I am a PhD student majoring in power electronics. Our laboratory has a lot of research on the design and operation of wind power converters.
We are new to this open source simulator and are still evaluating the feasibility of using OpenFAST for our research. Since our research is mainly focused on the power converter, we wonder how is the “Control and electrical system (servo) model” established?
What is the topology of the power converter, is it DFIG or back-to-back converters. Is the converter topology described in the simulator?
Is the converter modeled with detailed structures, e.g. power switches with pulse-width modulation method.
Or are there any files that we can refer to for more detials about these questions.
The simple built in generator and variable-speed control models within OpenFAST are quite simple…being able to calculate the generator torque, but not modeling the power conversion in any detail.
However, OpenFAST has been interfaced with, e.g., MATLAB/SImulink, where detailed models, e.g. DFIG, have been implemented. The following paper is likely of interest to you: nrel.gov/docs/fy14osti/59195.pdf.
I checked the techniqcal reports of NREL 5MW, DTU 10MW and IEA 15MW wind turbine models, it seems that these model all use the ROSCO bladed-style controller for the torque control. I wonder whether it is possible to use Simulink instead to simulate the detailed generator and converter behaviors with these aforementioned turbine models? Will it conflict with the ROSCO controller?
One more question, in the technical report you recommended “Simulation for Wind Turbine Generators—With FAST and MATLAB-Simulink Modules”, I found that power converter systems such as DFIG and full-power back-to-back converters have been successfully tested in the Simulink environment and linked to FAST s-function. But it does not mention what exactly is the turbine model used in this FAST model, like what is the power rating. Is it that the power rating can be arbitrarily decided in this case?
Normally the torque and pitch controllers are interrelated, i.e., the torque controller uses information from the pitch controller and vice versa. So, I would guess it would be preferable to implement the full (pitch + torque) controller in Simulink rather than to mix and match between Simulink and a ROSCO-based DISCON DLL controller.
I’m not an expert on the report NREL/TP-5D00-59195 that I referenced above, but from my quick skim, I gathered they used a couple turbine models as examples, including the AWT-27CR2 175-kW turbine (Test01) and the WindPACT 1.5-MW baseline turbine (Test12). Regardless, I’m sure the detailed drivetrain modeling approach presented could be adopted to other wind turbine models.
I am actually working with OpenFAST with Simulink, using a torque controller. But I am a bit confused about the type of generator used in OpenFAST in this case (VSContrl=4). I can’t find anywhere what kind of generator is actually used when OpenFAST is linked with Simulink. Do you have any idea please?
With VSContrl = 4, there is no generator model in OpenFAST / ServoDyn. Instead, the generator and torque controller is fully defined within the Simulink model. The torque and power provided to the OpenFAST model through Simulink are used directly in OpenFAST, without modification.