Some design considerations for coupled inductors for integrated buck-boost converters

This paper presents some design considerations for magnetically coupled inductors in buck-boost converters for distributed power generation. As compared to the conventional approach, the proposed integrated magnetic structure with coupled inductors enables reduction in core loss, core size, winding losses and in the number of turns. This paper discusses rough and simple design of the coupled inductor to achieve desired objectives. The methodology for the selection of inductance, core geometry, number of turns, air gap and isolation is described. In addition, general operation principles and conditions for the continuous conduction mode (CCM) and the discontinuous conduction mode (DCM) are presented. In order to verify the theoretical assumptions a prototype has been built. The experimental results are presented and discussed.