Classifications

• • H—ELECTRICITY
  • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
  • H02K—DYNAMO-ELECTRIC MACHINES
  • H02K3/00—Details of windings
  • H02K3/04—Windings characterised by the conductor shape, form or construction, e.g. with bar conductors
  • H02K3/12—Windings characterised by the conductor shape, form or construction, e.g. with bar conductors arranged in slots
• • H—ELECTRICITY
  • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
  • H02K—DYNAMO-ELECTRIC MACHINES
  • H02K3/00—Details of windings
  • H02K3/04—Windings characterised by the conductor shape, form or construction, e.g. with bar conductors
  • H02K3/28—Layout of windings or of connections between windings
• • H—ELECTRICITY
  • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
  • H02K—DYNAMO-ELECTRIC MACHINES
  • H02K3/00—Details of windings
  • H02K3/46—Fastening of windings on the stator or rotor structure
  • H02K3/50—Fastening of winding heads, equalising connectors, or connections thereto
  • H02K3/505—Fastening of winding heads, equalising connectors, or connections thereto for large machine windings, e.g. bar windings

Definitions

• the present invention relates to rotating electrical machines and more particularly to the stators of such machines.
• the invention relates more particularly to synchronous or asynchronous machines with alternating current. It relates in particular to traction or propulsion machines for electric motor vehicles (Battery Electric Vehicle) and / or hybrids (Hybrid Electric Vehicle - Plug-in Hybrid Electric Vehicle), such as passenger cars, vans, trucks or buses.
• the invention also applies to rotating electrical machines for industrial and / or energy production applications, in particular naval or wind turbines.
• the notches are semi-open, and house U-shaped electrical conductors, the electrical conductors being distributed between two sets of independent coils on four layers, two layers per set of coils.
• the conductors of two different coil sets are not electrically connected together in the stator.
• the connections between the phases are made outside the stator, in a terminal box.
• the stator has a number of notches per pole and per fractional phase.
• the stator yoke has fully open or semi-open notches in the direction of the air gap, so as to allow the introduction of the conductors of the windings.
• the semi-open slots receive electrical conductors of circular cross section arranged in bulk, while the fully open slots accommodate electrical conductors of rectangular cross section, arranged in a row.
• the patent application US 2010/001609 relates to a stator in which the slots are closed, and receive U-shaped electrical conductors of rectangular section, which are each connected to a conductor of the adjacent slot, in order to form a series winding corrugated. The winding is not fractional.
• U-shaped electrical conductors are twisted and then stacked on top of each other.
• a stator of a rotating electric machine comprising a stator mass comprising notches, electrical conductors being housed in the notches, at least. a part of the electrical conductors, or even a majority of the electrical conductors, being in the shape of a U-shaped pin, each comprising first and second legs extending axially respectively in first and second notches, each electrical conductor comprising several strands, the strands of the first leg of an electrical conductor being disposed in the first notch in a radially reverse order of the strands of the second leg of the same electrical conductor in the second notch.
• U-shaped pin-shaped electrical conductors advantageously achieves a high slot fill coefficient, and thus a reduction in low frequency Joule losses.
• each electrical conductor comprising several strands, a reduction in losses by induced currents, or Joule AC losses, is obtained, which is particularly advantageous when the operating speed is high. This also facilitates heat transfer to the cold source.
• the first and second notches can be non-consecutive. We can speak of the outward notch and the return notch respectively.
• the first and second notches can be separated by a number of notches between 3 and 20, better still between 6 and 16, being for example 7 or 8, or 10 or 11 notches.
• each notch can accommodate a single single electrical conductor.
• the electrical conductors form an entire winding, not fractional.
• each notch can accommodate at least a first and a second electrical conductor, the first leg of the first electrical conductor being disposed radially in the first notch in a first layer at a first radial position, and the second leg of the same first electrical conductor. being disposed radially in the second notch in a second layer at a second radial position different from the first radial position.
• each notch accommodates a first and a second electrical conductor, on two layers.
• each notch can accommodate two layers of two electrical conductors each, that is, four electrical conductors distributed over two layers. In this case, we can have both a reverse order of the strands of the same electrical conductor, and a layer change between the first and second legs of the electrical conductor.
• Each notch can accommodate two layers of two electrical conductors each, the relative positions of the two electrical conductors of the same layer being swapped between the first and second notches.
• a coil is made up of a number of phases m spatially shifted in such a way that when supplied by a multi-phase current system, they produce a rotating field.
• the electrical conductors can form a single coil, in particular whole or fractional.
• single winding is meant that the electrical conductors are electrically connected together in the stator, and that the connections between the phases are made in the stator, and not outside the stator, for example in a terminal box. .
• the electrical conductors can form a distributed coil.
• the winding is not concentrated or wound on tooth.
• the winding is in the invention whole or fractional.
• the winding can be full in pitch with or without shortening, or in a fractional variant.
