H∞ Controller Design for Robust Control in MMC-HVDC System

In this paper, a Modular–Multilevel–Converter based high voltage direct current (MMC-HVDC) system is considered. It is assumed that the grid is strong. The effects of load change and, PLL errors can cause voltage, current, and active/reactive power changes on the grid side. It is assumed that active/reactive power and q-axis voltage are disturbances. Based on the H theory, a robust controller is designed to deal with external disturbances. Purpose of controller maintains active/reactive power at the inverter station. The designed H controller is validated by a simulation using MATLAB/Simulink.