• Journal of the Korea Academia-Industrial cooperation Society
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• v.11 no.7
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• pp.2570-2578
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• 2010

This paper presents a digital-controlled single-phase power-factor correction (PFC) converter operating in critical current conduction mode. The proposed converter utilizes the DC-DC boost converter topology for the PFC and operates the inductor current in critical conduction mode. Because the proposed converter is controlled digitally using a micom, its control circuit is simplified and the converter operates more effectively. This paper first explains the operational principles of the proposed converter and then analyzes the converter circuit. And this paper explains the implementation method of proposed converter with a detail design example, which is divided into software and circuit design parts. Also, it is shown through the experimental results of the prototype converter by the designed circuit parameters that the proposed converter has good performance as a single-phase PFC converter.

• Proceedings of the KIPE Conference
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• 2017.07a
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• pp.1-2
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• 2017

In this paper a method is proposed to optimize the inductor design of PFC boost converter with maximum efficiency at rated load. The variables of switching frequency, the number of turns, core size and permeability are selected to improve the efficiency. The experimental result shows the proposed inductor design method can lead a higher efficiency when compared with the typical inductor design method.

• 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 Power Electronics
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• v.15 no.2
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• pp.366-377
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• 2015

In order to minimize switching losses for high power applications, a boost PFC rectifier with a novel passive lossless snubber circuit is proposed. The proposed lossless snubber is composed of coupled inductors merged into a boost inductor. This method compared with conventional methods does not need additional inductor cores and it reduces extra costs to implement a soft switching circuit. Especially, the proposed circuit can reduce the reverse recovery current of output diode rectifiers due to the coupling effect of the inductor. During turn-on and turn-off operating modes, the proposed PFC converter operates under soft switching conditions with high power conversion efficiency. In addition, the performance improvement and analysis of the operating effects of the coupled inductors were also presented and verified with a 3.3 kW prototype rectifier.

• Journal of Power Electronics
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• v.7 no.4
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• pp.318-327
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• 2007

The design and performance analysis of a power factor corrected (PFC), single-phase, single switch flyback buck-boost ac-dc converter is carried out for low power battery charging applications. The proposed configuration of the flyback buck-boost ac-dc converter consists of only one switch and operates in discontinuous current mode (DCM), resulting in simplicity in design and manufacturing and reduction in input current total harmonic distortion (THD). The design procedure of the flyback buck-boost ac-dc converter is presented for the battery charging application. To verify and investigate the design and performance, a simulation study of the flyback buck-boost converter in DCM is performed using the PSIM6.0 platform. A laboratory prototype of the proposed single switch flyback buck-boost ac-dc converter is developed and test results are presented to validate the design and developed model of the system.

• The Transactions of the Korean Institute of Power Electronics
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• v.19 no.1
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• pp.91-97
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• 2014

Recently, the LED(Light Emitting Diode) is expected to replace conventional lamps including incandescent, halogen and fluorescent lamps for some general illumination application, due to some obvious features such as high luminous efficiency, safety, long life, environment-friendly characteristics and so on. To drive the LED, a single stage PFC(Power Factor Correction) flyback converter has been adopted to satisfy the isolation, PFC and low cost. The conventional flyback LED driver has the serious disadvantage of high 120Hz output current ripple caused by the PFC operation. To overcome this drawback, a new PFC flyback with low 120Hz output current ripple is proposed in this paper. It is composed of 2 power stages, the DCM(Discontinuous Conduction Mode) flyback converter for PFC and BCM(Boundary Conduction Mode) boost converter for tightly regulated LED current. Since the link capacitor is located in the secondary side, its voltage stress is small. Moreover, since the driver is composed of 2 power stages, small output filter and link capacitor can be used. Especially, since the flyback is operated at DCM, the PFC can be automatically obtained and thus, an additional PFC IC is not necessary. Therefore, only one control IC for BCM boost converter is required. To confirm the validity of the proposed converter, theoretical analysis and experimental results from a prototype of 24W LED driver are presented.

• Journal of Electrical Engineering and Technology
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• v.9 no.5
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• pp.1592-1601
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• 2014

In this study, a novel single phase soft switched power factor correction (PFC) converter is developed with active snubber cell. The active snubber cell provides boost switch both to turn on with zero voltage transition (ZVT) and to turn off with zero current transition (ZCT). As the switching losses in the proposed converter are too low, L and C size can be reduced by increasing the operating frequency. Also, all the semiconductor devices operate with soft switching. There is no additional voltage stress in the boost switch and diode. The proposed converter has a simple structure, low cost and ease of control as well. It has a simple control loop to achieve near unity power factor with the aid of the UC3854. In this study, detailed steady state analysis of the proposed converter is presented and this theoretical analysis is verified by a prototype of 100 kHz and 500 W converter. The measured power factor and efficiency are 0.99 and 97.9% at full load.

• Proceedings of the KIPE Conference
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• 2014.07a
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• pp.13-14
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• 2014

This paper is proposed the PFC control method of boost converter using a charging current of the capacitor. Around AC voltage peak point, PFC operation is stopped and the charging current of the capacitor is flowed. The charging current of the capacitor and the switching current makes the AC input current. The 150[W] converter was confirmed high PF and low THD.

• Proceedings of the KIPE Conference
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• 2007.07a
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• pp.435-437
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• 2007

Authors propose a PFC(power factor correction) Buck-Boost AC-DC converter by soft switching method. The proposed converter for a discontinuous conduction mode eliminates the complicated control requirement and reduces the size of components. The input current waveform in the converter is got to be a sinusoidal form of discontinuous pulse in proportion to magnitude of ac input voltage under the constant duty cycle switching.Therefore,the input power factor is nearly unity and the control algorithm is simple. To achieve high efficiency system, the proposed converter is constructed by using a partial resonant technique. The control switches using in the converter are operated with soft switching for a partial resonant. The control switches are operated without increasing their voltage and current stresses by the soft switching method. The result is that the switching loss is very low and the efficiency of converter is high.

• Proceedings of the KIPE Conference
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• 2007.07a
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• pp.353-355
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• 2007

A simple technique for PFC circuit is presented using UC3854. This technique is about current peak controlling by a reference current generator. Decreased peak currents of the boost pre-regulator reduce circuit current stress and so rated currents of circuit elements are minimized. Simulation and experimental results will verify the viability of the new scheme.