Analysis of the influence of the power factor corrector on the level of electromagnetic interference of ac/dc converters

Abstract

The article presents the results of a study of a 220 V/50 Hz AC power source consisting of a power factor corrector and a DC/DC converter. The proposed model of the source, designed to work in the LTspice environment, allows you to investigate the power factors, nonlinear distortions of the network current, efficiency, as well as the spectra of the conductive interference generated during the operation of the source. The efficiency of the proposed model is confirmed by the fact that it provides efficient operation of the source in the range of the input voltage from 128 to 400 V. The studies of the power factor correction source model were conducted using independent automatic power factor correction key control systems and a DC/DC converter, which made it possible to study the level of conductive interference generated by the impulse power source from the power switching frequency of each key from the efficiency of the power keys the use of blurring of the spectrum of the signal of correction of the power factor and the DC/DC converter. Efficiency comparisons were made on the level of spectral components in the current spectrum of the network from which the source is supplied. Studies have shown the feasibility of using spectrum blurring technology in DC/DC converters. The efficiency of using this technology to reduce conductive interference is from 8 to 10 dB, depending on the power source parameters. It is shown in the paper that the selection of the switching frequency of the power factor correction key switches and the DC/DC converter should be made by simulation with the blur mode in the converter on. It has been shown that incorrect frequency selection of the power factor correction key and DC/DC converter key leads to a 10 dB increase in conductive interference. The analysis of the models of the power source and its individual units makes it possible reasonably make both the choice of the switching frequency of the power switches of the power source from the AC power source and the use of effective methods of reducing the electromagnetic interference created during the operation of the pulse power sources. The results obtained allow us to evaluate not only the potential of different methods of reducing the level of electromagnetic interference in the variation of the parameters of the control signals of the power keys of the converter nodes, but also to formulate recommendations on the combination of these methods for the best result.