Effective EMI Filter Design Method for Three-Phase Inverter Based Upon Software Noise Separation

This paper presents an electromagnetic interference (EMI) filter design method for a three-phase inverter applied to motor drives. The EMI filter design is based upon the results of software noise-separation method. Therefore, no hardware noise separator is required. Moreover, the presented EMI filter design approach provides systematic design procedure, and therefore, trial-and-error overhead is not required, and thereby, shortening the development time and saving the cost. The presented method determines common-mode choke and differential-mode choke based upon the required impedance to attenuate the noise. A three-phase inverter for inductor motor drives is used as the equipment under test (EUT), and the related conductive EMI filter is designed and verified. It will be shown that EMI filter designed by this systematic design method effectively attenuates the conductive EMI components to meet the requirement of EN 55011.