FR3091064A1 - SYNCHRONOUS ELECTRIC MACHINE - Google Patents

Abstract

The invention relates to a brushless and magnetless synchronous electric machine, characterized in that it comprises a stator (20) comprising a ring (22), a winding (28) and a toothing (24) comprising teeth (26). 'extending parallel to the axis of rotation from the ring (22), said winding being wound around the teeth (24), a rotor (10), comprising a first part (12a) extending in p directions (18a) preferred, a second part (12b) extending along p preferred direction (18b) offset by π / p with respect to the preferred directions of the first part (18a), and an intermediate part (14) connecting the first part (12a) to the second part (12b), and a rotor excitation coil (40), fixed relative to the stator, supplied by a direct electric current, arranged around the intermediate part (14) of the rotor and configured for generating an electrical flux in the rotor (10) by magnetic induction. Figure for abstract: 4a

Description

Description

Title of the invention: SYNCHRONOUS ELECTRIC MACHINE

Technical field of the invention

The invention relates to the field of electric machines, in particular synchronous electric machines which can serve both as an electric motor or an electric generator. In particular, the invention relates to a synchronous electric machine without brushes and without magnets.

Technical background

[0002] Synchronous electrical machines with rotor excitation flux are currently divided into two main categories: permanent magnet machines and brush machines.

Permanent magnet machines have the advantage of being able to reach high torque densities and of having low rotor losses, but they have the disadvantage of having to incorporate magnets which are expensive to purchase and which complicate the process of manufacturing.

In addition, the evolution of technology and its consequences on the general public market generates an exponential consumption of certain rare earths which can cause an increase in the cost of magnets using these rare earths (Samarium Cobalt or Neodymium Fer Bore magnets for example), even a shortage.

Broom machines do not have the disadvantages of magnets, but neither do they have their advantages. In addition, the brush system requires maintenance operations linked to the mechanical wear of the brushes (change of the brushes), which is restrictive for the user.

To avoid these drawbacks, solutions have been proposed.

We can cite, for example, multi-stage generators which use a "rotary transformer" which generates an alternating electrical signal on the rotor, on a first stage, which is then rectified by a rotating diode bridge (second stage) which supplies coils fixed on rotor magnetic projections (electromagnets forming the main excitation) which represent the third stage. These machines are often generators, called three-stage generators which have great complexity due to the transformer and the rotating rectifier.

The inventors have therefore sought other solutions to benefit from the advantages of permanent magnet machines without the disadvantages of brushes or equivalent requiring a mechanical rotating contact for the transmission of electricity.

Summary of the invention

To do this, the invention relates to a synchronous electric machine without brushes and without magnets, configured to rotate a rotary element about an axis of rotation of the electric machine or to generate electrical energy from mechanical energy transmitted by said rotary element, characterized in that it comprises:

a stator arranged around the axis of rotation of the electric machine, comprising a ring extending along a preferential plane perpendicular to said axis of rotation and comprising a winding and a toothing comprising teeth extending parallel to the axis of rotation from the ring, said coil being wound around the toothing according to the preferred plane and the toothing delimiting an interior zone of the stator around the axis of rotation, - a rotor, comprising a first part extending along p first preferred directions parallel to the preferred plane, a second part extending along p second preferred directions angularly offset by π / ρ relative to the first preferred directions of the first part and parallel to the preferred plane, and an intermediate part connecting the first part to the second part, the rotor being arranged so that at least the second part and the intermediate part are in the inner zone ure of the stator and so that the second part is on the side of the ring, and - an excitation coil of the rotor, fixed relative to the stator, supplied by a direct electric current, arranged around the intermediate part of the rotor and configured to generate a magnetic flux in the rotor by magnetic induction, so that the first part of the rotor constitutes p magnetic poles north of the rotor and the second part of the rotor constitutes p magnetic poles south of the rotor.

An electric machine according to the invention therefore allows the rotor to be polarized without requiring permanent magnets or brushes, thanks to the excitation coil (also called induction coil) located at the intermediate part of the rotor. .

The rotor excitation coil is fixed relative to the stator, which limits the complexity compared to the solutions of the prior art with rotating parts (three-stage generator in particular). The energization of the excitation coil is facilitated because the excitation coil does not enter the zone of movement of the north and south poles of the rotor (respectively the first part of the rotor and the second part of the rotor). The excitation coil thus creates the magnetic poles by magnetic induction at the intermediate part without causing any mechanical interaction with the mobile magnetic poles. The coil can be simple, for example only a concentric coil, supply direct current and thus have a reduced cost.

The rotor is said to be "cold" because no winding is attached to it and there is therefore no heating by conduction but only due to the radiation coming from the excitation coil. This radiation is all the weaker as the air gap with the excitation coil is large. The flux passing through the rotor is continuous because created by the excitation coil supplied continuously, which leads to the absence of losses by hysteresis and Loucault currents, except at the ends opposite the stator due to potential variations in reluctance. The rotor is also off-center with respect to the stator winding located at the teeth near the ring and the rotor does not receive calories radiated by the stator winding. For all these reasons, the service life of the components is improved, in particular the service life of bearings of the electric machine.

