An Efficient Control Scheme for Active Cross-Connected Modular Multilevel Converters

This paper proposes a new control strategy that reduces an ac-circulating current in the active cross-connected modular multilevel converters, which improves the current stresses on semiconductor devices, capacitors, and inductors. Instead of mitigating submodule capacitor voltage ripples completely, those ripples are controlled to be fluctuated within a specified range by decreasing the amount of power difference redistributing through active branch in each phase. The effectiveness of the proposed control strategy has been verified through simulation results.