Single stage AC/DC converter with input power factor correction

Author(s):  
V. Anunciada ◽  
H. Ribeiro
2004 ◽  
Vol 13 (03) ◽  
pp. 535-555 ◽  
Author(s):  
DYLAN DAH-CHUAN LU ◽  
DAVID KI-WAI CHENG ◽  
YIM-SHU LEE

In this paper, a new family of single-stage AC/DC power factor correction converters (S2PFCC), which possesses reduced voltage stress across the storage capacitor and no extra current stress on the power switch, is proposed. The converters are realized by reduced repeated power processing concept in which part of the input power is transferred to the load directly after the first power process. This results in lower storage capacitor voltage than that of previously developed S2PFCCs but maintaining high power factor. In addition, the inherent input current control allows the load current to reduce the input line current automatically when the load becomes light, preventing excessive amount of energy being stored in the storage capacitor. Although the proposed converters employed two power switches, a simple single-loop controller for the proposed S2PFCC to achieve power factor correction (PFC) and tight output regulation is also proposed. Experimental results are reported to verify the operation and concept of the new S2PFCC.


Electronics ◽  
2021 ◽  
Vol 10 (11) ◽  
pp. 1340
Author(s):  
Yih-Her Yan ◽  
Hung-Liang Cheng ◽  
Chun-An Cheng ◽  
Yong-Nong Chang ◽  
Zong-Xun Wu

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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