Quasi-integrated magnetic an avenue for higher power density and efficiency in power converters

This paper presents several topologies that lead to a better utilization of a transformer's magnetic core. In these topologies, the main transformer also becomes a magnetic storage element, reducing the size of the output filter. Quasi-integrated magnetics are presented as an intermediate step between conventional and fully-integrated magnetics underlying their advantages and limitations. The authors also present quasi-integrated magnetic topologies with and without secondary winding taps. Two methods of eliminating the secondary winding taps are suggested, one by using a current-doubler and the second by employing two symmetrical transformers. Two 100 W, 5 V, 20 A experimental power converters were built and evaluated, using quasi-integrated magnetics under two different implementations.