Techniques for the Analysis of Time-Domain Conducted Emissions of SMPS in Smart Grids

This work presents an analysis of two techniques used to analyze the frequency domain characteristics of conducted emissions measured in time domain using a LISN connected to two Switched-Mode Power Supplies. The considered interval is 10-150 kHz. The two techniques are the Short Time Fourier Transform and the Empirical Mode Decomposition method, focusing on spectral properties of impulsive phenomena, and compatibility with the typical settings of EMI receiver, whose output represents a validation reference case. The analysis points out the influence of the record length and resolution bandwidth with respect to the local signal non-stationarity.