Analysis and High-Frequency Model of Three-Phase Four-Wire Common Mode Chokes

Common mode chokes (CMCs) are key components in electromagnetic interference (EMI) filters, and accurate modeling of these components is critical for filter design and EMI noise simulation. This article proposes a behavioral model and parameter extraction technique for characterizing three-phase four-wire common mode chokes (4W-CMCs). The proposed model considers the inductance nonlinearity caused by the nonlinear permeability of manganese-zinc ferrite and nanocrystalline magnetic materials, as well as the asymmetry and local symmetry in the winding distribution of 4W-CMCs. The parameters for the common mode and differential mode (DM) models are extracted using a parameter extraction program and a simple equation-based method, respectively. For the DM model parameter extraction, this article proposes a measurement method that utilizes the local symmetry of 4W-CMCs. The equivalent circuit of this measurement method decouples the interwinding capacitance (<italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">C</i><sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">W</sub>) from the DM inductance parallel capacitance (<italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">C</i><sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">D</sub>) by transforming two-port network parameters, greatly simplifying the parameter extraction process. The accuracy of the model and the effectiveness of the method are validated through experiments using several 4W-CMCs with manganese-zinc ferrite and nanocrystalline magnetic cores.