Dynamic Response of a Wind Farm Consisting of Doubly-Fed Induction Generators to Network Disturbance - Simulation and Modeling Methodologies, Technologies and Application - page 131

The equation is completed by the mechanical coupling equation in pu between the
turbine and the generator using two mass model as derived in (10)-(15)

d ω 1

( )

r

= Ts − T

(28) 2 e

dt 2 H

g

the active and reactive power generated by the induction generator is given as

3
2

( )

Pv i = + v i (29)

s qs qs ds ds

3
2

( )

Qv = i − v i

(30)

s qsds dsqs

2.6 Grid Connection of DFIG

DFIG technology makes use of wound rotor. The stator is directly connected to the
grid while the rotor is coupled to the grid through a PWM) frequency converter as
shown in Fig. 7.

=

=

PQ VQ

ref , ref dcref , ref

Fig. 7. DFIG with PWM converter control system

For dynamic study of DFIG, the converter controller model is important. Stator
flux oriented control is commonly used in the decoupled control of DFIG.

2.7 DFIG Rotor Side Converter Controller

The control of the DFIG rotor is done in a synchronous rotating reference frame i.e.

ω= in equation (18)-(21). The rotor side converter controls the stator active and
reactive power of the DFIG. By aligning the d-q reference frame in the stator flux
reference frame as in figure 8 [16], then

e

v = 0 vv = , λλ = and λ = 0 .

ds qs s ds s qs

From (25) and (26)

L

i =−

m

i

(31)

qs qr

L

s