A MATLAB®-based Postprocessor for Multi-Blade Coordinate Transformation of Wind Turbine State-Space Models

by Gunjit Bir
National Wind Technology Center

MBC is a set of MatLab scripts that performs Multi-blade coordinate transformation (MBC) on wind turbine system model. The dynamics of wind turbine rotor blades are conventionally expressed in rotating frames attached to the individual blades. The tower-nacelle subsystem sees the combined effect of all rotor blades, not the individual blades. This is because the rotor responds as a whole to excitations such as aerodynamic gusts, control inputs, and tower-nacelle motion—all of which occur in a nonrotating frame. MBC helps integrate the dynamics of individual blades and express them in a fixed (nonrotating) frame.

MBC is mandatory to controls and stability analyses—erroneous predictions can result otherwise. A novel feature of this MBC code is that it can handle variable-speed operation and turbines with dissimilar blades. Depending on the analysis objective, a user may generate system models either in the first-order (state-space) form or the second-order (physical-domain) form. MBC3 can handle both types of system models. Key advantages of MBC are: capturing cumulative dynamics of the rotor blades and its interaction with the tower-nacelle subsystem, well-conditioning of system matrices by eliminating non-essential periodicity, and filtering operation.

You may download the following files from our server:

  • MBC Change Log (v1.00.00, 1 KB, 15-October-2008)

    This is a list of changes made to the code. Look at this text file to see if we've made worthwhile changes since you received your previous version of MBC.

  • MBC User's Guide (v1.00, 150 KB, 16-October-2008)

    This is the MBC User's Guide.  Please refer to it when trying to understand how the program works.

  • MBC Archive (v1.00.00a-gsb, 250 KB, 15-October-2008)

    This is the self-extracting archive of the latest alpha version of MBC. Simply execute it in an appropriate directory to extract the files. It contains a ReadMe file, alpha change log, the source code, sample data files, a certification script to test your installation, and a compiled version of the code. The scripts are compatible with MATLAB® 7.5.0 (R2007b).

  • Newest version of MBC for OpenFAST

Programming Language:     Wind and Water Tools:

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If you want to refer to this website in a report, here is a reference you can use:
NWTC Information Portal (MBC).  https://nwtc.nrel.gov/MBC. Last modified 04-April-2019 ; Accessed 05-April-2020