Synchronous Generator modelling (in Matlab)

[Florian95]

Hey,
as part of my master thesis, I'm trying to model a PMSM of a wind turbine. I found a couple sources which give me the fumdamental equations, namely for stator voltage in d- and q-axis and flux linkage, e.g. in 'Wind Power in Power Systems' chapter 36.7 by Thomas Ackermann (Can I post those 2 pages here or is that a copyright infringement?).
However, I'm confused about input/output variables. IMHO mechanical power, stator voltages and maybe rotor speed should be the input values, while active and reactive power/currents are output values. Which mostly confirms with the attached block diagram from said book. However, the equations are using stator current in d- and q-axis as input values to calculate stator voltages and flux linkages. Does anyone have ideas on this?
The equations are:

u_ds=-R_s*i_ds-w_s*psi_qs; %Stator voltage d-axis
u_qs=-R_s*i_qs+w_s*psi_ds; %Stator voltage q-axis

psi_ds = -L_ds*i_ds+psi_pm; %Flux linkage stator d-axis
psi_qs = -L_qs*i_qs; %Flux linkage stator q-axis

P_s = u_ds*i_ds+u_qs*i_qs;
Q_s = u_qs*i_ds-u_ds*i_qs;