Large Signal Stability Analysis of Offshore Wind Power Low Frequency Transmission System Based on Y-type Modular Multilevel Converter

Based on the characteristics of the offshore wind low-frequency power transmission system of the Y-connected Modular Multilevel Converter (Y-MMC), this paper deeply analyzes its large-signal stability. Firstly, the advantages of the offshore wind low-frequency power transmission system are elaborated, and its mathematical model is derived in combination with its working principle. Secondly, the TS fuzzy theory is used to model the low-frequency transmission system of offshore wind power. The LMI problem based on the global TS fuzzy model of the system is solved to obtain the fuzzy Lyapunov function of the system. Then, the attraction domain based on the steady-state equilibrium point is depicted, and the large signal stability of the offshore wind power low-frequency transmission system is analyzed. The article also discusses the influencing factors such as DC voltage, DC current, and AC voltage, and proposes solutions to improve the large-signal stability. Finally, the effectiveness of the proposed solutions is verified through simulation results, providing theoretical and practical reference for the large-signal stability of Y-MMC.