Modeling and voltage method for Modular multilevel converter

The Modular Multilevel Converter (MMC) is one of interesting transformerless multilevel converter topology intended for medium and high-voltage power conversion. The MMC is formed by a cascade connection of several identical submodules and requires charge balancing of the multiple floating capacitors of the submodules. This paper proposes a new balancing method for the floating capacitor voltage. The proposed control system uses the common component in the arms current to achieve the total leg voltage and differential arm voltage control. The dynamic modeling of the converter is presented. Therefore, the design of a digital system control is included. Experimental results based on 2.2 kW prototype are presented to demonstrate the performance of the proposed system.