Classification, terminology, and application of the modular multilevel cascade converter (MMCC)

Abstract

This paper presents the modular multilevel cascade converter (MMCC) family based on cascade connection of multiple reversible-chopper cells or multiple single-phase full-bridge cells. This converter family are classified from circuit configuration as follows; single-star bridge-cells (SSBC), singledelta bridge-cells (SDBC), double-star chopper-cells (DSCC), and double-star bridge-cells (DSBC). The term MMCC corresponds to a family name in a person while, for example, the term SSBC corresponds to a given name. Therefore, the term “MMCC-SSBC” can identify the circuit configuration without any confusion. Among the four circuit configurations, SSBC and DSCC are the most practical than the others in terms of cost and performance, although a distinct difference exists in application between SSBC and DSCC. This paper describes applications of SSBC and DSCC to a battery energy storage system and a motor drive, respectively.