• Proceedings of the KIPE Conference
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• 2000.07a
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• pp.396-399
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• 2000

기존이 역률보상회로가 별도의 전력변화단을 가지고 있어 소자수가 많아지고 복잡한 하드웨어 구성을 가지고 있는 단점이 있다 본 논문에서는 별 도의 전력변환단을 가지지않고 PFC기능을 가지는 단일 전력단(Single-Stage) 단상 AC/DC Forward Converter에 대하여 실험하여 검증하였다

• Proceedings of the KIPE Conference
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• 1998.10a
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• pp.252-257
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• 1998

Two-stage power factor correction (PFC) converter with a single PWM controller for universal input voltage (90-264V) is proposed. It consists of a power factor pre-regulator cascaded by a DC/DC converter as in a conventional two-stage approach. However, a single PWM controller is used as in a single-stage, single-switch PFC approach. The switch in the PFC part is synchronized with the switch in the DC/DC converter with a fixed switching frequency. Employing an adaptive delay scheme the switch in the PFC part is controlled to limit the energy storage capacitor voltage within a designed range for the optimum efficiency, and to reduce input current harmonic distortion. The experimental results obtained on a 200W (5V/40A) prototype PFC converter are given to verify the effectiveness of the proposed control method.

• Proceedings of the KIEE Conference
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• 2000.11b
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• pp.368-371
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• 2000

Two-stage power factor correction (PFC) converter with a single PWM controller is proposed. It consists of a power factor pre-regulator cascaded by an isolated DC/DC converter as in a conventional two-stage approach. However, a single PWM controller is used as in a single-stage, single-switch PFC approach. This converter gives the goof power factor correction, low line current harmonic distortions, and tight output voltage regulations. This converter also has a high efficiency by employing an soft switching method. The proposed approach has advantages such as high performance over the single-stage approach and low cost over two-stage approach. The experimental results obtained on a 300W (30V/10A) prototype PFC converter are given to verify the effectiveness of the proposed control method.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.15 no.6
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• pp.49-57
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• 2001

This paper analyzed PFC of active clamp ZVS flybark converter by adding two method PFC (Power Factor Correction) circuit-two-stage and single-stage. The addition of active clamp circuit also provide a mechanism fur achieving ZVS of both the primary and auxiliary switches. ZVS also limits the turn off di/dt of the output rectifier, reducing rectifier switching loss and switching noise, due to diode reverse recovery. As a results, the proposed converters have characteristics of the reduced switching noise and high efficiency in comparison to conventional flyback converter. The simulation and experimental results show that the proposed converters improve the input PF of 300[W] ZVS flyback converter by adding single-stage two-stage PFC circuit.

• Journal of Power Electronics
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• v.7 no.4
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• pp.328-335
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• 2007

A conventional Single-Stage Power-Factor-Correction (PFC) AC/DC converter has a link capacitor voltage problem under high line input and low load conditions. In this paper, this problem is analyzed by using the voltage conversion ratio of the DC/DC conversion cell. By applying this analysis, a new Single-Stage PFC AC/DC converter with a boost PFC cell integrated with a Voltage-Doubler Rectified Asymmetrical Half-Bridge (VDRAHB) is proposed. The proposed converter features good power factor correction, low current harmonic distortions, tight output regulations and low voltage of the link capacitor. An 85W prototype was implemented to show that it meets harmonic requirements and standards satisfactorily with near unity power factor and high efficiency over universal input.

• Proceedings of the KIEE Conference
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• 2003.04a
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• pp.270-272
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• 2003

Switching power supplies are widely used in many industrial fields. Power factor correction(PFC) circuits have tendency to be applied in new power supply designs. The input active power factor correction(APFC) circuits can be implemented using either the two-stage approach or the single-stage approach. The single-stage PFC circuit has advantage to reduce the number of components by eliminating a need for the PFC switch and control circuit. However, unlike in the two-stage approach, the do voltage on the energy storage capacitor in a single-stage PFC circuit is not well regulated. As a result. in universal line application($90{\sim}265Vac$), the storage capacitor voltage varies with the load and line variation. In this paper, the performance of output voltage regulation and transient response are clarified here. The validity of designed boost PFC circuit is confirmed by MATLAB simulation and experimental results of 2 [kW] prototype converter.

• Proceedings of the KIPE Conference
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• 1998.07a
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• pp.401-404
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• 1998

This paper proposes a new soft switching single stage AC/DC full bridge converter with unit power factor and isolated output. This circuit shows that it is possible to combine the boost converter which is for PFC(Power Factor Correction) and full bridge converter which is for DC/DC converter. A simple auxiliary circuit which includes neither lossy components nor active switches eliminates ringing of secondary side of the transformer. The characteristics of the proposed circuit are investigated and the validity is verified by the simulation results.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.29 no.9
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• pp.81-88
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• 2015

LED has been great attentions in lighting industry because of its long life-time, high efficiency, excellent light output characteristics. However, the life-time of the LED driving system is decreased because of the electrolytic capacitor which is used in the power conversion system for driving LED lighting. Therefore the capacitance reduction methods have been studied to replace an electrolytic capacitor with film or tantalum capacitor. This paper presents the Single stage PFC flyback converter with the simplified third harmonic current injection circuit to reduce output capacitance and the proposed system is theoretically analyzed and verified through the experiment.

• KIEE International Transaction on Electrical Machinery and Energy Conversion Systems
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• v.4B no.2
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• pp.65-72
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• 2004

Switching power supply systems are widely used in many industrial fields. Power factor correction (PFC) circuits have a tendency to be applied in new power supply designs. The input active power factor correction (APFC) circuits can be implemented in either the two-stage approach or the single-stage approach. The two-stage approach can be classified into boost type PFC circuit and dc/dc converter. The power factor correction circuit with a boost converter used as an input power source is studied in this paper. In a boost power factor correction circuit there are two feedback control loops, which are a current feedback loop and a voltage feedback loop. In this paper, the regulation performance of output voltage and compensator to improve the transient response presented at the continuous conduction mode (CCM) of the boost PFC circuit is analyzed. The validity of designed boost PFC circuit is confirmed by MATLAB simulation and experimental results.

• Proceedings of the KIEE Conference
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• 2000.07b
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• pp.1292-1295
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• 2000

In this paper, we proposed a new single-stage single-switch power factor correction(S-4 PFC) converter with output electrical isolation. The configuration of this converter is achieved by combining a fly back circuit and a forward circuit in one power stage. To verify the theoretical analysis of the proposed converter, a design example is given with its Pspice simu-lation and experimental results.