Research On Interleaved Buck Converter With Power Factor Correction

A step-up converter is widely used as a front-end conversion circuit for power factor correction in a DC power supply that is powered by a single-phase AC power supply.For low-voltage DC power supplies,the problem with boost power factor correction is to bring higher voltage stress to subsequent converter circuits.Using step-down power factor correction,low-voltage switching devices can be used in subsequent conversion circuits to reduce circuit cost and simplify the design of subsequent circuits.Although the buck converter realizes the power factor correction has the advantages of simple circuit structure,it also has its disadvantages,especially for larger power applications,it needs to further reduce the input current harmonics and reduce the output voltage ripple.This thesis aims at the application of low-voltage DC to study the problem of step-down power factor correction.In order to obtain larger output power,an interleaving control technique is used to increase the equivalent switching frequency,which is beneficial to AC side harmonic suppression,and the use of coupled inductors to further suppress DC ripple.This thesis first discusses the status of single-phase rectifier circuit power factor correction technology,analyzes the working principle of the step-down converter and the working principle of the interleaving parallel technology,and then,the working process of the inductive coupling interleaved shunt buck power factor correction system is analyzed and a small signal model of the converter is established.Based on the theoretical analysis of the converter,an inductively coupled interleaved step-down buck power factor correction circuit scheme is designed.Finally,using the peak current control strategy,simulation experiments and analysis of the interleaved step-down buck power factor correction circuit show that the inductive coupling staggered step-down buck power factor correction circuit to reduce the input current harmonics,improve the input power factor And suppress the effectiveness of the output voltage ripple.