• the electrical conductors form a fractional coil, in particular with a shortened pitch.
• the number of notches in the stator can be between 18 and 96, better still between 30 and 84, being for example 18, 24, 27, 30, 36, 42, 45, 48, 54, 60, 63, 72, 81 , 92, 96, better still being 60 or 63.
• the number of poles of the stator can be between 2 and 24, or even between 4 and 12, being for example 6 or 8.
• the combination of number of notches / number of stator poles can be chosen from the combinations of the following list, which is not restrictive: 30/4, 42/4, 45/6, 63/6, 60/8, 84/8.
• the number of phases is in this case three, but it does not depart from the scope of the present invention if the number of phases is different, being for example two, the machine then comprising a two-phase winding, or being for example 5 , 6 or 9.
• le0 coil is polyphase.
• Torque ripples and magnetic forces which depend on the spectrum of the induction in the air gap, are the main sources of electromagnetic noise5. This noise is manifested on the one hand by the torque ripples which interact with the transmission system and on the other hand by the magnetic forces which apply to the stator of the machine which can, depending on their amplitudes and their frequencies , excite the eigen modes of the machine, and therefore make it resonate.
• harmonics of magnetic forces and torque ripple which are at the source of these phenomena are due to the spatial harmonics of notches. These harmonics arise from the variation of the air gap permeance which depends on the notch opening and the discrete distribution of the magnetomotive force.
• the permeance spectrum is rich in harmonics, which increases the harmonic rate of the forces.
• magnetic; the stator yoke can then be more the subject of resonance problems since its rigidity is all the less if the notch opening is larger.
• fractional winding allows to reduce the harmonic content of the magnetomotive force in the air gap, thus reducing the torque ripples and the amplitudes of the radial and tangential magnetic pressures.
• the electrical conductors can be placed in series in a so-called corrugated winding or in a so-called nested winding.
• corrugated winding is understood to mean a winding in which the electrical conductors of the same phase and of the same pole are electrically connected to each other so that, for a winding path, the electric current of the phase circulates in the electrical conductors, rotating around the axis of rotation of the machine, always in one direction.
• the electrical conductors of the same phase and the same pole do not overlap when observed perpendicular to the rotation rate of the machine.
• nested winding is meant a winding in which the electrical conductors of the same phase of the same pole are electrically connected to one another so that the electric current of the phase flows through the electrical conductors in rotating around the axis of rotation of the machine alternately in one direction then in the other.
• the electrical conductors of the same phase and the same pole overlap when observed perpendicular to the axis of rotation of the machine.
• the winding can have a single winding path or several winding paths.
• electrical conductor flows the current of the same phase by winding.
• winding path is meant all the electrical conductors of the machine which are traversed by the same electric current of the same phase.
• These electrical conductors can be connected to each other in series or in parallel or in series-parallel. In the case where there is only one channel, the electrical conductors are connected in series. In the case where there are several channels, the electrical conductors of each channel are connected in series, and the channels are connected in parallel.
• each notch there can be one or more layers.
• layer denotes the series conductors belonging to the same phase arranged in the same notch.
• electrical conductors of the same phase In each layer of a notch, there are electrical conductors of the same phase.
• the electrical conductors of a stator can be distributed in one layer or in two layers. When the electrical conductors are distributed in a single layer, each notch only accommodates electrical conductors of the same phase.
• the electrical conductors can be divided into only two layers.
• one or more notches can house electrical conductors of two different phases. This is always the case for a winding with shortened pitch.
• the coil may not have more than two layers. In one embodiment, it is notably devoid of four layers. At least a first electrical conductor housed in a first notch can be electrically connected to a second electrical conductor housed in a second notch, at the outlet from said notches.
• electrically connected is meant any type of electrical connection, in particular by welding, with different possible welding methods, in particular laser, induction, friction, ultrasound, vibrations, or brazing, or by mechanical clamping, in particular by crimping, screwing or riveting for example.
• the first and second notches are preferably non-consecutive.
• the first and second electrical conductors can be electrically connected to the output of the first and second notches, that is to say that the electrical connection is formed on the electrical conductors just after their exit from the two notches, at an axial end of the stator mass.
• the electrical connection can be made in a plane perpendicular to the axis of rotation of the machine.
• the plane of the electrical connection can be away from the stator mass by less than 60 mm, better still less than 40 mm, for example 27 mm or 38 mm approximately.
• a majority of the electrical conductors housed in a first notch can each be electrically connected to a respective second electrical conductor housed in a second notch, at the exit from said notches.
• At least one notch, better still a majority of the notches, or even more than half of the notches, better still more than two-thirds of the notches, or even all the notches, may comprise first electrical conductors each electrically connected to a respective second electrical conductor housed in a second notch, at the exit of said notches.
