Classifications

• • H—ELECTRICITY
  • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
  • H02K—DYNAMO-ELECTRIC MACHINES
  • H02K1/00—Details of the magnetic circuit
  • H02K1/06—Details of the magnetic circuit characterised by the shape, form or construction
  • H02K1/22—Rotating parts of the magnetic circuit
  • H02K1/27—Rotor cores with permanent magnets
  • H02K1/2793—Rotors axially facing stators
  • H02K1/2795—Rotors axially facing stators the rotor consisting of two or more circumferentially positioned magnets
  • H02K1/2798—Rotors axially facing stators the rotor consisting of two or more circumferentially positioned magnets where both axial sides of the stator face a rotor
• • H—ELECTRICITY
  • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
  • H02K—DYNAMO-ELECTRIC MACHINES
  • H02K1/00—Details of the magnetic circuit
  • H02K1/06—Details of the magnetic circuit characterised by the shape, form or construction
  • H02K1/22—Rotating parts of the magnetic circuit
  • H02K1/24—Rotor cores with salient poles ; Variable reluctance rotors
  • H02K1/246—Variable reluctance rotors
• • H—ELECTRICITY
  • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
  • H02K—DYNAMO-ELECTRIC MACHINES
  • H02K16/00—Machines with more than one rotor or stator
  • H02K16/02—Machines with one stator and two or more rotors

Definitions

• the present invention relates to the field of rotating electrical machines, and more particularly that of rotating axial flow electrical machines.
• axial flow it should be understood that the flow flowing in the machine is oriented in the gap formed between the rotor and the stator in a direction parallel to an axis of rotation of the machine, in contrast with a so-called flow machine.
• radial in which the flow flows between the rotor and the stator in a direction perpendicular to the axis of rotation of the machine.
• the invention relates more particularly to reluctance synchronous machines, called synchro-reluctant machines.
• a reluctance machine is a machine configured to obtain in each pole of the machine a high saliency so as to have a machine with high salient torque.
• saliency of a pole is meant that the reluctance varies as one moves in the air gap along the pole during the rotation of the rotor.
• Axial flux and permanent magnet machines are known, for example from documents US Pat. No. 8,674,525, US 2012/0146445, US 2013/0285483, US 2014/0042852 or even US 2014/0292117. These machines have two rotors on which the magnets are mounted on the surface. These machines are devoid of saliency.
• US 2013/0049512 also discloses other topologies, with more stators than rotors and which have the disadvantage of being constituted by stator yokes which can lead to iron losses.
• the rotor also has magnets arranged on the surface.
• the machine comprises two stators and a flux concentration rotor, the two stators having outwardly protruding teeth.
• the rotor is weakly protruding.
• the rotors of such rotating electrical machines do not make it possible to provide relatively low polarity machines, for example less than 12, better still less than 8 or even 6, with efficient use of magnets, in particular ferrite magnets and / or at low energy density, or even being devoid of permanent magnets.
• the invention relates alternators as well as engines.
• an axial-flow rotating electrical machine comprising at least one stator and at least one rotor, arranged along an axis of rotation.
• rotation X of the machine the rotor comprising a rotor mass and housings formed in the rotor mass, these housings being in particular slot-shaped, the housings defining magnetic poles of the rotor, said housings possibly each containing at least one magnet permanent.
• stator (s) and rotor (s) of the machine are thus arranged successively along the axis of rotation of the machine, and not in a concentric manner, as in radial flow machines.
• the machine according to the invention with axial flow and synchronous reluctance, with or without permanent magnets, makes it possible to obtain a much higher saliency than on the state-of-the-art machines and minimize or even eliminate the need to use permanent magnets.
• the size of the machine can be reduced and its compactness improved.
• the surface of the gap between the rotor and the stator being larger, a better electrical conversion is obtained.
• the surface of the gap is, in the case of an axial flow machine, weakly related to the length of the stator and the rotor.
• the machine can be less bulky.
• the structure of the machine makes it possible to effectively use the pair of saliency obtained while retaining any possible permanent magnets.
• the total torque obtained is that coming from both permanent magnets possibly used and the saliency of the machine.
