An Internal Magnetic Core Termination Integration Method for LLC Four-Elemental Matrix Transformer

The existing four-elemental matrix transformer terminal integration methods lay out secondary rectifier devices (SRs) outside the magnetic core, resulting in additional footprint area or core loss problems. To address these limitations, this letter proposes an internal magnetic core terminal integration method by excavating the center area of the upper and lower magnetic plates and integrating SRs with the secondary winding. First, the center area of the upper and lower magnetic plates is verified to have a low magnetic density, so excavating this area has a small effect on the magnetic flux density of the core. Then, the transformer loss model of the proposed magnetic core is built, and the PCB winding integration with this core is implemented. Finally, two 480 W LLC prototypes were built to verify the superiority of the proposed method by comparing efficiency and temperature.