Modeling of common mode conducted noise emissions in PWM inverter - fed AC motor drive systems

In order to predict the common mode (CM) noise current in large systems, a modeling principle using transfer matrix ([T]) is used. This method is based on specific experimental characterizations and on the modelling of the complete CM circuit considered as a chain of quadripolar matrices. Each part of the system is represented by a two-port network and associated in cascade by using matrix [T]. Two configurations of the system are investigated; system insulated from ground plane, and system taking ground effects on the CM current path into account in the model. The comparison results between calculations and experiments for the both configurations in a variable-speed drive system confirm effectively the validity of the proposed approach.