• the machine according to the invention makes it possible to exploit the pair of saliency in addition to the torque coming from the permanent magnets.
• the torque due to the magnets is smaller, so that a smaller amount of permanent magnets can be used, or magnets with a lower energy density can be used.
• Another advantage of the invention is that for the same quantity and the same type of permanent magnets, the total torque obtained is greater because of the torque due to the saliency which is added to the torque due to the permanent magnets to obtain the total torque.
• the rotor may comprise a rotor magnetic mass comprising the housings, which can receive any permanent magnets, and a shaft extending along an axis of rotation, on which the rotor mass is arranged.
• This shaft is integral with the rotor or rotors, and rests by at least one bearing, for example one or two bearings, on a housing of the machine, in particular one or two flanges (s) end of the machine.
• the shaft may be made of a magnetic material, which advantageously makes it possible to reduce the risk of saturation in the rotor mass and to improve the electromagnetic performances of the rotor.
• the shaft may comprise a magnetic sleeve in contact with the rotor mass, the sleeve being mounted on an axis, magnetic or not.
• the rotor may comprise a non-magnetic shaft on which the rotor mass is arranged.
• the tree can for example be realized at least partly in a material of the following list, which is not limiting: non-magnetic steel, stainless steel, titanium or any other non-magnetic material
• the rotor mass may in one embodiment be disposed directly on the non-magnetic shaft, for example without intermediate rim.
• the rotor may comprise a rim surrounding the rotor shaft and coming to bear on the latter.
• the rotor magnetic mass may be wholly or partly made with magnetic sheets.
• the rotor magnetic mass may be wholly or partly made by means of one or more solid magnetic materials, for example chosen from: gray cast iron, spheroidal graphite cast iron, soft magnetic composite materials, otherwise known as soft magnetic composites (SMCs), amorphous magnetic materials, cast steel, forged steel, this list not being limiting.
• solid magnetic materials for example chosen from: gray cast iron, spheroidal graphite cast iron, soft magnetic composite materials, otherwise known as soft magnetic composites (SMCs), amorphous magnetic materials, cast steel, forged steel, this list not being limiting.
• the rotor magnetic mass may be wholly or partly made of an isotropic material, such as, for example, magnetic powders agglomerated by sintering or gluing, or by the addition of metal according to the so-called 3D printing methods.
• an isotropic material such as, for example, magnetic powders agglomerated by sintering or gluing, or by the addition of metal according to the so-called 3D printing methods.
• the rotor mass extends along the axis of rotation of the machine and is arranged around the shaft.
• the shaft may comprise torque transmission means for driving in rotation of the rotor mass.
• the housings according to the invention are entirely formed in the rotor mass.
• the rotor may be devoid of pole pieces that would be disposed between two consecutive magnets of opposite polarities, their polarity being oriented in a plane perpendicular to the axis of rotation of the machine.
• the number of possible housings and magnets total of the machine depends on the polarity of the rotor.
• the rotor mass may comprise any number of dwellings, for example between 4 and 96 dwellings, better still between 8 and 40 dwellings, or even between 16 and 32 dwellings.
• the number of housings per rotor pole may for example be between 1 and 12 dwellings, better between 2 and 10 dwellings, or even between 3 and 8 dwellings per rotor pole.
• Magnets can be buried in the rotor mass. In other words, the magnets are covered by the rotor mass at the gap.
• the surface of the rotor at the gap can be entirely defined by the edge of the rotor mass and not by magnets.
• the housing does not open outwardly along the axis of rotation.
• the housings can be filled at least partially with a non-magnetic synthetic material. This material can lock up the magnets in the housings and / or increase the cohesion of the rotor mass.
• the rotor mass may comprise, where appropriate, one or more reliefs contributing to the proper positioning of the magnets, especially in the radial direction.
• the rotor can be mounted cantilevered or not.
• the machine may be devoid of permanent magnets. It is said in this case that the rotating electrical machine according to the invention is pure synchronous reluctance.
• the housing of the rotor may in this case be empty or contain one or more non-magnetic parts.
• the machine may comprise housings comprising one or more permanent magnets.
• Any permanent magnets may be made at least partially of ferrite, rare earth, AINiCo or any other hard magnetic material.
