Black-Box Modeling of EMI Filters for Frequency and Time-Domain Simulations

Abstract

A procedure for the derivation of a black-box model of electromagnetic interference (EMI) filters is proposed and discussed. The modeling approach is assessed by resorting to a real EMI filter. The equivalent circuit of the filter is directly obtained from a rational approximation of the scattering-parameter matrix measured at the filter ports. Therefore, the modeling procedure does not require any information on the internal structure of the filter (e.g., components, electrical/magnetic properties of the involved materials, connections leads, etc.). The circuit model is compatible with SPICE solvers and can be used for the prediction of conducted emissions in both the frequency and time domain. Specifically, the proposed modeling approach allows time-domain simulation and performance analysis of EMI filters in combination with power-electronic equipment (i.e. non-linear, time-variant circuits).

Enhanced Impedance Measurement to Predict Electromagnetic Interference Attenuation Provided by EMI Filters in Systems with AC/DC Converters

“…Thus, the accuracy of the single-probe setup degrades when measuring low impedances. The minimum sensitivity coefficient in (12) should be kept as high as possible to improve the measurement accuracy for low impedances, i.e., the ideal transformer ratio k should stay small. This can be achieved in two ways, increasing the turn number N turns of the loop wire or choosing probes with a small N probe .…”

“…In terms of selecting the turn number N turns of the loop wire, there is a trade-off between many factors. On the one hand, increasing this number is helpful in improving the worst-case sensitivity (12). On the other hand, this choice can introduce two critical issues.…”

“…For instance, in [10,11], the standard or in-circuit IL was predicted using the EMI filter scattering parameters (S-parameter) obtained by modeling or experiments. In [12], a black-box model of EMI filters compatible with circuit solvers was proposed using the vector fitting technique, which can predict the IL in both time and frequency-domain simulation [12,13]. In [14], a single setup was presented to evaluate all modes of insertion loss and extended to an approximate worst-case measurement.…”

Study on ESD Protection Circuit by TCAD Simulation and TLP Experiment

“…Previous researchers have conducted a large amount of research on the ESD effect of IC and accumulated a lot of ESD protection circuit design and simulation experience [ 8 , 9 ]. At present, the commonly used circuit modeling schemes are the black box model based on chip port signal and the SPICE model of devices [ 10 , 11 , 12 ]. Although these models can describe the DC and AC characteristics of the circuit, it is difficult to describe the ESD effect of the device unless the model parameters are extracted by special experimental tests [ 13 ].…”

Measurement-Based Equivalent Circuit Model for Time-Domain Simulation of EMI Filters

“…In order to overcome these issues, a methodology to derive EMI filter circuit representations from the scatteringparameter (S-parameter) matrix measured at the external filter terminals via a Vector Network Analyzer (VNA) has been recently introduced in [11], [12]. Specifically, passive macromodeling techniques [13] allow approximating the frequency-response with rational functions, and an equivalent circuit is directly generated from S-parameters (i.e., without conversion into an admittance representation which would lead to numerical inaccuracy).…”