Hi,
When running an OpenFAST simulation with Vs_ControlMode different from 2 (different from TSR tracking) and the pitch saturation active (PS_Mode = 1), the rotor speed turns negative. If I turn off the pitch saturation, the simulation runs smoothly. Does anybody know how to solve this issue? I would like to run a simulation where in the below region the turbine is control by the k-omega squared law with a minimum rotor speed (so pitch saturation active), provided that is possible. (FYI I am using Openfast v2.4.0)
Thanks in advance for your response.
Kind regards,
Giorgio
Hi Giorgio,
I would recommend checking your initial conditions in ElastoDyn. VS_ControlMode of 0 should be what you are looking for, but it is hard to debug your issue without looking at time-series of wind speed, generator speed, blade pitch, and generator torque. Also, make sure you are using the latest version of ROSCO.
Best, Dan
Dear Dan,
I tried different initial condition of the rotor speed (0, 3, 5 rpm). With 3 and 5 rpm, the response is similar, except in the initial transient. With 0 rpm, it does not start (I assume it is a numerical problem). So, I considered a 3 rpm rotor speed as initial condition.
Below I attached a figure of the variables considering 3 different controls: VS_ControlMode = 2, VS_ContolMode = 0 and VS_ContolMode = 0 without pitch saturation. I don’t understand why with pitch saturation and VS_ControlMode = 0, it diverges. The turbine model is the IEA-15-240-RWT and the wind speed is constant at 3 m/s.
Thanks in advance for your response,
Greetings,
Giorgio
