Analysis of maximum power transfer capability of a hybrid modular multilevel converter

This paper presents a study on evaluating the power transfer capability of a novel hybrid cascaded modular multilevel voltage source converter topology. The configuration utilizes third harmonic injection to enable reactive power compensation by varying the ac side converter voltage in the presence of constant dc side voltage. The maximum converter voltage is determined by the number and rating of submodules and triplen harmonic compensation whereas the maximum allowable steady current through the converter determines its MVA rating. These constraints must be considered in determining the maximum power transfer capability of this converter configuration, connected to strong and weak ac buses. Further the reactive power required to be supplied by the converter under this condition is evaluated for these different system strengths. Results obtained from a developed Electro-Magnetic Transient (EMT) simulation model are presented in this paper, for validation of the theoretical calculations.