The absence of brushes increases reliability and reduces maintenance costs. The absence of magnets reduces costs and dependence on rare earths.

Finally, the arrangement of the stator teeth, parallel to the axis of rotation, makes it possible to simplify the positioning of the stator winding during manufacture, by simply inserting the winding through the face of the stator comprising the free ends. teeth opposite to the stator ring.

The electric machine can work as well as an engine as a generator. In generator operation, the rotor can be directly fixed to the rotary mechanical drive element, and the stator fixed to the fixed part of the rotary drive element. In this case, the electric machine can operate without rolling between the rotor and the stator: the rotor turns in the stator without requiring rolling. This is for example the case if the rotor is fixed on the output shaft of a reducer and the stator fixed on the housing of the reducer.

According to a characteristic of the invention, the electric machine comprises an integrated electronic device which is arranged inside the stator. Such a configuration is easy to implement since it makes it possible to fill the unoccupied space inside the stator. This makes it possible not to lengthen the electric machine nor to increase its diameter unlike other solutions of the prior art which provide for the arrangement of electronic elements at the rear of the electric machine or around it. The electric machine is thus compact.

Advantageously, but not limited to, the integrated electronic device is arranged in the interior area of the stator and between the rotor and a rear face of the stator ring along the axis of rotation.

According to another characteristic, the stator is laminated and produced in one piece so as to limit the losses of Loucault current.

Advantageously, but not limited to, the stator comprises a plurality of ferromagnetic sheet sheets arranged one above the other along a radial axis perpendicular to the axis of rotation.

According to a characteristic of the invention, the laminated stator is made from a single strip of ferromagnetic sheet.

According to another characteristic, the electric machine comprises a first housing comprising a first cooling fluid and in which is / are installed (s) the stator winding and / or the integrated electronic device. Such an arrangement makes it possible to cool the stator winding and / or the integrated electronic device more effectively to the core. The temperature gradients are reduced, which implies a more homogeneous internal temperature and increases the reliability of the electric machine. In addition, filling the first housing with coolant dampens vibrations.

According to another characteristic, the electric machine comprises a second housing comprising a second cooling fluid, the excitation coil being arranged inside this second housing. As explained above, installing the excitation coil in a casing filled with a cooling fluid makes it possible to cool it to the core more efficiently, to reduce the temperature gradients to increase the performance of the electric machine, to dampen vibrations during the operation of the electric machine and avoid the risk of fire.

Advantageously, but not limited to, the first and / or the second cooling fluid comprises an oil. The oil effectively acts as a shock absorber. Furthermore, the components which are arranged in the first housing and / or the second housing are not subjected to humidity and the entire space of this first and / or second housing being filled with oil, the risk of fire is limit.

According to another embodiment of the invention, the electric machine comprises a housing in which are housed at least the rotor, the excitation coil mounted around the intermediate part of the rotor and a drive shaft s' extending along the axis of rotation, the drive shaft comprising a first end which is coupled to a bottom of the casing. Such an arrangement makes it possible to free up space for the arrangement of the electronic device integrated inside the stator since the drive shaft (which is intended to be coupled to the rotary element) does not extend to through the stator ring. The drive shaft stops at the bottom of the housing.

The integrated electronic device is provided with a bore intended for the passage of a rotary element.

According to another characteristic of this embodiment, the drive shaft is rotatably mounted in the casing and is guided in rotation via rotationally guided bearings.

According to one characteristic, the housing comprises grooves or housings intended to each receive at least partially the free end of the stator teeth so as to stiffen the assembly.

According to another characteristic, the machine comprises a flange configured to close the casing, the flange comprising housings each intended to receive at least partially the free end of the stator teeth so as to stiffen the assembly.

Advantageously and according to the invention, the maximum length of the first part of the rotor is greater than the diameter of the internal area of the stator, and the first part of the rotor is outside the internal area of the rotor, opposite the ends of the teeth of the stator toothing, opposite the ring.

According to this aspect of the invention, the first part of the rotor operating as a succession of magnetic poles of the same polarity is positioned axially with respect to the magnetic circuit formed by the stator while the second part of the rotor operating as a succession of magnetic poles of opposite polarity to the first part is positioned radially with respect to the magnetic circuit formed by the stator.

Advantageously and according to the invention, the maximum length of the first part of the rotor is less than the diameter of the internal area of the stator, and the first part of the rotor is arranged in the internal area of the stator.

According to this aspect of the invention, the entire rotor is arranged in the interior area of the stator and the two successions of magnetic poles of the rotor are positioned radially relative to the magnetic circuit formed by the stator.

Advantageously and according to the invention, the first part of the rotor and the second part of the rotor have the shape of a straight cylinder having for base a truncated disc of p segments offset angularly by 2π / ρ, formed by separate strings. parallel and symmetrical with respect to the center of the disc, said cylinder comprising a bore around the center of the disc intended to receive the rotary element.

