Control strategies of MMC-HVDC connected to passive networks

Abstract

This paper introduces the structure and operational mechanism of Modular Multilevel Converter-High Voltage Direct Current (MMC-HVDC) and the mathematical model for the MMC-HVDC system in d-q synchronous reference frame is developed. When supplying power to passive networks, the MMC-HVDC controller at the passive network side, which contains a novel inner fast current loop and an outer voltage loop, is designed. The MMC-HVDC connected to passive network simulation model is set up in PSCAD/EMTDC. Simulation results, in the case of various operation conditions, verify that the designed control strategy is effective.