Grid following based power/DC voltage control with capacitor voltage regulation for modular multilevel converters

Conventionally the power and DC voltage control is realized with the vector current based grid following control. Considering the relationship between capacitor voltage and power/DC voltage control, with the constant submodule insertion number in each phase, the power and DC voltage can be realized with the modification of capacitor voltage. Therefore, in this paper, the power and DC voltage control is realized with the modification of capacitor voltage. Based on the traditional grid following based vector current control, the power and DC voltage control is cascaded with the capacitor voltage control so that the traditional grid following control can be easily modified for the proposed control. Simulations are carried out to verify the proposed method.