Bidirectional modular Dual Active Bridge (DAB) converter using multi-limb-core transformer with symmetrical LC series resonant tank based on cascaded converters in solid state transformer (SST)

This paper proposes a practical model for the DC-DC stage of solid state transformer (SST) focusing on analysis and modeling for modular Dual Active Bridge (DAB). The proposed converter topology is based on cascaded H-bridge to handle the high voltage conditions. The multi-limb core (MLC) medium/high-frequency transformer has been introduced to realize galvanic isolation. Synchronized half-duty-cycle switching method is applied to every H-bridge and relative DC voltage value is controlled to manipulate the power flow. LC symmetrical resonant network has been used to improve the converter performance. Simulation and experimental results are also presented for verification.