Methodology to model EMI from E-motors and controller in the frequency range from 30 to 200 MHZ

As EMC testing for E-motor drives gains significance due to the involvement of high-frequency switching and high current systems, the radiated emission testing as per CISPR 25 necessitates utilizing an EMC-proof dynamometer to load the E-motor drives during EMC testing inside EMC chamber, which presents a highly complex and expensive testing arrangement. This paper outlines a detailed approach for modelling radiated emission without the usage of EMC chamber, by measuring conducted high-frequency currents on the DC and AC lines of motors and MCUs while utilizing a non-EMC-proof motor dynamometer under loaded conditions. In this paper the measurements are conducted in the frequency range of 30 MHz to 200 MHz where usually more issues due to switching noise occurs. The developed model facilities early stage diagnosis of potential EMC issue, enabling mitigation strategies before motor EMC testing. Validation of the method was performed through experimental comparison with conventional 1m radiated emission measurement in semi anechoic chamber. This approach offers a practical and cost-effective solution for EMC motor testing at higher loading conditions in pre-compliance evaluation according to CISPR 25 standard.