According to this aspect of the invention, the rotor parts have a maximum length equal to the maximum diameter of the truncated disc forming the base of the cylinder and each segment making them up has a width equal to the distance between the two strings of this segment . The preferred direction of each segment of each rotor part is parallel to the two strings of this segment.

The rotor parts can be directly manufactured from a straight revolution cylinder based on the complete disc by machining the 2p segments.

The shape of the rotors is particularly suitable for rotating parts and adapts perfectly to the ring-shaped stator for the circulation of magnetic flux, minimizing the air gap on the parts forming the magnetic poles.

Advantageously and according to the invention, the intermediate part has the shape of a cylinder of revolution.

According to this aspect of the invention, the intermediate part is optimized to receive the excitation transmitted by the ring-shaped excitation coil around the intermediate part. In addition, the intermediate part does not show any imbalance during rotation. The cylinder is hollow to allow the introduction of the rotating element.

Advantageously and according to the invention, the electric machine comprises a direct voltage generator supplying the excitation coil, said direct voltage generator being configured to deliver a direct current of adjustable current value.

According to this aspect of the invention, a modification of the value of the direct current supplying the excitation coil allows the regulation of the magnetic flux circulating in the machine. In particular, this allows adjustment of the torque delivered by the electric machine when it is operating in motor mode. This also allows a simple "defluxing" when it operates in motor mode and it is necessary to increase it in speed by reducing its electro-motive force.

This also allows simple adjustment of the output voltage across the stator winding when it is operating in generator mode.

Advantageously and according to the invention, the stator winding comprises a multiple number of phases distributed over the teeth of the stator, in particular three phases.

According to this aspect of the invention, the stator is equipped with a standard three-phase winding for the operation of the electric machine.

According to other variants of the invention, the winding can include another number of phases depending on the desired application.

The invention also relates to an electric machine characterized in combination by all or part of the characteristics mentioned above or below.

The invention also relates to a method for producing a stator of an electric machine having any of the preceding characteristics, the method being characterized in that it comprises the following steps:

- supply of a strip of ferromagnetic sheet comprising a predetermined width L in a first direction, the width L being measured between a first side and a second side of the strip of ferromagnetic sheet,

- production of a plurality of notches by cutting so as to form legs, and

- winding of the sheet metal strip around a winding axis so that several tabs are superimposed along a radial axis perpendicular to the winding axis.

[Math.l]

X + n .e

Where n is an integer ranging from 0 to K-2 and K corresponds to the number of notches.

According to this method, e is calculated according to the formula:

[0050]

[Math.2]

Λ (θ) = (fp) -e + Ri

With Ri is the internal radius of the stator.

The invention also relates to a method for mounting an electric machine having any of the above characteristics. This mounting process includes the following steps:

assembly of a first sealed housing comprising a first cooling fluid, the stator winding and / or the integrated electronic device, insertion of the first housing assembled on the stator, and insertion at least partially of the rotor in the interior area of the stator.

Such an assembly process makes it easier to assemble and maintain the electric machine.

According to this mounting method, the step of assembling the first casing comprises the following steps:

installation of a first cover in a sealed manner on radially internal and external annular walls of the first housing, arrangement of the winding around projections extending from an internal surface of the first cover along the axis of rotation, connection of the stator winding with the integrated electronic device, sealing the first housing in a sealed manner with a second cover, injecting a cooling fluid into the first housing until it is filled.

Brief description of the figures

Other characteristics and advantages of the invention will appear during the reading of the detailed description which will follow for the understanding of which reference will be made to the appended drawings in which:

[0056]

[fig. the the]

Figure la is a schematic right view of a rotor of an electric machine according to an embodiment of the invention for p = 2; FIG. 1b is a schematic front view of a rotor of an electric machine according to an embodiment of the invention for p = 2; FIG. 1c is a diagrammatic left view of a rotor of an electric machine according to an embodiment of the invention for p = 2;

[0057]

[fig.2a-2b]

Figure 2a is a schematic right view of a stator of an electric machine according to an embodiment of the invention; FIG. 2b is a schematic front view of a stator of an electric machine according to an embodiment of the invention; [fig.3a-3b]

Figure 3a is a schematic right view of an excitation coil of an electric machine according to an embodiment of the invention; FIG. 3b is a schematic front view of an excitation coil of an electric machine according to an embodiment of the invention;

[fig.4a-4b]

Figure 4a is a schematic right view of an electric machine according to an embodiment of the invention; Figure 4b is a schematic front view of the electric machine illustrated in Figure 4a;

[Fig.5-6]

Figure 5 illustrates another embodiment of an electric machine comprising an electronic device integrated therein; Figure 6 is a rear view of the integrated electronic device of the electric machine shown in Figure 5

[Fig.7]

Figure 7 is an embodiment of an integrated electronic device according to the invention;

[Fig. 8]

Figure 8 is another embodiment of an integrated electronic device according to the invention;

[Fig.9]

Figure 9 is another embodiment of an integrated electronic device according to the invention;

[Fig.10]

