A Self-Resonant Transformer for CLLC Converter

To date, the dominant method of passive component miniaturisation in power converters is through increases in switching frequency, which is enabled by emerging high frequency Wide-Band-Gap devices. However, to push the performance limits for the next generation of high-power-density power converters, research into integrated passive components-such as inductors, capacitors, and transformers into a single structure is essential. This manuscript presents an integrated self-resonating transformer based on Flexible Multilayer Foil (FMLF) for CLLC converters. In this design, all resonant components on both the primary and secondary sides-such as leakage or physical inductance and capacitance-are combined into a single unit, referred to as a Self-Resonant Transformer. This not only reduces the volume, but also the cost and weight of the overall system thereby enabling next-gen highly power dense converters. Moreover, the proposed structure employs a novel trifilar winding configuration to mitigate the effects of bypass capacitance typically observed in conventional winding arrangements. Analysis, design, and experimental measurements are presented to show the efficacy of the proposed structure.