• Journal of Power Electronics
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• v.17 no.1
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• pp.1-10
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• 2017

This paper presents a novel predictive digital control method for boundary conduction mode PFC converters without the need for detecting the inductor current. In the proposed method, the inductor current is predicted by analytical equations instead of being detected by a sensing-resistor. The predicted zero-crossing point of the inductor current is determined by the values of the input voltage, output voltage and predicted inductor current. Importantly, the prediction of zero-crossing point is achieved in just a single switching cycle. Therefore, the errors in predictive calculation caused by parameter variations can be compensated. The prediction of the zero-crossing point with the proposed method has been shown to have good accuracy. The proposed method also shows high stability towards variations in both the inductance and output power. Experimental results demonstrate the effectiveness of the proposed predictive digital control method for PFC converters.

• Proceedings of the KIPE Conference
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• 2019.11a
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• pp.61-63
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• 2019

본 논문은 3.3 kW 전기자동차용 탑재형 충전기의 전력 밀도 향상을 위해 디커플링 기법이 적용된 PFC (Power factor correction) 회로의 초치적 설계 방안을 제안한다. 최적 설계를 위하여 buck-boost 컨버터 형태의 디커플링 회로 동작 원리를 기반으로 스위칭 주파수에 따른 PFC 회로의 손실과 부피를 분석하고 최적 설계점을 도출한다.

• Proceedings of the KIPE Conference
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• 2007.07a
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• pp.238-240
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• 2007

A new ZVZCS Single-Stage Power-Factor-Correction(PFC) AC/DC converter with boost PFC cell is integrated with voltage doubler rectified asymmetrical half-bridge(VDRAHB) is proposed in this paper. The proposed converter features good power factor correction, low current harmonic distortions, tight output regulations and low voltage of link capacitor. An 85W prototype was implemented to show that it meets the harmonic requirements and standards satisfactorily with nearly unity power factor and high efficiency over universal input.

• Journal of Power Electronics
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• v.8 no.2
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• pp.192-199
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• 2008

This paper is mainly concerned with a high frequency soft-switching PWM inverter suitable for consumer induction heating systems. The proposed system is composed of a soft switching chopper based boost PFC converter stage with passive snubber and phase shifted PWM controlled full bridge ZVZCS high frequency inverter stage. Its fundamental operating performances are illustrated and evaluated in the experimental results. Its effectiveness is substantially proved on the basis of the experimental results from a practical point of view.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.61 no.8
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• pp.1130-1139
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• 2012

This paper proposes a LED lighting system using integrated power system composed of bridgeless PFC, LLC DC-DC transformer, and dimmable constant current LED driver module. The proposed LED lighting system features high efficiency, high power factor, and dimming capability. In order to verify the validity of the proposed system, the 2kW prototype system was built and tested. From the experimental results, it was confirmed that the maximun efficiency of 92.6% and maximum power factor of 99.7% can be achieved.

• Proceedings of the KIPE Conference
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• 2001.10a
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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.

• Proceedings of the KIPE Conference
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• 2001.07a
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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.

• Proceedings of the KIEE Conference
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• 2003.10b
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• pp.187-189
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• 2003

Conventional Switched Mode Power Supplies(SMPS) with diode-capacitor rectifier have distorted input current waveform with high harmonic content. Typically, these SMPS have a power factor lower than 0,65. To improve with this problem the power factor correction(PFC) circuit of power supplies has to be introduced. Specially. to the reduce size and manufacture cost of power conversion device, the single-stage PFC converter is increased to demand as necessary of study. in this paper, The comparative analysis of power factor correction circuit using Feedforward control with average current mode flyback converter(single-stage) and boost converter(two-stage). Also, the validity of designed and manufactured high power factor flyback converter and boost converter is confirmed by simulation and experimental results.

• The Transactions of the Korean Institute of Power Electronics
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• v.24 no.4
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• pp.237-243
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• 2019

A high-efficiency and small-sized switched-mode line transformer (SMLT) is proposed in this study. The conventional structure of an adapter is composed of line transformer and rectifiers. This structure has a limit in miniaturizing due to low-frequency line transformer. Another structure is composed of power factor correction (PFC) and DC/DC converter. This structure has a limit in reducing volume due to two-stage structure. As the proposed SMLT is composed of an LLC resonant converter, a high-frequency transformer can be adopted to achieve isolation standards and size reduction. This proposed structure has different operation modes in accordance with line input voltage to overcome poor line regulation. In addition, the proposed SMLT is applied to the front of a conventional PFC converter, because the SMLT output voltage is restored to rectified sinusoidal wave by using a full-bridge rectifier in the secondary side. The design of the PFC converter is easy, because the SMLT output voltage is controlled as rectified sinusoidal wave. The validity of the proposed converter is proven through a 350 W prototype.

• The Transactions of the Korean Institute of Electrical Engineers P
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• v.65 no.4
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• pp.285-291
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• 2016

A light-emitting diode (LED) has been increasingly applied to various industrial fields and general lightings because of its high efficiency, low power consumption, environment-friendly characteristic and long lifetime. To drive the LED lighting, a power converter with the constant output current is needed. Among many power converters, the flyback converter is chosen by many converter designers due to high power density, structural simplicity, and miniaturization. In this converter, an electrolytic capacitor is generally chosen for the stabilization of the DC voltage because of having the large capacitance and the low price. However, the disadvantages are the short expected life time and 120Hz ripple currents on the converter output node. In this paper, a single-stage dimmable PFC DCM flyback converter without the electrolytic capacitor is proposed to prolong the lifetime of the LED driver. For the long lifetime of the converter, the polyester film capacitor with the small capacitance is substituted for the electrolytic capacitor on the output node and an LC resonant filter is added to damp 120Hz ripple current. The proposed converter is verified through the simulation and the experimental works.