EP3994789A1

EP3994789A1 - Rotating electric machine comprising an internal rotor cooling circuit

Info

Publication number: EP3994789A1
Application number: EP20733298.2A
Authority: EP
Inventors: Matthieu BOIRLAUD
Original assignee: Moteurs Leroy Somer SA
Current assignee: Moteurs Leroy Somer SA
Priority date: 2019-07-04
Filing date: 2020-06-19
Publication date: 2022-05-11
Also published as: FR3098361B1; FR3098361A1; WO2021001180A1

Abstract

Rotating electric machine (1) comprising: a casing (3) comprising a primary cooling circuit (13) operating by circulation of a cooling fluid; a stator (5) which is arranged inside the casing and preferably in thermal contact with same; a rotor (7); and a secondary cooling circuit comprising at least one fan (11) for generating the closed-circuit forced circulation of a secondary fluid in thermal contact with the rotor, said secondary fluid being cooled by the primary circuit, the secondary circuit being arranged radially inwardly with respect to the primary circuit, the casing and the stator being separated by at least one separator (31) forming a spacer, the at least one separator being inserted into an arrangement formed in the casing and/or the stator.

Description

Title: Electric rotating machine with an internal rotor cooling circuit

Technical area

The present invention relates to the field of electrical rotating machines, and more particularly to so-called closed electrical rotating machines, that is to say without air circulation between the interior of the machine along the rotor and the exterior.

These may in particular be electric generators or electric motors.

Prior art

Closed machines are not cooled directly by the ambient air but by a cooling fluid, usually in liquid form, circulating within a casing in physical contact with the stator and cooling it.

Closed electric rotating machines cooled by a main cooling circuit have separate cooling mechanisms for the stator and for the rotor.

Thus, a known stator cooling solution consists in circulating a primary cooling fluid inside the carcass itself. The coolant then exchanges heat with the carcass. The heat is transmitted by conduction to the outer surface of the stator, the latter being in direct physical contact with the inner surface of the casing. Finally, conduction heat transfer occurs in the stator up to the stator winding.

The thermal contact resistance between the frame and the stator tends to limit the extent of heat transfer.

Regarding the cooling of the rotor, it is known to use the fluid present inside the closed machine, without circulating it. This fluid, usually air, exchanges heat with the solid parts of the rotor in the form of convective transfers. The air can be stirred by the rotating movement of parts attached to the rotor for this purpose. To a lesser extent, the rotor also exchanges heat with the internal walls of the stator by radiation.

Cooling according to this method is relatively inefficient because of the low air movement speeds and the absence of a cold source. US Pat. No. 8,519,580 describes an electric machine comprising a rotor cooling circuit which is contained in the machine. However, in the absence of a circulation of a cooling fluid in the casing of the machine, the solution disclosed cannot achieve optimum cooling of the rotor without requiring complex construction arrangements. In addition, the air in the rotor cooling circuit is cooled only by contact with the stator, by circulating within stator channels. However, the stator sheets being made of steel, the latter do not conduct heat efficiently.

It is also known from application US 2017/0033641 A1 to provide external channels along the carcass, in which a cooling fluid circulates. However, the presence of channels on the outside of the carcass results in a larger footprint of the machine. The design of the machine is also made more complex, in particular because of the presence of additional material to form the external channels and because of the difficulty of sealing a circuit with external channels.

There is a need to improve closed electric rotating machines, in particular in order to improve the efficiency of the cooling while keeping the machine very compact, and this whatever the type of winding and the voltage, power or range ranges. speed considered.

The invention aims to at least partially meet this need.

Disclosure of the invention

To do this, the invention relates to a rotating electrical machine, comprising:

a casing comprising a primary cooling circuit by circulation of a cooling fluid,

a stator arranged inside the casing and preferably in thermal contact with it,

a rotor,

a secondary cooling circuit, comprising at least one fan for generating a forced circulation in a closed circuit of a secondary fluid, preferably a gas, in thermal contact with the rotor, this secondary fluid being cooled by the primary circuit. Advantageously, the secondary circuit is arranged radially inside relative to the primary circuit. In other words, the fluid which circulates in the secondary circuit does not reach the outside of the carcass, but always remains radially inside the primary circuit. This results in greater compactness and the production of sealing at the interface between the carcass and the channels outside the latter of the previous solution is avoided. The reliability of the machine according to the invention is thereby enhanced.

