• The Transactions of The Korean Institute of Electrical Engineers
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• v.62 no.8
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• pp.1090-1094
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• 2013

In this paper, a method to cope with short-term interruption is proposed. The proposed method uses a capacitor bank consisting of supercapacitors. A supercapacitor is a good means for energy storage for short-term usage. The proposed circuit is simple and accordingly easy to construct and to control. A prototype of 360 W single-phase PFC ac-dc converter is constructed and experimental results are presented.

• Proceedings of the KIPE Conference
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• 2004.07b
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• pp.547-550
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• 2004

An interleaved single-stage power-factor-correction (PFC) AC/DC converter is presented in this paper. The proposed converter is combined by two single-stage AC/DC converters based on flyback converter Each PFC stage operates in discontinuous conduction mode (DCM). By exploiting the interleaving technique, the input ripple current and output ripple voltage are reduced. The proposed converter complied with EN/1EC61000-3-2 harmonic regulations achieves high efficiency and low cost. The performance of the proposed converter was evaluated on a 180W $(90W\times2,\;24V,\;7.5A)$ experimental prototype.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2013.05a
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• pp.534-535
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• 2013

최근 LED 기술을 활용한 LED 조명은 밝기와 수명 및 저전력이라는 장점으로 인하여 현재 시중에 급속도로 퍼저 나가고 있다. 이러한 LED를 조명으로 사용하기 위한 기반 기술은 SMPS(Switching Mode Power Supply) 설계 기술이라 할 수 있다. 또한 LED 성능은 입력 전원 상태 및 LED 조명의 부하 조건에 따라 오차가 발생하여 LED등의 균일한 밝기를 유지하는데 기술적으로 많은 어려움이 있다. 본 논문에서는 12[W] 급 LED 다운 라이트에 대하여 LED SMPS의 전류 출력에 대하여 정전류제어를 함으로서 입/출력 조건의 변동에 대응하여 보다 안정적인 LED 등의 균일한 밝기를 유지하기 위한 12[W] 급 LED 다운 라이트용 SMPS에 PFC(Power Factor Correction) 회로를 추가하여 역율을 개선을 하며, 전압 위상에 따른 전류 위상 분포를 규일 비율로 제어 하여 보다 안정적인 밝기를 제공하는 12[W] 급 LED 조명용 SMPS를 개발하여 상품화를 제안하고자 한다.

• Journal of Power Electronics
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• v.11 no.3
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• pp.264-270
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• 2011

In this paper a novel passive snubber is proposed, which can suppress the voltage spike across the bridge leg of the isolated full-bridge boost topology. The snubber is composed of capacitors, inductors and diodes. Two capacitors connected in series are used to absorb the voltage spike and the energy of each capacitor can be transferred to the load during one switching cycle by the resonance of the inductors and capacitors. The operational principle of the passive snubber is analyzed in detail based on a three-phase power factor correction (PFC) converter, and the design considerations of both the converter and the snubber are given. Finally, a 3kW laboratory-made prototype is built. The experimental results verify the theoretical analysis and evaluations. They also prove the validity and feasibility of the proposed methods.

• Proceedings of the KIEE Conference
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• 2005.04a
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• pp.172-175
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• 2005

Recently international regulations governing the amount of harmonic currents(e.g IEC 61000-3-2) became mandatory and active Power factor correction (PFC) pre-regulator circuit became inevitable for the AC/DC converters. Among these topologies, the boost topology represents an optimum solution for a PFC pre-regulation in a high power application. This paper propose improved ZVT(Zero Voltage Transition) AC/DC PFC Boost using the average current control employing a soft-switching technique of the auxiliary switch with a minimum number of components. The conventional ZVT PFC Boost Converter has a disadvantage that the auxiliary switch turns off hard, which influences the overall efficiency and the EMI problem. In this paper, an improved ZVT PFC Boost converter using active snubber is proposed to minimize the switching loss of the auxiliary. The prototype of 100kHz, 640W system was implemented to show the improved performance.

• The Transactions of the Korean Institute of Power Electronics
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• v.23 no.6
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• pp.389-396
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• 2018

This study proposes a control method using a repetitive controller for a boost-type PFC rectifier with an APD circuit structure to improve the current distortion caused by DCM condition. Conventional proportional integral controllers have bandwidth limitations in DCM conditions. The performance improvement of the APD controller in the DCM region is verified through simulations and experiments on the compensation of harmonics by the repetitive controller.

• Proceedings of the KIPE Conference
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• 2002.07a
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• pp.781-783
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• 2002

In this paper, the experiment results of the Boost converter for PFC(power factor correction) are presented. The performance of the 1kW class PFC rectifier with the average current mode control are evaluated. A 1kW, 100kHz system prototype was built and experimental results are presented to verify the design. As a results, power conversion efficiency above $95\%$ and power factor above $99\%$ were obtained.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.13 no.3
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• pp.82-92
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• 1999

In this paper, we realize the active PFC(Power Factor Correction) system of the BF(Boost Forward) converter with the PWM-PFM control technique to control DC output voltage, to rermve the noise like hanronics at the output voltage, amd to control the input ClUTent with sinusoidal wave synchronized by the source voltage. We take the simulation and analyze the switching signal of the BF converter, input/output voltage and current, its harmonics and power factor through PSpice. And it has bren obtained harmonic reduction and efficiency improverrent.errent.

• The Transactions of the Korean Institute of Power Electronics
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• v.20 no.1
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• pp.65-71
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• 2015

This paper presents the efficiency analysis of a critical current mode interleaved PFC rectifier, in which each of three different semiconductor switches is employed as the active switch. The Si FET, SiC FET, and GaN FET are consecutively used with the prototype PFC rectifier, and the efficiency of the PFC rectifier with each different semiconductor switch is analyzed. An equivalent circuit model of the PFC rectifier, which incorporates all the internal losses of the PFC rectifier, is developed. The rms values of the current waveforms main circuit components are calculated. By adapting the rms current waveforms to the equivalent model, all the losses are broken down and individually analyzed to assess the conduction loss, switching loss, and magnetic loss in the PFC rectifier. This study revealed that the GaN FET offers the highest overall efficiency with the least loss among the three switching devices. The GaN FET yields 96% efficiency at 90 V input and 97.6% efficiency at 240 V, under full load condition. This paper also confirmed that the efficiency of the three switching devices largely depends on the turn-on resistance and parasitic capacitance of the respective switching devices.

• Proceedings of the KIPE Conference
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• 2003.07a
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• pp.434-438
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• 2003

This paper present an investigation of the influence on the PFC(power factor correction) circuit with characteristics variation of MPP (Molybdenum permalloy powder) core. The experiment results of the 1.5kW class Boost converter for PFC rectifier with the average current mode control are evaluated to verify the influence on the PFC converter with inductance variation of the MPP core. As a results, it is shown that the ripple of the inductor using a MPP core increase with output power of the converter.