Electromagnetic Time Reversal in the Near Field: Characterization of Transient Disturbances in Power Electronics

In the article, the electromagnetic time reversal technique (EMTR) is studied in the electromagnetic compatibility context. The main issue addressed by this approach is to deal with electromagnetic (EM) radiating source identification. This article is intended to provide a time-domain (TD) study of EMTR in the near field (NF) and prove its efficiency in characterizing transient disturbances in power electronics. The reconstruction of EM emissions is based on two stages. First, the modeling process relies on the use of TD analytical expressions. Second, signal processing is referring to the time reversal technique, which defines an inverse problem resolution. The method proposes to identify a set of equivalent dipoles. The validation is carried out experimentally using a TD measurement bench. The main purposes of this method is to extract the dipoles locations, moments, and orientation. The magnetic field maps calculated at each time step using obtained equivalent sources are compared with measured distributions. Adequate agreement is achieved, which confirms the efficiency of the proposed method. In addition, for validation purposes, the equivalent model is compared with that obtained by a frequency-domain (FD) method based on the standard genetic algorithms. Unlike FD, TD investigations allow characterizing transient disturbances in power electronic systems that emit strong EM interferences, by finding a sufficient equivalent model valid on a wide frequency band at once.