A Matlab/Simulink model for capacitor voltages balancing in modular multilevel converters

Abstract

The modular multilevel converter (MMC) is a potential candidate for high power applications due to its modularity, availability, and enhanced power quality features. Nevertheless, the voltage balancing of the floating capacitors in the series-connected submodules (SMs) of the MMC represents a bottleneck in this type of multilevel converters. In this paper, a generalized voltage balancing technique for MMCs is modelled using Matlab/Simulink platform. The presented model can be simply extended to any number of levels where the switching frequency can be as low as the fundamental frequency. A 9-level MMC is modelled and simulated using half bridge topology where the switches are controlled using phase disposition carrier-based pulse width modulation (PD-PWM) scheme to validate the proposed concept. 2016, Institution of Engineering and Technology.