Figure 10 is another embodiment of an integrated electronic device according to the invention;

[Fig. 11]

Figure 11 is an embodiment of a laminated stator and made in one piece according to the invention;

[Fig. 12-13]

FIG. 12 shows a step in producing an example of a laminated stator in one piece according to the invention; FIG. 13 illustrates an example of a strip of ferromagnetic sheet metal intended to produce a laminated stator in one piece according to the invention;

[Fig. 14]

FIG. 14 shows another embodiment of an electric machine comprising at least one casing insulating organs of the electric machine according to the invention;

[Fig. 15]

Figure 15 is a perspective view of a housing in which are housed components of an electric machine such as an integrated electronic device according to the invention;

[Fig. 16]

Figure 16 is a sectional and detailed view of the housing shown in Figure 16 according to the invention;

[Fig. 17-18]

Figure 17 is an axial sectional view of another embodiment of an electric machine comprising an integrated electronic device; Figure 18 is a rear view of the integrated electronic device intended to equip the electric machine shown in Figure 17;

[Fig. 19-21]

Figure 19 shows schematically and in perspective a housing in which are housed components of the electric machine such as a rotor according to the invention; Figure 20 is a front view of the housing shown in Figure 19 according to the invention; Figure 21 is an axial and detailed sectional view of the housing intended to equip the electric machine shown in Figure 17 according to the invention. Detailed description of the invention

The following embodiments are examples. Although the description refers to one or more embodiments, this does not necessarily mean that each reference relates to the same embodiment, or that the characteristics apply only to a single embodiment. Simple features of different embodiments can also be combined to provide other embodiments. In the figures, the scales and the proportions are not strictly observed, for purposes of illustration and clarity.

The following figures describe the components of a brushless synchronous electric machine and without magnets according to an embodiment of the invention, configured to drive in rotation a rotary element around an axis of rotation of the electric machine or to generate electrical energy from the mechanical energy transmitted by said rotary element.

Figures la, 1b and schematically represent a rotor 10 of an electric machine according to an embodiment of the invention, respectively seen from the right, from the front and from the left.

The rotor 10 comprises a first part 12a and a second part 12b connected by an intermediate part 14.

The first part 12a and the second part 12b have the shape of a straight cylinder having for base a truncated disc of two segments formed by separate strings parallel and symmetrical with respect to the center of the disc. Each first and second part includes a bore (respectively referenced 16a and 16b) around the center of the disc intended to receive the rotary element.

The intermediate part 14 is a cylinder of revolution comprising in the same way a bore intended to receive the rotary element.

The three bores 16a, 16b and 16c are thus the same size and aligned so as to form a through bore 16 configured to receive the rotary element in the rotor 10.

As shown in Figure 1b, the first part 12a has a first preferred direction 18a, and the second part 12b has a second preferred direction 18b. The first preferred direction 18b is perpendicular to the second preferred direction 18b.

Figures 2a and 2b schematically represent a stator 20 of an electric machine according to an embodiment of the invention, respectively seen from the right and from the front.

The stator 20 comprises a ring 22 extending along a preferential plane 23, a toothing 24 and a winding 28.

The toothing 24 includes a plurality of teeth (only part of which is referenced under the reference 26 in the figures for reasons of clarity) extending from the ring 22 parallel to the axis of the ring which will the axis of rotation of the rotary element. The coil 28 is shown in part in Figure 2b, and is wound around the teeth 26 of the teeth. A single phase of the winding is shown here, the winding can include several phases in known manner. Likewise, the winding around the teeth is shown by way of example and other winding diagrams can be used depending on the characteristics of the stator desired.

The teeth of the toothing delimit an interior zone 30 of the stator, which forms a cylinder of revolution around the axis of rotation of the rotary element.

Figures 3a and 3b schematically show a coil 40 for exciting an electric machine according to an embodiment of the invention, respectively seen from the right and from the front.

The excitation coil 40 takes the form of a ring in which is wound the conductive wire 42 forming the excitation coil 40. The excitation coil is supplied by a generator 44 of direct current whose value can be adjustable.

The inside diameter 46 of the excitation coil 40 must be slightly greater than the outside diameter of the intermediate part 14 of the rotor in order to allow the magnetic induction thereof.

Figures 4a and 4b schematically represent an electric machine 50 according to an embodiment of the invention, respectively viewed from the right and from the front. The electric machine is the assembly of the rotor 10, the stator 20 and the excitation coil 40 as described above.

The rotary element 100 associated with the electric machine 50 is shown inserted in the rotor 10. It rotates around the axis 200 of rotation.

In the assembled electrical machine, the axis 200 of rotation is also the axis of rotation of the rotor, and the axis around which are arranged the excitation coil 40 and the stator 20.

The stator winding 28 is represented by a single element to schematize and is arranged on the side of the ring 22 of the stator 20.

The rotor 10 is arranged at least partially in the inner zone 30 formed by the teeth of the stator. Here, the intermediate part 14 and the second part 12b are arranged in the interior zone 30. When the electric machine 50 is in operation, the stator 20 is fixed and the rotor 10 is rotated relative to the stator 20. One or more bearings (not shown) disposed between the rotor 10 and the stator 20 can be used to maintain elements in place. Alternatively, in generator operation, the rotary element keeps the rotor 10 in place in the stator 20 and no bearing is necessary.

The excitation coil 40 is arranged in the stator 20 around the intermediate part 14 of the rotor 10 leaving a gap 52. When it is supplied, it induces by induction the appearance of a continuous magnetic flux in the rotor 10, represented by arrows. The continuous electric flow allows the polarization of the rotor, so that the first part 12a behaves like a north magnetic pole and the second part 12b behaves like a south magnetic pole. Thus, the electric flow moves from the south pole to the north pole, therefore from the second part 12b of the rotor to the first part 12a of the rotor, is transmitted axially by the teeth of the stator via the air gap 54 between the first part 12a and the stator 20. In other words, the electric flux circulates axially (along the axis 200 of rotation) in the teeth 26 of the stator 20. The magnetic flux then circulates towards the stator.

Due to its positioning at the intermediate part 14, the excitation coil 40 is not influenced by the poles that it creates during the rotation of said poles.

As can be seen in FIG. 4b, the passage of the magnetic flux from the stator 20 to the south pole of the rotor, that is to say the second part 12b, takes place radially via the air gap 56. The fact that the preferred directions of the first part 12a and of the second part 12b being perpendicular allows the teeth of the toothing 24 to be alternately close to one pole and then to the other, allowing circulation of the fluxes from the rotor to the stator or from the stator to the rotor in directions perpendicular to each other.

Another embodiment of this electric machine is shown in Figures 5 to 10. The electric machine 50 includes components similar to those of the electric machine of Figures 4a and 4b. This embodiment differs from the previous one in that the electric machine further comprises an integrated electronic device 300 inside of it.

In particular, as we can see in Figure 5, the integrated electronic device is arranged at least partially inside the stator 20. This integrated electronic device 300 is arranged in the interior area 30 of the stator. This is mounted along the axis 200 of rotation between the rotor 10 (in particular the second part 12b) and a rear surface 201 of the stator.

Referring to Figure 6, the integrated electronic device 300 has an annular shape with a central axis C. It has a diameter or a length along a radial axis 350 perpendicular to the axis 200 of rotation. The diameter of the integrated electronic device 300 is less than the diameter of the interior zone 30 of the stator 20. The integrated electronic device 300 comprises a through hole 310 which passes through it on either side along the central axis C. The latter is coaxial with the axis 200 of rotation. The element 100 is inserted through the integrated electronic device 300.

Figures 7 to 10 illustrate different arrangements of the integrated electronic device 300 in the electric machine 50.

In FIG. 7, the electric machine constitutes a synchronous electric motor supplied by an electric power source 316. In the present example, it is a continuous electric power source. The synchronous electric motor provides the necessary torque for the rotating element 100. The integrated electronic device includes an inverter 311 which is powered by the DC power source. The inverter supplies electrical energy to the winding 28 to which it is connected. This 311 inverter is multi-phase. This comprises in particular two DC terminals coupled to the power source 316 and an AC terminal coupled to the coil 28.

The integrated electrical device 300 further comprises a control unit 312 which is electrically connected to the inverter 311 and to the continuous electrical power source 316. This control unit 312 is configured so that the correct setpoints are generated towards the inverter and a chopper described below of the excitation of the electric machine.

A "rectifier + chopper + filter" assembly of the excitation of the electric machine.

The integrated electronic device 300 is completed by a chopper + filter 313 which is supplied by the DC power source by two DC terminals. The chopper 313 is also coupled to the rotor excitation coil 40 so that the latter is supplied with direct current. The chopper is also electrically coupled to the control unit 312 by two terminals.

In FIG. 8, the electric machine constitutes a synchronous electric motor supplied by an electric power source 316, here alternating. The synchronous electric motor provides the necessary torque for the rotating element 100. The integrated electronic device 300 includes an inverter 311, a chopper + filter 313 and control unit 312 which are configured similarly to the previous embodiment. In this exemplary embodiment, the integrated electronic device comprises a rectifier upstream of the inverter as well as a rectifier upstream of the chopper. The rectifier and inverter module then comprises three alternating current terminals coupled to the AC power source and an alternating current terminal coupled to the winding 28.

The rectifier and chopper module comprises three alternating current terminals coupled to the electrical power source and two direct current terminals coupled to the excitation coil 40 of the rotor so that the latter is supplied with direct current. This module is also electrically coupled to the control unit 312.

The control unit 312 generates the control instructions for the inverter and the chopper to ensure the proper functioning of the machine.

In FIG. 9, the electric machine constitutes a generator delivering an alternating multi-phase current. The integrated electronic device 300 includes a set 315 rectifier + chopper + filter. The chopper is powered by the AC power source 316 here and coupled to the excitation coil 40. For this, the assembly + rectifier + chopper includes a current terminal coupled to the AC power source and two current terminals coupled to the excitation coil 40.

