Control Approach for a Class of Modular Multilevel Converter Topologies

This paper presents a generalised control that can be applied to a class of modular multilevel converter topologies. The approach splits up into current control based on the state-space representation and branch energy balancing. For the branch energy balancing, an optimisation process leading to minimal additional current stress is presented. After describing the control approach independently from any specific topology, it is applied exemplarily to the Modular Multilevel Matrix Converter. A comparison with a previously published branch energy balancing for the Modular Multilevel Matrix Converter is conducted, and the control approach is verified by simulation and experimental results.