PSI- Issue 9

Mohammed Ezzahi et al. / Procedia Structural Integrity 9 (2018) 221–228 Author name / Structural Integrity Procedia 00 (2018) 000–000

226

6

s 

i . _

p M .

.

T

i

i







 

(18)

qs ds .

em

ds qs

qr

L

s

From the equation (18) above, we notice that we have a coupling between currents and fluxes. In order to make the FOC control of the machine possible we adopt the assumptions:  We consider the current and frequency as constants;  We use the rotating d-q frame;  We consider that the rotor flux is oriented according to the d axis (  dr =  r and  qr =0);  We neglect the stator resistance (V ds =0 and V qs =  s .  s );  Considering commonly used DFIG machines of medium and high powers. 6. Experimental and simulation results As a result of the simulation in Matlab\simulink for both the DFIG modelling through the field oriented control, we obtain in the sub-synchronous mode (slip <0):

Fig. 5. Rotor magnetic field evolution in sub-synchronous mode

Fig. 6. Measured and simulated speed in sub-synchronous mode

In the hyper-synchronous mode (slip >0), we obtain:

Fig. 7. Rotor magnetic field evolution in hyper-synchronous mode