Optimal Power-Line-Filter Desing for Three-Phase Electric-Vehicle Charging Stations

Due to the recent growth of automotive market and three phase applications, conducted emissions are becoming an increased concern for electric vehicles manufacturers. The main problem is that the design of an optimal power line filter for three phase equipment is not an easy task. This is mainly due to several factors, such as lack of a clear methodology to be followed, impedances of the equipment under test not characterized, and usage of inadequate measurement instrumentation. In this paper, a straightforward methodology to design an optimal power line filter in order to comply with the relative EMC standard is proposed and validated. Conducted emissions are studied starting from 9kHz to assess the filter behavior in for frequencies closer to the switching frequency of typical modern battery chargers.