The invention relates to a wind or water energy installation having the features according to the precharacterizing clause of claim 1.
For many years, electrical energy has been obtained from the wind with the aid of wind turbines, which have become ever larger. The achievable power levels are dependent, inter alia, on the diameter of the wind turbine. Higher power levels therefore also mean larger wind turbine diameters and larger propeller blade lengths. Since the circumferential speed of the propeller tips is technically limited, this results in ever lower rotation speeds.
The invention is based on the object of specifying a wind or water energy installation which can generate high electrical power levels but nevertheless is of simple and lightweight design.
According to the invention, this object is achieved by a wind or water energy installation having the features claimed in patent claim 1. Advantageous refinements of the wind or water installation according to the invention are described in dependent claims.
According to the invention, a wind or water energy installation is accordingly provided for production of electrical energy having at least one propeller and at least one generator, which comprises a rotor and a stator. The wind or water energy installation is characterized in that the stator is formed by at least two stator modules which are mechanically and electrically independent of one another and each interact with the rotor, each of the stator modules in each case comprises at least one module-specific magnet, at least one coil through which at least a portion of the magnetic flux of the magnet flows, and each of the stator modules in each case forms a module-specific magnetic circuit with the rotor, with each stator module producing a module-specific output voltage in the event of a relative movement between the rotor and the stator.
One major advantage of the wind or water energy installation according to the invention is that the stator is formed from separate stator modules; this allows particularly simple installation of the stator, in particular at a great height above the ground, as is normal for wind power installations. There is therefore no need, as in the case of already known wind or water energy installations, for the entire stator to be transported and installed in one piece for installation of the stator and in fact, it can be moved stator module by stator module to the respective installation location, and can be installed on site, for example using a crane.
A further major advantage of the wind or water energy installation according to the invention is that, in the event of a defect, individual stator modules can be replaced. There is therefore no need to replace the entire stator, thus making it possible to save costs in the event of repair.
An additional advantage of the wind or water energy installation according to the invention is that all of the components which are heated and may need to be cooled during operation of the generator in order to prevent limit temperatures from being exceeded can be arranged in the stator of the generator. Cooling of the stator from the outside is technically relatively simple, and can be carried out at low cost. Those parts and elements which carry flux, are arranged in the rotor and can be heated by remagnetization or eddy currents, and can also be heated by the stator by heat transfer and/or radiation can be formed by parts whose temperature is not critical in the case of the wind or water energy installation according to the invention, as a result of which there is no need for additional cooling. In other words, one major advantage of the wind or water energy installation according to the invention is also that only stator sections need be cooled and there is no need for cooling of the rotor, even when very high electrical power levels are produced.
The stator-side coils of the stator modules may, for example, be electrically interconnected in order to make it possible to provide the appropriate currents or voltages, depending on the configuration of the electrical power supply system to which the wind or water energy installation is connected.
The wind or water energy installation is preferably an installation which has a rating of at least 1 kW. A rating such as this is generally necessary in order to allow economic use in power transmission systems.
The stator modules are preferably designed such that they can each be removed from the generator, and fitted into it, independently of other stator modules, and can be replaced independently of other stator modules.
It is also considered to be advantageous for the stator modules each to have a mounting device by means of which the distance between the respective stator module and the rotor can be adjusted on a module-specific basis.
Preferably, at least one of the stator modules, preferably all of the stator modules, has or have a module-specific cooling device.
Furthermore, it is considered to be advantageous if the stator module has a magnetic yoke, and the module-specific cooling device is arranged indirectly or directly on that yoke outer face of the magnetic yoke which is averted from the rotor.
At least one of the stator modules, preferably all of the stator modules, has or in each case have a converter or rectifier, which converts or rectifies an AC voltage produced by the module-specific coil or coils, and produces a module-specific AC voltage or DC voltage as the module-specific output voltage.
Preferably, the converter or rectifier is arranged on an outer face of the module-specific cooling device which is averted from the rotor and the yoke outer face.
In terms of achieving low construction costs, it is considered to be advantageous for the stator modules of the stator to be physically identical.
Preferably, on its surface facing the stator modules, the rotor has a magnetic reluctance (Rm), which is dependent on its respective rotation angle, such that the magnitude of the magnetic flux in the coils of the stator modules is dependent on the respective rotation angle of the rotor, and varies during rotation of the rotor.
Preferably, the magnets of the stator modules are formed by permanent magnets. Alternatively, it is also possible to use electromagnets for production of a magnetic flux, instead of permanent magnets or in combination with permanent magnets.
Preferably, the arrangement of the stator modules around the rotation axis of the rotor is rotationally symmetrical.
By way of example, the rotor may be arranged externally around the stator or within the stator.
Preferably, a propeller of the wind or water energy installation is connected to the rotor of the generator such that they rotate together. There is therefore no need for a gearbox between the rotor and the propeller, thus minimizing the weight and costs.
In order to allow a polyphase, for example three-phase, electricity production, it is considered to be advantageous if the rotational symmetry angle of the arrangement of the stator modules of the stator and the rotational symmetry angle of the local distribution of the magnetic reluctance on the rotor are different. A rotational symmetry angle difference leads to a different pole pitch on the stator and on the rotor, thus making it possible to generate electric current for polyphase systems.
