Effective Mitigation of Radiated Emissions from a Variable Speed Motor Drive

A detailed analysis of radiated emissions from a variable speed motor drive is presented. Large variation of radiated emissions by changes of the EMC setup without modifying the converter itself are demonstrated and explained. Modifications of the setup include the use of either a shielded or unshielded supply cable, the use of a CMAD, or changes of the cable ground connections. The strong variations in measured radiated emissions are in agreement with full-wave simulations, and can be predicted by an effective model presented here.