High-Density Planar Integrated Magnetics With Two-Sided Merged Inductor Windings and Integrated Cores for Resonant DC/DC Converter

Magnetic integration effectively reduces the total magnetic volume for a converter with multiple magnetic components. However, the existing integrated inductor and transformer still face some problems, such as a large core cross-sectional area due to the small effective inductor winding number or low printed-circuits-board (PCB) utilization due to unreasonable winding structure design. A new inductor and transformer integrated magnetic (IM) structure with high PCB utilization and a small core volume for the resonant converter is proposed in this article. The integrated resonant inductor is constructed by both the primary and secondary side windings, which increases not only the effective inductor turn number but also the utilization of the PCB. What is more, the core plates of the inductor and the transformer are integrated to furtherly increase the utilization of the core. The design methodology for the proposed IMs is also given in this article. Finally, the proposed IMs and design methodology are verified on a 2-kW China Power Supply Society (CLLC) prototype. Compared with the discrete magnetic components, the IMs’ volume is reduced by about 25% with a similar loss.