EP2572442A2

EP2572442A2 - Pole shoe

Info

Publication number: EP2572442A2
Application number: EP12713017A
Authority: EP
Inventors: Gerhard Lenschow
Original assignee: Wobben Properties GmbH
Current assignee: Wobben Properties GmbH
Priority date: 2011-04-01
Filing date: 2012-03-26
Publication date: 2013-03-27
Also published as: RU2013148723A; MX2013011321A; DE102011006681A1; CA2830803A1; AU2012234318B2; AU2012234318A1; US20140091650A1; CL2013002800A1; BR112013024947A2; JP2014514902A; CN103460567A; KR20130135989A; JP5746417B2; WO2012130814A2; KR101546175B1; WO2012130814A3

Abstract

The invention relates to a pole shoe of an electrical machine, in particular a rotor of an electrical generator of a wind turbine generator system, comprising a pole shoe body for conducting a magnetic field and for receiving a winding for conducting an electrical current, in particular an excitation current, for producing the magnetic field, and at least one heat sink, entirely or partially surrounding the pole shoe body, for cooling the pole shoe, wherein the heat sink is arranged between the pole shoe body and the winding.

Description

pole

The present invention relates to a pole piece of an electrical machine, in particular a rotor of an electrical generator of a wind turbine. In addition, the present invention relates to a generator, in particular a ring generator, as well as a Polschuhkühlkörper and a wind turbine. In addition, the present invention relates to a method for producing a pole piece and to a method for operating a power plant.

A pole piece generally serves to guide a magnetic field and to let out and distribute the magnetic field lines in a defined shape. In this case, such a pole piece consists of a material with a high permeability. In electrical machines, for example in an electrical generator of a wind energy plant, pole shoes are arranged in the stator and / or in the rotor of the generator. Below a pole piece is in the following a Polschuhblechpaket, which is constructed to avoid or at least reduce eddy currents from many individual, mutually insulated laminations understood. Such a pole piece essentially consists of a pole shoe head and a pole shoe body.

Especially with slowly rotating generators such as those of a gearless Wndenergieanlage a high excitation current is needed, so the current flowing through a field winding and thereby generates a magnetic field. This leads to an increase in the exciter lost power. One way to increase the performance of such a generator is to increase the excitation current. Cooling systems are used to cool the generator in order to dissipate the increasing energy losses.

From the document DE 10 124 268 A1, for example, a generator cooling is known. The document relates to a power plant with a ring generator and a nacelle housing of the wind turbine surrounding the ring generator, the nacelle housing having a thermally conductive housing section in the region of the bovine generator and a predetermined distance being formed between the outer circumference of the ring generator and the thermally conductive housing section, so that the heat energy is above or below the wind turbine is transmitted through air. Generally for air generators, water cooling or combined air-water cooling are known. Such prior art solutions sometimes have a low cooling capacity or are very expensive and expensive due to design changes to the generator. As a further prior art, the following publications are generally referred to: CH 425 984 A, US Pat. No. 6,774,504 B1 and EP 0 793 870 B1.

It is therefore an object of the present invention to remedy, at least reduce, at least one of the problems described above. In particular, an improved cooling of a pole piece of an electrical machine, in particular a rotor of an electrical generator of a wind turbine, to be made possible. At least an alternative solution should be proposed.

To solve the problem, a pole piece of an electric machine according to claim 1 is proposed according to the invention.

Such a pole piece of an electrical machine, in particular a rotor of an electrical generator of a wind turbine, has a pole shoe body for guiding a magnetic field and for receiving a winding for guiding an electric current, in particular an exciter current, for generating the magnetic field. In this case, the Polschuhkörper is either completely or partially surrounded by at least one heat sink, which can also be called Polschuhkühlkörper, cooled to cool the pole piece. The heat sink is disposed between the pole piece and the Wcklung. The Wcklung can be part of the pole piece.

The heat sink is preferably formed so that it receives the winding and thus forms a cooled, in particular water-cooled bobbin.

