PSI- Issue 9

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

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reactive power of the generator. Indeed, there are FOC based on current oriented control and the one based on the stator flux oriented control. The second one is widely used in the DFIG control designs in which the q-axis current component is used for active power control and the d-axis component is used for reactive power control Wei Qiao(2008) et Yongchang Zhang (2011. While for the first one, we are reversing the axis purpose Shuhui Li (2009), the d-axis component is used for active power control and the q-axis current component is used for reactive power control. In this paper, we apply the vector control of the DFIG called field oriented control by approximating the machine model as naturally decoupled current-field machine. However, employing an appropriate choice of reference frame upon which control of the field-oriented quantities allows an independent control of the electromagnetic torque known as FOC. The controlled back-to-back converter of a DFIG is typically connected through slip rings to the rotor windings, and independent torque control is usually achieved through control of the rotor current. The model of the FOC can be developed for the DFIG by taking into consideration that the rotor field is oriented according the d axis, fixe rotor field and neglecting the stator resistance. We obtain in rotating (d-q) frame, the total transmitted power as mentioned by the figure 3:   qr s s r s t i L P P P g V M 1 . .     (16)   qs qs dr s s s s s r s t i V i L g V M L Q Q Q V . 1 . . .        (17)

DFIG

Fig. 3. DFIG control scheme

The representation of the vector control is given in the Figure 4.

Fig. 4. Rotor flux orientation The electromagnetic torque of the DFIG based on the fluxes and stator currents is given by: