Optimal Configuration Strategy for Flexible DC Control Parameters Considering System Operational Constraints

With the large-scale integration of renewable energy sources, the stability and control of flexible DC (VSC-HVDC) grid-connected systems have become critical issues. This paper proposes an optimal configuration strategy for the control parameters of grid-forming VSC-HVDC systems considering multiple operational constraints. First, a state-space model of the grid-forming VSC-HVDC system connected to a wind farm is established, and the effects of key control parameters on the small-signal stability are analyzed using eigenvalue and participation factor methods. Then, based on the stability analysis, an optimization model is constructed with the objectives of minimizing the steady-state DC operating voltage under operational constraints and maximizing system damping. To solve the optimization problem, the NSGA-II genetic algorithm is employed. Case studies in MATLAB/Simulink demonstrate that the proposed method effectively enhances the small-signal stability of the system across various operating points, reduces overshoot and settling time during power step changes, and ensures stable operation under the maximum transferable power limit. The results verify the robustness and effectiveness of the proposed parameter configuration strategy, providing a practical approach for the design and tuning of grid-forming VSC-HVDC systems in renewable energy integration applications.