Information Technology Reference
In-Depth Information
q
v
are the d-q reference voltage which will be converted to a-b-c
frame to generate command for the rotor end PWM converter. The block diagram is
shown in figure 9.
*
dr
*
respectively.
v
and
=
=
i
i
i
ar
br
cr
P
−
*
P
PWM
+
i
v
*
ar
*
br
v
*
cr
v
L
L
(
)
i
abc
ω−ω
m
λ
abc
dq
e
r
s
PI
dq
s
i
i
i
qr
dr
v
*
qr
i
*
qr
v
*
dr
dr
+
+
+
+
−
+
(
)
PI
ω−ω σ
L
e
r
−
+
−
PI
(
)
ω−ω σ
L
+
e
r
Q
*
dr
i
−
PI
*
+
Q
i
qr
Fig. 9.
Rotor side Controller system
2.8
DFIG Grid Side Converter Controller
The main objective of grid side controller is to maintain the dc link between the back
to back PWM converters at constant voltage irrespective of the direction of power
flow [14]. The voltage for the grid side converter is represented by (38) [17]
v
i
i
v
as
as
as
a1
d
v
=
r
i
+
Li
+
v
(38)
bs
bs
bs
b1
dt
v
i
i
v
cs
cs
cs
c1
The d-q transformation of equation (38) yields (39)
di
q
v
=+
i
L
+
ω
Lv
+
q
q
e
id
q
1
dt
di
(39)
v
=+
i
L
d
−
ω
Lv
+
d
d
e
iq
d
1
dt
Re-arranging (39) with
q
v
= , the governing voltage equation for the grid side
converter can be obtained as (40)
0
k
(
)
*
*
v
=−
k
+
1
i
i
−
i
−
ω
L
q
1
1
p
q
q
e
id
s
k
(40)
(
)
*
*
v
=−
k
+
2
i
i
−
i
+
ω
L
+
v
d
1
2
p
d
d
e
iq
d
s
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