By "thermal contact", it should be understood that there can be a significant thermal transfer between the two elements in thermal contact, when their temperatures are different. This thermal contact can be achieved by direct physical contact between the two elements, possibly with the presence of thermal paste, or by the interposition of a third heat conducting element between the two.

The machine thus comprises a secondary rotor cooling circuit, which is contained inside the frame of the machine, and the coolant of which is cooled by the primary stator cooling circuit by thermal contact with the stator and / or the carcass as it travels along the stator and / or the carcass. The invention allows efficient cooling of the rotor, thanks to the forced circulation of the secondary fluid which is cooled by the primary cooling circuit.

In addition, thanks to the invention, it is not necessary to provide channels on the exterior of the carcass, as mentioned above. It suffices to provide arrangements in the stator and / or in the casing, and / or separators arranged between the stator and the casing to provide one or more passage channels for the secondary fluid circulating in a closed loop inside the machine. , circulated by the fan.

According to a particular embodiment, the carcass and the stator are separated by at least one separator forming a spacer, the at least one separator being inserted into a groove formed in the carcass and / or the stator.

As the separators forming a spacer between the frame and the stator are inserted into grooves formed in the frame and / or in the stator, the invention advantageously makes it possible to facilitate the positioning of the separators. In addition, it improves the mechanical strength of the assembly.

Preferably, the coolant of the primary circuit is a liquid, for example an oil or water, optionally added with an additive such as an antifreeze for example. The secondary fluid forced into circulation by the fan is preferably in gaseous form, more preferably air, but could be other. According to a particular embodiment, the fan is driven in rotation by the rotor, being for example carried by the shaft thereof and rotating at the same speed as the rotor. As a variant, the fan has its own motor, and for example rotates relatively to the rotor shaft. As a further variant, the machine comprises two fans, each arranged on one side of the rotor along the longitudinal axis. Each fan may or may not be of different shape and size.

In exemplary embodiments, the rotor comprises at least one internal rotor channel through which the secondary fluid circulated forced by the fan. Preferably, said inner rotor channel is produced within a packet of rotor sheets. In particular, the rotor sheets can be cut with openings to form internal channels allowing the rotor to be cooled.

The term “internal rotor channel” is understood to mean a channel whose walls are defined solely by the rotor.

The circulation of the secondary fluid in a closed loop can be done on the way through the rotor and back through the stator and / or the casing or in one or more passages between the two.

When the fluid forced into circulation by the fan circulates at least in part through the stator, the latter may include at least one stator internal channel through which the fluid passes.

By “stator internal channel” is meant a channel whose walls are defined only by the stator.

Preferably, said inner stator channel is produced within a package of stator sheets, for example using openings formed during the cutting of the sheets.

As the stator is in thermal contact with the cooled casing, the fluid circulating in an internal stator channel is cooled by the primary cooling circuit. Preferably, the stator inner channels are arranged near the outer surface of the stator, in particular at a distance less than 50% of the thickness of the stator yoke.

Preferably, the internal stator channels are dimensioned so that the secondary fluid can circulate with a sufficient flow rate for adequate cooling of the rotor, without however the passage of the magnetic flux in the stator sheets being significantly affected. . In an exemplary embodiment, the carcass comprises at least one internal channel through which the secondary fluid circulated forced by the fan. Thus, the fluid circulating in an internal channel of the carcass is cooled by the primary cooling circuit. The cooling of the fluid can be more efficient in an internal channel of the carcass than in an internal channel of the stator, the carcass being preferably made of aluminum or an aluminum alloy, or even another metal or metal alloy which better conducts the heat than the steel of the stator sheets. In addition, the fluid can circulate in the casing at a shorter distance from the primary cooling circuit. The circulation of the secondary fluid in the carcass supposes to provide one or more passages allowing the fluid to reach the carcass from the rotor and to return to the fan, or vice versa. This or these passage (s) can be made within the stator and / or the carcass. Preferably, the internal channels of the carcass are dimensioned so that the secondary fluid can circulate with a sufficient flow rate for adequate cooling of the rotor, while keeping the carcass sufficient mechanical strength.

