Design-Oriented Analysis and Performance Evaluation of Buck PFC Front-End

Choi

IEEE Trans. Power Electron.

et al. 2017

Abstract-This paper presents an ac-dc LED driver that consists of two parallel inverted buck converters. To buffer the twice-line-frequency energy, one inverted buck converter (also known as a floating buck converter) conveys energy to a storage capacitor, simultaneously performing the power factor correction (PFC). The other inverted buck converter regulates the LED current to maintain a constant brightness in the LEDs for reducing light flicker to low-risk levels. The proposed architecture reduces the voltage stress and the size of the storage capacitor, enabling the use of a film capacitor instead of an electrolytic capacitor. Considering the power factor and the flicker standards, a design procedure to achieve a high power factor, while minimizing the storage capacitance and the LED current ripple, is presented. A prototype of the proposed LED driver has been implemented with an on-chip controller IC fabricated in a 0.35 μm CMOS process and its functionality and performance have been verified experimentally. It demonstrates a power factor of 0.94 and a peak power efficiency of 85.4% with an LED current ripple of 6.5%, while delivering 15 W to the LEDs.

“…where D is the duty cycle of the power switch M1 and fsw is the switching frequency of the buck PFC converter [42]. It is noted that i1_AVG shown in Fig.…”

Section: Mode 2 (T 2 < T < T 3 )mentioning

confidence: 99%

“…Citation information: DOI 10.1109/TPEL.2016.2582856, IEEE Transactions on Power Electronics output voltage permits the use of lower voltage-rated semiconductor devices and capacitors[42]-[44]. The averaged current (i1_AVG) flowing into the buck PFC converter operating in a DCM can be expressed as…”

mentioning

confidence: 99%

An AC–DC LED Driver With a Two-Parallel Inverted Buck Topology for Reducing the Light Flicker in Lighting Applications to Low-Risk Levels

Choi

IEEE Trans. Power Electron.

et al. 2017

IEEE Trans. Power Electron.

“…from (14). ( ) pk i θ is the peak value of inductor current over the whole line period, as shown in (15).…”

Section: A) Harmonics Analysismentioning

confidence: 99%

An Improved Buck PFC Converter With High Power Factor

Xie

Zhao

Zheng

et al. 2013

An improved buck PFC converter topology is proposed in this paper. By adding an auxiliary switch and two diodes, the dead zones in AC input current of traditional buck PFC converter can be eliminated. An improved constant on-time control is proposed and utilized in this improved buck PFC converter to force it operate in critical continues conduction mode (CRM). With optimal control parameters, nearly unit power factor can be achieved and the input current harmonics can meet the IEC61000-3-2 Class C standard within the universal input voltage range. Moreover, the efficiency of the proposed converter is not deteriorated compared to the conventional buck converter. Detailed theoretical analysis and optimal design considerations for the proposed converter are presented and verified by a 100-W lab-made prototype.

“…However, the boost PFC rectifier has several disadvantages because of its high output voltage: (i) the voltage stresses on the components are relatively high; (ii) a second stage DC–DC converter is usually used to step down the high voltage to a low voltage, which results in a high cost; and (iii) the relatively high common noise will be yielded. Accordingly, the active buck PFC rectifiers are presented . The buck PFC rectifiers can transfer a high input AC voltage to a low DC voltage, and the voltage stresses on the components are much higher than that of the boost PFC rectifier.…”

Section: Introductionmentioning

confidence: 99%

A new bridgeless buck PFC rectifier

Hwu

Shieh

Jiang

2016

Circuit Theory & Apps

Summary In this study, a new bridgeless buck power factor correction (PFC) rectifier is presented. The proposed buck PFC rectifier is designed to operate in the discontinuous conduction mode (DCM). Because of the DCM operation, the control scheme of the proposed buck PFC rectifier is simple and easy, and the reverse recovery problem of the diodes can be alleviated. Because the input current follows the input voltage naturally, the current loop circuit is not required. Thus, only the traditional voltage‐mode control is employed to sense the output voltage, and a suitable control effort for the proposed buck PFC rectifier is generated to drive the power switches. Consequently, the output voltage of the proposed buck PFC rectifier can be kept at a desired value. Finally, the mathematical deductions and experimental results are provided to verify the effectiveness of the proposed bridgeless buck PFC rectifier. Copyright © 2016 John Wiley & Sons, Ltd.