Environmental Engineering Reference
In-Depth Information
(a)
Fixed base
Semi-active control
σ
lim
-
σ
lim
(b)
x
lim
-x
lim
Fixed base
Semi-active control
(c)
Fig. 13.20 PRK load case: SA control via the 2VAR controller and comparison of the response
with the FB case
Table 13.5 PRK input: peak
response of the FB structure
and of the SA case using the
2VAR controller
Case max|r| max|x|
Fixed base 29 MPa 25 mm
Semi-active 2VAR 20 MPa 23 mm
FB ? SA
-31 % -8%
Percentage variation from the first to the second condition
As previously done with reference to the other application, the peak values for
base stress and top displacement are assumed as synthetic indicators of the
response for both FB and 2VAR controlled cases. Table
13.5
shows these values
and the percentage variation from the FB to the SA case. It allows to conclude that
the 2VAR control logic, for the PRK load case, lead to a significant reduction of
the peak base stress (31 %), even if smaller than the one (48 %) obtained with the
CLES controller. On the other hand, the 2VAR control logic has also been able to
damp the top displacement, making the peak value 8 % smaller with respect to the
FB case.
13.7 Conclusions
The theoretical base and the experimental activity about an SA control system for
wind turbines based on MR devices has been described. The main findings of the
research activity are as follows:
