An Improved Behavioural Modelling Approach for any Type of Common Mode Choke

Common mode chokes (CMC) are widely used passive components to suppress conducted electromagnetic interferences. Models for such components are needed to simulate the electromagnetic compatibility behaviour of an electrical circuit. A state of the art strategy for modelling common mode chokes is the use of behavioural models. These models consist of circuits constructed of resistors, capacitors and inductances, based on the common and differential mode impedance of the CMC being modelled. Normally, the modelling strategy (network topology and value approximation) is designed for a specific type of CMC with a certain impedance characteristic. In this work, a novel approach based on a genetic algorithm is presented to generate models for any type of CMC across a broad frequency range. The results show that with this approach, CMC with different characteristics can be modelled very accurately in frequency ranges from as low as 40 Hz up to 1 GHz. The new strategy provides improved results compared to other strategies at low computational cost.