In an exemplary embodiment, the outer surface of the stator and the inner surface of the casing define between them at least one channel through which the secondary fluid circulated forced by the fan. The facing surfaces of the carcass and the stator may include channels formed recessed in at least one of the stator and the carcass.

The carcass and the stator can be separated by at least one separator forming a spacer, better still by a plurality of separators, two adjacent separators forming with the outer surface of the stator and the inner surface of the carcass a channel through which the secondary fluid circulated. forced by the fan. The separators extend for example longitudinally by being evenly distributed angularly around the axis of rotation of the machine.

Preferably, the separators are dimensioned so that they do not unduly increase the size of the rotating machine, while allowing sufficient secondary fluid flow to be provided to adequately cool the rotor.

The separator or separators are preferably made of a material that is a good thermal conductor, such as a metal, without this being imperative.

The presence of one or more separators can be combined with the presence of channels formed recessed on at least one of the stator and of the carcass. The separators can include, where appropriate, at least one internal separator channel through which the secondary fluid circulated forced by the fan.

The combination in the same machine of several types of cooling channels for the secondary fluid, for example internal stator channel and / or channel inside the casing and / or intermediate channel between the stator and the casing and / or channel inside the separator, allows to increase the number of channels and therefore, at constant fluid flow, to reduce the dimensions of the individual channels. This advantageously makes it possible to minimize the influence of the secondary fluid cooling channels on the magnetic performance and on the mechanical strength of the machine.

In an exemplary embodiment, the rotor shaft is mounted on a bearing, the latter being in thermal contact with the secondary fluid. Thus, advantageously, the secondary cooling circuit also makes it possible to cool the bearing of the machine, on the side opposite to the mechanical coupling, for example by being placed in the air flow of the secondary circuit. This advantageously makes it possible to extend the life of the bearing. In an exemplary embodiment of the invention, the rotating machine is an electric rotating machine operating in generator mode. Alternatively, it is an electric rotating machine operating in motor mode. The motor can be synchronous or asynchronous.

Brief description of the drawings

The invention may be better understood from reading the detailed description which follows, of non-limiting examples of implementation thereof, and by examining the appended drawing, in which:

[Fig 1] Figure 1 is a schematic and partial view in cross section of a rotating machine according to the invention;

[Fig 2] Figure 2 shows a detail of an embodiment of a cooling channel of the machine of Figure 1;

[Fig 3] Figure 3 is partial and schematic axial section of the rotary machine of Figure 1;

[Fig 4] Figure 4 is a partial and schematic perspective view of a rotary machine according to the invention, some faces of the carcass not being shown;

[Fig 5] Figure 5 is a perspective view illustrating an embodiment of a stator according to the invention; [Fig 6] Figure 6 illustrates an alternative stator;

[Fig 7] Figures 7 to 13 show variants of stators;

[Fig 8] Figures 7 to 13 show variants of stators;

[Fig 9] Figures 7 to 13 show variants of stators;

[Fig 10] Figures 7 to 13 show variants of stators;

[Fig 11] Figures 7 to 13 show variants of stators;

[Fig 12] Figures 7 to 13 show variants of stators;

[Fig 13] Figures 7 to 13 show variants of stators;

[Fig 14] Figure 14 shows an example of a carcass according to the invention;

[Fig 15] Figure 15 is a cross-sectional view of the carcass of Figure 14;

[Fig 16] Figure 16 is a perspective view of the carcass of Figure 14;

[Fig 17] Figure 17 shows the frame of Figure 14, the stator being mounted in the latter;

[Fig 18] Figures 18 to 21 illustrate alternative embodiments of a carcass according to the invention;

[Fig 19] Figures 18 to 21 illustrate alternative embodiments of a carcass according to the invention;

[Fig 20] Figures 18 to 21 illustrate alternative embodiments of a carcass according to the invention;

[Fig 21] Figures 18 to 21 illustrate alternative embodiments of a carcass according to the invention;

[Fig 22] Figures 22 to 24 show carcasses and a stators according to alternative embodiments of the invention;