The Polschuhkörper is for example laminated and made of iron. As a result, eddy currents within the pole piece can be avoided or at least reduced. Preferably, the pole shoe body is in the form of a cuboid, in which the corners are recessed. Through the recess material of the winding is saved. For example, can be saved in a winding of a pole piece of a rotor of a generator of a wind turbine, especially copper, up to or even more than 2kg or more than 3kg of material per pole piece. If such a pole piece is fastened, for example, in a rotor of a generator of a wind power plant, by arranging a cooling system, the excitation current which is fed into the winding and thus the power of the generator can be increased. Because the heat sink is located between the pole piece body and the winding, a close thermal contact between the heat sink and the heat source, ie the winding, is achieved and the heat source is cooled directly. The heat is thus dissipated before the pole piece is too warm, so that there is no damage due to overheating of the winding. Warming that occurs in the pole shoe body, such as by eddy current losses and iron losses can also get from the Polschuhkörper to the heat sink and be removed in a simple manner.

In a preferred embodiment of the pole piece according to the invention, the heat sink is designed as a wound body. In this case, the winding body is preferably adapted to the Polschuhkörper and is pushed onto this. On the winding body, the winding is arranged. Thus, the heat sink between the Polschuh- body and the winding and the heat of the heat source can be dissipated directly. Alternatively, a winding body and a heat sink could be arranged between the winding and the pole shoe body.

Preferably, the pole piece has an electrical insulation means to electrically insulate the heat sink against the winding and / or to conduct heat from the heat to the heat sink. The insulating means may comprise, for example, an insulating film, mica disks or ceramic plates. For isolation, electrically insulating layers of oxides, such as, for example, aluminum oxide, are also suitable as passivation layers. Also suitable for insulating layers in the form of paints into consideration, for example, similar to the insulating varnish of a copper wire. In a preferred embodiment of the pole piece according to the invention, the heat sink is designed to be hollow for guiding a cooling medium. As a cooling medium in particular a cooling liquid is used. Such a cooling liquid may include, for example, water. This has the advantage that a uniform heat transfer is ensured and a large amount of heat is dissipated. It is advantageous if such a cooling liquid has an antifreeze agent such as glycol. This ensures that the cooling liquid does not freeze even when the electric machine is at a standstill. Alternatively, the cooling medium may also be gaseous or at least partially have solid substances or substance mixtures, or be formed for example as a gel.

According to one embodiment, it is proposed that the heat sink is made of aluminum. Aluminum has the advantage that it is a good heat-conductive metal and thus the heat loss can be derived by heat conduction from the heat-generating component, so the winding. Alternatively, the heat sink could also be made of copper, which is also a good heat conductive metal.

Preferably, the heat sink at least two connection points for connection to a cooling system, so that the cooling system can form a cooling circuit together with the heat sink. In this case, one or the cooling medium is introduced via one of the connection points and the cooling medium is discharged via one of the other connection points. Thus, the cooling medium flows into the heat sink with an inlet temperature which is lower than the temperature of the heat source, and there is a heat transfer from the warmer to the colder medium, ie to the cooling medium. Thereafter, the heated cooling medium is removed and introduced after cooling again in the cooling circuit. In this case, the cooling takes place for example by means of a recooler, which emits the dissipated heat to the environment. Such a recooler is arranged, for example, in a wind turbine in or on the nacelle of the wind turbine. If the pole shoe body is provided with recesses at its corners, as already described above, the connection points of the heat sink can be arranged in these recesses, or in two of these recesses, and thereby make efficient use of the space.

According to the invention, the pole piece is prepared for use in a salient pole machine, in particular a ring generator. Such a salient pole machine is a three-phase synchronous machine designed for low speeds, which is used as a generator, for example, in wind turbines. A ring generator is characterized by a high number of rotor and stator poles, which are arranged annularly along the air gap. Due to the large number of poles, for example, 30, 40, in particular 48, 50 and more rotor poles can be provided, a very slowly rotating operation is made possible, in which the generator with less than 30, 20, 15 and in particular less than 10 U per minute turns. Preferably, the invention comprises a generator, in particular a ring generator, for converting kinetic energy into electrical energy with a stator and a rotor. In this case, the stator and / or the rotor at least two pole pieces according to the invention. With such a ring generator, for example a wind energy plant, the excitation of the magnetic field takes place via the pole shoes attached to the rotor. If these pole pieces are cooled directly, the power of the wind turbine can be increased thereby or an increase can be made possible by the fact that power loss generated by a high excitation current is dissipated. On the other hand, the life of the wind turbine can be increased by a good cooling and therefore by avoiding too high temperatures. By using liquid cooling instead of cooling by ambient air, exposure to the ambient air can be avoided. Moisture and dirt can be kept away from the system.

