I’m attempting to model sinusoidal pitching of turbine blades but am encountering negative outputs, namely in RtSpeed, GenTq, and GenPwr. I am using 5MW_Land_BD_DLL_WTurb as a starting point with a 400 second run time, 0.0015 DT, and 8 m/s inflow wind with low IECKAI turbulence. I am using simulink for the pitch controller and all other options in servoDyn uses default values. The pitching simulink is a simple sine wave generator set to O(t) = 0.044sin(2pi/63 *t) with identical outputs for each blade. My goal is to reproduce results from this paper.
Attached are the results; as you can see, RtSpeed, GenTq, and GenPwr all follow disjointed paths and have negative values.
Debugging that I’ve tried
- Reducing the time step to 0.0009 but saw no change
- Doubling the inflow speed, that prevented negative values for GenTq and GenPwr and appeared normal but resulted in a tower strike error.
I can attach any additional input/source files if needed.
Dear @Ben.Pelson,
Can you clarify how you are computing the generator torque? I would guess the rotor speed fluctuations are commensurate with the torque control you are using. If you are continuing to use the baseline variable-speed torque controller, I would guess this could be problematic because the torque control region in this controller is impacted by the blade-pitch angle computed by the controller, which you are overriding by your Simulink signal. My guess is that you’ll need to change the torque control logic a bit.
Best regards,
Thank you for the response. I started looking at the generator torque more carefully and am trying to generate it through simulink for a 5MW Land turbine. I am using the prebuilt Test_01_SIG, which includes a feedback loop for torque that takes gen speed as an input. I’m still unsure why I am getting a negative generator torque, as everything is now controlled by Simulink.
Simulation results.
Overall Simulink diagram.
Simple Induction Generator within Simulink.
Dear @Ben.Pelson,
Are the parameters of your Simple Induction Generator (SIG) model (SIG_SlPc, SIG_SySp, SIG_RtTq, SIG_PORt, GBRatio, and GenEff) set to reasonable values for our use case?
Best regards,
