A Novel Structure of Variable Inductance High-Frequency Transformer for Power Level Enhancement in Dual-Active-Bridge Converters

This study presents a novel structure proposal of a variable inductance high-frequency transformer for enhancement power level of a dual-active-bridge (DAB) converter. The DAB converter is a solid-state transformer (SST) that requires high efficiency, power density, flexibility, and stability. Variable inductance facilitates achieving and extending maximum power levels. The proposed method adjusts the inductance based on the core insertion conditions of the transformer used in the DAB converter without requiring an additional inductor. The method was verified by analyzing the variable inductance characteristics of the transformer based on core insertion conditions via finite element analysis (FEA) and simulation and experiments within the variable inductance range.