Özet:

This paper presents the study of conducted electromagnetic interference (EMI) currents flowing through the power cables of a DC-DC converter system and its correlation with the near field radiated from these cables. The radiated emission measurement contains a common mode (CM) and a differential mode (DM), and accurate separation of the radiated emissions of these two modes is necessary. The finite-difference time-domain (FDTD) method is used to predict the electromagnetic radiation caused by CM currents and DM currents. An experimental bench has been designed to allow access to the measurement of EMI disturbances at various sensitive places. The CM and DM voltages resulting from the experimental measurement are implemented in the FDTD algorithm as voltage sources of disturbances, these disturbance voltages causing the generation of CM and DM currents flowing through the cable. Finally, single and bifilar wire models for modeling the near field using the FDTD method are presented and the simulation results of the near field caused by both of the modes are evaluated and compared with the experimental ones. The main objective is to investigate the significance of the contribution of each of the current modes on the radiated emissions from the cable using the FDTD method, thus characterizing the level of cable radiation versus a specific standard. This allows showing that the radiation is often caused by the CM current along the cable and the largest level is located in the switching noise zone located within the frequency range from 1 MHz to 10 MHz.

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