Improved Virtual Inertia Control of Wind Turbine Generators Considering Fatigue Load

To alleviate the fatigue load caused by wind power participating in frequency regulation and enhance the life of wind turbine generator, an improved virtual inertia control method considering the torque limit and fatigue load of wind turbine generator is proposed. Based on the traditional virtual inertia frequency modulation control, the torque limit is comprehensively considered and the process of power reduction and rotor speed recovery are improved. A rotor speed recovery strategy based on exponential function gradual approach is designed to reduce torque impact so that the fatigue load will be alleviated. Finally, a 2MW wind turbine generator is taken as an example to carry out the joint simulation study based on Matlab and Bladed. The simulation results verify that the proposed strategy can significantly reduce the torque pulsation and full-life cycle fatigue load of the wind turbine drive chain and tower, while provides similar frequency response power inertia support process.