Modular Multi-level Converter Control Method Based on CPS - PWM

The traditional voltage output of light DC transmission is mostly two-level or three-level. It is difficult to meet the high voltage and high power requirements of the power grid; MMC(Modular multi-level converter, MMC) becomes a hot spot in recent years because of modular structure, small harmonic content, easy to expand and so on. In this paper, according to the equivalent single-phase MMC topology and analyze the principle of MMC, using the voltage outer loop and current inner loop cooperate control strategy to control the capacitance of the sub-module and the system circulation by the carrier phase shift PWM modulation technique to modulate the power switch device. Finally verify the correctness of the control strategy by building the MMC model to simulation experiments through MATLAB/Simulink.