Abstract

Multilevel converters can reach medium-voltage operation increasing the efficiency of high power applications. Among the existing multilevel converter topologies, modular multilevel converter provides the advantages of high modularity, availability and high power quality. Moreover, the main advantage compared to cascaded multilevel converters is the lack of input transformer which results in a reduction of cooling requirements, size and cost. One of the drawbacks of this topology when used as AC-AC converter is the input and output frequency components in the control loop, resulting in a more complex controller design. In this paper, a single-phase AC-AC modular multilevel converter predictive control approach is proposed. The controller minimizes the input, output and circulating current errors and balance the DC voltages. Experimental results show the performance of the proposed predictive control scheme.