Modeling of modular multilevel converter based high voltage direct current transmission system

The modular multilevel converter (MMC) is a trending topology that has revolutionized voltage source converter (VSC) based high voltage direct current (HVDC) transmission. In this paper a MMC based VSC-HVDC transmission system has been modeled, designed and simulated under balanced three-phase operation in semiconductor based time-domain simulation environment. MMC based VSC-HVDC transmission system has been positioned between two separate large generation centers to provide real power flow control and reactive power/voltage control at AC terminals of both converters. MMC has been preliminary designed using five half-bridges at each arm. An efficient modulation strategy for the switching of IGBT switches has been decided and verified. The dynamic responses of the controllers of the MMC based VSC-HVDC transmission system have been evaluated to draw some conclusions at the end of the study.