[Fig 23] Figures 22 to 24 show carcasses and a stators according to alternative embodiments of the invention;

[Fig 24] Figures 22 to 24 show carcasses and a stators according to alternative embodiments of the invention;

[Fig 25] Figure 25 shows a detail of Figure 24;

[Fig 26] Figures 26 to 32 show variants of carcasses and stators according to the invention;

[Fig 27] Figures 26 to 32 represent variants of carcasses and stators according to the invention; [Fig 28] Figures 26 to 32 represent variants of carcasses and stators according to the invention;

[Fig 29] Figures 26 to 32 show variants of carcasses and stators according to the invention;

[Fig 30] Figures 26 to 32 show variants of carcasses and stators according to the invention;

[Fig 31] Figures 26 to 32 show variants of carcasses and stators according to the invention;

[Fig 32] Figures 26 to 32 show variants of carcasses and stators according to the invention;

[Fig 33] Figure 33 shows a detail of the embodiment illustrated in Figure 30;

[Fig 34] Figure 34 shows a frame and a stator separated by a plurality of separators according to an alternative embodiment of the invention;

[Fig 35] Figure 35 shows the frame and stator of Figure 34;

[Fig 36] Figure 36 shows the separators of Figure 34;

[Fig 37] Figure 37 is a sectional view of the machine of Figure 34;

[Fig 38] Fig. 38 shows a detail of the embodiment of an alternative embodiment where the frame and the stator are separated by a plurality of separators; and

[Fig 39] Figure 39 shows a detail of the embodiment of Figure 34.

detailed description

There is shown in Figures 1 to 4 a rotary machine 1 according to the invention.

This machine 1 comprises a carcass 3 which seals off the machine. Inside this casing 3 are arranged a stator 5 and a rotor 7 carried by a shaft 9. The stator 5 is fixed relative to the casing 3, while the rotor 7 rotates with the shaft 9 around a axis of rotation which is a longitudinal axis for the machine.

The carcass 3 has a length along the longitudinal axis greater than that of the stator 5. It is also conceivable that the carcass 3 is of the same length as the stator 5.

As can be seen in FIG. 3, the machine has no external channels attached to the carcass 3.

The machine 1 also comprises a fan 11 disposed inside the machine 1. This fan 11 is in the example considered a turbine driven in rotation by the rotor 7. The fan 11 can be any type of mechanical device allowing to raise the fluid pressure internal to the machine 1, and thus making it possible to create a forced circulation of fluid.

A primary cooling circuit 13 is provided in the casing 3. The fluid circulating in the primary circuit 13, which is preferably a liquid, makes it possible to cool the casing 3 as well as the stator 5, the latter being in thermal contact with the casing. 3.

In the embodiment of FIG. 1, the stator 5 is in physical contact with the carcass 3, the carcass 3 being for example force-mounted on the stator 5.

The stator 5 comprises a plurality of teeth 15 defining notches for receiving the stator windings 17, in a conventional manner, the invention not being limited to a particular technology for producing the stator winding.

The rotor 7 can be of any type, cage, wound or permanent magnets.

In the example considered, the rotor 7 comprises a plurality of permanent magnets 19 intended to interact magnetically with the magnetic circuit of the stator 5.

A secondary rotor cooling circuit, entirely housed within the machine 1, allows the secondary fluid set in motion by the fan 11 to circulate in a closed loop in order to cool the rotor.

This secondary circuit comprises a plurality of internal rotor channels 21.

The rotor inner channels 21 may extend parallel to the longitudinal axis of the machine 1 all along the rotor and have a constant section, for example of trapezoidal, rectangular or circular shape.

In the example under consideration, the channels 21 are arranged radially between the permanent magnets 19 and the shaft 9.

In the example illustrated in Figures 1 to 4, this circuit also comprises a plurality of intermediate channels 27 located between the stator 5 and the frame 3.

The intermediate channels 27 may have a constant cross section and extend parallel to the axis of rotation of the rotor 7, respectively all along the rotor and all along the stator.

