Rotating electric machine stator with asymmetrical winding
Patent Information
- Application Number
- FR2019013234
- Authority / Receiving Office
- FR · FR
- Patent Type
- Patents
- Current Assignee / Owner
- Filing Date
- 2019-11-26
- Publication Date
- 2025-03-14
- Estimated Expiration
- 2039-11-26
Smart Images
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Abstract
Description
Title of the invention: Stator of a rotating electrical machine with asymmetrical winding
[0001] The present invention relates to rotating electrical machines and more particularly to the stators of such machines. Technical field
[0002] The invention relates more particularly to synchronous or asynchronous alternating current machines. It relates in particular to traction or propulsion machines for electric (Battery Electric Vehicle) and / or hybrid (Hybrid Electric Vehicle - Plug-in Hybrid Electric Vehicle) motor vehicles, such as individual cars, vans, trucks or buses. The invention also applies to rotating electrical machines for industrial and / or energy production applications, in particular naval, aeronautical or wind power applications.
[0003] There is a need to benefit from a rotating electrical machine stator that is easy to assemble and allows efficient filling of the slots, while ensuring satisfactory electromagnetic performance.
[0004] There is still a need to reduce the manufacturing cost of electrical machines, in particular by simplifying the stator winding, for example by minimizing the number of parts to be used.
[0005] There is also a need to further improve the stators of electrical machines and in particular to reduce torque ripples and AC Joule losses due to induced currents, vibrations and electromagnetic noise. Stator Invention Statement
[0006] The invention aims to meet all or part of these needs and it achieves this, according to one of its aspects, by means of a stator of a rotating electrical machine, comprising a stator mass comprising notches arranged between teeth, electrical conductors being housed in the notches, at least a portion 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 A and second R notches, at least one of the first and second legs of the electrical conductors extending outside the notches by a welded portion inclined relative to a plane perpendicular to a longitudinal axis of the stator to overhang the stator mass circumferentially at the level of a notch or a tooth,this notch or tooth being separated from the first A or the second R notch respectively by a number N1 and / or N2 of, teeth, at least a portion of the electrical conductors each having an innermost welding portion relative to the longitudinal axis of the stator, or even a majority, better all the electrical conductors each having an innermost welding portion relative to the longitudinal axis of the stator, said innermost welding portions being inclined with the same inclination relative to the plane perpendicular to the longitudinal axis of the stator.
[0007] The numbers NI and N2 can be equal or different.
[0008] The first A and second R notches are separated by a number Nd of teeth.
[0009] The number Nd of teeth is preferably the same for all the conductors U-shaped electrical conductors of the stator. We can also speak of the number Nd of pitch teeth of an electrical conductor, which in the invention is the same for all the electrical conductors of the stator which are U-shaped. This facilitates the manufacture of the U-shaped pins, and simplifies the step of positioning them in the stator mass, in particular their insertion.
[0010] Given the constant spacing between the legs of all the electrical conductors, the invention makes it possible to reduce the height of the buns on the side opposite the welds, which is advantageous for minimizing the size of the machine and the quantity of material, in particular copper, required for the electrical conductors. This results in a better compactness of the stator, including when it is assembled, and therefore of the resulting machine, which can in particular be shorter. The rotor shaft can be shorter, the casing can be shorter, the integration of the machine into its environment of use can be facilitated. Finally, the overall mass of the machine can be minimized.
[0011] On the other hand, the spacing between each of the buns is more regular, which can make it possible to minimize the risks of contact between them, and thus to eliminate the step of covering them with an insulator.
[0012] Furthermore, the invention makes it possible to reduce the number of pin shapes to be used in the same stator. Thus, the manufacture of the stator can be accelerated, with fewer manufacturing steps. This simplifies manufacturing, the space required and the tooling to be used.
[0013] Finally, the invention makes it possible to free up space on either side of the pins at the outlet of the notch, which can make it possible to position the connections to the other phases or to an inverter, in particular on the side of the stator yoke. The spacing between the pins at the outlet of the notch can be, in one embodiment, constant or substantially constant. This can facilitate the production of welds on the one hand, and the cooling of the electrical conductors on the other hand.
