EMV-Fachtagung 2023

High frequency modelling of low-winding common mode chokes for conducted EMI Analysis

Christoph MAIER
Michael FUCHS
TU Graz, Institute of Microwave and Photonic Engineering

Matthias KEHRER
Fronius International GmbH



A key component in the context of EMI filters is the common mode choke (CMC). Their simple operating principle allows for effective reduction of common mode interference, yet the coupling effect and different magnetic core materials make them difficult to model.

We propose a behavioural model for SPICE simulation that can be seen as an extension to existing models in the literature. It has a simple structure but is yet able to accurately reflect the characteristic of common mode chokes with a low number of windings for frequencies below 100 MHz. Curve fitting techniques are employed for model generation as well as parameter extraction from measurement data, making the model generation a hybrid process with reasonable complexity. The proposed models are compared to other models in literature and those of manufacturers.