THREE-PHASE CLLC BIDIRECTIONAL DIRECT CURRENT TRANSFORMER AND CONTROL METHOD THEREFOR

摘要

The present invention relates to the technical field of direct current transformers, and specifically relates to a three-phase CLLC bidirectional direct current transformer and a control method therefor, for solving the problems of existing modular high-voltage side series connection and low-voltage side parallel connection structures having a large number of modules and low reliability, and existing multilevel technology-based transformer circuits having complex circuit topology, uneven capacitance voltage division, and high clamp tube voltage stress. The invention comprises: a high-voltage side voltage division capacitor module comprising three voltage division capacitors; a three-phase half bridge series/parallel connection module comprising three series/parallel connected bridge arms, each bridge arm comprising two switches connected in series; a three-phase primary/secondary resonant module comprising a, b, and c three-phase primary/secondary resonant cavities; a three-phase isolation transformer comprising three a, b, and c single-phase transformers; and a low-voltage side capacitor module. The present invention reduces clamp tube voltage stress by means of the voltage division capacitors implementing high-voltage side voltage division, and reduces switch loss by means of high-frequency soft-switching technology, increasing the efficiency and power density of the transformer.