[0014] In the invention, NI can vary from Nd / 2 - 0.5 to Nd teeth, and N2 can vary from 0 to Nd / 2 +1.5 teeth.
[0015] In an exemplary embodiment, NI is equal to Nd or Nd + 1 and N2 is equal to 0 or 1.
[0016] In another exemplary embodiment, NI and N2 are equal or nearly equal. NI and N2 can each be equal to one of Nd / 2 or Nd / 2 + 0.5 or Nd / 2 - 0.5 or Nd / 2 + / - 1 or Nd / 2 + 1.5.
[0017] In one embodiment, the welding portion of the second leg of the electrical conductor is aligned with it. In this case, N2 is zero.
[0018] In the other cases where N2 is non-zero, each of the first and second legs of the electrical conductors can extend outside the notches by a welding portion inclined relative to a plane perpendicular to a longitudinal axis of the stator to overhang the stator mass circumferentially at the level of a notch or a tooth, this notch being separated from the first A or the second R notch respectively by a number NI and N2 of teeth, the numbers NI and N2 possibly being equal or different.
[0019] When NI and N2 are equal or nearly equal, the compactness of the stator can be further improved.
[0020] The two welding portions of each of the first and second legs of the electrical conductors may be oriented away from each other, which may in particular be the case when the winding is corrugated. Alternatively, they may be oriented in the same direction, which may in particular be the case when the winding is nested.
[0021] The invention also relates, according to another of its aspects, to a stator of a rotating electrical machine, comprising a stator mass comprising notches, electrical conductors housed in the notches, at least a portion 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 A and second R notches, the first A and second R notches being separated by a number Np of notches. The number Np of notches is the same for all the U-shaped electrical conductors of the stator.
[0022] We can also speak for the number Np of pitch notches of an electrical conductor, which is in the invention the same for all the electrical conductors of the stator which are in the form of a U-shaped pin. This makes it easier to manufacture the U-shaped pins, and simplifies the step of positioning them in the stator mass, in particular their insertion.
[0023] At least one of the first and second legs of the electrical conductors may extend out of the notches by a welding portion inclined relative to a plane perpendicular to a longitudinal axis of the stator to overhang the stator mass circumferentially at the level of a notch, this notch being separated of the first A or the second R notch respectively by a number NI and / or N2 of teeth. The numbers NI and N2 can be equal or different.
[0024] In one embodiment, NI may vary from Np / 2 - 0.5 to Np notches, and N2 may vary from 0 to Np / 2 + 0.5 notches. In one exemplary embodiment, NI is equal to Np and N2 is equal to 0. In another exemplary embodiment, N1 and N2 are equal, being equal to Np / 2 or Np / 2 + 0.5 or Np / 2 - 0.5.
[0025] In one embodiment, the welding portion of the second leg of the electrical conductor is aligned with it. In this case, N2 is zero.
[0026] In the other cases where N2 is non-zero, each of the first and second legs of the electrical conductors can extend outside the notches by a welding portion inclined relative to a plane perpendicular to a longitudinal axis of the stator to overhang the stator mass circumferentially at the level of a notch, this notch being separated from the first A or the second R notch respectively by a number NI and N2 of teeth, the numbers NI and N2 possibly being equal or different.
[0027] Legs of pins
[0028] At least a portion of the electrical conductors each have a welding portion that is the innermost relative to the longitudinal axis of the stator, or even a majority, better still all of the electrical conductors each have a welding portion that is the innermost relative to the longitudinal axis of the stator.
[0029] At least a portion of the electrical conductors each have a welding portion that is the outermost relative to the longitudinal axis of the stator, or even a majority, better still all of the electrical conductors each have a welding portion that is the outermost relative to the longitudinal axis of the stator.
[0030] The inner portions are arranged closer to the rotor than the outer portions.
[0031] In the invention, the innermost welding portions are inclined with the same inclination relative to the plane perpendicular to the longitudinal axis of the stator. These innermost welding portions all extend parallel to each other.
[0032] As regards the outermost welding portions, they are not necessarily all inclined with the same inclination relative to the plane perpendicular to the longitudinal axis of the stator. They may be inclined with at least two, or even three or four, different inclinations relative to the plane perpendicular to the longitudinal axis of the stator.