• all the electrical conductors having a free end located at the same circumferential position around the axis of rotation of the machine, regardless of their radial position, are electrically connected together.
• the first and second electrical conductors can each have an oblique portion.
• the oblique portions may extend in a circumferential direction, around the axis of rotation of the machine.
• the two oblique portions can be configured to converge towards each other and thus allow the electrical connection to be made.
• An electrical conductor can have two oblique portions, one at each of its two ends.
• the two oblique portions of the same electrical conductor can extend in opposite directions. They can diverge from each other. They can be symmetrical with respect to each other.
• a majority of the electrical conductors can include one or more oblique portions as described above.
• the electrical conductors can be arranged in the notches in a distributed manner.
• distributed it should be understood that the outgoing and return electrical conductors are each housed in different and non-consecutive notches. At least one of the electrical conductors can pass successively through two non-consecutive notches.
• the electrical conductors can be arranged in a row in the notches.
• row is meant that the electrical conductors are not arranged in the slots in bulk but in an orderly manner. They are stacked in the notches in a non-random manner, being for example arranged in a row of electrical conductors aligned in the radial direction.
• the electrical conductors may have a generally rectangular cross section, in particular with rounded edges.
• the circumferential dimension of an electrical conductor can correspond substantially to the width of a notch.
• a notch may have only one electrical conductor in its width.
• the width of the notch is measured in its circumferential dimension around the axis of rotation of the machine.
• Electrical conductors can be adjacent to each other by their long sides, otherwise called the flat.
• Optimization of the stack can allow a greater quantity of electrical conductors to be placed in the slots and thus obtain a stator of greater power, at constant volume.
• Each notch can include two to 36 electrical conductors, in particular two to 24, better still 2 to 12 electrical conductors.
• Each notch may include two to eight electrical conductors, in particular two to four electrical conductors, for example two or four electrical conductors.
• each notch has two electrical conductors.
• each notch has four electrical conductors.
• Pins Electrical conductors at least, see a majority of electrical conductors, can be in the shape of pins, U or I.
• the pin can be U-shaped ("U-pin” in English) or straight, being in form of I ("I-pin” in English).
• the hairpin and flat electrical conductors increase the fill factor of the slot, making the machine more compact. Thanks to a high filling coefficient, the thermal exchanges between the electrical conductors and the stator mass are improved, which makes it possible to reduce the temperature of the electrical conductors inside the slots.
• the manufacture of the stator can be facilitated by the electrical conductors in the form of pins.
• the winding with pins can be easily changed by changing only the connections between the pins at the coil heads.
• Electrical conductors extend axially into the notches.
• the electrical conductors can be introduced into the corresponding notches through one or both axial ends of the machine.
• An I-shaped electrical conductor has two axial ends each placed at one of the axial ends of the stator. It passes through a single notch, and can be welded at each of its axial ends to two other electrical conductors, at the axial ends of the stator.
• the stator may for example comprise six or twelve electrical conductors in the shape of an I, the other electrical conductors possibly all being in the shape of a U.
• a U-shaped electrical conductor has two axial ends both placed at one of the axial ends of the stator. It passes through two different slots, and can be welded at each of its axial ends to two other electrical conductors, at the same axial side of the stator. The bottom of the U is on the other axial side of the stator.
• each electrical conductor has several strands (“wire” or “strand” in English).
• strand is meant the most basic unit for electrical conduction.
• a strand can be of round cross section, then we can speak de'fil ', or flat.
• the flattened strands can be shaped into pins, for example U or I.
• Each strand is coated with an insulating enamel.
• each notch can include several conductors and / or several strands makes it possible to minimize losses by induced currents, or Joule AC losses, which vary with the square of the supply frequency, which is particularly advantageous at high frequency and when the operating speed is high. It is thus possible to obtain better efficiency at high speed.
• the presence of the closed notches can make it possible to obtain a reduction in the flow of leaks seen by the conductors, which results in a decrease in eddy current losses in the strands.
• each electrical conductor may include several pins, each forming a strand, as explained above. All strands of the same electrical conductor can be electrically connected to each other at the exit of the notch. The strands electrically connected to each other are placed in short circuit. The number of strands electrically connected together may be greater than or equal to 2, being for example between 2 and 12, being for example 3, 4, 6 or 8 strands.
• Several strands can form the same electrical conductor.
• the same electric current of the same phase flows through all strands of the same electrical conductor.
• All the strands of the same electrical conductor can be electrically connected to each other, especially at the exit of the notch.
• All the strands of the same electrical conductor can be electrically connected to each other at each of their two axial ends, in particular at the exit from the notch. They can be electrically connected in parallel.
• each electrical conductor has three strands.
• a notch can therefore accommodate six strands, for example, distributed between the two electrical conductors.
• a notch has four electrical conductors. Each electrical conductor can have two strands. The notch then accommodates eight strands, distributed between the four electrical conductors.