The integrated electrical device 300 further comprises the control unit 312 which is electrically connected to the rectifier + chopper + filter 315 and to the alternative electrical power source generated by the generator. This control unit 312 is configured so as to control the chopper so that the excitation of the generator is adapted to the correct operation.

FIG. 10 represents an electric machine 50 constituting a DC generator. This exemplary embodiment is comparable to the system of FIG. 9, with a rectifier which transforms the alternative continuously to the network.

In the case of an electric machine powered by an alternating power source, the alternating electric flow circulates axially (along the axis 200 of rotation) in the teeth 26 of the stator 20. Likewise, the alternating electric flow circulates circumferentially in the stator 20 (in particular the ring 22) around the axis 200 of rotation. The magnetic flux then flows to the stator.

To limit the eddy current losses, the stator 20 ’illustrated in FIG. 11 is laminated and is made in one piece. In other words, the laminated stator is in one piece. The fact of making the stator in one piece makes it possible to minimize the manufacturing costs of the latter. Indeed, only one sheet metal strip is necessary for the production of this stator and a limited number of steps as we will see in the following description.

In a first embodiment of this laminated stator 20 ′ illustrated in FIG. 11, each tooth 26 comprises a plurality of sheets of ferromagnetic sheet metal arranged, one above the other, along a radial axis perpendicular to the axis of the ring (here the axis 200 of rotation). The ring 22 of the stator 20 ’also includes a plurality of sheets of ferromagnetic sheet metal which are arranged along the axis 200 of rotation.

The stator 20 'laminated in one piece is produced according to a method illustrated in part in Figures 12 and 13. The method includes the provision of a single strip of ferromagnetic sheet 400. The latter has width L predetermined according to a first direction. This first direction is parallel to the axis 200 of rotation in an installed state of the stator in the electric machine. The sheet metal strip 400 is advantageously flat. The width L is measured between a first side 401 and a second side 402 of the strip of ferromagnetic sheet. The first and second sides 401, 402 are opposite in the first direction and are parallel. The strip of ferromagnetic sheet 400 also includes a first edge 403 and a second edge 404 opposite in a second direction. This second direction is here perpendicular to the first direction.

Several notches 405 are produced by cutting from the strip of ferromagnetic sheet metal 400 so as to form tabs 406. Each tab 406 is defined by two notches on either side thereof in the second direction. The latter are intended to form the teeth 26 of the stator. The notches 405 are arranged in the second direction. Each notch 405 extends from the first side 406 in the first direction and has a width less than that of the strip of ferromagnetic sheet. The part of the strip of sheet metal not cut allows to form the ring of the stator.

The strip of ferromagnetic sheet 400 is then wound around a winding axis 407 so that the tabs 406 overlap one above the other radially with respect to this winding axis. The winding axis is perpendicular to the second direction and is coaxial with the axis of rotation 200 in an installation situation in the electric machine.

We then obtain a stator formed from several sheets of this strip of ferromagnetic sheet.

According to this embodiment, the difference or the distance between each successive notch is defined by the formula

[0115] [Math.l]

X + n .e

Where n is an integer ranging from 0 to K-2 and K corresponds to the number of notches.

The calculation of e is done by considering that the stacking or superposition of the legs of the strip of ferromagnetic sheet metal obtained is an Archimedes spiral whose pitch e is equal to the thickness of the strip of ferromagnetic sheet metal. Its polar equation is therefore expressed by the following formula:

[Math.2]

Where Ri is the internal radius of the stator.

It is of course possible to make the notches after winding the strip of ferromagnetic sheet to form the laminated stator.

The notches are produced by any suitable type of tool, for example using a wire.

With such a production method, there is no geometry defect in the stator.

FIG. 14 shows another embodiment of an electric machine 50 with an integrated electronic device 300 which are effectively cooled in order to improve the performance of the electric machine. As we have seen in the embodiment of Figure 5, the integrated electronic device is installed inside the stator. In this exemplary embodiment, the electric machine 50 comprises a first housing 29 in which is / are installed the stator winding 28 and / or the integrated electronic device 300.

As we can see in Figure 14, the coil 28 and the integrated electronic device are arranged inside the first housing 29. This first sealed housing 29 includes a coolant 31. The arrangement of the first housing filled with a cooling fluid is possible because the winding 28 is at a distance from at least the air gap 52. This first housing makes it possible to isolate the winding 28 and the integrated electronic device 300 from the other components of the machine electronics 50.

According to an advantageous but non-limiting characteristic, the cooling fluid 31 is supplied by an external source so as to circulate the fluid in the first housing. In this case, the outer surface 32 of the first housing 29 can act as a heat exchanger. Of course, there is no need to circulate the fluid inside the first housing.

