Environmental Engineering Reference
In-Depth Information
actuator (10). A set of micro-controllers (3) collect all the sensor information
(6, 7, 8, 9, 10) and drives the pitch (5) and yaw (4) motors. The sensors collect in
real-time data of rotor speed (6), pitch angle (7), yaw angle (8), and current (9) and
voltage (10) at the output of the generator. In addition, with the above information,
the system identifies in real-time the mechanical torque T
r
applied to the shaft—
see
Eq. (
14.43
)—and
the
power
P—see
Eq. (
14.1
)—generated
by
the
wind
turbine.
The mechanical structure of the turbine, including the foundation, tower, blades
and gearboxes for the pitch and yaw systems are built of LEGO blocks and wheels,
giving highly modular characteristics to the prototypes. The real-time control
system runs on LEGO microprocessors (3) and an external computer with Mat-
lab—(2) in Fig.
14.1
.
14.2.1.1 Aerodynamics: Rotor Blades
Figure
14.3
presents the four wind turbines of the wind farm, with three different
rotor options (3, 4 and 6 rotor-blade) and a particular site configuration, while
generating power into the electrical grid, and with the hierarchical control system:
five NXT LEGO microprocessors for the distributed individual wind turbine
control and the central computer under Matlab for the SCADA and central control
system.
Each wind turbine uses a horizontal axis rotor that (1) can be configured to use
two, three, four, five or six blades each, and (2) can be easily lengthened by adding
an additional piece at the blades' root. The blades themselves have a drag model
airfoil design, meaning the drag coefficient C
D
of the blade is significantly larger
than the lift coefficient C
L
. In addition to a drag model airfoil, the blades each have
additional texturing near the end of the blade to contribute to the effectiveness of
the drag system. Figure
14.4
shows a 3-blade and a 6-blade rotor options.
Fig. 14.3 Wind farm control
for optimum energy
production with 3, 4 and 6
rotor-blade wind turbines
