Bessem Zitouna

By Bessem Zitouna and Jaleleddine Ben Hadj Slama

Flyback converters have been widely used in low- and high-power applications because of their simplicity and low cost. However, they incur electromagnetic compatibility problems which are more difficult to control. The present chapter proposes an efficient modeling method based on the near-field technique to solve real-world radiation problems of the power electronics circuits. Firstly, for the characterization of an AC/DC flyback converter, several experimental measurements of the magnetic near field are performed in the time domain over the converter. Subsequently, we have applied the time domain electromagnetic inverse method based on the genetic algorithms on the measured signals to find the equivalent radiating sources of the studied circuit. The accuracy and the efficiency of the proposed approach have been demonstrated by the good agreement between cartographies of the near magnetic field components calculated using the developed model and those measured. Finally, the developed equivalent model has been used to predict cartographies of other components of the magnetic field which will be compared to measured cartographies. This confirms that the identified equivalent sources can represent real sources in the studied structure. The proposed method could be used for diagnosis and fault location in power electronics systems.

Part of the book: Advances in Complex Analysis and Applications

By Walid Labiedh, Bessem Zitouna, Mohamed Tlig and Jaleleddine Ben Hadj Slama

This chapter deals with modeling the radiation from rectangular film capacitors as a power electronics component. The rectangular film capacitors are sources of electromagnetic radiation, where its characterization is crucial for electronic circuits EMC. Our study presents the analyses and modeling of the magnetic near field radiated by the plastic and the polyester capacitors. An electromagnetic inverse method is combined with an optimization method based on genetic algorithms to create a radiating equivalent model. A very good agreement is observed between the magnetic near field cartography measured above the studied structure and calculated using the developed model parameters. Finally, a generic radiating model is proposed for various types of rectangular film capacitors. The generic model is validated using the measurements on a rectangular capacitor. The obtained equivalent model can calculate the magnetic field at any near field zone and far field around the capacitors. Circuit designers can use the field distribution to optimize the placement of the capacitors on the printed circuit board to reduce their coupling and potential interaction with other equipment in the vicinity of the system.

Part of the book: Recent Topics in Electromagnetic Compatibility

By Sassia Hedia, Bessem Zitouna, Jaleleddine Ben Hadj Slama and Lionel Pichon

Recently, modern power electronic systems have been introduced in different applications, such as in avionics and wireless communication. The increasing technological complexity of these systems is posing serious challenges regarding electromagnetic compatibility (EMC) issues. Indeed, the radiation emitted from electronic circuits can induce harmful effects on nearby devices. Thus, several research works have been conducted using the nearfield technique to deal with electromagnetic interferences (EMI) that might occur, especially due to rapidly changing currents and voltages. In the present work, a detailed study about the characterization of the electromagnetic nearfield-radiated emissions is established using a time-domain analysis to provide an equivalent model constituted of a set of electromagnetic dipole parameters. Source reconstruction has been obtained using electromagnetic time reversal (EMTR), which has proven successful and efficient in identifying transient disturbance sources in power electronics. Experimental measurements of the magnetic nearfield have been carried out under an AC/DC flyback converter. The accuracy of the proposed method has been confirmed by visualizing measured magnetic field components, which are in good agreement with the calculated maps. The results of a reasonable computing time have shown that, particularly in transient signals with a wide frequency band, the suggested inverse method is an adequate alternative to overcome frequency domain limitations.

Part of the book: Recent Topics in Electromagnetic Compatibility