• the permanent magnets can in particular be made at least partially of ferrite. They may for example not contain rare earths, or at least contain less than 50% rare earth en masse.
• the arrangement of the housings receiving the magnets makes it possible to concentrate the flux of the magnets and to obtain with interesting ferrite magnets.
• the polarity of the magnets can be oriented along an axis parallel to the axis of rotation of the machine.
• the rotor mass Thanks to the arrangement of the magnets in the rotor mass, sufficient induction levels in the air gap are obtained, even with a relatively low rotor polarity, for example less than or equal to 6, while not necessarily using magnets.
• high volume energy such as magnets made of rare earths, but on the contrary low energy density, for example made of ferrite.
• the cost of the rotor can thus be reduced.
• the polarity of the rotor can be reduced if the application requires it.
• the rotor according to the invention makes it possible to increase the level Induction in the gap without increasing the polarity and using magnets with low energy density.
• the permanent magnets can be oriented radially, along a radius of the machine, and / or axially, perpendicular to the longitudinal axis of the machine.
• all the housings of the rotor may comprise permanent magnets.
• the rotor of the machine may comprise housings devoid of permanent magnets and others comprising one or more permanent magnets.
• the same magnetic pole of the machine can be defined by housings comprising permanent magnets and empty housing of any permanent magnet. All the magnetic poles of the machine can thus be defined.
• the machine may comprise magnetic poles which differ from one another by at least one of the arrangement of the housings, the shape of the latter, their number to form a pole, their filling by permanent magnets or not, by non-magnetic parts or not.
• the rotor of the machine may comprise a first magnetic pole and a second magnetic pole adjacent to the first magnetic pole, the first and second magnetic poles being of different polarity, the housings of the first magnetic pole being devoid of permanent magnets and housings of the second magnetic pole having one or more permanent magnets.
• a housing devoid of permanent magnet can be filled at least partially with one or more non-magnetic parts.
• shims may be inserted into one or more housings to allow the permanent magnets or non-magnetic parts to be maintained or separated. These wedges may themselves be non-magnetic.
• the permanent magnets may be rectangular in cross section. As a variant, the magnets may be in curvilinear cross-section, for example of ring-shaped shape.
• the permanent magnets may have a thickness e of between 4 and 20 mm.
• the magnet or magnets of a second housing may be of the same thickness as the magnets of another first housing, or alternatively of a different thickness. housing
• the housing of the rotor may be oriented radially, substantially along a radius of the machine, and / or axially, perpendicular to the longitudinal axis of the machine. They can be U-shaped or V-shaped when observed in a cutting plane that contains the axis of rotation of the machine. U or V are oriented towards the gap. By "U or V facing the air gap” means that the U or V is open towards the air gap.
• Each side branch of a U or a V can contain a single permanent magnet.
• each lateral branch of a U or of a V contains more than one permanent magnet, in particular two magnets forming, for example, each branch of the U or V. Such a segmentation of the magnets can make it possible to improve the circulation of the flow in the rotor mass and / or introduce bridges to stiffen it.
• a magnetic pole of the rotor may be defined by at least one housing of generally cylindrical, cylindrical, conical or frustoconical shape.
• the housing or housing may form an angle with a radial axis of the corresponding pole, for example between 0 and 45 °, better than 30 °.
• the housing may be of cylindrical general shape.
• the cylindrical housing can be, when observed in a plane perpendicular to the axis of rotation of the machine, of generally annular shape, in particular circular, square, triangular, rectangular, or of any other geometrical shape, or else having two convergent slots towards the axis of rotation of the machine.
• a magnetic pole of the rotor can be defined by a housing.
• a magnetic pole of the rotor can be defined by a plurality of concentric cylindrical housings to each other, in particular between two and seven concentric housings, for example three concentric housings.
• a generally cylindrical housing of revolution may comprise a bottom portion.
• the housing thus has a general shape of pot
• the bottom portion may have a generally circular shape, square, triangular, or rectangular.
• the machine may be devoid of magnets disposed on the surface of the magnetic mass of the rotor.
• the machine may comprise at least one permanent magnet disposed on the surface of the magnetic mass of the rotor.