Referring to Figures 15 and 16, the first housing 29 comprises a radially inner wall 33 and a radially outer wall 44 which are annular and which are coaxial with the axis 200 of rotation. The first housing 29 also comprises a first cover 35 and a second cover (not shown) each having the shape of a disc and intended to close upstream and downstream respectively, along the axis 200 of rotation, the first housing29. Fixing means 36 such as screws make it possible to fix the first and second covers 35 on the radially internal and external walls 33, 35. For this purpose, at least the radially external wall 33 comprises orifices 37 (FIG. 16) making it possible to receive the fixing means. Another arrangement and attachment are of course possible.

Seals 38 are arranged between each first and second covers 35 and the radially inner and outer walls so that the first housing is waterproof.

The first cover and the second cover each include openings 39 passing through their wall on either side along the axis 200 of rotation. The lights 39 are distributed regularly and in a circumferential direction.

The second cover includes passage for power cables 49 of the integrated electronic device 300.

In this embodiment, the first housing 29 includes an external diameter which is greater than that of the stator. The first housing has an internal diameter (defined by the radially internal wall) which is greater than that of the rotary element 100.

Advantageously, the cooling fluid 31 comprises an oil which makes it possible to effectively dampen the vibrations which can be harmful for the connections, for example by welding of the elements making up the integrated electronic device 300.

Advantageously, filling the housing with oil helps prevent fire linked to an electrical fault.

According to an alternative embodiment not shown, the excitation coil 40 is also arranged in a second housing which is filled with a second cooling fluid. This second coolant can also be an oil.

According to an example of a method for mounting the electronic machine 50 illustrated in FIG. 14, the first housing 29 is inserted on the stator 20, 20 ’. Prior to this mounting step, the winding 28 and the electronic device 300 are mounted in the first housing. The winding 28 is preformed in advance, that is to say before it is mounted in the electric machine 50.

For this, the radially inner and outer annular walls 33, 34 and the first cover 35 are assembled in a sealed manner. The radially internal and external walls extend from an internal face 41 of the first cover.

The winding 28 is disposed respectively around several projections 42 extending from the internal face 41 of the first cover along the axis 200 of rotation. These projections 42 each have a rectangular section here. The winding 28 is then connected to the integrated electrical device 300 by current terminals 43. Next, the second cover is mounted so as to close the first housing with sealing.

The cooling fluid (here oil) is then injected inside the first housing 29.

After insertion of the first cover on the stator, the first cover of the first housing is advantageously, but not limited to, in contact with the ring 22 of the stator 20, 20 ’.

For this purpose, the teeth 26 of the stator are inserted in the slots 39 of the first and second covers.

The excitation coil 40 is mounted around the rotor 10, then the latter is inserted at least partially into the inner zone 30 of the stator 20, 20 ’.

In the case where the excitation coil 40 is arranged inside the second housing according to an alternative embodiment of the electric machine, the second housing is first inserted around the intermediate part 14. The rotor 10 fitted with the second housing is then inserted into the stator 20.

The second housing comprising the excitation coil 40 is configured similarly to the first housing.

Another embodiment is illustrated in FIGS. 17 to 21 in which the electric machine comprises an integrated electronic device 300 ’.

In this embodiment, the electric machine is completed by a rotor module 500 comprising at least one casing 501, a drive shaft 110, an excitation coil 40 and a magnetic circuit of the rotor. In particular, the casing 501 comprises an annular wall 502 extending (along the axis 200 of rotation) from a bottom 503. The latter comprises a plurality of orifices 504 passing through the wall of the bottom on either side along the 200 axis of rotation. These orifices 504 are distributed regularly and in a circumferential direction. Each orifice 504 is intended to receive a tooth 26 of the stator. The edge 505 of the annular wall 502 defines an opening which is closed by a flange 506.

According to an exemplary embodiment, the annular wall 501 comprises slots 507 which extend from the edge 505 in the annular wall. The slots 507 are arranged along the circumference of the annular wall.

The drive shaft 110 extends along the axis 200 of rotation and between the flange 506 and the bottom 503. As we can see in particular in Figure 21, the drive shaft 110 does does not extend beyond the bottom 503 of the casing 501. More specifically still, the drive shaft 110 comprises a first end 111 which is coupled to the bottom of the casing and a second end 112 (axially opposite the first end) which passes through the flange 506 and which extends outside the casing.

The shaft 110 is mounted for rotation inside the casing. For this, guide bearings 509 in rotation are mounted upstream and downstream of the drive shaft and inside the casing. In this example, the rotating guide bearings 509 include bearings with balls 510.

This drive shaft is intended to be coupled to the rotary element 100. Such an arrangement frees up space for the integrated electronic device 300 ’. More specifically, the integrated electronic device is full. In other words, this does not include a through hole 310 as is the case with the embodiment of FIG. 6.

The integrated electronic device 300 ’is arranged axially between the bottom 503 of the casing and the rear face 201 of the stator 20, 20’.

The rotor 10 is mounted in the casing 501 and around the drive shaft 110.

In this figure, we can see that the maximum length of the first part

12a of the rotor is less than the diameter of the inner zone 30 of the stator 20, 20 ’and that the first part 12a of the rotor is arranged in the inner zone 30 of the stator. In other words, the entire rotor 10 is disposed in the inner zone 30 of the stator. The two successions of magnetic poles of the rotor are positioned radially with respect to the magnetic circuit formed by the stator.

