| Budget Amount *help |
¥3,600,000 (Direct Cost: ¥3,600,000)
Fiscal Year 2006: ¥800,000 (Direct Cost: ¥800,000)
Fiscal Year 2005: ¥2,800,000 (Direct Cost: ¥2,800,000)
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| Research Abstract |
This intelligent wind turbine generator has the following peculiarities. (1) Both wind rotors start rotating at the low wind speed, but the rear wind rotor counter-rotates against the front wind rotor. (2) The increase of the wind speed makes both rotational speeds increase, and the rear wind rotor reaches the maximum rotational speed at the rated wind speed. (3) With more increment of the wind speed, the rear wind rotor decelerates gradually and begins to rotate in the same direction as the front wind rotor, and the output can be kept constant. (4) Moreover, the counter-rotation makes the output higher even if in the poor wind circumstance. To get the optimum profiles of this unit, the characteristics of the double rotational armature type doubly fed induction generator were examined in the bench tests, and the blade profiles of both wind rotors were optimized in the wind tunnel and by CFD.
1. Generator
It was confirmed that the generator works well in cooperation with the tandem wind r
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otors and the secondary output can be got from the input circuit, namely the inner armature.
2. Optimum diameter ratio between both wind rotors
The output increases with the increase of the rear wind rotor diameter, under the ratio D=(rear wind rotor diameter)/(front wind rotor diameter)=1. The rear wind rotor under D=0.84 can rotate in the same direction as the front wind rotor at the higher wind speed, but the rotor over D=0.84 can not change the rotational direction in response to the wind speed. That is, the optimum ratio is about D=0.84.
3. Optimum span between both wind rotors
It is desirable to make the rear wind rotor close to the front wind rotor as possible, to get the fruitful output.
4. Flow condition around wind rotors
The meridian flow velocity decreases every through the wind rotor. At the higher wind speed, the rear wind rotor comes to rotate in the same direction as the front wind rotor, and makes the flow runs upstream along the hub wall. Then, the rear wind rotor plays in place of the brake and/or pitch control which suppresses the over rotation.
5. Proposal of the optimum blade profile
It is desirable that the blade profile of the front wind rotor has not the camber at the hub side for giving the sufficient wind energy to the rear wind rotor.
6. Acoustic noise
The noise level of the tandem wind rotors is larger than that of the single wind rotor, and the level at the counter-rotating operation is larger than that at the rotating operation in the same direction. The noise becomes lower with the decrease of the diameter of the rear wind rotor. Less
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