|Title of Invention||
A METHOD OF CONTROLLING A WIND POWER INSTALLATION
|Full Text||wOBBEN, Aloys Argestrasse 19, 26607 Aurich
Air density-dependent power regulation
The present invention concerns a wind power installation having a control apparatus for operational management of the wind power installation and a method of controlling a wind power installation having a control apparatus for operational management.
A wind power installation converts a part of the kinetic energy contained in the wind into electrical energy. For that purpose the wind power installation has a rotor which takes kinetic energy from the wind and converts it into rotational energy.
DE 198 44 258 Al discloses a wind power installation and a method for the operation thereof in which, in dependence on sensors, in the presence of the air density at the wind power installation, the operational management system sets the speed at which the wind power installation shuts down at a higher level, with decreasing air density. If therefore, with a normal level of air density, the shut-down speed assumes its predetermined value, the shut-down speed is increased when the air density is less.
Stored in the control apparatus of a wind power installation is a power characteristic which permits the control means of the wind power installation, on the basis of the ascertained rotor speed which is dependent on the wind speed, to ascertain the associated generator power. That generator power which the wind power installation is intended to furnish affords the exciter power required and in turn therefrom the generator moment. In order to produce that required generator moment the rotor must afford at least that rotary moment, by way of the drive train.
The power P of the wind power installation corresponds to the amount of energy flowing through the rotor circuit of the wind power installation and arises out of the cross-sectional area F which corresponds to the circular surface area of the rotor, in accordance with the following equation:
P = VipV3 F [W].
At a given wind speed v and a predetermined circular surface area F of the rotor, the foregoing equation gives the dependency of the amount of energy on air density p. If the amount of energy is too low the rotor cannot apply that moment and therefore the rotor speed drops as a consequence of the excessively high generator moment.
The object of the invention is to optimise operation of a wind power installation insofar as the largest possible amount of energy, that is to say the highest possible power, can always be furnished.
The object according to the invention is attained by a method having the feature set forth in claim 1 and by a wind power installation having the feature set forth in claim 2.
In previous wind power installations, besides a characteristic curve, the high-speed running variable X, is also predetermined. In that respect the high-speed running variable corresponds to the quotient of the peripheral speed of the rotor blade tip and the wind speed. As already stated, when the power characteristic is not matched to the corresponding air density, there is a deviation in respect of the high-speed running variable X which is fixed in the control apparatus.
In the present invention the control apparatus takes account of the height of the location of erection of the wind power installation and/or the height of the wind power installation, that is to say the air density which prevails at the site of the wind power installation.
The invention is based on the realisation that air density becomes less with increasing height. The reference scale is always sea level normal zero (NZ). The higher the location at which the wind power installation is erected is above NZ, the corresponding lower is the air density and the correspondingly less is the energy contained in the wind.
It is particulariy advantageous in the present invention that taking account of the height of the location of erection of the wind power installation above NZ means that this lower air density is taken into consideration in the power characteristic. In that way the power which is associated with a rotor speed and thus a given high-speed running variable
X and which is to be produced by the wind power installation can be suitably adapted, that is to say reduced, so that the generator moment, as a consequence of the exciter power which is introduced by the control apparatus, does not exceed the torque which is furnished by way of the rotor. In that way the level of efficiency which is established by way of the power characteristic is maintained and the maximum energy can be tal
In a preferred development of the invention the wind power installation is provided with a measuring apparatus for detecting the air density and particularly preferably a measuring apparatus for detecting the air pressure and the temperature. The air density can be determined from those two items of data. In that way it is possible to forego setting the parameters as the control apparatus automatically ascertains those parameters from the data acquired by the measuring apparatus.
In a preferred embodiment the control apparatus includes at least one microprocessor so that control of the wind power installation can be implemented on the basis of a control software.
In addition the object of the invention is attained by a method which is characterised in that:
a) the air density is detected,
b) signals which are derived from the air density and which represent the air density are transmitted to the control apparatus, and
c) the air density is taken into consideration by the control apparatus in operational management.
In that respect in step a) the air pressure and the temperature can be detected and in step b) signals which represent the air density can be
derived from the air pressure and the temperature, in accordance with a predetermined algorithm.
