High-voltage multicellular converters applied to ac/ac conversion

This paper considers arrangements for multilevel, multicellular power converters with emphasis on applications in the field of transmission and distribution. A classification system for such converter structures is proposed which allows the many possible topological variations to be individually identified. A description and analysis of the power flow and energy balance characteristics of multicellular converters is presented. This analysis is applied to specific multilevel multicellular topologies and switching strategies. Two methods of achieving power balance in the case of multiple dc energy storage elements are presented, along with both stimulation and experimental results.