WO2008107402A2

WO2008107402A2 - Rotating electric machine

Info

Publication number: WO2008107402A2
Application number: PCT/EP2008/052519
Authority: WO
Inventors: Gèrard HEMERY; Pierre Freche
Original assignee: Alstom Technology Ltd
Priority date: 2007-03-02
Filing date: 2008-02-29
Publication date: 2008-09-12
Also published as: DE102007010674A1; WO2008107402A3

Abstract

The invention relates to a rotating electric machine, particularly an electric motor or a generator, preferably of a power plant, comprising a rotor (2), a stator (3), and a cooling apparatus (5) which has several cooling ducts (6) that are formed in the stator (3) and are open towards an annular space (7) radially formed between the rotor (2) and the stator (3). In order to increase the cooling effect, at least one separating element (11) which at least fluidically disconnects a radially interior zone (12) from a radially exterior zone (13) is disposed inside the annular space (7). Cooling gas flows into the exterior zone (13) through at least one cooling duct (6), and cooling gas flows out of said exterior zone (13) through at least one cooling duct (6).

Description

Rotating electrical machine

Technical area

The invention relates to a rotating electrical machine, such as an electric motor or a generator, in particular in a power plant.

State of the art

Such machines usually have a stator and a rotor arranged therein, which rotates during operation of the machine. Especially in machines with high power, for example in the megawatt range, it is necessary to cool the machine. Accordingly, such a machine usually has a cooling device which has a plurality of cooling passages which are preferably radially oriented with respect to an axis of rotation of the rotor and which are formed in the stator. Radial between the rotor and the stator, an annular space is formed, in which open the cooling channels.

As the power requirements of such electrical machines increase and as the efficiency of the machines depends, among other things, on the temperature, it is desirable to improve the cooling of the machine. Presentation of the invention

This is where the present invention begins. The invention, as characterized in the claims, deals with the problem of providing for a rotary electric machine of the type mentioned in an improved embodiment, which is characterized in particular by improved cooling.

According to the invention, this problem is solved by the subject matter of the independent claim. Advantageous embodiments are the subject of the dependent claims.

The invention is based on the general idea that, in a region of the annular space in which cooling gas flows over at least one cooling channel into the same or into at least one other cooling channel, a radially outer region in which this overflow takes place flows from a radially inner region to decouple. This decoupling is achieved in the invention by means of at least one separating element which is arranged in a suitable manner in the annular space. The invention uses the knowledge that the rotation of the rotor during operation of the machine by friction effects in the annulus generates an oriented in the circumferential direction annular flow of the cooling gas. By virtue of the fluidic decoupling between the inner region of the annular space and the outer area of the annular space proposed according to the invention, disturbing interactions between the high-velocity annular flow, which is then present in the interior region, and the transition flow, which in comparison thereto is significantly lower flow velocity and with a different flow direction, can be achieved between the cooling channels, which is then in the outer area, significantly to reduce. The cooling gas can pass through the outer region virtually undisturbed by the annular flow in the respective cooling channel, which significantly reduces the flow resistance within the cooling gas path, whereby the flow rate of cooling gas increases, which improves the cooling effect.

The respective separating element may for example be arranged and dimensioned such that it covers at least in the case of a cooling channel an associated orifice opening, which is open towards the annular space, in the circumferential direction and in the axial direction. The respective separating element can thus be a single cooling channel or a plurality of cooling channels or a group of

Be assigned to cooling channels. In particular, the respective separating element can form a ring which is closed in the circumferential direction and can be arranged and dimensioned such that it covers the outlet openings in the circumferential direction and in the axial direction in an axial section of the annular gap in all cooling channels arranged in this axial section. Furthermore, it is basically possible to arrange and dimension the respective separating element in a circumferential section of the annular space in which a plurality of cooling channels are axially adjacent, such that it covers the mouth openings of these cooling channels in the circumferential direction and in the axial direction. In addition, it is conceivable to design the respective separating element to be arranged and dimensioned so that it forms a circumferentially closed ring and extends axially in the annulus via orifices of at least two axially adjacent cooling channels and this covers it in the circumferential direction and axial direction. Thus, with the aid of the separating elements, different configurations for the cooling gas path within the stator can be formed using the outer region or regions of the annular gap formed with the aid of the separating element (s) in order to optimize the cooling of the stator. Preferably, the respective separator is fixed to the stator, which is comparatively easy to implement. Likewise, it is basically possible to fix the respective separating element on the rotor.