The intermediate channels 27 can be formed between grooves 26 cut in the outer surface of the stator 5 on the one hand, and by the inner surface of the casing 3 opposite on the other hand. These grooves can for example be produced by cutting the sheets from the pack of sheets constituting the stator 5. Figures 3 and 4 illustrate by arrows the direction of circulation of the secondary fluid in the cooling circuit of the rotor.

It can be seen that the secondary fluid, leaving the fan 11, first passes through an interior space 33 delimited by the internal walls of the machine 1, the fan 11, the coils 17 and the stator 5. The secondary fluid passes over the heads 35 coils before entering the intermediate channel 27. During its passage through the channel 27, the secondary fluid is cooled by thermal contact with the stator 5 and the casing 3, in which circulates the fluid of the primary circuit 13. The fluid secondary opens onto a second interior space 37, delimited by the internal walls of the machine 1, the stator 5, the windings 17 and the rotor 7. The secondary fluid then enters the rotor channels 21, where it exchanges heat with the rotor 7 to cool the latter. The secondary fluid then returns to the fan 11 where a new cycle starts.

In the example illustrated in FIG. 3, the shaft 9 is mounted on a bearing 10. Advantageously, this bearing 10 is in thermal contact with the secondary fluid during its circulation in the cooling circuit of the rotor, being exposed to the flow of secondary fluid.

As shown in Figure 4, the primary circuit 13 can be shaped as a single channel which occupies most of the volume of the casing 3 in order to maximize the heat exchanges of the primary coolant. This single channel has a plurality of channel sections 12 which each run around the circumference of the carcass in a circumferential direction. Each channel section 12 is fluidly connected to adjacent channel sections by a baffle passage 14. Two adjacent sections share a common wall.

The primary circuit fluid can enter the casing 3 through opening 16 and exit through opening 18. It can be set in motion by an external fluid circulation pump, not shown. It passes through an external heat exchanger, not shown, configured to cool it.

The primary circuit can also cool a drive of the machine, not shown.

In Figure 5, the geometry of the grooves 26 is clearly visible.

Figures 6 to 13 illustrate in cross section several alternative embodiments. As can be seen in these figures, the secondary fluid circulation channels can be formed in the stator and / or on the external surface of the stator. In the first case, they form internal stator channels 23; in the second case, they form, in cooperation with the internal surface of the carcass 3, intermediate channels 27.

When stator inner channels 23 are provided, they are preferably arranged near the outer surface of the stator, in particular at a distance from the outer surface of less than 50% of the thickness e of the stator yoke.

In the example of FIG. 6, the grooves 26 are formed on the outer surface of the stator 5, that is to say on the surface of the stator opposite the teeth 15 defining notches for receiving the stator windings.

In the example of Figure 8, the cross section of the grooves 26 is shaped in the shape of a semi-circle, the diameter of which is greater than the width of the ridges 39 separating two adjacent grooves.

In the example of Figure 11, the stator 5 comprises stator channels 23 of rectangular section arranged in close proximity to the outer surface of the stator. Thus, only a thin sheet metal separates the channels 23 from the surface.

FIGS. 14 to 16 represent a carcass 3 whose internal surface comprises a plurality of grooves 28 whose walls form, in cooperation with the external surface of the stator 5, intermediate channels 27.

As can be seen in Figure 16, the presence of these grooves 28 in the casing 3 is compatible with the circulation of a cooling fluid in the primary circuit 13.

Figure 17 shows an assembly consisting of a casing 3 as illustrated in Figures 14 to 16 and a stator 5 comprising grooves 26 on its outer surface. In this example, the grooves of the carcass 28 and those of the rotor 26 are arranged so as to face each other and together define the intermediate channels 27.

In the examples of FIGS. 18 to 21, the casing 3 comprises internal channels 25 intended for the circulation of the fluid of the secondary circuit.

It is possible to combine the characteristics of the different embodiments which have just been described.

The use in combination of internal stator channels 23 and / or internal carcass channels 25 and / or intermediate channels 27 makes it possible to increase the flow rate of the secondary fluid circuit or, at constant flow rate, to reduce the dimensions of the channels. This therefore makes it possible to minimize the risks of affecting the magnetic and / or mechanical performance of the machine. FIGS. 22 to 28 represent different embodiments of the invention in which the carcass 3 and / or the stator 5 define the cooling channels for the secondary fluid. It is not necessary, within the framework of the invention, for the stator 5 and the casing 3 to be in direct physical contact. Indeed, the cooling of the stator by the primary circuit 13 can be achieved without physical contact: it suffices that there is sufficient thermal contact between these two elements.