• the strands of the same electrical conductor can be in contact in pairs over their entire length. They can in particular be in contact at the level of the coil heads. In addition, they can in particular be in contact at the weld ends. They can be contiguous. In one embodiment, the strands may be welded in pairs of three strands. Such a configuration allows good optimization of the space available in and around the stator. We gain in particular in compactness at the level of the height of the buns. In addition, the risk of short circuits between electrical conductors can be reduced.
• the strands can be positioned in the notch so that their circumferential dimension around the axis of rotation of the machine is greater than their radial dimension. Such a configuration allows a reduction in the losses by eddy currents in the strands.
• a strand may have a width of between 1 and 5 mmm, being for example of the order of 2.5 or 3 mm.
• the width of a strand is defined as its dimension in the circumferential direction around the axis of rotation of the machine.
• a strand can have a height of between 1 and 4 mm, being for example of the order of 1, 6 or 1, 8 mm.
• the height of a strand is defined as its thickness in the radial dimension.
• a ratio of the width of a strand to its height can be between 1 and 2.5, better still between 1.2 and 2, or even between 1.4 and 1.8, being for example 1.56 or 1 , 66. Such a ratio allows a reduction in eddy current losses in the strands.
• the electrical conductors can be made of copper or aluminum.
• the electrical conductors are electrically insulated from the outside by an insulating coating, in particular an enamel.
• the electrical conductors can be separated from the walls of the notch by an insulator, in particular by at least one insulating sheet. Such a sheet insulation allows better insulation of the electrical conductors with respect to the stator mass.
• the use of closed notches can make it possible to improve the retention of the insulators around the electrical conductors in the notches. Partially closed or fully closed notches
• the notches can be at least partially closed.
• a partially closed notch makes it possible to provide an opening at the level of the air gap, which can be used, for example, for the installation of the electrical conductors for filling the notch.
• a partially closed notch is in particular formed between two teeth which each have pole shoes at their free end, which close the notch at least in part.
• the notches can be completely closed.
• “fully closed notch” is meant notches which are not open radially towards the air gap.
• the notches can be closed on the air gap side with a magnetic band.
• the hoop can be attached to the teeth on the air gap side.
• the magnetic hoop can preferably have the same magnetic permeability as the stator. It can in particular be made of the same material as the stator mass. It may be generally annular in shape and disposed in the air gap. It forms bridges of material between the teeth, which close the notches on the side of the air gap. These bridges of material are not integral with the teeth defining the notch.
• This magnetic hoop can in particular be in one piece over the entire circumference of the stator. It can be formed from a stack of rolled sheets.
• the magnetic hoop may have at least one localized constriction formed by at least one groove.
• the hoop may in particular include at least one groove per bridge of material closing a notch, said grooves being able to be placed in front of each of the notches.
• stator does not have an added hoop serving to close the notches.
• Each of the notches may have a continuously closed contour.
• At least one notch, or even each notch can be continuously closed on the side of the air gap by a bridge of material formed in one piece with the teeth defining the notch. All the notches can be closed on the side of the air gap by material bridges closing the notches. The bridges of material can be formed in one piece with the teeth defining the notch. The stator mass is then without any cutout between the teeth and the bridges of material closing the notches, and the notches are then continuously closed on the side of the air gap by the bridges of material coming in one piece with the teeth defining the notch.
• the notches can also be closed on the side opposite the air gap by an attached cylinder head or integrally with the teeth. The notches are then not open radially outwards.
• the stator mass may have no cutout between the teeth and the cylinder head.
• each of the notches has a continuously closed contour.
• continuously closed it is meant that the notches have a continuous closed contour when viewed in cross section, taken perpendicular to the axis of rotation of the machine. You can go all the way around the notch without encountering a cutout in the stator mass.
• closed notches makes it possible to improve the performance of the electric machine in terms of the quality of the magnetic field in the air gap, by minimizing the harmonic content and the losses by eddy currents in the electrical conductors, and the leakage fluxes in the air gap. the notches, as well as the fluctuations of the magnetic field in the air gap and heating of the machine.
• the closed notches make it possible to have a closed cylindrical air gap, to reduce the leakage flow in the notches, which makes it possible to reduce the AC losses in the stator winding. The battery life is therefore extended thanks to the increased efficiency of the machine due to the reduction in AC losses.
• the presence of these closed notches improves the mechanical rigidity of the stator, mechanically strengthening the stator and reducing vibrations.
• the reduction of vibrations can help make the operation of the machine quieter, which can be particularly advantageous when the stator is intended to be associated with a gearbox system.
• closing the notch can reduce the parasitic capacitance between the stator windings and the rotor, which reduces leakage currents and can eliminate the need for drain rings or brushes. tree currents.
• the stator mass can be produced by stacking magnetic sheets, the notches being formed by cutting the sheets.
• the stator mass can also be produced by cutting from a mass of sintered or agglomerated magnetic powder. The closing of the notches on the side of the air gap is obtained by bridges of material coming in one piece with the rest of the sheets or of the block forming the stator mass.
• the stator according to the invention does not have any attached magnetic wedges for closing the notches. This eliminates the risk of accidental detachment of these wedges.
• the stator mass may include teeth formed between the notches, which are interconnected on the side of the air gap by material bridges.
• each notch is closed on the side of the air gap by a material bridge connecting between them two consecutive teeth of the stator mass.
• the material bridges each connect two teeth adjacent to their base on the air gap side and define the bottom of the notch between these teeth on the air gap side.
• the material bridges are integral with the adjacent teeth.
• the two consecutive teeth are connected on the opposite side by a yoke.
• the cylinder head can be made in one piece with the teeth.
• the stator can thus be without a yoke attached to a serrated crown.
• the absence of opening of the notches towards the air gap makes it possible to avoid producing electromagnetic disturbances, in particular an increase in the “magnetic” air gap due to the flux fringes, higher iron losses. at the rotor surface for the same reason, or alternatively pulsating torques, and radial forces, and Joule AC losses.
• the electromagnetic performance of the machine is improved.
• the bridges of material can be made so as to be magnetically saturated during machine operation. This limits the flow of flow from one notch to another without preventing the flow of flow from the rotor to the stator.
• the bridges of material are preferably undeformable. This increases the stiffness of the stator and improves the life of the electrical machine.
• the smallest width of the bridges of material is for example between 0.2 and 0.5 mm. It can be of the order of 0.35 mm for example.
• the width of the material bridge can be of the same order of magnitude as the thickness of the sheet.
• stator mass is in the form of stacked sheet metal, having teeth interconnected at their base on the side of the air gap by bridges of material.
• the bridges of matter came in one piece with the teeth.
• the bridges of material can each have at least one localized constriction formed by at least one groove.
• the section of the material bridge available for the passage of the flow can be locally reduced, for example by providing a groove.
• the grooves are open towards the notches.
• the bottom of the notches on the side of the material bridge has at least one bearing surface, better still at least two bearing surfaces, oriented transversely and the bottom of the groove is set back relative to this or these surfaces.
• the support surface (s) may be oriented obliquely with respect to the radial axis of the corresponding notch or oriented perpendicular to this axis.
• the groove forms a break in slope from the support surface (s).
• the electrical conductors, preferably of substantially rectangular section, inserted into the corresponding notch are preferably resting against the bearing surfaces and recessed from the bottom of the groove. Preferably, the electrical conductors are without contact with the groove.
• the support surface (s) are preferably flat.
• the bottom of the notch can be flat, except for the groove. This allows good filling of the notches by the electrical conductors in the case of electrical conductors of rectangular cross section, by allowing the coils to rest flat in the bottom of the notches.
• the groove in the bottom of the notch preferably forms a clearance between the material bridge and the corresponding electrical conductor.
• the material bridge may include at least two grooves as described above, for example two grooves per notch.
• the groove or grooves can be centered with respect to the notch or notches, or on the contrary be offset with respect to a plane of symmetry of the notch or notches.
• the groove or grooves each have a curved profile in section in a plane perpendicular to the axis of the stator, in particular of substantially semi-circular section.
• the bottom of the groove can be in the form of a circular arc, or of any other suitable shape, for example semi-elliptical or wavy.
• the internal surface of the stator is preferably cylindrical of revolution.
• At least one notch may be generally rectangular in cross section.
• At least one notch may include radial edges having a rib, each in particular a rib.
• the rib can improve the retention of electrical conductors in the notches.
• the rib can help minimize AC Joule losses.
• the rib may extend parallel to the axis of rotation of the machine.
• the rib can be placed in a central part of the radial edges, for example halfway between the bottom of the notch and the bridge of material closing it.
• at least one notch can comprise radial edges each having several ribs, for example two or three. This can be particularly useful in the case where the notch is intended to receive three, four, six or eight electrical conductors.
• the notch may have a rib between each of the layers of electrical conductors.
• the radial edges are rectilinear, being devoid of ribs.
• At least one notch may have opposite radial edges parallel to each other, better all the notches have radial edges parallel to each other.
• the width of a notch is preferably substantially constant over its entire height. There is thus a better filling rate of the notches.
• the radial edges of the notches are not parallel to each other.
• At least one notch can have a rectilinear, arcuate or other bottom.
• the bottom of the notch is the bottom of the notch located on the cylinder head side, opposite the material bridge and the air gap.
• At least one notch can have a ratio of the length of the notch to its width between 2 and 6, better between 3 and 4.
• the width of a notch corresponds to its dimension in the circumferential direction measured around the axis of rotation of the machine, and its length to its dimension in the radial direction.
• the stator may include a sensor for measuring the temperature of the electrical conductors, the sensor being arranged in the notch, for example a thermocouple.
• This sensor can be housed at least partly in the groove of the material bridge closing the notch.
• the sensor is for example housed in a space between the conductor closest to the material bridge and the material bridge.
• At least one tooth, better still all teeth may be generally trapezoidal in cross section. At least one tooth, better all teeth, may have divergent edges as one moves away from the axis of rotation of the machine.
• the stator mass can be produced by stacking sheets.
• the teeth are connected to each other by bridges of material, and on the opposite side by a cylinder head. Closed notches can be produced entirely by cutting from the sheets.
• Each sheet of the stack of sheets can be made in one piece.
• Each sheet is, for example, cut from a sheet of magnetic steel or containing magnetic steel, for example steel 0.1 to 1.5 mm thick.
• the sheets can be coated with an electrically insulating varnish on their opposite faces before they are assembled in the stack. Electrical insulation can still be obtained by heat treatment of the sheets, if necessary.
• stator mass can be made from compacted or agglomerated magnetic powder.
• Another subject of the invention is a rotating electrical machine, such as a synchronous motor or a synchronous generator, comprising a stator as defined above.
• the machine can be synchronous or asynchronous.
• the machine can be reluctance. It can constitute a synchronous motor.
• the maximum speed of rotation of the machine can be high, being for example greater than 10,000 rpm, better still greater than 12,000 rpm, being for example of the order of 14,000 rpm at 15,000 rpm. min, or even 20,000 rpm or 25,000 rpm.
• the maximum speed of rotation of the machine may be less than 100,000 rev / min, or even 60,000 rev / min, or even less than 40,000 rev / min, better still less than 30,000 rev / min.
• the rotating electric machine may include a rotor.
• the rotor can be permanent magnet, with surface magnets or buried.
• the rotor can be in flux concentration. It can include one or more layers of magnets arranged in I, U or Y. As a variant, it can be a wound rotor or squirrel cage, or a variable reluctance rotor.
• the diameter of the rotor may be less than 400 mm, better still less than 300 mm, and greater than 50 mm, better still greater than 70 mm, being for example between 100 and 200 mm.
• the rotor may have a rotor mass extending along the axis of rotation and disposed around a shaft.
• the shaft may include torque transmission means for rotating the rotor mass.
• the rotor may or may not be cantilevered.
• the machine can be inserted alone in a housing or inserted in a gearbox housing. In this case, it is inserted in a housing which also houses a gearbox.
• Another subject of the invention is a method of manufacturing a stator of a rotating electrical machine, in particular a stator as defined above, in which electrical conductors are placed in the notches of a stator mass of the stator by inserting them into the corresponding notches through one or both axial ends of the stator.
• At least one electrical conductor, or even a majority of the electrical conductors, introduced into the notches, are in the shape of a U-shaped pin. They can be shaped prior to their introduction into the notches. All the electrical conductors in the shape of a U-pin can be shaped, simultaneously or successively, then introduced into the stator mass simultaneously or successively.
• the shaping may include a first step of assembling the strands of the same electrical conductor.
• the shaping may include a second step of twisting the second leg of the electrical conductor relative to the first leg, at an angle of 180 °, in order to enable the strands of the first leg of the electrical conductor to be obtained. arranged in the first notch in a radially reverse order of the strands of the second leg of the same electrical conductor in the second notch, after introduction of the electrical conductor in the first and second notches.
• the same U-shaped electrical conductor can be placed in two different non-consecutive notches of the stator mass of the stator. If an electrical conductor is U-shaped, it can be soldered to two other electrical conductors on the same side of the machine.
• I-shaped electrical conductors can be connected together beforehand in two different non-consecutive notches of the stator mass of the stator.
• an electrical conductor is I-shaped, it can be soldered to two other electrical conductors on two opposite sides of the machine.
• all electrical conductors having a free end located at the same circumferential position around the axis of rotation of the machine can be electrically connected together, regardless of their radial position.
• Figure 1 is a perspective view, schematic and partial, of a stator made in accordance with the invention.
• FIG 2 is a perspective view, schematic and partial, of the stator of Figure 1.
• FIG 3 Figure 3 a detail view, in perspective, of the stator of Figure 1.
• Figure 4 shows in cross section, schematically and partially, the stator according to the invention.
• Figure 5 shows in cross section, schematically and partially, the stator mass of the stator according to the invention.
• Figure 6 illustrates the variation of the radial air gap field, in Tesla, as a function of the angular position in °.
• Figure 7 is a perspective view of an electrical conductor.
• Figure 8 is another perspective view of the electrical conductor of Figure 7.
• Figure 9 is a perspective view, schematic and partial, of the stator comprising the electrical conductor of Figures 7 and 8.
• Figure 10 is a perspective view of an electrical conductor.
• Figure 11 is another perspective view of the electrical conductor of Figure 10.