Preferably, the at least two pole pieces on the rotor or the stator in each case a so arranged around the respective heat sink winding, that the heat sink between Polschuhkörper and winding is arranged. Direct cooling of the heat source is thus possible.

In addition, the invention proposes a Polschuhkühlkörper for cooling a pole piece and for use with a pole piece according to the invention. Such a Polschuhkühlkörper is designed as a rigid body and adapted to a pole piece, in particular to the Polschuhkörper a pole piece. Thus, the Polschuhkühlkörper can be used for various embodiments of the pole piece, such as various sizes or shapes. In this case, the pole piece learns even little or no structural changes. After mounting the heat sink and the insulating foil, the pole shoe body can be provided with the winding and introduced into the electrical machine. Only the connections for the cooling circuit and the associated cooling system result in a different structural design compared to generators without or with other cooling.

According to one embodiment, it is proposed that the Polschuhkühlkörper, which is also referred to as simplifying only as a heat sink, a receiving space for receiving a Polschuhkörpers has or forms. In this case, a receiving space is understood to be a space defined by the shape of the heat sink, which is intended to receive at least the part of the pole shoe body which is separated from the body Polschuhkühlkörper should be surrounded. In this way, the heat sink, which is preferably designed as a rigid body, can be pushed without great effort, for example, on the pole piece.

In addition, a wind turbine with a generator according to the invention is proposed according to the invention. In this case, the required heat output can be dissipated by a cooling system and thus the performance can be increased.

In addition, a method for producing a pole piece according to the invention is proposed according to the invention. Preferably, such a method comprises the following steps: 1. First, one or the heat sink is arranged on one or the pole shoe body for cooling the pole piece. This can be done for example by pushing on the pole piece.

2. Subsequently, one or the winding is arranged on the heat sink. In this case, the heat sink is arranged on the pole shoe body in such a way that it completely or partially surrounds the pole shoe body and is arranged between the heat sink and the pole shoe body. Thus, the general manufacturing method of a pole piece is supplemented only by the arrangement of the heat sink.

Alternatively, it is proposed to provide the winding on the heat sink and then postpone the heat sink together with the winding already arranged thereon on the pole shoe body.

In addition, a method for operating a wind turbine according to the invention is proposed. In this case, the generator is cooled by means of a cooling medium, in particular by a cooling liquid which is pumped through at least one Polschuhkühlkörper. When operating a wind power plant, the medium for cooling the generator is preferably routed via a connection point or points to a recooler. This recooler is located in or on the nacelle of the wind turbine, preferably on at least one outer side of the nacelle. Such a recooler, for example, exposed to an air flow and has a sufficiently large surface area to ensure a required heat dissipation. As a result, the cooling medium in the recooler can be cooled and fed via one or more connection terminals. be pumped back into the Polschuhkühlkörper to continue to dissipate the heat loss of the pole piece can.

The invention will be explained in more detail below by way of example with reference to the accompanying figures.

Figure 1 shows a wound body with a Polschuhkühlkörper invention.

Figure 2 shows an embodiment of a Polschuhkühlkörpers.

Figure 3 shows another embodiment of a Polschuhkühlkörpers.

FIG. 4 shows a connection region of a pole shoe cooling body according to a further embodiment.

FIG. 5 shows a pole shoe cooling body with a pole shoe body of a pole shoe according to a further embodiment.

FIG. 6 shows an embodiment of a pole piece according to the invention.

Figure 7 shows a section of a pole piece according to another embodiment.

1 shows a winding body 100 for a pole piece with a heat sink in the form of a Polschuhkühlkörpers 101, two connection points 102 and a receiving space 103. In this case, the Polschuhkühlkörper 101, which consists of three via the connection points 102 interconnected part bodies 106, already on the winding body 100th appropriate. To accommodate a pole piece, a receiving space 103 is provided. The heat sink 101 encloses the receiving space 103 and thus completely after insertion of the Polschuhkörpers the Polschuhkörper, so that a uniform cooling is ensured.