[0033] The first leg may be disposed closer to the rotor than the second leg. The second leg may be disposed closer to the stator yoke than the first leg. Alternatively, the first leg may be disposed closer to the stator yoke than the second leg, and the second leg may be disposed closer to the rotor. than the first leg.
[0034] At least a portion of the electrical conductors may have a second leg extending out of the notch by a welding portion extending in the same radial plane as the second leg, or even being aligned with it. When only the first leg of the electrical conductors has an inclined welding portion, the manufacture of the stator is facilitated, insofar as the operations of tilting the pins can be simplified and accelerated. In this configuration, only one of the legs of the electrical conductor is inclined, so that it is possible to limit the deformations and stresses on the electrical conductors. In particular, it is possible to reduce the risks of electrical contact between the phases of the stator winding.
[0035] In one embodiment, only the first leg of the electrical conductors has an inclined welding portion. The welding portion of the second leg may be aligned with, extending in line with, and being straight with the second leg. When only the first leg of the electrical conductors has an inclined welding portion, the first leg may be disposed closer to the rotor than the second leg. Alternatively, the inclined first leg may be disposed closer to the stator yoke than the second leg.
[0036] At least a portion of the electrical conductors may have a second leg extending out of the notch by a welding portion forming a step relative to the notch, while extending in the same radial plane as the second leg. The step of the electrical conductor may make it possible to reach metal elements of a phase connector. The metal elements may be arranged radially externally relative to the electrical conductors to which they are connected.
[0037] At least a portion of the electrical conductors may have a second leg extending out of the notch by a circumferentially extending welding portion.
[0038] At least a portion of the electrical conductors may have a second leg extending out of the notch by a weld portion extending out of a circumferential surface. These weld portions outside a circumferential surface may provide access to a phase connector that may be disposed around the weld portions, rather than above them, relative to a longitudinal axis of the stator.
[0039] The stator may comprise two electrical conductors per notch.
[0040] The electrical conductors may form a distributed winding. The winding may be corrugated or interleaved. The electrical conductors may form a fractional winding. The winding may be full-pitch. In one embodiment, the winding may be short-pitch.
[0041] Multi-phase winding
[0042] The electrical conductors housed in the slots may form a multi-phase winding having at least a first phase a and a second phase b, an input electrical conductor A of the first phase a being located in a first slot (slot number 1), one or more electrical conductors of the second phase b being located in a second slot (slot number 2), the second slot immediately following the first slot when moving circumferentially around the axis of rotation of the machine, in the direction of circulation of the electric current around the axis of rotation of the machine
[0043] The input electrical conductor of the first phase is in this case located in a first notch just before a second notch receiving one or more electrical conductors of the second phase, when moving circumferentially around the axis of rotation of the machine, in the direction of circulation of the electric current around the axis of rotation of the machine.
[0044] Thus, the input electrical conductor of the first phase is located opposite the usual position, namely a position in which the first notch receiving the input electrical conductor of the first phase is immediately followed by a second notch receiving one or more electrical conductors of the same first phase, when moving circumferentially around the axis of rotation of the machine, in the direction of circulation of the electric current around the axis of rotation of the machine.
[0045] The input notch of a first phase may be followed by a notch housing electrical conductors of a second phase different from the first.
[0046] Thus, the number of notches between the input electrical conductor and the output electrical conductor of the same phase is reduced. The first input notch of a phase can be brought closer to a third output notch of this same phase. In other words, the number of notches separating the first input notch of a phase and the third output notch of the same phase can be smaller. Thus, the implementation of the invention makes it possible to reduce the tooth pitch of the electrical conductors which serve to connect the different winding paths which progress in the same direction around the axis of rotation of the machine, and the average length of each phase thanks to a better interleaving of the subsets of electrical conductors constituting the winding, measured circumferentially around the axis of rotation of the machine.Shortening the average length of a phase improves linear resistance and thermal performance, and reduces the mass of copper required.
[0047] It is also possible to obtain for the electrical conductors bun heads of lesser height, on the side opposite the welds. The quantity of copper required for the fa The construction of the conductors is therefore reduced, which is economically advantageous. In addition, the insertion of the electrical conductors into the notches can be made easier.
