Bessem Zitouna

Development and validation of analytic equations of the electromagnetic fields radiated by the elementary dipoles in time domain

In this paper, we will present the development of the analytic equations and the corresponding calculating code to models and evaluate the electromagnetic field radiated by the elementary dipoles in time domain. Results obtained with analytic equations are compared to those obtained after simulations made with software based on numerical method in the time domain. Then, they are compared to results obtained with analytic and numerical methods working in frequency domain. In this paper, the development of analytic resolution is carried out in order to implement the electromagnetic inverse method in time domain.

Enhancement of Time-Domain Electromagnetic Inverse Method for Modeling Circuits Radiations

To ensure the reliability and safety of the modern electronic systems face of these electromagnetic interference which are becoming more and more important, modeling methods based on the emissions in the near field of these systems are needed. However, the developed methods and in particular the electromagnetic inverse method in the frequency domain have several limitations to model and characterize the systems which emit a nonsinusoidal electromagnetic radiation. To cope with these limitations, in this paper, the electromagnetic inverse method in the time domain has been developed. Using measured near-field cartography above the studied system, the method, based on genetic algorithms, consists in identifying equivalent emitting dipoles. The identification traverses the entire mapping by identifying all sources from the most intense to the lowest source. The proposed method has been validated, first, using calculated cartographies above known dipoles and, second, using measured cartographies above actual dc-dc converters. A very good agreement has been observed between the near magnetic field cartography calculated using the obtained model and thats emitted by the studied system. The proposed method can be used for the identification of equivalent emitting sources of systems excited by nonsinusoidal currents in a widely lowest time as that of the frequency method.

Time domain electromagnetic inverse method for non-sinusoidal circuits

In this paper, we propose a new method of an electromagnetic compatibility study. The electromagnetic inverse method in the time domain is proposed to analyze the electromagnetic radiation of power electronic circuits which emit signals that are not sinusoidal. Using measured near-field cartography above the studied circuit, the method, based on genetic algorithms, consists in identifying the dipole sources. To validate the proposed method, we have applied it to theoretical temporal signals emitted by the known electric and magnetic dipoles. The obtained results show a good agreement between the cartography of the near magnetic field, obtained by the developed model, and the calculated one. The results allow us to conclude that the proposed method is suitable for the identification of equivalent-source structures excited by different current forms.

Implementation of the time domain electromagnetic inverse method: Application of structures with single excitation source

The objective of this paper is to develop and implement the time domain electromagnetic inverse method to model the radiated emissions of structures excited by a single excitation source. This approach is based on the use of the near-field cartography to extract and identify the parameters of equivalent radiation sources. The first part of the paper is devoted to the description of the electromagnetic inverse method in the time domain and its resolution with an optimization method based on genetic algorithms. Subsequently, and to test the proposed method with respect to near-field measurement errors, we propose to validate the time domain inverse method with an experimental model. To validate our approach, we will present and compare the measured field cartography with the calculated field cartography by using the parameters of the estimated model. The obtained results showed that the proposed approach is very suitable for modeling simple structures with a single excitation source.

Improvement of the convergence of the time domain electromagnetic inverse method by using the PSO algorithm

In this paper, we propose a method for modeling the electromagnetic disturbances. This proposed method is based on the coupling between the electromagnetic inverse method in the time domain and the PSO optimization tool. In order to avoid measurement errors, the proposed method was applied to a near field cartography calculated through analytical expressions that describe the magnetic radiation of simple elementary dipoles. To evaluate the contribution of the proposed method, we compare the results obtained using the PSO algorithm with those given by the temporal inverse method based on genetic algorithms. The comparison between the results given by these two approaches has shown that the inverse temporal method based on the PSO is very robust in terms of convergence and simplicity of implementation.

Time domain extraction of the radiated magnetic near field from the measured voltage by the magnetic probe

In this paper, we have presented the technique for measuring the near field in the time domain of electronic circuits. The synoptic of the bench of the near field in the time domain is proposed and explained. The direct measurement of the radiated field is based on the scanning of an electronic probe. Synchronized measurements of the time signals have been carried out over a power electronics structure. Thereafter, we have proposed a mathematical relation to know the radiated emissions that have detected by the electronic probe. This transformation equation was applied to extract the cartography of the magnetic field radiated by the studied structure from the detected voltage at the terminals of the electronic probe. Finally, the cartography of the experimental measurements was explored in order to identify a radiation model equivalent to the structure studied by the inverse method developed in the time domain.