A Valley-Locking Control Scheme for an Audible Noise-Free Valley-Skip-Mode Flyback Converter

Wu, Qiang; Li, Xun; Han, Yueyun; Di, Zengru; Feng, Quanyuan

doi:10.1109/tie.2021.3099223

Cited by 9 publications

(2 citation statements)

References 22 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The general analysis, operation, and design of a QRF are well explained in [15], [16], [17], [18], [19], and [20], hence will not be repeated. The smallsignal analyses, that are relevant for this kind of converters, are covered in [20], [21], [22].…”

Section: Introductionmentioning

confidence: 99%

Quasi-Resonant Flyback Converter in an 800 V Inductive Charging System: Abnormal Operation and Control Aspects

Vračar

2024

IEEE Access

View full text Add to dashboard Cite

This paper studies quasi-resonant flyback (QRF) dc-dc converter 57 W with valley-switching mode (VSM) in an emerging application. The QRF was supplied from variable 800 V input and was used as the auxiliary power supply of an inductive charging system. When choosing switch rated voltage it was shown that one shall consider maximum voltage during short-circuits too. Influence of high temperatures on transformer magnetizing inductance were analyzed and showed why this shall be considered when evaluating different vendors and designs. Operational waveforms are simulated and measured showing that key quantities were matched. Comprehensive overview of QRF abnormal operations presented for the first time covering start-up, short-circuit and over-power cases including experiments. It was demonstrated that when solving noise-related start-up problem, by increasing filtering capacitance, one got positive influence on QRF operation (e.g. switching-frequency range was reduced, efficiency increased, and control loop bandwidth, phase margin and gain margin got improved). The short-circuits were evaluated through nine test-cases. When QRF operated in VSM the short-circuit protection worked as expected. But, if short-circuit happened at non-regulated output, at no load, it may go undetected-which is dangerous. Hence several mitigation strategies were proposed to prevent damage of converter. For converters with variable switching frequency one shall state whether efficiency measurements were done when load was increasing or decreasing thus considering influence of controller's hysteresis. The transition thresholds, which ensure VSM operation, presented as "input power vs. input voltage", showed non-linear dependence.

show abstract

Section: Introductionmentioning

confidence: 99%

Quasi-Resonant Flyback Converter in an 800 V Inductive Charging System: Abnormal Operation and Control Aspects

Vračar

2024

IEEE Access

View full text Add to dashboard Cite

show abstract

“…The QRF general analysis, operation, and design are explained in [15], [16], [17], [18], [19], and [20]. Some methods for noise-free and valley-locking operation are covered in [21], [22]. Hence, readers are advised to check those references for more information.…”

Section: Introductionmentioning

confidence: 99%

Quasi-Resonant Flyback Converter as Auxiliary Power-Supply of an 800 V Inductive-Charging System for Electric Vehicles

Vracar

2022

IEEE Access

View full text Add to dashboard Cite

This paper presents evaluation of quasi-resonant flyback (QRF) dc-dc converter 57 W with valley-switching in an emerging application. The QRF was supplied from an 800 V variable dc-link and was used as the auxiliary power-supply of a wireless inductive-charging system (ICS). Comparison of stateof-the-art QRF control ICs is presented and suggestions for their improvements are given. Notes on the power-supply architecture, design items specific for the ICS application, over-power protection, and keycomponent choice are provided. During experiments several original and novel results are generated. The efficiency graphs in ICS power transfer, ICS stand-by, and constant-load operation are analyzed. The maximum efficiency of 87.1 % was reached at 620 V and rated load. Moreover, the unique analysis of QRF losses at no-load, showed their quadratic dependency vs. input-voltage. The measured "switching frequency vs. load" graph is presented. It was changeable with load and input-voltage as expected. From Bode plots the bandwidth, phase-margin, and gain-margin are extracted and plotted versus input-powerfor the first time. They were changeable with input-voltage and load as expected. Comparison of simulated and measured Bode plots showed that, even when they were not matched, one can design a Type-2 compensator that ensures stable operation. Evaluation of cross-regulation, when output with 24.1 % of total power was regulated, showed that such approach-contrary to the more common of regulating the biggest one-is feasible too. It is discovered that, for a QRF with variable switching frequency, choice of compensator or the regulated output has influence on its efficiency. The power-thresholds to ensure valleyswitching operation represented as "input power vs. input voltage" are shown for the first time. Comparison of bandwidth, phase margin, and gain margin vs. input power, between an ACF and the QRF, were discussed. Conclusion is that QRF, for the same specification, cannot have the same compensator as an ACF. The difference must be at least in a placement of a zero.

show abstract

An Improved Interleaved Flyback Converter with Reduced Voltage Stress and Current Auto-sharing

Chen,

Shen,

2023

J. Electr. Eng. Technol.

View full text Add to dashboard Cite

A Valley-Locking Control Scheme for an Audible Noise-Free Valley-Skip-Mode Flyback Converter

Cited by 9 publications

References 22 publications

Quasi-Resonant Flyback Converter in an 800 V Inductive Charging System: Abnormal Operation and Control Aspects

Quasi-Resonant Flyback Converter in an 800 V Inductive Charging System: Abnormal Operation and Control Aspects

Quasi-Resonant Flyback Converter as Auxiliary Power-Supply of an 800 V Inductive-Charging System for Electric Vehicles

An Improved Interleaved Flyback Converter with Reduced Voltage Stress and Current Auto-sharing

Contact Info

Product

Resources

About