• the shape of the housing in section parallel to the longitudinal axis X may be chosen to optimize the waveform of the induction in the gap.
• at least one end of the housing in section parallel to the longitudinal axis X may be rectangular, triangular or curved. Both ends are optionally rectangular, triangular or curved.
• the part (s) of the housing without magnet at one of its ends or ends may be in the shape of a right-angled or rounded triangle.
• the rotor may comprise permanent magnets inserted in all or part of the dwellings, for example in at least half of the dwellings, or even in more than two thirds of the dwellings, or even in all the dwellings.
• the stator may include teeth and coils disposed on the teeth.
• the stator may be concentrated winding, that is to say wound on teeth, with each winding surrounding a tooth, and each tooth carrying a winding.
• the stator winding is multiphase.
• the number of phases may be at least 3, being for example equal to 3, or greater than 3, for example 5, 7, 11, 13, or 17, or even more.
• stator may be distributed winding.
• the number of teeth and notches per pole and per phase can be between 2 and 9 teeth, for example 3 teeth per pole and per phase.
• the electrical conductors of the stator windings can be arranged in the corresponding winding "in bulk", or on the contrary being “stored”.
• the windings can be made in the form of distributed windings, for example being distributed in multi-stages, with any number of layers. Such a configuration may be favorable to the reduction of space harmonics related to the winding distribution, as is often the practice in conventional topology machines.
• the electrical conductors of the stator windings can be made with son of circular cross section, or oblong, the conductor then being called "flat wire".
• the son used can be insulated at low voltage, being enamelled or even glazed gimped, or medium voltage, being isolated by mica paper for example, or even at very high voltage, being for example made with high voltage cable. Cooling of the windings can be achieved by the gas contained in the machine, for example air, in forced convection for example, or not, or alternatively by a liquid circulating in coils appropriately included in the windings, or even in the wires themselves windings, which can then be made with hollow electrical conductors.
• the stator may be without breech, or alternatively it may include a breech.
• the stator may comprise between 6 and 48 teeth, for example 12 teeth in one embodiment.
• the stator may comprise at least 6 teeth, for example 6, 12 or 18 teeth, or even more.
• the stator windings are preferably each wound around a winding axis parallel to the axis of rotation of the machine.
• the windings may comprise copper or aluminum wires, or any other electrically conductive material.
• the teeth of the stator may each be of substantially prismatic general shape, comprising in particular, in cross section taken perpendicular to the axis of rotation of the machine, two portions of concentric circles connected by two radii or alternatively two linear portions connected by two radii .
• the largest portion of the two linear or partially circular portions may be located towards the outside of the machine.
• the teeth of the stator may be of other shape, being for example rectangular.
• the axial length of a stator tooth, measured along the axis of rotation of the machine may be greater than the axial length of a winding measured along the axis of rotation of the machine.
• the windings of the stator may be of corresponding shape.
• the stator teeth have a front face facing the rotor. Said faces are preferably flat and extend perpendicular to the axis of rotation of the machine.
• stator teeth can be attached to an annular stator reinforcement
• the teeth can be made in one piece with this annular stator frame, or alternatively be held on by any means such as for example bonding, welding, screwing, assembly, for example by dovetails, this list being not limiting.
• the teeth may be formed of a stack of sheets, held together by any means such as for example gluing, latching, riveting and attached to the annular stator frame for example by screwing.
• the sheets can be stacked along a radial parallel stacking axis, this stack axis being perpendicular to the axis of rotation of the machine.
• the sheets used in the stack have a size that increases as one moves away from the axis of rotation of the machine.
• Cutting teeth in the sheet stack can be designed to reduce material losses. It is for example performed with the teeth oriented head to tail, so as to avoid falls. At equivalent cost, it can be used to make the teeth a more expensive magnetic material, for example of better quality and more efficient.
• the teeth may also be made of an isotropic material, such as, for example, magnetic powders agglomerated by sintering or gluing, amorphous magnetic materials, or by the addition of metal according to the so-called 3D printing methods.
• an isotropic material such as, for example, magnetic powders agglomerated by sintering or gluing, amorphous magnetic materials, or by the addition of metal according to the so-called 3D printing methods.
