The control method of modular multi-level converter based on low and high frequency circulating current

Abstract

The modular multilevel converter (MMC) is attractive for high-power applications because of the advantages of its high modularity and high power quality. This paper analyze the low and high frequency circulating current in MMC based on the phase-shifted carrier-based PWM(PSC-PWM) scheme. It can draw such conclusion that the DC component of circulating current can control the total sub-module capacitors voltage in one phase leg, while the fundamental frequency component can control the sub-module capacitors vo…