In a preferred embodiment, it may be provided that at least one separating element is made permeable overall or at least in a partial region for cooling gas, for example through a perforation or through at least one passage opening. Additionally or alternatively, it may be provided that at least one passage for cooling gas, which connects the inner region to the outer region of the annular gap, is formed between two adjacent separating elements. With the aid of such a passage or with the aid of a separating element permeable to gas, it is achieved that the inner area is communicatively connected to the outer area in the annular space, so that gas exchange is possible in spite of the fluidic decoupling. By this construction is achieved, for example, that cooling gas, which flows to cool the rotor in the annulus or in the interior, can flow from the interior to the outside and be discharged with the serving for cooling the stator cooling gas and thereby contribute to the cooling of the stator.

Other important features and advantages of the invention will become apparent from the dependent claims, from the drawings and from the associated figure description with reference to the drawings.

Brief description of the drawings

Preferred embodiments of the invention are illustrated in the drawings and are explained in more detail in the following description, wherein like reference numerals refer to the same or similar or functionally identical components. Show, in each case schematically,

1 and 2 each show a greatly simplified, principal longitudinal section through a portion of a rotating electrical

Machine, in various embodiments,

3 and 4 are each a part of a cross section of the machine in the region of an annular space, in various embodiments.

Ways to carry out the invention

Referring to FIGS. 1 and 2, a rotary electric machine 1, which is preferably an electric motor or a generator, which may be arranged in particular in a power plant, a rotor 2 and a stator 3, with respect to a rotation axis or Rotor axis 4, around which the rotor 2 rotates during operation of the machine 1, are arranged coaxially. The machine 1 is also equipped with a cooling device 5, by means of which at least the stator 3 and preferably also the rotor 2 are cooled by means of a cooling gas in order to increase the efficiency of the machine 1. In this case, the stator 3 can be flowed through radially by the cooling gas, for which purpose the cooling device 5 has a plurality of cooling channels 6 formed in the stator 3. These cooling channels 6 can pass through the stator 3 with respect to the axis of rotation 4 substantially radially. The cooling channels 6 are open to an annular space 7, which is formed with respect to the axis of rotation 4 radially between the rotor 2 and the stator 3. Said annular space 7 encloses the rotor 2 in the circumferential direction completely and expediently extends over the entire axial length of the rotor 2. A radial flow of cooling gas through the cooling channels 6 in the Annulus 7 and flows back from this through the cooling channels 6, is indicated in FIGS. 1 and 2 by arrows 8. The cooling gas flow is driven, for example, by a conveying device 9, for example a fan, which is only symbolically indicated here by a propeller.

In the examples shown, the cooling of the rotor 2 is achieved by way of example with an axial cooling gas flow, which is also indicated by arrows 10. Within the rotor 2, corresponding, unspecified cooling channels can be formed for this purpose. It is noteworthy that the cooling gas serving to cool the rotor 2 also enters the annular space 7 from the rotor-side cooling channels, but exits from the annular space 7 via the cooling channels 6 of the stator 3.

In the annular gap 7 at least one separating element 1 1 is arranged. In the embodiments of FIGS. 1 and 2, for example, three such separating elements 1 1 are indicated. It goes without saying that a higher or a lower number of separating elements 1 1 is possible. Each separating element 1 1 causes an at least fluidic decoupling within the annular space 7 between a radially inner region 12 (inner region 12) and a radially outer region 13 (outer region 13). In the present context, a fluidic decoupling means such a separation between the inner region 12 and the outer region 13, which considerably reduces the interactions between a flow in the inner region 12 and a flow in the outer region 13. However, this separation does not have to be gas-tight, so that in particular a gas exchange between inner region 12 and outer region 13 may be possible. In the outer region 13, the flow deflection of the cooling gas flow, which enters through at least one cooling channel 6 in the annular space 7 and its outer region 13 and by at least one cooling channel 6 from the annular space. 7 or exits from the outer area 13 again. In this case, the cooling gas can flow through at least one cooling channel 6 into the outer region 13 and flow from the outer region 13 into the same cooling channel 6 or into the same cooling channels 6 or into at least one other cooling channel 6.

