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Measured Velocity at Hub Local Coordinate
Dear David,
I’m trying to apply torque controller to a floating tidal turbine with a fixed-pitch blades. I tried to use the exiting controllers (ROSCO/DTU/TUBCON) but to no avail. Hence, I intend to use Software in Loop feature of QBlade to apply HSS Torque based on the measured inflow velocity measured at hub. I have performed steady BEM to identify the target HSS Torques at various inflow velocities. However, I’m struggling to find a suitable variable to input into the Torque Controller due to floating configuration of the turbine.
Is there any way I could obtain the measured fluid velocity at hub in local coordinate system of hub (i.e. “X_h Meas. Wind Vel. at Hub [m/s]”) for SIL Torque Controller input?
The existing variables “X_g Meas. Wind Vel. at Hub [m/s]” is given in global coordinate which is not applicable due to the floating orientation of the turbine is rarely oriented along with the global x-axis.
Thanks & regards,
Andhi
Dear Andhi,
This is a good idea. Having the measured inflow velocity available directly in the hub-local coordinate system could indeed be useful for floating turbine configurations where the rotor orientation changes continuously. We will consider adding such a variable in a future version of QBlade.
That said, most turbine controllers do not rely on a direct measurement of the local inflow velocity. Instead, they use turbine response variables such as rotor or generator speed and torque to define the control action, or to infer the current operating condition indirectly. Therefore, I am not entirely sure how useful such a local measurement would be in practice.
For now, a possible workaround is to reconstruct the local inflow velocity within your SIL script. You can use the global hub wind speed measurement together with the platform orientation sensors (yaw, pitch, and roll) to transform the full velocity vector from the global coordinate system into the hub coordinate system.
With this, you should be able to obtain the inflow component along the rotor axis and use it as an input for your torque controller.
Best regards,
David
