S-domain Analysis of Feed-forward Active Common Mode Output Filters for Induction Motor Drives

This paper presents a technique to analyse the performance of an active feed-forward EMI filter in minimizing common mode emissions coming from a PWM inverter towards an induction motor. Detailed mathematical formulas describing the single parts of the system are developed in the Laplace domain. The model is implemented in Matlabreg/Simulink software environment in order to evaluate the active filter voltage attenuation. Simulation results are compared with laboratory experiments on an induction motor drive.