The rotational symmetry angle of the stator and that of the rotor may, of course, also be identical, if the intention is to produce only a single current and voltage phase.
Preferably, on its surface facing the stator, the rotor has teeth which extend radially outward. A tooth structure or a tooth profile makes it possible to produce a magnetic reluctance, which is dependent on the respective rotation angle of the rotor, on the surface of the rotor in a particularly simple manner. Preferably, the teeth on the surface of the rotor consist of a material having low magnetic reluctance, that is to say a material which causes a high magnetic flux when a magnetic field is applied. For example, one material which is suitable for the teeth is ferromagnetic material, since it has a very high permeability.
The intermediate space between adjacent teeth of the stator may, for example, be entirely or partially filled with a material which has a higher magnetic reluctance than the material of the teeth. For example, the intermediate space between adjacent teeth may be filled with a plastic or a resin.
However, it is considered to be particularly advantageous for the intermediate space between adjacent teeth to remain free, since, when the rotor rotates, exposed teeth lead to swirling of the air in the air gap between the stator and the rotor, thus resulting in cooling of the rotor and the stator.
Particularly preferably, each stator module in each case has a flux-guiding element, which is passed through the at least one stator-side coil, with the cross-sectional area of the flux-guiding element in the coil area being less than the cross-sectional area of the stator-side magnet.
If the cross sections are refined in this way, this leads to flux concentration in the area of the stator-side coil.
In a corresponding manner, it is possible for the flux-guiding stator-side element to be smaller in the coil area than in the area of its limb ends, with which it forms the interface to the rotor. This refinement as well leads to flux concentration in the coil area, but in this case it is possible to influence the air-gap field at the interface between the rotor and the stator.
In order to guide the lines of force through the stator in as optimum a manner as possible, the stator-side sections of the magnetic circuits can each be provided with at least one magnetic flux barrier, which has a higher specific magnetic reluctance than the rest of the material in the respective stator-side section. Flux barriers such as these modify the profile of the lines of force, since the lines of force cannot pass through the flux barriers, or can do so only poorly, and in consequence have to (at least predominantly) pass around the flux barriers.
Furthermore, it is considered to be advantageous for the stator-side magnet or magnets to be embedded in the flux-guiding stator-side material.
Converters are preferably used to convert the generator output voltage and output frequency, which are dependent on the propeller rotation speed.
It is also possible to incline the rotor structure in one direction or—for example half in each case—in both directions (arrow inclination) in order, inter alia, to reduce cogging torques and to positively influence the sound which is produced.
The invention will be explained in more detail in the following text with reference to exemplary embodiments; in this case, by way of example:
For the sake of clarity, the same reference symbols are always used for identical or comparable components in the figures.
The wind energy installation 10 comprises a propeller 30, which may have a plurality of blades 40. In the exemplary embodiment shown in
The propeller 30 rotates about a shaft 50 which is connected to a generator 60 of the wind energy installation 10. If the action of the wind on the propeller 30 causes it to rotate about the shaft 50, as a result of which the generator 60 will produce electric current I, which is fed into the power transmission system 20.
By way of example,
The reference symbol 120 in
Furthermore, the magnetic circuit 120 covers a section of the rotor 110. The section of the rotor 110 forms a magnetic reluctance Rm which depends on the respective rotation angle of the rotor relative to the stator. For example,
For example, if it is assumed that the module-specific magnet 130 produces a constant magnetic field strength, then the magnetic flux which flows through the magnetic circuit 120 will therefore depend on the respective position of the rotor. If the rotor 110 is aligned as illustrated in
Furthermore, as can be seen from
In order to achieve a smooth rotor surface, the gaps 160 may be filled with a material which has a different magnetic reluctance to that of the teeth 150. For example, the gaps 160 may be filled with plastic or a resin.
However, it is considered to be particularly advantageous for the gaps 160 to be filled only with air, as a result of which air is swirled in the gap between the rotor and the stator when the rotor rotates, and both the rotor and the stator are cooled by the airflow.
The module-specific magnet 130 may be a permanent magnet or an electromagnet.
By way of example,
By way of example,
The pole pitch of the stator module 100 and the pole pitch of the rotor are identical in the exemplary embodiment shown in
In the exemplary embodiment shown in
As can also be seen from
By way of example, a converter or rectifier may be integrated in the second outer ring segment 540, which is fitted to the first outer ring segment 530, converting or rectifying an AC voltage produced by the module-specific coil or coils, and producing a module-specific AC voltage or DC voltage as the module-specific output voltage. In the exemplary embodiment shown in
By way of example,
By way of example
By way of example,
By way of example,
By way of example,
By way of example,
By way of example,
In a corresponding manner, the limbs of the flux-guiding, stator-side element or elements 125 of the stator modules 100 may also be aligned obliquely or at an angle to the rotation axis 50 of the generator.
By way of example,
Number | Date | Country | Kind |
---|---|---|---|
09 075 430.0 | Sep 2009 | EP | regional |
10 075 096.7 | Mar 2010 | EP | regional |
Filing Document | Filing Date | Country | Kind | 371c Date |
---|---|---|---|---|
PCT/EP10/05608 | 8/30/2010 | WO | 00 | 3/19/2012 |