High power density interleaved DC/DC converter using a 3-phase integrated close-coupled inductor set aimed for electric vehicles

Among eco-friendly electric vehicles, some incorporate DC/DC converters in their electrical drive systems to make full use of their power sources. For increasing the power density of the converters, a 3-phase interleaved converter using an inductor set of inductors and close-coupled inductors is investigated. The inductor set of a 3-phase topology is shown to be smaller in size and lose less power in comparison to that of a 2-phase topology while meeting the required specifications for high powered electric vehicles having a 200~400 volt battery. The 3-phase converter using the inductor set was designed on the condition of using IGBT with a switching frequency of 15 kHz. It achieved a high power density of 21.4 kW/liter at 120 kW output on a boost ratio of 1.38 with 98.0% efficiency and it achieved an efficiency of more than 97% in a frequent usage zone with low temperature rise.