Disturbance-Tracking-based Backstepping Control for VSC-HVDC Systems with Mismatched Uncertainties

This paper presents the disturbance-tracking-based backstepping control for VSC-HVDC (Voltage source converter high voltage direct current) transmission system to enhance the dynamic responses under the situations of mismatched uncertainties such as external disturbances and internal model perturbations. Firstly, the actual mathematical model of the converter with mismatched uncertainties is established. Next, the detailed controller design process of the enhanced disturbance-tracking-based backstepping control scheme of the rectifier and inverter is given. The mismatched uncertainties are estimated with the disturbance-tracking method to eliminate the adverse effects on system response. A benchmark simulation model of two-terminal VSC-HVDC system is established in PSCAD/EMTDC. The simulation results show the effectiveness of the proposed control strategy during transients, and the robustness against the internal model perturbations is also validated.