Analytical Model of DC-DC Converters Based onSwitching Impedances and EMI Sources

International audienceSince studies are intended to be used to predictthe compliance with Electromagnetic standards, an accuratecomputing of a common and differential mode conducted noise isnecessary. Nowadays, the modern networks -as the car’s networksupplying many electrical actuators- include many powerconverters to manage efficiently the power transfer, but also along cable (conductors), which creates new issues (interactionbetween cable and converter’s noise sources), and therefore theEMC study becomes more complex. For this reason, in this paperwe propose an analytical model to compute a common modeequivalent conducted noise sources, inside the network, at anysite of the DC-network (all along the cable). Firstly, noise sourcesmodelling the EMC behaviour of converters connected to theDC-network, are extracted and identified in both frequency andtime domains. Therefore, converter’s electric equationsmodelling its behaviour are performed by defining amathematical switching function. The model is tested with timedomain simulations and validated by experimentalmeasurements. Secondly, the extracted converter’s model, basedon equivalent noise sources, is used to predict the conducted noiseinside a defined network, at any location of the cable (network).The process of the network’s modelling is built by using theTransmission Line theory (TL) of lossless bifilar lines. Thisnetwork’s model is crucial for EMC analysis, to evaluate theinteraction degree between the noise sources and cableparameters. Finally, the network’s model is tested by a timedomain simulation (LTSpice), and validated by an experimentalsetup