• Figure 12 is a perspective view, schematic and partial, of the stator comprising the electrical conductor of Figures 10 and 11.
• FIG 13 is a perspective view, schematic and partial, of the stator comprising the electrical conductors of Figures 10 and 11.
• Figure 14 shows in cross section, schematically and partially, the stator of Figure 13.
• Figure 15 shows in cross section, schematically and partially, an alternative embodiment.
• Figure 16 shows in cross section, schematically and partially, another variant embodiment.
• Figure 17 is a view similar to Figure 7 of an alternative embodiment.
• stator 2 of a rotating electrical machine 1 also comprising a rotor not shown.
• the stator is used to generate a rotating magnetic field to drive the rotating rotor, as part of a synchronous motor, and in the case of an alternator, the rotation of the rotor induces an electromotive force in the electrical conductors of the stator.
• the stator 2 comprises electrical conductors 22, which are arranged in notches 21 formed between teeth 23 of a stator mass 25.
• the notches 21 are closed.
• the notches 21 are closed on the side of the air gap by bridges of material 27, each connecting two consecutive teeth of the stator mass 25, and on the opposite side by a yoke 29.
• the latter and the teeth 23 are in one piece.
• the cylinder head 29 can be where applicable, traversed by longitudinal ribs of semi-circular section intended to house conduits for circulating a cooling liquid.
• the notches 21 are, in the examples described and as shown in Figure 5, with radial edges 33 parallel to each other, and are in section in a plane perpendicular to the axis of rotation of the machine of substantially rectangular shape.
• the bottom 35 of the notches 21 is of substantially complementary shape to that of the electrical conductors 22, with the exception of a groove 40, as can be seen in FIG. 5.
• the bottom 35 of the notches 21 is connected to the radial edges 33 by rounded edges 38.
• the groove 40 of each notch 21 is centered on the bottom of the notch 35 and extends along the axis of rotation of the machine. In an alternative embodiment not shown, the groove is not centered, or the bottom 35 has several grooves.
• the grooves 40 have, in section in a plane perpendicular to the axis, a rounded shape, in particular substantially semi-circular. They have a depth p of between 0.3 mm and 0.6 mm, for example equal to 0.5 mm.
• the presence of the grooves 40 leads to a localized narrowing of the bridges of material 27. Such a narrowing allows a magnetic saturation of the sheet for a lower magnetic flux along the bridge 27, which limits the passage of the magnetic flux.
• the smallest width / of the material bridges 27 is preferably between 0.2 mm and 0.5 mm, for example equal to 0.35 mm.
• the electrical conductors 22 are mostly pin-shaped, i.e. U or I, and extending axially into the notches.
• a first electrical conductor housed in a first notch is electrically connected to a second electrical conductor housed in a second notch, at the outlet from said notches.
• the first and second notches are non-consecutive. In the example shown, they are separated by 7 other notches. Alternatively, the first and second notches are separated by 3, 4, 5, 6, 8, 9, 10 or 11 other notches, for example.
• FIG. 3 shows the end surfaces 22a of the first and second electrical conductors intended to receive the electrical connection.
• the electrical connection is made in a plane perpendicular to the axis of rotation of the machine.
• the plan of the electrical connection can be separated from the stator mass by less than 40 mm, in particular by approximately 27 mm.
• the electrical connection is formed on the electrical conductors just after their exit from the two notches, at one axial end of the stator mass.
• the two conductors each have an oblique portion 22b, which converge towards each other.
• the electrical conductors are arranged in the notches in a distributed manner, and they form a distributed coil, which in the example described is fractional.
• the number of notches is 63.
• the number of stator poles is 6.
• the number of notches / number of stator poles combination is 63/6.
• FIG. 4 shows in isolation a one-phase coil in the case of a three-phase fractional winding.
• a coil is formed by the outgoing electrical conductors of the same phase passing through adjacent slots, and by the return electrical conductors of the same phase passing through adjacent slots.
• the electrical conductors 22 are arranged in a row in the notches 21, in a row of aligned electrical conductors.
• the electrical conductors may have a generally rectangular cross section, in particular with rounded corners. They are in the example described superimposed radially in a single row.
• the circumferential dimension of an electrical conductor corresponds roughly to the width of a notch.
• the notch has only one electrical conductor in its width. It can include several electrical conductors in its radial dimension. It has two in the example described.
• the electrical conductors 22 are made of copper or aluminum, or any other conductive material enamelled or coated with any other suitable insulating coating.
• Curve A illustrates this variation for a stator with closed slots according to the invention, and is presented in comparison with curve B which illustrates this variation for a stator with semi-slots. open, with an opening of 2 mm. It can be seen that the radial air gap field obtained with a stator according to the invention (curve A) is less rich in harmonics.
• a notch has two electrical conductors of different phases, and each electrical conductor has several pins, each forming a strand 32 within a notch.