• the annular stator reinforcement is preferably non-magnetic. It is for example made of aluminum. Thus, the stator may be devoid of magnetic yoke, which is less expensive. In a variant, the annular stator reinforcement is not non-magnetic.
• the windings can be wound on a support intended to be itself threaded on the corresponding tooth.
• This support is preferably made of electrical insulating material, for example plastic.
• the machine may comprise a single stator and a single rotor.
• the machine may comprise at least two rotors disposed on either side of the stator along the axis of rotation X of the machine.
• the two rotors surrounding the stator may be angularly offset relative to each other, or not.
• the two rotors may be symmetrical with respect to a plane perpendicular to the axis of rotation of the machine.
• the stator teeth may each carry two coils disposed on the corresponding tooth on either side of the annular stator reinforcement, each of the two coils facing one of the two rotors.
• the teeth of the stator can in particular be attached in their middle to said annular stator reinforcement.
• the two resulting half-teeth may be of the same size, as well as the windings they carry.
• the stator may be symmetrical with respect to a plane perpendicular to the axis of rotation of the machine.
• the machine may comprise two stators and a central rotor.
• the machine may comprise several stators and several rotors, as described below.
• the machine can constitute a synchronous motor or a synchronous generator
• the machine according to the invention can constitute a motor.
• the number of poles of the machine can be at least 4, being for example 4, 6, 8 or 12.
• One of the advantages of such a machine is its compactness.
• the machine can also be a generator. In this case, it may have 4 or 6 poles for example. In an alternative embodiment, the machine comprises for example 4 poles and 6 teeth.
• the ventilation of the machine can be forced by suction of air into the machine. This aspiration can be done by the middle of the machine, especially when it comprises two rotors arranged on either side of the stator.
• FIG. 1 Another subject of the invention is a rotating electrical machine comprising a plurality of assemblies as described above, each consisting in particular of a stator and two rotors disposed on a common axis of rotation.
• Such a machine comprises for example two assemblies each consisting in particular of a stator and two rotors, or even more, for example three or four sets, or even more, depending on the desired electrical or mechanical power.
• the invention particularly relates to a machine comprising three assemblies according to the invention, each consisting in particular of a stator and two rotors arranged on a common axis of rotation, in which the windings of the stators are three-phase, with one phase per stator .
• FIG. 1 is a diagrammatic and partial perspective view of a machine produced according to the invention
• FIG. 2 is a view along the arrow II
• FIG. 3 is a detail view, schematic and partial, along the axis of rotation X, of the stator of FIG. 1;
• FIG. 4 is a view similar to FIG. 2 of an alternative embodiment, with a distributed winding stator
• FIG. 5 is a schematic and partial perspective view of the rotor of FIG. 1,
• FIG. 6 is a view in section parallel to the axis of rotation X
• FIG. 7 is an exploded perspective view of the magnets of a pole of the rotor
• FIGS. 8a to 8c are views similar to FIG. 5 of variant embodiments.
• FIG. 9 is a view similar to FIG. 6 of an alternative embodiment
• FIGS. 10a, 10b, 11 to 13 are views similar to FIG. 5 of variant embodiments.
• Figure 14 is a view similar to Figure 6 of another embodiment.
• FIGS. 1 to 3 and 5 to 7 illustrate a rotary electrical machine 10 according to the invention, comprising a stator 20 and two rotors 40, disposed respectively on either side of the stator 20 along the axis of X rotation of the machine.
• the stator has teeth 21 and coils 22 arranged on the teeth 21.
• the coils 22 are each wound around a winding axis Y parallel to the axis of rotation X of the machine.
• the teeth 21 of the stator 20 each comprise a face 23 facing one of the two rotors 40.
• the faces 23 are flat and extend perpendicular to the axis of rotation X of the machine.
• the stator comprises in the example described 12 teeth, but could include 6 or 8, or even more.
• the stator is symmetrical with respect to a median plane for the stator, perpendicular to the axis of rotation X of the machine.
• the stator 20 is devoid of a cylinder head.
• the teeth 21 are configured such that they exceed windings of a distance d.
• the teeth 21 are delimited when observed along the X axis by two portions 21a and 21b connected by two spokes 21c, as can be seen in Figure 3.
