Lyapunov control strategy for low-frequency offshore wind power based on hexagonal converters

Abstract The low-frequency transmission system (LFTS) for offshore wind power is a promising integrated solution. Hexverter, as a topology derived from the Modular Multilevel Matrix Converter (M3C), exhibits certain advantages in low-frequency transmission. However, its application in offshore wind power faces challenges due to the stochastic nature and nonlinear characteristics of renewable energy, making linear PID control less effective. In contrast, the Lyapunov control strategy has shown better performance in controlling nonlinear systems than PID control. Therefore, this paper proposes a Lyapunov control strategy for Hexverter. Firstly, the global asymptotic stability of the Lyapunov control strategy for Hexverter is analyzed. Then, based on the topology of Hexverter, the control laws for bilateral Lyapunov control of Hexverter are derived, and the parameter selection problem for Lyapunov control is discussed. Subsequently, a Lyapunov control system for Hexverter is established using Simulink and RT-LAB platforms. The operating results under various conditions are simulated, and the feasibility and effectiveness of the proposed Lyapunov control strategy are validated by comparing the simulation results with PID control.