Matrix Transformer with Integrated Leakage Inductance

Due to the rapid growth of electric aircraft, the need for high-power converters with significant weight reduction has increased. This article proposes a matrix transformer as a solution for isolated DC/DC converters $(270 \mathrm{~V} / 28 \mathrm{~V})$. The matrix transformer enable the integration of leakage inductance through a five-leg magnetic core geometry. Four legs are used for the transformer windings, while the central leg is used for the integration and control of leakage inductance. Two winding structures are analyzed and compared: a configuration with separate primary and secondary windings, and an interleaved winding structure. The structure with lowest magnetic losses and AC resistance is selected. An optimization of the magnetic core geometry is then carried out to achieve the desired leakage inductance value while minimizing losses. The final transformer is designed for an output power of around 1 kW, reaching an efficiency of around $98 \%$.