In the embodiment shown in Fig. 1, the respective separating element 1 1 is fixed to the stator 3. In contrast, in the embodiment according to FIG. 2, the respective separating element 11 is fixed to the rotor 2. In principle, a construction is conceivable in which at least one separating element 1 1 on the stator 3 and at least one other separating element 1 1 is fixed to the rotor 2.

In the simplified representations of Figs. 3 and 4, the individual cooling channels 6 are each in the circumferential direction of the rotor 2 between longitudinal grooves 14, which for receiving electrical conductors, namely from

Winding rods serve with which a stator winding is constructed. These longitudinal grooves 14 are incorporated in the stator 3 or in an unspecified core of the stator 3 and are preferably closed radially inward, ie in the region of the annular space 7, each with a wedge not shown here. In Figs. 1 and 2 such winding rods or electrical conductors are indicated and designated 15.

The cooling channels 6 are preferably divided into inlet channels 16, via which the cooling gas enters the annular space 7, and outlet channels 17, via which the cooling gas exits from the annular space 7. This allows a targeted

To achieve flow guidance through the stator 3. In principle, however, it is also possible to guide the flow of cooling gas within the stator 3 such that the cooling gas enters the annulus 7 through the same cooling channels 6 and exits therefrom. The respective separating element 11 or the separating elements 11 are arranged in the annular space 7 such that they decouple the inner region 12 from the outer region 13 to the extent that in the outer region 13 the cooling gas flows from at least one inlet channel 16 via the outer region 13 into at least one outlet channel 17 can overflow. For this purpose, the respective separating element 1 1 can be arranged and dimensioned so that it covers at least in a cooling channel 6, the associated, the annular space 7 through the open mouth opening in the circumferential direction and in the axial direction. Suitably, the respective separating element 1 1 thereby form a circumferentially closed ring and thereby be arranged and dimensioned so that it covers the mouth openings in the circumferential direction and in the axial direction in an axial portion of the annular space 7 at all arranged in this axial section cooling channels 6. Additionally or alternatively, the respective partition element 1 1 in a peripheral portion of the annular space 7, in which a plurality of cooling channels 6 are axially adjacent to each other, arranged and dimensioned so that it covers the mouth openings of these cooling channels 6 in the circumferential direction and in the axial direction. Additionally or alternatively, the respective separating element 1 1 again form a ring closed in the circumferential direction and be arranged and dimensioned so that it extends in the annular space 7 via the mouth openings of at least two axially adjacent cooling channels 6 and these in the circumferential direction and in the Axial direction covered.

In the embodiment shown in Fig. 3 covers the respective

Separating element 1 1 at least in the reproduced sectional plane respectively the mouth openings of an inlet channel 16 and an adjacent thereto in the circumferential direction outlet channel 17, in the circumferential direction and in the axial direction. In the embodiment shown in Fig. 4, the partition member 1 1 is a in the circumferential direction extending ring, which covers the mouth openings of a plurality of inlet channels 16 and a plurality of outlet channels 17 in the circumferential direction and in the axial direction.

The respective separating element 1 1 may for example consist of a plate-shaped or a cup-shaped body. This means that the respective separating element 1 1 in the radial direction has a much smaller dimension than in the circumferential direction and in the axial direction. Furthermore, the respective separating element 1 1 is preferably made of an electrically insulating material, for example of a plastic or of a ceramic or of a glass fiber material.

In the embodiment shown in FIG. 3 as well as in the embodiments of FIGS. 1 and 2, a passage 18 is formed in each case between two adjacent separating elements 1 1, through which the inner region 12 with the

Outdoor area 13 can communicate. The respective passage 18 makes it possible, in particular, to exchange gas between the inner region 12 and the outer region 13, so that, for example, cooling gas can pass from the inner region 12 in accordance with arrows 19 into the outer region 13 and from there into the outlet channels 17. The respective passage 18 is designed and dimensioned such that an interaction between the cooling gas flow 8 in the stator 3 and the cooling gas flow 10 in the rotor 2 is comparatively low or does not occur.