The excitation coil 40 is arranged around the intermediate part 14.

Furthermore, the rotor module includes grooves or housings each intended to receive at least partially the free end of the stator teeth. In particular, the radially internal wall of the casing 501 comprises a plurality of grooves 511 or housings extending in the direction of the axis 200 and distributed regularly around this axis. These grooves are used to receive the stator teeth in order to immobilize them. This helps to stiffen the whole. Alternatively, the flange 506 comprises housings regularly distributed circumferentially around the axis 200. This makes it possible to trap at least the free end of the stator teeth so as to stiffen the assembly.

Claims (1)

Claims [Claim 1] Synchronous electric machine (50), configured to drive in rotation a rotary element (100) around an axis (200) of rotation of the electric machine or to generate electric energy from the mechanical energy transmitted by said rotary element (100), characterized in that it comprises: - A stator (20, 20 ') disposed around the axis (200) of rotation of the electric machine, comprising a ring (22) extending along a preferential plane (23) perpendicular to said axis of rotation and comprising a winding (28) and a toothing (24) comprising teeth (26) extending parallel to the axis of rotation from the ring (22), said coil being wound around the toothing (24) according to the preferred plane and the toothing (24) delimiting an interior zone (30) of the stator around the axis of rotation, - A rotor (10), comprising a first part (12a) extending in p first preferred directions (18a) parallel to the preferred plane, a second part (12b) extending in p second preferred directions (18b) offset angularly by π / ρ relative to the first preferred directions of the first part (18a) and parallel to the preferential plane, and an intermediate part (14) connecting the first part (12a) to the second part (12b), the rotor being arranged so at least the second part (12b) and the intermediate part (14) are in the area (30) inside the stator and so that the second part (12b) is on the side of the ring ( 22), and - a rotor excitation coil (40), fixed relative to the stator, supplied by a direct electric current, arranged around the intermediate part (14) of the rotor and configured to generate a magnetic flux in the rotor (10) by magnetic induction, so that the first part (12a) of the rotor constitutes p magnetic poles north of the rotor and the second part (12b) of the rotor constitutes p magnetic poles south of the rotor. [Claim 2] Electric machine (50) according to claim 1, characterized in that it comprises an integrated electronic device (300, 300 ’) which is arranged inside the stator (20, 20’). [Claim 3] Electric machine (50) according to any one of the preceding claims, characterized in that the integrated electronic device (300, 300 ’) is arranged in the area (30) inside the stator (20, 20’), and between the rotor (10) and a rear face (210) of the ring (22) of the stator (20, 20 ’) along the axis (200) of rotation. [Claim 4] Electric machine (50) according to any one of the preceding claims, characterized in that the stator (20 '') is laminated and is formed in one piece. [Claim 5] Electric machine (50) according to any one of claims 2 to 4, characterized in that it comprises a first housing (29) comprising a first cooling fluid (31) and in which is / are installed (s) the winding (28) stator (20, 20 ') and / or the integrated electronic device (300, 300'). [Claim 6] Electric machine (50) according to any one of claims 2 to 5, characterized in that it comprises a second housing comprising a second cooling fluid, the excitation coil (40) being arranged inside this second housing. [Claim 7] Electric machine (50) according to any one of claims 1 to 5, characterized in that it comprises a casing (501) in which are housed at least the rotor (10), the excitation coil (40) mounted around of the intermediate part (14) of the rotor (10) and a drive shaft (110) extending along the axis (200) of rotation, the drive shaft (110) comprising a first end (111) which is coupled to a bottom (503) of the housing (501). [Claim 8] Method for producing a stator (20 ’) of an electric machine (50) according to any one of the preceding claims, the method being characterized in that it comprises the following steps: - supply of a strip of ferromagnetic sheet (400) comprising a predetermined width L in a first direction, the width L being measured between a first side (401) and a second side (402) of the strip of ferromagnetic sheet, - production of a plurality of notches (405) by cutting so as to form tabs (406), and - winding the strip of ferromagnetic sheet (400) around a winding axis (407) so that several tabs (406) are superimposed along a radial axis perpendicular to the winding axis. [Claim 9] Method for producing a stator according to the preceding claim, characterized in that the difference between each successive notch (405) is defined by the formula: [Math.l] X + n .e where n is an integer ranging from 0 to K-2 and K corresponds to the number of notches. [Claim 10] Method for producing a stator according to the preceding claim, characterized in that e is calculated according to the formula [Math.2] Κ (θ) = (fp) -e + Ri with Ri is the internal radius of the stator. [Claim 11] Method of mounting an electric machine according to any one of claims 1 to 7, characterized in that it comprises the following steps: - assembly of a first sealed housing (29) comprising a first cooling fluid (29), the stator winding (28) and / or the integrated electronic device (300, 300 ’), - insertion of the first housing assembled on the stator (20, 20 ’), and insertion at least in part of the rotor (10) in the area (30) inside the stator (20). 1/6