Modular Hybrid-Full-Bridge DC Transformer With Full-Process Matching Switching Strategy for MVdc Power Distribution Application

This article proposes a modular hybrid-full-bridge dc transformer (MHDCT) with full-process matching switching strategy MHDCT for MVdc power distribution application. The proposed MHDCT merges the advantages of DCTs based on dual-active-bridge and modular multilevel converter, it not only has good reliability, but also has good modularity and flexibility. Especially, full-process matching switching strategy has good voltage regulation ability to ensure the voltage match of high-frequency-link under various states, then circulating current can be decreased and efficiency can be improved. The universal operation and modulation, voltage, current, power, and switching characterizations of MHDCT are analyzed and the control strategy is proposed in this article. Finally, an MHDCT prototype is built and the experimental results verify the correctness and effectively of the proposed solution. The MHDCT will be a practical scheme for MVdc distribution application.