Robust Control Strategy for VSC-HVDC Considering Renewable Energy Fluctuation

High-voltage direct current (HVDC) transmission technology based on voltage source converter (VSC) is an ideal solution for scaled integration and consumption of renewable energies However, disturbances from renewable energy can easily cause system instability. Therefore, a robust DC voltage control strategy renewable energy fluctuation is proposed. Firstly, a dynamic model of VSC-HVDC considering the coupling characteristics of cable lines is established, which can respond to the pole-to-ground coupling and inter-pole coupling relationship. Secondly, the stability of the VSC-HVDC is examined, and the influence of transmission power and AC system strength on stability is investigated. On this basis, an improved H∞ robust controller design method is suggested. The effectiveness of proposed method is subsequently subjected to simulation and verification. The results demonstrate the efficacy of the proposed control strategy in effectively mitigating oscillations induced by uncertain disturbances. It effectively increases the upper limit of the transmission power of the flexible system and ensures the robustness and flexibility of the system operating in a larger power range.