[0048] Furthermore, an output electrical conductor of the first phase may be located in a first notch, one or more electrical conductors of the second phase being located in a second notch, the second notch immediately following the first notch when moving circumferentially around the axis of rotation of the machine, in the direction of circulation of the electric current around the axis of rotation of the machine.
[0049] The output electrical conductor of the first phase may be located in a first notch just before a second notch receiving one or more electrical conductors of the second phase, when moving circumferentially around the axis of rotation of the machine, in the direction of circulation of the electric current around the axis of rotation of the machine.
[0050] Thus, the output electrical conductor of the first phase is located opposite the usual position, namely a position in which the first notch receiving the output electrical conductor of the first phase is immediately followed by a second notch receiving one or more electrical conductors of the same first phase, when moving circumferentially around the axis of rotation of the machine, in the direction of circulation of the electric current around the axis of rotation of the machine.
[0051] The output notch of a first phase may be followed by a notch housing electrical conductors of a second phase different from the first.
[0052] The phase inputs can be offset by an angle of 30°, 60°, 90° or by an angle of 120° for example.
[0053] The second notch may comprise one or more electrical conductors of the same phase only.
[0054] The first input notch of a first phase may comprise one or more electrical conductors of the first phase only.
[0055] Alternatively, the first input notch of a first phase may comprise one or more electrical conductors of the first phase and one or more electrical conductors of the second phase. The electrical conductor(s) of the first phase may be placed on the yoke side or alternatively on the air gap side. The electrical conductor(s) of the second phase may be placed on the air gap side or alternatively on the yoke side. The phase inputs and outputs may be placed on the yoke side or alternatively on the air gap side.
[0056] At least one 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 of said notches.
[0057] All 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, can be electrically connected together.
[0058] The stator may comprise a phase connector comprising metal elements connected to electrical conductors of the stator. The metal elements may be arranged radially externally or internally relative to the electrical conductors to which they are connected. The metal elements connected to conductors of the stator windings may be held by an insulating support. Furthermore, the phase connector may have connection tabs to a power bus. The machine may thus be connected to an inverter, electrically connected to the connection tabs of the connector.
[0059] Pins
[0060] At least some, if not a majority of, electrical conductors may be pin-shaped, U-shaped, or I-shaped. The pin may be U-shaped or straight, being I-shaped.
[0061] The pin and flat electrical conductors make it possible to increase the filling coefficient 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.
[0062] Furthermore, the manufacture of the stator can be facilitated thanks to the pin-shaped electrical conductors. Finally, since the pins do not require open notches, it is possible to have closed notches which allow the pins to be held and it is therefore possible to eliminate the step of inserting the stator shims.
[0063] Electrical conductors, or even a majority of the electrical conductors, extend axially in the notches. The electrical conductors can be introduced into the corresponding notches through one or both axial ends of the machine.
[0064] 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 have 6, 10, 12, 14, 18, 22 or 26 I-shaped electrical conductors, the other electrical conductors all being U-shaped.
[0065] The stator may be devoid of an I-shaped electrical conductor.
[0066] A U-shaped electrical conductor has two axial ends both placed at one of the axial ends of the stator. These two axial ends are defined by the two legs of the U. It passes through two different notches, 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, that is to say the side of the U forming the bun or coil head, is arranged on the other axial side of the stator.
[0067] At least a portion of the electrical conductors, or even a majority of the electrical conductors, may be U-shaped.
[0068] In addition, the size of the electrical conductors at the coil heads is reduced. This facilitates the nesting of the electrical conductors.
[0069] The winding may be devoid of U-shaped pins of a width different from Np. In certain embodiments of the prior art, there are U-shaped pins of at least three different widths. The width of a U-shaped pin is equal to the number of dental pitches + 1. The width of a U-shaped pin is defined by the number of notches separating the first and second legs of the U-shaped pin, including the two notches housing the two legs of the U-shaped pin in question. The first and second legs may be separated by a number of notches between 3 and 20, better between 6 and 16, being for example 6, 7, 8, 9 or 10 or 11 notches.
[0070] Strands
[0071] In the invention, each electrical conductor may comprise one or more strands (wire or strand in English). By "strand" is meant the most basic unit for electrical conduction. A strand may be of round cross-section, in which case it may be referred to as a 'wire', or flat. The flat strands may be shaped into pins, for example U-shaped or I-shaped. Each strand is coated with an insulating enamel.
