High power density DC/DC converter using the close-coupled inductors

Among the specifications of eco-friendly electric vehicles, some will incorporate voltage converters in their systems to make full use of their power sources. The DC-DC converter using coupled inductors is known as one of converter types that may achieve higher power density. This paper focused on this circuit type especially using close-coupled inductors. Following, the elucidation of design guidelines for the close-coupled inductors theoretically, the superiority of the circuit in terms of reducing the size and losses in the magnetic components was demonstrated clearly through comparison with coupled inductors with looser coupling used in interleaved boost circuits and an inductor of boost chopper circuits. Finally, test results for a prototype of the proposed converter achieved a maximum power density of 24.7 kW/liter and a maximum efficiency of 98.4 % on an output of 42 kW (a maximum input current of 233 A) for a time rating of a few minutes.