Design of a high-frequency isolated DTHB CLLC bidirectional resonant DC-DC converter

A novel high-frequency isolated dual three-level neutral point clamped (NPC) half bridge (DTHB) CLLC bidirectional resonant DC-DC converter with a symmetric series LC resonant network is proposed for a transformerless high power cascaded multi-level converter. This converter combines the advantages of bidirectional three-level half-bridge converters and the LC resonant converter and can be used in high power high voltage applications. This paper analyses the operating modes and characteristics of the equivalent circuit in detail. Then a design example is given to verify the analysis. In the end, the experimental results are shown which verify the theoretical analysis.