Derivation and Comparison for Modular Multilevel Converter Topologies with Hybrid Structures

Kinds of modular multilevel converters have been proposed and applied in high-voltage scenarios. In order to systematically provide more new topologies and screen the solutions with better performance, a topology derivation method is proposed in this paper. By orderly constructing the arm with basic elements, the three-terminal three-arm DC/AC modular multilevel converters are derived and categorized. One of the new topologies, called the HB-T-AAMC, shows its potential of high cost-efficient characteristic. The arm phase-shift conducting modulation is designed for it to balance the capacitor energy. Furthermore, the construction costs and the operating characteristics for the typical topologies are compared. The merits and demerits are concluded for each type of topologies.