Feedback Linearization Controller for MMC-HVDC System Connecting to Passive Networks

Compared with traditional voltage-source converter (VSC) in low level topology, modular multilevel converter (MMC) is suitable for supplying passive networks. A stable and well controller is important to ensure the high quality power supply to passive network connecting to MMC. In this paper, a double closed-loop controller containing an inner current loop and an outer voltage loop is designed for the rectifier station. The feedback linearization controller is adopted in the inner current loop, which is much simpler and better than the traditional PI controller. And a constant AC voltage controller is designed for the inverter station. The performance of the proposed controllers under different operation conditions are simulated in PSCAD/EMTDC. The simulation results show that the proposed controllers can ensure MMC-HVDC system provide highquality power supply to passive networks.