Input impedance of modern embedded networks including many power electronics converters: An analytical investigation

Abstract

Z i N et wo rk S ou rce Z 0 Z 1 N o d al 0 N o d a l i N o d a l 1 A ft e r t h e fi lt e r Be fo r e t h e f il te r Z lAbstract-Power by wire concept is a novel trend in modern electrical systems. Hence, system networks have become more and more sophisticated, and their modeling is no longer an easy task. In this paper, we propose an analytical analysis of a global EMC of a modern electrical network. Explicitly, we develop an analytical model to evaluate differential mode impedance at different sites of a complex network. To this end, we use a Transmission Line "TL" theory applied in the case of bifilar cables. Bifilar cable parameters, such as the propagation constant and the characteristic impedance, are identified by measurement via the impedance analyzer Agilent 4294A. Such parameters are included into the analytical model for the computation process. The impedances, computed at different sites are compared to each other, and on the same time, to the impedance of Line Impedance Stabilization Network (LISN) in accordance with the CISPR 22 standard. To assess the model performance, we have carried out an experimental test bench. The measured impedances agree with those computed analytically.

Analytical Models Synthesis of Power Electronic Converters

“…Power converters, especially DC-converters are supplied by two wires "L" for "Plus" and "N" for "Minus", but also connected to a third wire "G" which is the safety conductor commonly called "Ground" conductor, since the converter is the main source of conducted interferences, due to its operation principle. Thus, DC-converters may be considered as three ports systems, as drawn in the Fig.2 [11].Where: ZLG, In addition, by definition both CM impedance ZCM and DM impedance ZDM are computed according to the equation (1) [1] and [12].…”

“…Actually, YLG and YNG, expressed in (2) and appearing in the model of (8), are parasitical capacitances' impedances to the referential conductor "G" [3]; they are expressed, respectively in (11) and (12).…”

“…Note that, in (11) and (12) impedances are an addition of two terms. The first one, is dependent on the inner capacitance CLG (or CNG), the second term at (1-α) time, there is an addition capacitances (Cm of the middle point "M") which comes to be added on this inner capacitance.…”

“…In this section we will study the effect of some parameters of the buck converter on its DM impedance profile. Equations (2) and (11)(12)(13), reveal that for the buck converter case, the impedance model depends on some intrinsic converter's parameters:…”

“…According to (2) and (11)(12)(13), the DM impedance depends on the ZCf impedance, otherwise on the value of the capacitor Cf.…”