Advantageous developments of the invention are recited in the appendant claims.
An embodiment of the present invention is described in greater detail hereinafter with reference to the Figure. The Figure shows a simplified block circuit diagram of the present invention.
The Figure shows the wind power Installation with a rotor 10, a generator 12, a force transmission 14 between the rotor and the generator, a device 16 for detecting the air pressure, a device 18 for detecting the temperature and a control apparatus 20 with a microprocessor.
The device 16 for detecting the air pressure is connected by way of a connection 22 to the control apparatus 20, the device for detecting the temperature is connected by way of a connection 24 to the control apparatus 20 and the rotor speed is transmitted to the control apparatus 20 by way of a connection 26. Those connections can be for example galvanic connections or other suitable connections such as wireless connections.
From the transmitted items of information, the control apparatus 20 ascertains on the basis of predetermined power data the power which is to be delivered by the generator and, by way of a connection 28, influences the exciter power which is fed to the generator 12.
In this respect the mode of operation of the control apparatus 20 can be predetermined in such a way that changes in air density which can be ascertained from changes in air pressure or temperature are taken into consideration by the control apparatus 20 only when they exceed a predeterminable amount and/or those changes are ascertained for a predeterminable time.
It will be appreciated that, instead of detecting the air density, it is also possible to predetermine a value in respect of air density at the respective site. In this respect for example the height above N2 of the wind power installation or the rotor hub of the wind power installation is also taken into consideration. In a corresponding manner it is also possible to predetermine a mean value in respect of the corresponding air density at
Bremen 18th February 2003
Our ref: W 2524 KGG/dw
Direct dial: 0421/36 35 16
Applicant/proprietor: WOBBEN, Aloys
Office ref: PCT/EP02/01814
the predetermined height and store it in the control apparatus. Accordingly the invention provides that the respective power characteristic of a wind power installation is also adapted to the corresponding air density at the location of the wind power installation. That makes it possible for the level of efficiency of the wind power installation always to be maintained at the maximum possible value, more specifically even when the air density fluctuates to a considerable degree or the wind power installation is erected at some hundred metres above NZ, even if the power characteristic is initially ascertained for a site at a height of 00 above NZ.
New claims 1 to 6
1. A method of controlling a wind power installation comprising an electrical generator using statistical, inputted and/or measured air density data at the location of the wind power installation, characterised in that the generator of the wind power installation is controlled by means of a control apparatus which processes the air density data, and power data of the generator, in particular an exciter power supplied to the generator, are set in dependence on the air density.
2. A wind power installation comprising an electrical generator and a control device for operational management of the generator of the wind power installation, wherein there are provided means for detecting and/or setting air density data, wherein the detected and/or set air density data are processed in the control apparatus, characterised in that power data with the power to be delivered by the generator of the wind power installation, in particular the exciter power supplied to the generator, can be set in consideration of the detected and/or set data in respect of air density.
3. A wind power installation according to claim 2 characterised in that there is provided a measuring apparatus (16, 18) for detecting air density,
wherein the measuring apparatus is connected to the control apparatus (20).
4. A wind power installation according to claim 3 characterised in that
the measuring apparatus (16, 18) includes at least one device for detecting
the air pressure (16) and the temperature (18) at the site of the wind power installation.
5. A wind power installation according to one of the preceding claims characterised in that the value or the data which correspond to the respective air density are predeterminable by way of input means and are stored in the control apparatus.
6. A wind power installation according to one of the preceding claims characterised in that the control apparatus includes a microprocessor in which the air density data are processed together with a control program of the wind power installation.
7. A method of controlling a wind power installation substantially as herein descriDea witn reference to the accompanying drawings.
|Indian Patent Application Number||1328/CHENP/2003|
|PG Journal Number||05/2007|
|Date of Filing||25-Aug-2003|
|Name of Patentee||ALOYS WOBBEN|
|Applicant Address||ARGESTRASSE 19, D-26607 AURICH, GERMANY|
|PCT International Classification Number||F03D7/02|
|PCT International Application Number||PCT/EP02/01814|
|PCT International Filing date||2002-02-21|