Design of Robust Controllers for Load Reduction in Wind Turbines - Wind Turbine Control and Monitoring - page 119

Hu b Wind Speed

22

21

20

19

18

17

16

15

14

13

200 210 220 230 240 250

Time (s)

Fig. 5.21 Speed of the power production wind with mean of 19 m/s

Generator Speed

1200

1150

1100

C1
C2
C3

1050

200 210 220 230 240 250

Time (s)

Fig. 5.22 Generator speed regulation for the power production wind

Figure 5.24 shows some important moments in different components of the
wind turbine. The co-ordinate systems of blades, tower and hub are explained in
[ 46 ]. The C4 control strategy reduces the activity at the 1P frequency in the blade
out-of-plane moment M oop and mitigates the activity of the M flap moment around
1P. However, the M edge moment hardly depends on the 1P frequency and it is very
difficult to mitigate loads in this variable. If the pitch actuator bandwidth was
bigger, the activity of the blade first in-plane moment at 1.1 Hz in M edge could be