Modelling, simulation and control of Modular Multilevel Converter

This paper describes first the mathematical model of the Modular Multilevel Converter with n submodules based on differential equations. Secondly, by using this model the simulation block diagram in Simulink is presented. After that, the special output AC voltage control of this converter is analysed, considering the capacitors' voltage control loop that usually is included in this topology. The modulation that also performs the capacitors' voltage balancing is not deeply studied in this paper. Finally, simulation results show that the proposed model can be useful to simulate the MMC topology with a large number of submodules, while on the other hand, the proposed AC voltage control is valid to regulate the total voltage of the converter capacitors as well as to exchange sinusoidal currents at any operation mode.