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Ramp-up Fixed
Could you advise me effect of the Ramp-up Fixed in simulation?
I would like to know the difference between Ramp-up Fixed and Free.
Analysis with Ramp-up Fixed is easy to be more stable than Free?
- Ramp-Up Fixed: The RPM is fixed only during the ramp-up time of the simulation so that when the simulation starts the rotor is operating at the chosen RPM. During the simulation time the rotor rotation is governed by the balance of aerodynamic- and generator torque. This is the recommended setting for simulations that contain a Controller.
- Free: For ramp-up and simulation time the rotor rotation is governed by the balance of aerodynamic- and generator torque
BR,
Dear Knunoura,
the ramp-up time is a means to start a highly transient precursor simulation of the wind turbine before the recording of values is started.
Ramp up fixed in this sense means that the RPM is only prescribed during the ramp-up time of the simulation. After the ramp up time is finished the rotor will accelerate/decellerate based on the balance of aerodynamic torque and generator torque.
Free implies that the RPM is not prescribed during the entire simulation. Instead, the rotor’s ‘start-up’ is solely determined by the aerodynamic forces acting upon it.
It’s important to note that the presence of opposing generator torque in the simulation hinges on the inclusion of a controller library. Without such a controller library, the rotor will continue to accelerate until either the simulation becomes unstable or the aerodynamic forces balance to zero.
BR,
David