In the embodiment shown in FIG. 4, the respective separating element 1 1 may, for example, be designed to be permeable to the cooling gas in a subregion assigned to the outlet channels 17, which is here indicated by a brace 20. For example, the separating element 11 may be provided with a perforation 21 in this partial region 20 or may contain at least one, preferably a plurality of through-openings. Also through this gas-permeable portion 20 of the partition member 1 1, a gas exchange between the inner region 12 and outer region 13 is possible, so that in particular cooling gas from the inner region 12 corresponding to the arrows 19 passes through the respective partition element 1 1 in the outer region 13 and from this into the outlet channels 17th Instead of individual gas-permeable subregions 20, the respective separating element 1 1 can also be designed so that it is designed to be gas-permeable overall. With the aid of the passages 18 or the gas-permeable subregions 20, the cooling gas serving to cool the rotor 2 can be discharged via the outlet passages 17 of the stator 3.

In the embodiment shown in FIG. 4, a plurality of inlet channels 16 arranged adjacent to one another in the circumferential direction are combined to form a group 22, which is indicated by a curly bracket. This entry group 22 will be exemplified by the

Conveyor 9 is acted upon by the cooling gas. Furthermore, a plurality of outlet channels 17 arranged adjacent to one another in the circumferential direction are likewise combined to form a group 23, which is likewise indicated by a curly bracket. This outlet group 23 is arranged adjacent to the inlet group 22 in the circumferential direction. Furthermore, a further outlet group 23, which can not be recognized here, can be provided, which is axially adjacent to the inlet group 22 shown here. Likewise, a further inlet group 22 may be axially adjacent to the exit group 23 shown. In this case, a fluid coupling in the axial direction is formed on the annular space side, so that the

Inlet channels 16 of the respective inlet group 22 communicate with the outlet channels 17 of the respective outlet group 23 adjacent in the axial direction, specifically via the outer region 13 formed with the aid of the respective separating element 11. The respectively associated separating element 11 extends at least along the two axially adjacent ones Groups 22, 23. In the embodiment shown in Fig. 3, the inlet channels 16 and the outlet channels 17 are arranged alternately in the circumferential direction. In this case too, a group formation is basically possible, the groups 22, 23 being formed in the axial direction. Accordingly, for example, a group 22 of axially adjacent to each other arranged inlet channels 16 may be provided, which is arranged circumferentially to a group 23 adjacent to each other in the axial direction outlet channels 17 adjacent. Here, the inlet channels 16 of a group 22 on the Au ßenbereich 13 with the

Exit channels 17 of the other group 23 communicate. Here, too, the respective separating element 11 then extends at least along the two groups 22, 23.

Thus, the cooling gas from the respective inlet channel 16 passes through the outer region 13 in the respective outlet channel 17, an overflow path 24 is formed in the respective outer region 13, which creates the required fluidic coupling. This Überströmpfad 24 may have at least one opening 25 or recess 25, which may be formed for example in the core of the stator 3 or in a wedge to close the respective longitudinal groove 14. Furthermore, it is particularly possible to attach the respective separating element 1 1 to such a wedge or at least partially integrally formed on such a wedge. This construction simplifies the design and arrangement of the separating elements 1 1 and the overflow path 24.

At the back of the stator 3 (outer diameter of the core) is a fluidic foreclosure of the inlet channels (16) and outlet channels (17) is advantageous. This foreclosure can be achieved by appropriate collection boxes or collection channels. Depending on the selected design principle for this mutual partitioning of the inlet and outlet channels (16, 17) These boxes or channels may extend individually or in groups in the axial or circumferential direction.

LIST OF REFERENCE NUMBERS

1 machine

2 rotor

3 stators

4 rotation axis

5 cooling device

6 cooling channel

7 annulus

8 cooling gas flow

9 conveyor

10 cooling gas flow

1 1 separating element

12 indoor area

13 outdoor area

14 longitudinal groove

15 electrical conductors

16 entrance channel

17 exit channel

18 passage

19 cooling gas flow

20 subarea of 11

21 perforation

22 group of 16

23 group of 17

24 overflow path

25 opening

Claims

claims

1. Rotary electric machine, in particular electric motor or generator, preferably a power plant, at least comprising

a rotor (2) and a stator (3),

- A cooling device (5) having a plurality of in the stator (3) formed cooling channels (6) which are open to a radially between the rotor (2) and stator (3) formed annular space (7) out, characterized

- That in the annular space (7) at least one separating element (11) is arranged, which at least fluidically decouples a radially inner region (12) from a radially outer region (13), in which cooling gas from at least one cooling channel (6) flows and from the cooling gas in the same cooling channel (6) or in the same cooling channels (6) or in at least one adjacent cooling channel (6) flows out.

