimized circulating current, reduced filter inductor size, and better utilization of transformers than other hybrid dc-dc converters. The feasibility of the proposed converter has been verified by experimental results under an output voltage range of 250-420V dc at 3.3 kW.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.29 no.6
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• pp.96-108
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• 2015

his study deals with a power conversion unit of an anti-start air conditioner compressor system for the commercial vehicle. In case of converter, to reduce the switching losses and current stresses of the device, applies LLC resonant topology. Transformer leakage inductance in the full-bridge converter is used for making the resonance with the capacitor of the voltage-doubler. Through this method we can increase power and decrease volume of system. Both circuit analysis and design guideline are described. So in this paper, power conversion unit is designed. 2.5kW anti-start air conditioner compressor system was implemented, and system operation and stability was verified through experiment.

• Proceedings of the KIPE Conference
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• 2012.11a
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• pp.85-87
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• 2012

This paper describes the design and analysis of an integrated transformer magnetic core which comprises of two different power cores with PFC inductor and LLC resonant transformer magnetic cores. The equivalent magnetic circuit modeling approach is employed to analyze the variations in coupling coefficient and inductance in terms of air gaps under the operations of the respective power core. Simulation and experimental studies are performed with a fabricated prototype integrated core and their results are discussed.

• Proceedings of the KIPE Conference
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• 2015.07a
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• pp.319-320
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• 2015

A hybrid converter for the on-board charger consisting of a soft switching full bridge (SSFB) and a half bridge (HB) LLC resonant converter is proposed. The proposed topology adopts an additional switch and a diode at the secondary side of SSFB converter to guarantee the wide ZVS range of primary side switches and to eliminate the circulating current. The output voltage is regulated by controlling the duty cycle of secondary side switch. The effectiveness of the proposed converter was experimentally verified using a 10-kW prototype circuit. The experimental results show 96.8% peak efficiency.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.64 no.8
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• pp.1207-1211
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• 2015

Various laser systems have been widely used in almost all industrial technologies because they have high energy density, directivity and coherence. Recently the clinical application is becoming wider in medical parts such as incurable disease, diagnosis and so on. Generally, ruby laser beam has the greatest efficacy for removing tattoos, freckle and other skin problem. But current medical ruby laser system has the maximum repetition rate of 2Hz and optical output beam energy of 1J. Many medical doctors really want to have a high repetition ruby laser system because that can reduce the operation time. We investigated a new ruby laser system with high repetition rate of 4Hz using double cavities. Furthermore, we develop a new power supply system adopting zero voltage switching(ZVS) to minimize switching loss by LLC resonant converter designed as 2kW class.