Implementation of the ‘smart’ rotor concept - Wind Power Generation and Wind Turbine Design - page 495

Pitch system
Strain sensor
(PZT patch)

Actuator

Actuator

Table

Figure 18: Wind tunnel set-up for load alleviation experiments. The airfl ow goes
from right-to-left in this picture.

Figure 19: Design of the active control surface.

the dSpace™ system. Inputs and outputs for, e.g. setting values and plotting and
recording signals can also be incorporated and linked to Control Desk™, a graphi-
cal user interface (GUI) (Fig. 20). From the dSpace™ hardware, one signal goes
to the pitch system, which consists of a linear motor and two signals go to the high
voltage amplifi er which drives both sets of piezoelectric benders.
Inputs to dSpace™ include: the actual pitch displacement (feedback from the
pitch system), the actual voltage on the piezoelectric benders (output of the amplifi er),
strain at the root of the blade and acceleration of the tip.
A critical part of the blade's design is the dynamics. The fi rst natural vibration
mode should be scaled with respect to two parameters:
The frequencies of the disturbances on the blade. HAWT blades are mainly sub- 1.

jected to loads associated with its rotational frequency or multiples of that - 1P, 2P
and 3P. Proximity of vibrational modes will infl uence the dynamic response under