DM EMI Reduction using the Gate Drive Signal in a Flyback Converter

The main contribution of this paper is to show a new AC/DC converter based on the rearrangement of the flyback converter. The proposed circuit only manages part of the energy and the rest is delivered directly from the source to the load. Therefore, with the new topology, the efficiency is increased, and the stress of the components is reduced. The rearrangement consist of the secondary of the flyback is placed in parallel with the load, and this arrangement is connected in series with the primary side and the rectified voltage source. The re-arranged flyback is only a reductive topology and with no magnetic isolation. It was studied as a power supply for LEDs. A low frequency averaged analysis (LFAA) was used to determine the behavior of the proposed circuit and an equivalent circuit much easier to analyze was obtained. To validate the theoretical analysis, a design methodology was developed for the re-arranged flyback converter. The designed circuit was implemented in a 10 W prototype. Experimental results showed that the converter has a THDi = 21.7% and a PF = 0.9686.

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Design of a Wide-Input-Voltage PCB-Embedded Transformer Based Active-Clamp Flyback Converter Considering Permeability Degradation

IEEE Transactions on Power Electronics ◽

10.1109/tpel.2021.3064536 ◽

2021 ◽

pp. 1-1

Author(s):

Jiewen Hu ◽

Bo Wen ◽

Rolando Burgos ◽

Yonghan Kang

Keyword(s):

Input Voltage ◽

Flyback Converter ◽

Active Clamp

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Radiated EMI Reduction by Layout Improvement in Power Converters in Automotive Applications

2020 IEEE 9th International Power Electronics and Motion Control Conference (IPEMC2020-ECCE Asia) ◽

10.1109/ipemc-ecceasia48364.2020.9367662 ◽

2020 ◽

Author(s):

Juntao Yao ◽

Shuo Wang ◽

Zheng Luo

Keyword(s):

Power Converters ◽

Automotive Applications ◽

Emi Reduction

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A Novel Single-Switch Single-Stage LED Driver with Power Factor Correction and Current Balancing Capability

Electronics ◽

10.3390/electronics10111340 ◽

2021 ◽

Vol 10 (11) ◽

pp. 1340

Author(s):

Yih-Her Yan ◽

Hung-Liang Cheng ◽

Chun-An Cheng ◽

Yong-Nong Chang ◽

Zong-Xun Wu

Keyword(s):

Power Factor ◽

High Power ◽

Pulse Width Modulation ◽

Power Factor Correction ◽

Harmonic Distortion ◽

Boost Converter ◽

Single Stage ◽

Led Driver ◽

Flyback Converter ◽

High Power Factor

A novel single-switch single-stage high power factor LED driver is proposed by integrating a flyback converter, a buck–boost converter and a current balance circuit. Only an active switch and a corresponding control circuit are used. The LED power can be adjusted by the control scheme of pulse–width modulation (PWM). The flyback converter performs the function of power factor correction (PFC), which is operated at discontinuous-current mode (DCM) to achieve unity power factor and low total current harmonic distortion (THDi). The buck–boost converter regulates the dc-link voltage to obtain smooth dc voltage for the LED. The current–balance circuit applies the principle of ampere-second balance of capacitors to obtain equal current in each LED string. The steady-state analyses for different operation modes is provided, and the mathematical equations for designing component parameters are conducted. Finally, a 90-W prototype circuit with three LED strings was built and tested. Experimental results show that the current in each LED string is indeed consistent. High power factor and low THDi can be achieved. LED power is regulated from 100% to 25% rated power. Satisfactory performance has proved the feasibility of this circuit.

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