Research on control strategy of MMC DC transmission system

Based on the basic principle and mathematical modeling of the DC transmission system, which the control core is modular multilevel converter (MMC), the DC transmission system is divided into three control systems: system level, converter station level and converter valve stage level, and this three control levels were analyzed in depth. And then the corresponding control strategy is put forward for the two kinds of HVDC systems with both active and passive power supply. Finally, the RT-LAB simulation software is used to build the control simulation platform model of the MMC DC transmission system, By analyzing the AC load and AC voltage of two kinds of mutation control system response strategy and system conditions, verify the accuracy and effectiveness of the control strategy.