• Journal of Power Electronics
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• 제4권4호
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• pp.197-204
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• 2004

Two-stage Power-Factor-Correction (PFC) converters are the most common circuits for drawing sinusoidal and in phase current waveforms from an ac source with a good regulated output voltage. The first stage is a boost PFC converter with average-current-mode control for achieving the near-unity power factor and the second stage is a forward converter with voltage-mode control to regulate the output voltage. Stability analysis and design methods of two-stage PFC converters have previously been discussed using linear models. Recently, new nonlinear phenomena have been detected in pre-regulator boost PFC circuits and a new nonlinear model has been proposed for pre-regulated PFC converters. Therefore, investigation of two-stage PFC converters from the nonlinear viewpoint becomes important because the second stage DC/DC converter adds more complexity to the circuit. So, this paper introduces a study of the stability of two-stage PFC converters. A novel nonlinear model of two-stage PFC converters is proposed. Then, a stability analysis is made based upon this nonlinear model. The high correspondence between the simulated and experimental results confirms our analysis.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2000년도 추계학술대회 논문집 학회본부 B
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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.

• 전력전자학회:학술대회논문집
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• 전력전자학회 1998년도 Proceedings ICPE 98 1998 International Conference on Power Electronics
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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.

• 조명전기설비학회논문지
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• 제15권6호
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• pp.49-57
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• 2001

본 논문에서는 single-stage, two-stage 두가지 역률보상(PFC)기법을 기존의 능동 클램프 플라이백 컨버터에 적용하여 역률개선을 하였다. 삽입된 플라이백 컨버터의 능동클램프회로가 주스위치와 보조스위치의 영전압스위칭(ZVS)을 구현하며, 스위칭 손실을 줄임으로써 고효율을 얻을 수 있고, 높은 주파수에서의 스위칭이 가능하다. 하지만 일반적으로 사용되는 다이오드정류기, 평활용커패시터에 의한 낮은 역률의 문제점이 남아있다. 본 논문에서는 300[W급] 능동 클램프 ZVS 플라이백 컨버터를 설계하여 single-stage two-stage방식을 적용, 입력역률개선을 시뮬레이션과 실험에 의해 입증하고자 한다.

• 대한전기학회논문지:전기기기및에너지변환시스템부문B
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• 제52권12호
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• pp.655-660
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• 2003

This paper proposes new single stage power factor correction (PFC) full bridge converter. The proposed converter is combined previous ZVS full bridge DC/DC converter with two inductors, two diodes, two magnetic coupling transformer for PFC. This process of power is isolated from the source and also regulate stable DC output voltage in a category. In this topology, the voltage stress of main switches is reduced by zero voltage switching. Moreover, the proposed converter doesn't need active PFC switch and auxiliarly circuits, like control and gating board, so it could decrease the size and cost and increase the efficiency.

• KIEE International Transaction on Electrical Machinery and Energy Conversion Systems
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• 제4B권2호
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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.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2001년도 Proceedings ICPE 01 2001 International Conference on Power Electronics
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• pp.611-616
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• 2001

This paper analyzed PFC of active clamp ZVS flyback converter by adding two methods PFC (power Factor Correction) circuit - two-stage and single-stage. The addition of active clamp circuit also provides a mechanism for 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 result, 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 converter improve the input PF of 300W ZVS flyback converter by adding single-stage, two-stage PFC circuit.

• 융합신호처리학회논문지
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• 제3권3호
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• pp.70-75
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• 2002

본 논문은 새로운 단일 전력단 역률보상 풀 브리지 컨버터를 제안하였다. 제안된 컨버터는 역률보상을 위하여 앞단에 2개의 인덕터, 2개의 다이오드, 2개의 자성결합 변압기를 가진 2VS 풀브리지 DC/DC 컨버터로 구성되어 있다. 이러한 구성방법에 의해 전력은 전원에서 분리되고, 안정된 직류출력전압을 얻을 수 있다. 이 토폴로지에서 주소자의 전압스트레스는 영전압스위칭에 의해서 감소되며, 또한 제안된 컨버터는 능동 역률보정 스위치와 제어 및 게이팅 보드와 같은 보조회로가 필요치 않게되어 규격과 단가를 낮출 수 있을 뿐 아니라 효율을 증가시킬 수 있다.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2001년도 전력전자학술대회 논문집
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• pp.538-541
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• 2001

This paper analyzed PFC of active clamp ZVS flyback converter by adding two method PFC (Power Factor Correction) circuit - Two-Stage and Single-Stage. It improves on Flyback converter's disadvantage - loss increasing by switching, noise increasing, high voltage stress of switch - by adding active clamp circuit. Simulation results show to improve the input PF of 300W ZVS flyback converter by adding Single-Stage, Two-Stage PFC circuit.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2002년도 하계학술대회 논문집 B
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• pp.986-989
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• 2002

This paper proposes a new single stage power factor correction (PFC) full bridge converter which operates at continuous conduction mode(CCM). The proposed single stage PFC consists of typical zero voltage switching(ZVS) full bridge DC/DC converter, two transformer auxiliary windings, and two small inductors, and two diodes. Neither additional active switch nor any control circuit are added for PFC resulting in very low cost. The proposed converter provides input power factor correction with CCM control and tight output voltage regulation. All switching devices are operated under ZVS with minimum voltage stress. Operation principle and analysis are explained and verified with computer simulation and experimental results on a 1.2kW, 100kHz prototype.