Dear Bonnie,

I want to do an experiment about the pitch angle control, now I saw an example on the <<Definition of a 5-MW Reference Wind Turbine for Offshore System Development>>.The flowchar is in below. Could you provide the specific Simulink files? When I use the provided parameters, I still have problems to build the Simulink model.

Thank you.

What’s the value of the gain schedule( Gain Factor)? 1 ?

Does the Proportional Gain have two inputs(Gain Factor and Speed Error)?

The maximum value of the Integral Term is the maximum value of the Pitch Limit Saturation?

Dear Peter.Wang,

I have not used this myself, but Leonardo.Lopez uploaded his Simulink implementation of the baseline controller for the NREL 5-MW turbine in the Mar 03, 2017 post in the following forum topic: http://forums.nrel.gov/t/baseline-nrel-5mw-controller-on-simulink/1557/12.

Best regards,

Dear Bonnie,

When I read the materials about the Control of the Variable Speed Wind Turbuines, I found that the Troque Controller has two input parameters, Gen Torque and Power, as I know, someone only use the one input parameter, Gen Torque to control, What’s the difference about this two kinds of the methods. I also read some material that said the variable speed wind turbines has two control methods, they are torque control and power control, can you explain why we need power control because I think the torque control can fix the control issues well.

Thank you!

Hi Peter,

Generally, the torque control logic is described as “constant torque” or “constant power”, but in either case, the generator torque is the primary control input. Traditionally, the generator torque controller will follow the k*omega^2 law in below-rated operation, and then regulate for constant torque or constant power above-rated.

For constant power: tau_g = P_rated/omega

For constant torque: tau_g = P_rated/omega_rated,

where tau_g is the generator torque, P_rated is the rated power, and omega is the generator speed (rated, or as a function of time). Constant power control will maintain the rated power output for the turbine in above-rated operation, but at the cost of increased generator torque actuation. Constant torque control will hold the generator torque constant in above-rated operation, but the power will only be as constant as the rotor speed is (based on the above equation).

In any case, the inputs to the SFunction block coming from the Torque Controller in the simulink model you have shown should be such that Power = generator torque * generator speed * generator efficiency.

If you think it might be useful, a simulink model of the ROSCO controller is made available via the ROSCO toolbox. This can be found at: https://github.com/NREL/ROSCO_toolbox. This might be a good reference for you to understand the general controller work-flow within OpenFAST.

Cheers,

Nikhar