2. Rotary electric machine according to claim 1, characterized in that - the respective separating element (11) is arranged and dimensioned so that at least at a cooling channel (6) the respective, to the annular space (7) open towards orifice in the circumferential direction and in Axial direction covered, and / or

- That the respective separating element (11) forms a circumferentially closed ring and is arranged and dimensioned so that in an axial portion of the annular space (7) at all in this axial section arranged cooling channels (6) covers the mouth openings in the circumferential direction and in the axial direction, and / or

- That the respective separating element (11) is arranged and dimensioned so that in a peripheral portion of the annular space (7) in which a plurality of cooling channels (6) are axially adjacent, opening openings of these cooling channels (6) in the circumferential direction and in the axial direction, and /or

- That the respective separating element (11) forms a circumferentially closed ring and is arranged and dimensioned so that it covers in the annular space (7) orifices of at least two axially adjacent cooling channels (6) in the circumferential direction and in the axial direction.

3. Rotary electric machine according to claim 1 or 2, characterized in that - each or at least one such separating element (11) on the stator (3) is fixed, and / or

- That each or at least such a separating element (11) is fixed to the rotor (2).

4. Rotary electric machine according to one of claims 1 to 3, characterized

- That the respective separating element (11) consists of a plate-shaped or cup-shaped body, and / or

- That the respective separating element (11) consists of an electrically insulating material.

5. Rotary electric machine according to one of claims 1 to 4, characterized - That each or at least such a separating element (1 1) is designed to be permeable overall or at least in a partial region (20) for cooling gas, and / or

- That between two adjacent separating elements (1 1) at least one the inner region (12) with the outer region (13) of the annular space (7) connecting passage (18) is formed for cooling gas.

6. Rotary electric machine according to one of claims 1 to 5, d ad h c h e ce n e c i n e t, - that the cooling channels (6) inlet channels (16), through the cooling gas in the

Annulus (7) enters, and exit channels (17), through the cooling gas from the annular space (7) emerges,

- That the respective separating element (1 1) in the annular space (7) is arranged so that it decouples the inner region (12) at least fluidically from the outer region (13), in the cooling gas from at least one inlet channel (16) in at least one outlet channel ( 17) overflowed.

7. Rotary electric machine according to claim 6, characterized in that at least one group (22) of inlet channels (16) arranged adjacent to each other in the circumferential direction extends beyond the outer region (13) of the annular space (7) axially adjacent thereto group (23) is coupled in terms of flow adjacent to each other in the circumferential direction adjacent outlet channels (17), wherein the respective separating element (11) at least along both groups (22, 23) may extend, and / or

- That at least one group (22) of axially adjacent to each other adjacent inlet channels (16) over the outer region (13) of the annular space (7) with a circumferentially adjacent thereto group (23) of axially adjacent to each other arranged outlet channels (17) is fluidically coupled, wherein the respective separating element (11) can extend at least along both groups (22, 23), and / or

- That inlet channels (16) and outlet channels (17) are arranged alternately in the circumferential direction.

8. Rotary electric machine according to claim 6 or 7, characterized

- That in the respective outer region (13) of the annular space (7) an overflow path (24) is formed, via which the group (22) of the inlet channels (16) with the adjacent group (23) of the outlet channels (17) or via the at least one Inlet passage (16) with at least one adjacent outlet channel (17) is fluidly coupled, and / or

- That the overflow path (24) at least one opening (25) or recess (25) which in a core of the stator (3) or in a wedge to the

Closing a in the stator (3) formed longitudinal groove (14) for receiving at least one electrical conductor (15) is formed.

9. Rotary electric machine according to one of claims 1 to 8, characterized in that the respective separating element (11) on a wedge for closing a in the stator (3) formed longitudinal groove (14) for receiving at least one electrical conductor (15) is mounted and / or at least partially integrally formed thereon.