Practical Analytical Model and Comprehensive Comparison of Power Loss Performance for Various MMCs Based on IGCT in HVDC Application

This paper gives a comprehensive analysis and characterization of power loss of a high-power integrated gate-commutated thyristor (IGCT) in a modular multilevel converter (MMC) for a high voltage dc application. The practical scheme, power loss models, calculation methods, characterization of MMC based on IGCT are analyzed in detail. Especially, a comprehensive comparison of both half-bridge MMC (HB-MMC) and full-bridge MMC (FB-MMC) based on IGCT, press-pack insulated gate bipolar transistor (IGBT), module-type IGBT, press-pack injection enhanced gate transistor (IEGT), and module-type IEGT is analyzed in this paper. According to the study in this paper, the snubber power loss of MMC based on IGCT is far less than the conduction and switching power losses. Both the conduction and switching power losses of IGCT are always lower than that of press-pack and module-type IGBTs and IEGTs in MMC. The power loss of FB-MMC is higher than that of HB-MMC with the same transmission power because more switches are employed in FB-MMC. If taking diodes into account, the HB-MMC and FB-MMC based on IGCT can decrease power loss about 1.9%-49.3% and 8.3%-45.1% under different operation states, respectively. The study in this paper will provide a valuable reference and promote the application of IGCT in MMC.