Adaptive Robust Control Strategy Based on Improved Linear Extended State Observer for High-Capacity Offshore Wind Turbine DC Grid-Connected DC/DC Converters

Under wind power fluctuations and various internal/external disturbances, the input voltage of wind turbine DC grid-connected DC/DC converters is prone to oscillations, resulting in power transmission imbalance between input and output sides and degraded system stability. To address these issues, an adaptive robust control strategy based on an improved linear extended state observer is proposed. First, the fundamental principles of DC grid-connected DC/DC converters for wind turbines are analyzed. A system disturbance model is established according to control requirements, upon which an adaptive proportional controller is designed. Second, the parameter coupling problem existing in the traditional linear extended state observer is investigated. To resolve this limitation, an improved linear extended state observer is introduced, which eliminates parameter coupling and enhances disturbance rejection capability. Finally, an integrated control strategy is developed by addressing the power balancing issue in modular DC/DC converters. A simulation model of the wind turbine DC grid-connected system is built in MATLAB/Simulink to validate the effectiveness of the proposed control strategy.