A MMC-Based Multiport AC-N-DC Converter for Hybrid AC/DC Systems

Multiport converters are going to be the critical equipments in future hybrid AC/DC systems. Based on this, a MMC-based multiport AC-N-DC converter topology is proposed in this brief, where multiple upper arms and one shared lower arm are configured to obtain one AC port and multiple DC ports. By designing the submodule (SM) number in multiple upper arms, the voltage levels at multiple DC ports can be flexibly configured. Moreover, the DC port can be further expanded by adding extra upper arm. Therefore, the proposed multiport AC-N-DC converter has good extensibility and configuration flexibility. Due to the utilization of shared lower arm, the multiple ports are in direct electrical connection, and only one power conversion stage is needed among the multiple ports. Thus, a large number of SMs and passive components can be saved. In addition, the experimental results are provided to verify the feasibility of proposed multiport AC-N-DC converter.