# Implementing variable speed and collective pitch control for NREL 5MW turbine **URL:** \ **Category:** Controls\ **Created:** [December 8, 2023, 3:37pm UTC](https://forums.nlr.gov/t/implementing-variable-speed-and-collective-pitch-control-for-nrel-5mw-turbine/6167 "2023-12-08T15:37:28Z")\ **Posts on this page:** 5\ **Page:** 1
**Author:** ![Tongzhou.Zhang](https://dub1.discourse-cdn.com/nrel/user_avatar/forums.nlr.gov/tongzhou.zhang/32/4868_2.png) [@Tongzhou.Zhang](https://forums.nlr.gov/u/Tongzhou.Zhang)\ **Post date:** [December 8, 2023, 3:37pm UTC](https://forums.nlr.gov/t/implementing-variable-speed-and-collective-pitch-control-for-nrel-5mw-turbine/6167/1 "2023-12-08T15:37:28Z")
Dear all, I want to implement variable speed and collective pitch control for NREL 5MW blade. My simulation is based on 5MW\_Land\_BD\_DLL\_WTurb.fst. Since I’m recently to OpenFAST, there is no DISCON.dll file in the 5MW\_Baseline/ServoData folder, but only a DISCON.F90 file. I don’t want to make any modification to the controller so I don’t want to compile the .F90 file. Instead, I copied a DISCON\_x64.dll file from the FAST V8 archive instead but got the following warning: **fast\_solution:fast\_advancestates:srvd\_updatestates:dll\_controller\_call:bladedinterface option was designed for an explicit-loose coupling scheme. using last calculated values from dll on all subsequent calls until time is advanced. warning will not be displayed again.** The reason for my implementing the control model is that I want to see the influence on blade root flapwise bending moment with or without pitch control, especially when the 10-min wind speed is beyond the rated wind speed. However I didn’t see any dropdown for blade root flapwise bending moment when pitch control is enabled compared with totally diable ServoDyn. I totally don’t know the reason except for the warning message above. Could anyone help me solve this problem? Thanks in advance. ---
**Author:** ![Jason.Jonkman](https://dub1.discourse-cdn.com/nrel/user_avatar/forums.nlr.gov/jason.jonkman/32/3086_2.png) [@Jason.Jonkman](https://forums.nlr.gov/u/Jason.Jonkman)\ **Post date:** [December 8, 2023, 4:00pm UTC](https://forums.nlr.gov/t/implementing-variable-speed-and-collective-pitch-control-for-nrel-5mw-turbine/6167/2 "2023-12-08T16:00:37Z")
Dear @Tongzhou.Zhang, Precompiled DLL versions of the baseline controllers for the NREL 5-MW baseline wind turbine models are available with the OpenFAST releases–see: [Releases · OpenFAST/openfast · GitHub](https://github.com/OpenFAST/openfast/releases) (you don’t need to go back to the FAST v8 archive for those). The baseline controllers for these models are not targeted at reducing blade loads; rather, they focus on generator speed control. Independent blade-pitch control could be added to reduce blade loads. Best regards, ---
**Author:** ![Tongzhou.Zhang](https://dub1.discourse-cdn.com/nrel/user_avatar/forums.nlr.gov/tongzhou.zhang/32/4868_2.png) [@Tongzhou.Zhang](https://forums.nlr.gov/u/Tongzhou.Zhang)\ **Post date:** [December 9, 2023, 3:28am UTC](https://forums.nlr.gov/t/implementing-variable-speed-and-collective-pitch-control-for-nrel-5mw-turbine/6167/3 "2023-12-09T03:28:44Z")
Dear Jason, Thank you for your kindly reply. In your technical report “Definition of a 5-MW Reference Wind Turbine for Offshore System Development”, you mentioned the usage of variable speed and collective pitch. Does the Discon.dll file in the figure below include these features? If not, I wonder how I can obtain the dll file that contains variable speed and collective pitch control features? ![image](https://europe1.discourse-cdn.com/nrel/original/2X/a/af1505a7dffdbffa53eac3fc4a1504e79a5713af.png) Best regards, ---
**Author:** ![Jason.Jonkman](https://dub1.discourse-cdn.com/nrel/user_avatar/forums.nlr.gov/jason.jonkman/32/3086_2.png) [@Jason.Jonkman](https://forums.nlr.gov/u/Jason.Jonkman)\ **Post date:** [December 9, 2023, 4:25am UTC](https://forums.nlr.gov/t/implementing-variable-speed-and-collective-pitch-control-for-nrel-5mw-turbine/6167/4 "2023-12-09T04:25:08Z")
Dear @Tongzhou.Zhang, Yes, all of these DISCON controllers support variable speed and collective pitch. Best regards, ---
**Author:** ![Tongzhou.Zhang](https://dub1.discourse-cdn.com/nrel/user_avatar/forums.nlr.gov/tongzhou.zhang/32/4868_2.png) [@Tongzhou.Zhang](https://forums.nlr.gov/u/Tongzhou.Zhang)\ **Post date:** [December 9, 2023, 1:32pm UTC](https://forums.nlr.gov/t/implementing-variable-speed-and-collective-pitch-control-for-nrel-5mw-turbine/6167/5 "2023-12-09T13:32:15Z")
Thank you for your kindly reply!