Analysis of the influence of inductor saturation on the level of electromagnetic interference of DC/DC-converters

Abstract

The results of the study on the effect of the design parameters of a nonlinear inductor on the level of electromagnetic interference generated by DC/DC converters are presented. The paper proposes models designed for the LTspice XVII environment, which allow investigating conducted interference spectra, efficiency and output voltage ripple of the converter using a nonlinear inductor model. The simulation results showed that the level of conducted interference is affected by the volume and material of the inductor core, as well as the presence of an air gap in the core. The results of measurements of conducted interference spectra at different values of the cross-sectional area of the inductor core of the DC/DC converter are presented. With the nominal cross-sectional area of the core, calculated taking into account converter output power, the study of the relationship between the level of conducted interference and the width of air gap in the inductor core is carried out. In the course of studies, using the Chan model, the influence of inductor core material on the level of interference generated by the DC/DC converter is analyzed. Analysis of the influence of the width of the air gap in the inductor core on the level of conducted interference is carried out. It is shown that air gap width should be selected taking into account inductor core material. Simulation results for a number of commonly used materials made it possible to determine the most effective one in terms of generated interference.The results obtained in the analysis of switching voltage converter operation, taking into account inductor nonlinearity, allow us to formulate recommendations to reduce the level of generated conducted interference by 4.5 to 6 dB due to the correct choice of inductor material and design parameters