Environmental Engineering Reference
In-Depth Information
Grid50 Hz
Stator power
DFIG
Rotor side
converter
Gridside
converter
Rotor
power
u
v
v
n
MPPT
I
r
ω
Second-Order
Sliding Mode Controller
r
T
em
v
2
v
1
Speed
Turbine
Fig. 2.5
The high-order sliding mode control structure
2.3.3 High-Gain Observer
A high-gain observer can be used to estimate the aerodynamic torque. A key
feature of a high-gain observer is that it will reduce the chattering induced by a
sliding mode observer [
18
].
From Eq. (
2.4
), we have
x
¼
T
a
J
K
t
x
T
em
J
ð
2
:
17
Þ
J
The following notations are introduced.
x
1
¼
x
x
2
¼
T
J
ð
2
:
18
Þ
Thus, we have
x
1
¼
x
2
J
x
1
T
e
J
x
2
¼
f
ð
t
Þ
x
¼
ð
2
:
19
Þ