A prediction model for electromagnetic interferences radiated by an industrial power drive system

Power conversion systems and, in particular, power drives, are now present in a large number of applications and environments. The switching operations of power drive systems (PDSs) are sources of radiated and conducted EMIs that give rise to problems of electromagnetic compatibility (EMC) with other systems. This paper proposes an efficient numerical technique to evaluate the radiated emissions due to a PDS, taking into account the radiation from intentional apertures (i.e., those for ventilation). The power section of the PDS is simulated by a combination of radiating dipoles in which the current is known. The radiated electromagnetic (EM) field induces on the PDS metallic cage surface currents that, in turn, radiate outside the cage. These currents are computed by an efficient numerical method known as the partial-element equivalent circuit technique. The proposed prediction model is, hence, able to predict the total radiated emission from a PDS in its design stage in order to fulfill the ERIC requirements called for by the international standards.