• each electrical conductor has three strands 32. All the strands 32 of the same electrical conductor 22 are electrically connected to each other at the outlet of the notch, and to each of their two axial ends 22a.
• Each electrical conductor 22 is surrounded by an insulating sheet not visible in the figures, making it possible to insulate the electrical conductors of the walls 33 and 36 of the notch and the electrical conductors 22 of different phases between them within a notch.
• the winding of the machine illustrated in Figures 1 to 5 comprises electrical conductors of three different types, namely electrical I-connectors, electrical connectors called “belt", comprising a portion extending in a plane perpendicular to the axis of rotation of the machine. Finally, there are U-shaped electrical conductors. An example of such a U-shaped electrical conductor is illustrated in Figures 7 and 8.
• the electrical conductor 22 comprises a first leg 22e and a second leg 22 f, each intended to extend axially in a notch, namely respectively in a first notch A called the outward notch and in a second notch R called the return notch, as illustrated in figure 9 and in figure 14.
• the strands 32 of the first electrical conductor 22 are numbered from 1 to 3, and the strands of the second electrical conductors present in the notches A and R are numbered from 4 to 6.
• the wire noted 1 is located at the top of the outward notch and located at the bottom of the return notch.
• each notch housing in the example described a first and a second electrical conductor 22, the first leg 22e of the first electrical conductor is disposed radially in the first outward slot A in a first layer at a first radial position, and the second leg 22f of the same first conductor electrical 22 is disposed radially in the second return notch R in a second layer at a second radial position different from the first radial position.
• the conductors which are in the upper layer in the outward notch return to the lower layer in the return notch.
• U-shaped electrical conductors can have different lengths depending on the pitch of the winding, corresponding to the number of notches located between the outward and return notch. There may be standard U-shaped electrical conductors, as well as shortened U-shaped electrical conductors, and others elongated. The shape of the pins is the same regardless of their length.
• the U-shaped portion 22d of the U-shaped electrical conductor 22 is curved in order to allow the transposition of the strands and the change of layer.
• the curvature can be chosen in order to allow the installation of all the electrical conductors in the stator mass.
• the curvature can gradually extend over the entire portion of the electrical conductors outside the notches, as shown in Figures 7 and 8.
• FIGS. 10 to 13 have illustrated an exemplary embodiment in which the U-shaped electrical conductors have a curvature constricted in a central portion, the curvature extending in a radial plane containing the axis of rotation of machine, and perpendicular to a plane in which extend the adjacent non-curved portions of the electrical conductor.
• each notch can accommodate a single single electrical conductor.
• the electrical conductors form an entire winding, not fractional.
• each notch can accommodate two layers of two electrical conductors each, that is to say four electrical conductors distributed over two layers.
• FIG. 16 there is a coil with two layers and four conductors per slot, and two strands in each conductor.
• the illustrated coil is wavy.
• the first and second electrical conductors each have an oblique portion 22b, which extend in a circumferential direction, around the axis of rotation of the machine, converging towards each other.
• the coil is not corrugated but nested for example.
• the first and second electrical conductors each have an oblique portion 22b, which extend in a circumferential direction, around the axis of rotation of the machine, diverging from each other, as illustrated in FIG. 17.
• the ends may cross for the nested coil, which is not the case for the corrugated coil.
• the stator mass 25 is formed from a bundle of magnetic sheets stacked along the axis of rotation, the sheets being for example identical and exactly superimposed. They can be held together by clipping, gluing, rivets, tie rods, welds and / or any other technique.
• the magnetic sheets are preferably made of magnetic steel.
• the teeth 23 of the stator mass 25 may have complementary surface reliefs making it possible to clip the various sheets making up the stator mass 25 together.
• the stator can be obtained by means of a manufacturing process in which the electrical conductors 22 are inserted into the notches 21 by one or both axial ends of the stator, by sliding in the notches 21 along an axis parallel to the stator. longitudinal axis.
• all the electrical conductors having their free end located at the same circumferential position around the axis of rotation of the machine are electrically connected together, regardless of their radial position.
• the invention is not limited to the embodiments which have just been described, and the rotor associated with the stator described can be wound, with a squirrel cage or with permanent magnets, or else with variable reluctance.

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• Engineering & Computer Science (AREA)
• Power Engineering (AREA)
• Windings For Motors And Generators (AREA)
• Insulation, Fastening Of Motor, Generator Windings (AREA)

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• 2019
  • 2019-02-28 FR FR1902072A patent/FR3093386B1/fr active Active
• 2020
  • 2020-02-25 CN CN202080017423.8A patent/CN113646995A/zh active Pending
  • 2020-02-25 EP EP20713724.1A patent/EP3931947A1/de active Pending
  • 2020-02-25 WO PCT/FR2020/050361 patent/WO2020174179A1/fr unknown
  • 2020-02-25 US US17/426,623 patent/US20220103038A1/en active Pending

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