A new control for modular multilevel converters and their use as DC circuit breaker

Abstract

This paper presents a new modulation for modular multilevel converters (MMC) based on a simple idea, which is very easy to implement. It consists of playing with the relative behaviour of each phase in order to obtain the desired AC voltage. This method also assures that the voltage capacitor in each sub-module remains constant. Moreover, this converter allows the operation of the system under unbalanced conditions, and it can be used intrinsically as a DC circuit-breaker (DC-CB) without the need for additional power electronics and control if full bridge sub-modules are used.