Evaluation and Comparison of Multilevel LLC Resonant DC-DC Converter for Solid-State Transformer

This work presents a theoretical evaluation of the LLC resonant converter intended for the DC-DC stage of a solid-state transformer (SST) system. For this, four topologies are considered for the implementation of the DC-DC stage: asymmetric half-bridge (HB) and multilevel topologies (three, five, and seven-level) derived from the HB-series concept. The power converters are compared in terms of semiconductor losses and number of devices. The performance analysis is carried out based on mathematical models and a selection of commercially available components. Simulation results are presented to validate the theoretical study.