Figures 29 to 33 illustrate different examples of machines in which the frame and the stator are separated by a plurality of separators 31. The separators 31 are arranged between the interior surface of the frame 3 and the exterior surface of the stator 5 and extend preferably all along the stator 5. It is also conceivable that the separators 31 have a shorter length than that of the stator 5.

Thus, the walls of two adjacent separators define, in cooperation with the interior surface of the carcass 3 and the exterior surface of the stator 5, an intermediate channel 27 allowing the circulation of the fluid of the secondary circuit.

In the example of FIG. 31, the stator 5 also comprises stator channels 23, in a number equal to that of the intermediate channels 27. The channels 23 and 27 are distributed equiangularly, but they could also be distributed unevenly. The stator channels 23 are arranged with an angular offset relative to the intermediate channels 27, so that a part of each stator channel 23 is located opposite a separator 31.

In the example of FIG. 32, the carcass has channels 25 equal in number to that of the intermediate channels 27. The channels 25 and 27 are distributed equiangularly, but they could also be distributed unevenly. The channels 25 are arranged with a slight angular offset from the intermediate channels 27, so that a part of each intermediate channel 27 is located opposite a solid area of the carcass 3.

As shown in FIG. 33, the channel of the primary circuit 13 of the casing 3 is disposed radially outside the channels of the casing 25 for circulating the secondary fluid. The fluid of the primary circuit 13 circulates in a circumferential direction, that is to say in a direction orthogonal to the direction of circulation of the secondary fluid in the channels 23, 25, 27. It could also circulate in a direction parallel to the channel. direction of circulation of the secondary fluid, or in any other direction. Preferably, the separators 31 are made of a metal or any other material that is a good conductor of heat.

The separators 31 may also consist of a stack of two or more layers of different thermal conductive materials. For example, there is a better thermal conductor on the side of the separator in contact with the carcass than on the side of the separator in contact with the stator. This advantageously makes it possible to limit the amount of material of the best thermal conductor, which can be expensive. This also makes it possible to preferentially cool the secondary fluid rather than the stator.

The separators 31 can be fixed to the stator and / or to the carcass, and this by any type of process, for example by welding, brazing, screwing or shrinking. These fixing methods are given by way of example and are not exhaustive.

In some embodiments, such as those of Figures 34 to 39, the separators 31 are inserted into grooves formed in the casing or the stator, which can facilitate the positioning of the separators and improve the mechanical strength of the 'set obtained. As illustrated in Figures 34 to 37 and 39, it is possible to provide interior separator channels 29 extending inside the separators 31 to circulate the fluid from the secondary circuit. This advantageously makes it possible to further increase the number of cooling channels for the secondary fluid.

In the example of Figure 34, the separators 31 have internal channels 29. The secondary fluid can thus circulate both in the intermediate channels 27 between two adjacent separators and in the internal channels 29 of the separators 31.

The invention is not limited to particular geometries, in particular to particular cross sections, internal stator channels 23, internal carcass channels 25, intermediate channels 27 or internal separator channels 29.

These channels are for example of round, oval, rectangular, semicircular or even triangular section.

The invention is also not limited to a particular number, to a particular angular distribution or to a particular radial distribution of the internal stator channels 23, the internal carcass channels 25, the intermediate channels 27 or the internal separator channels 29. . It is possible to increase the heat exchanges of the fluid of the secondary circuit with the stator and / or the carcass by producing local disturbances of the flow, for example by placing baffles or other deviations on the path of the secondary fluid.

Claims

1. Rotating electric machine (1), comprising:

a casing (3) comprising a primary cooling circuit (13) by circulation of a cooling fluid,

a stator (5) arranged inside the casing and preferably in thermal contact with it,

a rotor (7),

a secondary cooling circuit, comprising at least one fan (11) for generating a forced circulation in a closed circuit of a secondary fluid in thermal contact with the rotor, this secondary fluid being cooled by the primary circuit, the secondary circuit being arranged in 'a radially interior manner with respect to the primary circuit, the carcass and the stator being separated by at least one separator (31) forming a spacer, the at least one separator being inserted in a groove formed in the carcass and / or the stator.

