The presence of numerous power electronics converters on embedded networks, originates EMC issues. EMC modeling of power electronic converters is tricky due to modeling complexity. Indeed, on one side, EMC study needs the finest characterization of each element, thus, only a few numbers of converters plugged to the network can be described. On the other hand, a conventional network approach, representing the converters on a pure functional point of view, does not allow such analysis of each element. Therefore "black box" or "grey box" approaches, representing the global behavior of the converters, are a good compromise between those two antagonistic needs. This article aims to sum-up characteristics of different EMC models in order to justify the choice of terminated approach. Then, all identification issues will be addressed: * Theoretical difficulties such as the physical meaning of the identified impedances * Practical difficulties like attenuated conditions sizing and measurement protocol.