EMI noise modeling and filter design in power converter circuits used in industrial applications

Developments in the fields of power electronics and semiconductor technologies enable high-frequency switching in electrical/electronic device designs, and thus, compact designs with high efficiency and high power density are made. However, the electromagnetic interference problem emerges with increasing switching frequency. This problem threatens the safe working conditions of the devices, preventing them from working properly or causing them to malfunction. One of the methods used to attenuate electromagnetic interference is to prevent unwanted interference with electromagnetic interference filter design. The traditional approach in filter design is that the designer determines the appropriate filter structure and elements by trial and error, based on the experience and knowledge he/she has gained over the years. This method, based on reducing interference by trying different filter combinations, is challenging in terms of both time and cost. Obtaining the proper filter design may take time and even prolong the product's production process. For this reason, it is necessary to determine the possible interference paths by extracting the high-frequency model of the noise source in the power electronics circuit and designing the filter according to the obtained results. In this study, the electromagnetic interference noise models for single-phase PFC and three-phase PV inverter circuits are extracted, and the electromagnetic compatibility of the circuits is examined. For these circuits, the relevant electromagnetic compatibility limits specified in the conducted emission standards have been evaluated, and an electromagnetic interference filter has been designed to attenuate unwanted interference. In the filter design, the tolerance value of the filter capacitors, the different winding shapes for the common mode choke, and the impedance mismatch are examined, and the effects of the filter on the noise attenuation have been analyzed both by simulation and experimentally. Simulation results were compared to real measurement results, and it was seen that the results were compatible with each other.