In order to be able to pump a cooling medium, preferably water, into the heat sink 101 and to be able to discharge it again, there are two connection points 102 on the heat sink 101. The cooling medium is admitted, for example, via one of the connection points 102 led a recooler and cooled there. Via the second connection point 102, the cooling medium is pumped back into the heat sink 101.

The illustrated winding body 100 is pushed onto a pole shoe body of a pole piece. On the heat sink 101, an insulation means not shown here is applied, on which in turn a winding is arranged. The thus prepared pole piece can then be attached to the appropriate location of the electrical machine.

FIG. 2 shows a rigid heat sink 201, which encompasses three likewise rigid partial bodies 206. The heat sink 201 defines a receiving space 203 for receiving a Polschuhkörpers. The three partial heat sinks each form a rigid, circumferential and hollow band-like element, can be passed through the water as a cooling liquid. If the pole shoe body is inserted into the receiving space 203, the heat sink 201 encloses this almost completely, so that a uniform cooling is ensured.

In addition, two connection points 202 can be seen in FIG. As a result, the cooling medium can be introduced or removed into the heat sink 201.

FIG. 3 shows a further embodiment of a heat sink 301 with three part bodies 306. The latter also has a receiving space 303 for receiving a pole shoe body and two connection points 302 for supplying or discharging a cooling medium. The heat sinks 201 according to FIGS. 2 and 301 according to FIG. 3 differ essentially by the size of the pole piece or pole shoe body of the pole piece to be accommodated.

FIG. 4 shows a partial section of a heat sink 401, which consists of three partial bodies 406 brought together at the connection points 402. The connection points 402 are tubular. Within the tubular connection points 402, connecting points 405 to the hollow partial bodies 406 can be seen. In this way, the cooling medium can be pumped from one of the connection points 402 via the connection points 405 into the heat sink 401, in order to flow through the latter and dissipate the heat. By the other of the two connection points 402, the cooling medium is discharged via the connection points 405 again. In addition, a receiving space 403 for receiving a pole piece body is partially shown in FIG.

FIG. 5 shows a pole shoe body 504 of a pole shoe. Furthermore, a heat sink 501 with three partial bodies 506, which encloses the pole shoe body 504, can be seen. In this case, the pole piece body 504 is made of a material having a high permeability such as iron. In addition, it is made of laminated mesh to avoid or reduce eddy currents within the pole piece. The pole shoe body 504 is formed in the shape of a cuboid, in which the respective corners 507 are flattened. In the area of these flattened corners, connections for connecting the heat sink to a cooling circuit can be arranged.

Furthermore, two connection points 502 for guiding the cooling medium to or from a recooler can be seen.

The pole piece may also comprise a package, not shown here, which is attached to the heat sink 501. Thus, the pole piece can be installed in the electric machine, for example in a rotor of a generator of a wind turbine.

FIG. 6 shows an embodiment of a pole shoe 600 according to the invention. In this case, the pole shoe 600 is designed in the shape of an arrow in the region of its pole shoe head 610. The illustrated pole shoe head 610 and pole shoe body 620 together form the pole shoe 600. The pole shoe 600 is preferably produced from individual sheet metal laminations which are insulated from one another. Therefore, the pole piece 600 is also referred to as a Polschuhblechpaket.

On the pole shoe body 620 shown an inventive, not shown here, Polschuhkühlkörper is arranged, which surrounds the Polschuhkörper 620 wholly or partially. Then a winding is attached, which is directly cooled by the close thermal contact with the heat sink.

