Environmental Engineering Reference
In-Depth Information
x 10
5
4
Single Rotor
Counter Rotor
3
2
1
0
-1
0
5
10
15
20
25
0
5
10
15
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Wind Velocity m/s
Wind Velocity m/s
(a) AEP of single wind rotor
(b) AEP of the CRWT
Figure 5: AEP of CRWT and single wind rotor located in the isolated island.
The tandem wind rotors produce more energy than the single wind rotor, regardless
of the wind velocity. The annual production at the wind velocity 5 m/s and over is
2966 MWh for the tandem wind rotors, while 2066 MWh for the single wind rotor.
That is, the annual energy can be increased about 43.5%, as compared with the
single wind rotor type.
It is very important to notice that the works of these previous tandem wind
rotors quite differ from the works of the wind rotors which are boarded on intelli-
gent wind power unit proposed by the authors. The proposed tandem wind rotors
are in cooperation with the double rotational armature type generator.
3 Superior operation of intelligent wind power unit
Many researchers/engineers have proposed the tandem wind rotors to increase the
output, as reviewed just before. Intelligent wind power unit proposed by the authors
has the promising advantages that the output is not only increased but also controlled
in response to the wind circumstances without accessories such as the gearbox, the
pitch control mechanism, the braking system and so on. That is, the operation of
the tandem wind rotors quite differ from the conventional wind rotors, and is in
cooperation with the new type generator with double rotational armatures [8].
In the upwind type unit as shown in Fig. 6, the large-sized front wind rotor and the
small-sized rear wind rotor drive the inner and the outer armatures in the peculiar
generator, respectively, while the rotational torque is counter-balanced in both arma-
tures. As for the tandem wind rotors, the rotational torque of the front wind rotor must
be the same, in the opposite direction, as that of the rear wind rotor. The rotational
direction and speed of both rotors/armatures, however, are free and adjusted
automatically/smartly in response to the wind circumstances, as follows (see Fig. 7).
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