A novel virtual voltage control strategy for modular multilevel converter

Abstract

A novel virtual voltage control strategy is proposed for modular multilevel converter in order to reduce the quantity of voltage sensors at the terminal. The output voltage of the inverter is obtained through the upper and lower arm currents of the converter and used to trace the reference active and reactive power, respectively. According to the Routh-Hurwitz criterion, the root trajectory of the controlled system is revealed and the dynamic characteristics of the controlled system are analyzed in the paper. Based on the root trajectory, the controller parameter is designed, which simplifies the parameter tuning. The simulations are carried out in the PSCAD/EMTDC. Results show that the proposed control strategy has good control performance.