• the coils 22 are of corresponding shape.
• the stator is concentrated winding. It is not beyond the scope of the present invention if it is otherwise.
• the stator may for example be distributed winding, as shown in Figure 4.
• the number of teeth and notches per pole and per phase is 3.
• the two rotors surrounding the stator are in the described example arranged face to face, being non-angularly offset relative to each other.
• the rotors could also be angularly offset relative to each other, in particular to minimize torque ripples.
• Each of the two rotors 40 comprises a rotor magnetic mass 41 comprising housings 42, able to receive any permanent magnets 43, and a shaft 50 extending along the axis of rotation X, on which the rotor mass 41 is arranged, as illustrated in FIG. Figure 1.
• Housing 42 of a rotor defines a magnetic pole of the rotor.
• a magnetic pole of the rotor is defined by housings of generally cylindrical shape of revolution, in particular three cylindrical housings concentric with each other.
• Each housing has a cylindrical portion 42a and a disc bottom portion 42b.
• the housing thus has a general shape of pot.
• the magnetic mass 41 of the rotor may comprise magnetic portions 41 'not integral with the rest of the magnetic mass, which are arranged between the different housings of the same pole.
• a housing thus having a length L measured along the axis of rotation of the machine, and may have a thickness e.
• all the housings 42 are filled with permanent magnets 43, as illustrated.
• the permanent magnets of a magnetic pole of the rotor comprises a tubular portion 43a housed in the cylindrical portion 42a of a housing 42, and a discoid portion 43b housed in the discoid bottom portion 42b of the housing 42.
• Each of the rotors 40 further includes a yoke 45 on the side opposite the gap.
• the housings are, when observed in a plane perpendicular to the axis of rotation of the machine, of generally circular shape. It is not beyond the scope of the present invention if it is otherwise.
• the housings can be for example, when observed in a plane perpendicular to the axis of rotation of the machine, of other general shape, for example square, as shown in Figure 8a, triangular, as shown in Figure 8b, or still having two slots converging towards the axis of rotation of the machine, as shown in Figure 8c. It can be seen in FIG. 8c that the housings are U-shaped when observed perpendicularly to the axis of rotation of the machine. The U are oriented towards the gap.
• the housings can be V-shaped, when observed in a section plane which contains the axis of rotation X, as shown in Figure 9.
• the V are also oriented towards the air gap.
• the housings 42 are filled with permanent magnets 43. It is not beyond the scope of the present invention if the housings are devoid of permanent magnets.
• FIG. 10a illustrates such an exemplary embodiment in which all the housings 42 are empty of magnets
• FIG. 10b an exemplary embodiment in which the rotor comprises a first magnetic pole and a second magnetic pole adjacent to the first magnetic pole, the first and second magnetic poles being of different polarity, the specific housings of the first magnetic pole being devoid of permanent magnets and housings of the second magnetic pole having one or more permanent magnets.
• the housings 42 are open towards the gap. It is not beyond the scope of the present invention if it is otherwise, and if the housings are closed on the air gap side by a magnetic overlap portion 46, which can be formed in one piece with the rest of the rotor magnetic mass, as illustrated in Figure 11, or reported thereon, as shown in Figure 12, and maintained for example by gluing.
• the magnetic covering portion 46 may be made of the same material as the rotor magnetic mass, or in a different material. This magnetic portion of recovery then constitutes a tangential bridge at the gap for the circulation of the magnetic flux.

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• Engineering & Computer Science (AREA)
• Power Engineering (AREA)
• Permanent Field Magnets Of Synchronous Machinery (AREA)
• Iron Core Of Rotating Electric Machines (AREA)
• Permanent Magnet Type Synchronous Machine (AREA)

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• 2017
  • 2017-02-24 FR FR1751473A patent/FR3063400B1/fr active Active
• 2018
  • 2018-02-14 WO PCT/EP2018/053635 patent/WO2018153738A1/fr unknown
  • 2018-02-14 US US16/488,870 patent/US11569717B2/en active Active
  • 2018-02-14 CN CN201880013703.4A patent/CN110337769A/zh active Pending
  • 2018-02-14 EP EP18704026.6A patent/EP3586426A1/fr active Pending

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