FIG. 7 shows a pole shoe body 704 of a pole shoe. Furthermore, a heat sink 701 can be seen, which is not divided into partial bodies, but is formed as a body. The heat sink 701 encloses the pole shoe body 704 substantially from three sides. The cutout of the pole shoe body 704 shows two corner regions 707, which respectively have a recess 717. In one of these two recesses 717, a connection 727 in the form of a connection pipe is provided for connecting the heat sink 701 in order to connect the heat sink 701 to a cooling circuit. In the region of the further recess, a corresponding connection 727 is still missing and guide channels 730 can be seen, which are designed to guide a cooling medium in the cooling body 701. Here too, such a connection 727 is to be provided on completion, which is arranged in one of the recesses 717 and is thereby at least partially integrated into the pole shoe body 704. The heat sink can here, possibly supplemented by insulation, take a winding and thereby form a cooled bobbin.

Claims

claims

Pole shoe (600) of an electrical machine, in particular a rotor of an electrical generator of a wind turbine, comprising a pole piece (504) for conducting a magnetic field and for receiving a winding for carrying an electric current, in particular an excitation current, for generating the magnetic field, at least one the pole piece (504) wholly or partially surrounding the heat sink (101, 201, 301, 501) for cooling the pole piece (100, 500), wherein the heat sink (101, 201, 301, 501) between the Polschuhkörper (504) and the Wcklung is arranged.

Pole shoe (600) according to claim 1, characterized in that the cooling body (101, 201, 301, 501) is formed as a winding body (100) for receiving the winding.

Pole shoe (600) according to claim 1 or 2, characterized by an insulating means, in particular an insulating film for electrically insulating the heat sink (101, 201, 301, 501) against the winding, and / or for conducting heat from the winding to the heat sink ( 101, 201, 301, 501).

Pole shoe (600) according to one of the preceding claims, characterized in that the cooling body (101, 201, 301, 501) for guiding a cooling medium, in particular a cooling liquid, is hollow.

Pole shoe (600) according to one of the preceding claims, characterized in that the cooling body (101, 201, 301, 501) is made of aluminum.

Pole shoe (600) according to one of the preceding claims, characterized in that the heat sink (101, 201, 301, 501) has at least two connection points (102, 202, 303, 403, 503) for connection to a cooling system, one of the Connection points or the cooling medium introduced and via one of other connection points (102, 202, 302, 402, 502), the cooling medium is discharged.

A pole piece (600) according to any one of the preceding claims, prepared for use in salient pole machines. 8. generator, in particular ring generator, for converting a kinetic energy into electrical energy with a stator and a rotor, wherein the stator and / or the rotor at least two pole pieces (600) according to one of the preceding claims.

9. Generator according to claim 8, characterized in that the at least two pole pieces (600) are fixed to the rotor or the stator, such that each

Polschuh so arranged around the respective heat sink (101, 201, 301, 501) winding, that the heat sink (101, 201, 301, 501) between Polschuhkörper (504) and winding is arranged.

10. Polschuhkühlkörper for cooling a pole piece (600) and for use with a pole piece (600) according to one of claims 1 to 6, wherein the Polschuhkühlkörper (101, 201, 301, 501) is designed as a rigid body and to a pole piece (100 , 500), in particular a pole shoe body (504) of a pole shoe (100, 500), is adapted.

1 1. Polschuhkühlkörper (101, 201, 301, 501) according to claim 10, characterized by a receiving space (103, 203, 303, 403) for receiving a Polschuhkörpers (504).

12. Wndenergieanlage with a generator according to any one of claims 8 or 9.

13. A method for producing a pole piece (600) according to one of claims 1 to 7, comprising the steps in the following order:

1 . Arranging a or the heat sink (101, 201, 301, 501) on one or the pole shoe body (504) for cooling the pole piece (600),

2. arranging one or the winding on the heat sink (101, 201, 301, 501), wherein the heat sink (101, 201, 301, 501) is arranged on the pole piece (504) such that it forms the pole piece (504) completely or partially surrounds and is arranged between the winding and the pole shoe body (504).

A method of operating a wind turbine according to claim 12, wherein the generator is cooled by means of a cooling medium, in particular by a cooling liquid, which is pumped through at least one Polschuhkühlkörper (101, 201, 301, 501).

A method according to claim 14, characterized in that the cooling medium via one or the connection point (102, 202, 302, 402, 502) is guided to a recooler, wherein the cooling medium is cooled in the recooler and via one or the other connection point (102, 202, 302, 402, 502) is pumped back into the pole shoe heat sink (101, 201, 301, 501).