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.

We have not officially released MBC and it is currently in testing. An alpha version is available from our MBC Alpha-Testers page.

You may download the following files from our server:

• MBC Change Log (v1.00.00, 0 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

  The official release is not yet available.

If you want to refer to the MBC website in a report, here is a reference you can use:

NWTC Design Codes (MBC by Gunjit Bir).  http://wind.nrel.gov/designcodes/postprocessors/mbc/.  Last modified 16-October-2008; accessed 16-October-2008.

Additional links:

• MBC Alpha-Tester's Page

  If you want to test pre-release versions of MBC, please check this page for the latest alpha version.