2. Machine according to claim 1, the carcass and the stator being separated by a plurality of separators (31) forming a spacer,

two adjacent separators forming with the outer surface of the stator and the inner surface of the casing a channel (27) through which the secondary fluid circulated forced by the fan.

3. Machine according to any one of the preceding claims, the separators comprising at least one internal separator channel (29) through which the secondary fluid circulated forced by the fan.

4. Machine according to any one of the preceding claims, the separators being made of a single material or of a stack of several materials, the material or materials preferably being heat conductors.

5. Machine according to any one of the preceding claims, the outer surface of the stator and the inner surface of the carcass defining between them at least one channel (27) through which the secondary fluid circulated forced by the fan, the outer surface of the stator and the inner surface of the casing each comprising grooves (26, 28), the grooves of the casing and the grooves of the stator being arranged so as to face each other and together define the channels (27) through which the fluid passes secondary circulated forced by the fan.

6. Machine according to any one of the preceding claims, the stator comprising at least one internal stator channel (23) through which the secondary fluid circulated forced by the fan.

7. Machine according to the preceding claim, said stator channel being produced within a package of stator sheets.

8. Machine according to any one of the preceding claims, the cooling fluid being a liquid, preferably an oil or water, optionally added with an additive such as an antifreeze.

9. Machine according to any one of the preceding claims, the at least one fan being rotated by the rotor.

10. Machine according to any one of the preceding claims, the rotor comprising at least one internal rotor channel (21) through which the secondary fluid circulated forced by the fan.

11. Machine according to the preceding claim, said internal rotor channel being produced within a pack of sheets of the rotor.

12. Machine according to any one of the preceding claims, said secondary fluid being in gaseous form, preferably being air.

13. Machine according to any one of the preceding claims, the carcass comprising at least one internal channel (25) through which the secondary fluid circulated forced by the fan.

14. Machine according to one of the preceding claims, the shaft (9) of the rotor (7) being mounted on a bearing, the bearing being in thermal contact with the secondary fluid.

15. Machine according to one of the preceding claims, the machine being an electric rotary machine operating in motor mode.

16. Machine according to one of claims 1 to 14, the machine being an electric rotating machine operating in generator mode.

17. Rotating electric machine (1), comprising:

a stator (5) arranged inside the carcass and preferably in thermal contact with the latter, a rotor (7),

a secondary cooling circuit, comprising at least one fan (11) for generating a forced circulation in a closed circuit of a secondary fluid in thermal contact with the rotor, this secondary fluid being cooled by the primary circuit, the secondary circuit being arranged in 'a radially interior manner with respect to the primary circuit, the carcass and the stator being separated by a plurality of separators (31) forming a spacer, two adjacent separators forming with the external surface of the stator and the internal surface of the carcass a channel (27 ) traversed by the secondary fluid circulated forced by the fan.

18. Rotating electric machine (1), comprising:

a rotor (7),

a secondary cooling circuit, comprising at least one fan (11) for generating a forced circulation in a closed circuit of a secondary fluid in thermal contact with the rotor, this secondary fluid being cooled by the primary circuit, the secondary circuit being arranged in 'a radially interior manner with respect to the primary circuit, the exterior surface of the stator and the interior surface of the casing defining between them at least one channel (27) through which the secondary fluid circulated forced by the fan, the exterior surface of the stator and the inner surface of the casing each comprising grooves (26, 28), the grooves of the casing and the grooves of the stator being arranged so as to face each other and together define the channels (27) through which the secondary fluid passes forced into circulation by the fan.

19. Rotating electric machine (1), comprising:

a rotor (7), a secondary cooling circuit, comprising at least one fan (11) for generating a forced circulation in a closed circuit of a secondary fluid in thermal contact with the rotor, this secondary fluid being cooled by the primary circuit, the secondary circuit being arranged in 'a radially internal manner relative to the primary circuit, the stator comprising at least one internal stator channel (23) through which the secondary fluid circulated forced by the fan.