Dear Jannik,
Just a couple comments:
- MBC and azimuth-averaging should eliminate the influence of the generator-azimuth state, which should then be removed from the linear model before use. This is discussed e.g. in the following forum topic: FAST linearization V7. This will reduce your state-space model from 10 states down to 9 states.
- In the paper you reference, Eq. (3.8 ) is based on a one-state model shown in Eq. (3.1), with only the generator speed state active. You can obtain such a model from OpenFAST by enabling only GenDOF. This will result in a two-state model, and then, as in the first bullet, you can reduce this down to one state by azimuth averaging and susbsequently eliminating the generator azimuth state.
I hope that helps.
Best regards,