Application of Voltage Source Type Multilevel Converter in HVDC

This paper analyzes the topology,working principle and modulation strategy for various kinds of voltage source type multilevel inverter used in high flexible DC transmission system,and compares their merits and demerits.The paper focuses on the application of streamlined modular multilevel converter(MMC) in the high flexible DC transmission system,as well as various modulation methods for MMC,the key points and difficulties in actual engineering utilization.In the end.the paper introduces some of the major application example of the voltage source type multilevel inverter in flexible HVDC in the world,and gives a good application prospect of MMC.