EMC measurements and simulation in variable speed drives

Experiments are carried out to investigate conducted EMC phenomena in a PWM induction motor drive system. Time domain simulation models which take into account the high frequency characteristics are proposed. Good agreement between the measured and simulated results is obtained for a well defined laboratory test system, thus validating the numerical simulation models. Digital simulation can be used to predict the general EMC performance of the drive system, and to evaluate and compare the effectiveness of various EMI reduction techniques during the design stage. Three dominant modes of conducted interference are identified. It is shown that the motor has a significant influence on these modes and high frequency modelling of the induction motor corresponding to each mode is addressed.