Dear @Hairui.Jiang,
The figure you took from the NREL 5-MW baseline specifications report was generated with distinct simulations at each wind speed, finding the steady state solution from each simulation, and plotting this solution as a function of wind speed.
You can, however, perform a similar analysis with a single simulation. For simple wind time histories, such as step changes in the wind speed, InflowWind’s simple uniform wind file format can be used, such as in the example attached to my post dated Mar '14 in the following forum topic: Beginner Guide for MATLAB Simulink and FAST - #12 by Jason.Jonkman.
Best regards,