[0072] The fact that each notch can comprise several conductors and / or several strands makes it possible to minimize losses by induced currents, or AC Joule losses, which vary with the square of the supply frequency, which is particularly advantageous at high frequency and when the operating speed is high. Heat transfer to the cold source is also facilitated. This makes it possible to obtain better efficiency at high speed.
[0073] When the notches are closed, a reduction in leakage fluxes seen by the conductors can be achieved, resulting in a reduction in eddy current losses in the strands.
[0074] In one embodiment, each electrical conductor may comprise several pins, each forming a strand, as explained above. All the strands of the same electrical conductor may be electrically connected to each other at the outlet 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.
[0075] Several strands can form the same electrical conductor. The same current of the same phase flows through all the strands of the same electrical conductor. All the strands of the same electrical conductor can be electrically connected to each other, in particular 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 of the notch. They can be electrically connected in parallel.
[0076] All the strands of all the electrical conductors having a free end located at the same circumferential position around the axis of rotation of the machine, whatever their radial position, can be electrically connected to each other.
[0077] In one embodiment, each electrical conductor comprises a single strand. In another embodiment, each electrical conductor comprises three strands.
[0078] In the case where a notch comprises two electrical conductors, a notch can therefore accommodate two strands, or alternatively six strands, for example, distributed between the two electrical conductors.
[0079] Alternatively, a notch comprises four electrical conductors. Each electrical conductor may comprise two strands. The notch then houses eight strands, distributed between the four electrical conductors.
[0080] The strands may be positioned in the notch such that their circumferential dimension around the axis of rotation of the machine is greater than their radial dimension. Such a configuration allows for a reduction in eddy current losses in the strands.
[0081] A strand may have a width of between 1 and 5 mm, for example being 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.
[0082] A strand may have a height of between 1 and 5 mm, for example being of the order of 1.6 or 1.8 mm. The height of a strand is defined as its thickness in the radial dimension.
[0083] The electrical conductors can be made of copper or aluminum.
[0084] Winding
[0085] A winding consists of a number of phases m offset in space in such a way that when they are supplied by a multi-phase current system, they produce a rotating field.
[0086] The electrical conductors may form a single winding, in particular with a whole or fractional pitch. By "single winding", it 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.
[0087] The electrical conductors may form a distributed winding. The winding is not not concentrated or wound on tooth.
[0088] The winding may be full pitch. Each slot only accommodates electrical conductors of the same phase and / or the width of an electrical conductor is equal to the number of slots divided by the number of poles.
[0089] Alternatively, the winding may have a shortened pitch. Slots may accommodate electrical conductors of different phases. In one embodiment, at least one slot accommodates an electrical conductor of the first phase and an electrical conductor of the second phase and / or the width of the majority of the electrical conductors is less than the number of slots divided by the number of poles.
[0090] The winding is in the invention whole or fractional. The winding can be whole with or without shortening, or in a fractional variant. In one embodiment, the electrical conductors form a fractional winding.
[0091] For a fractional winding, the number of slots per pole and per phase is fractional, that is to say that the ratio q defined by <?=Ne / (2pm) s’écrit sous la forme d’une fraction irréductible zln, zetn étant deux nombres entiers non nuis, n étant différent de 1, où Ne est le nombre d’encoches du stator, m le nombre de phases du bobinage et p le nombre de paires de pôles du stator.
[0092] The number of notches of the stator may be between 18 and 96, better between 30 and 84, being for example 18, 24, 27, 30, 36, 42, 45, 48, 54, 60, 63, 72, 78, 81, 92, 96, better being 60 or 63. The number of poles of the stator may be between 2 and 24, or even between 4 and 12, being for example 6 or 8.
[0093] The combination of number of slots / number of poles of the stator can be chosen from the combinations in the following list, which is not limiting: 30 / 4, 42 / 4, 45 / 6, 48 / 8, 63 / 6, 60 / 8, 78 / 8, 84 / 8.
[0094] In one embodiment, the combination number of slots / number of poles of the stator is 60 / 8. In this case we have ^=60 / (2*4*3)=5 / 2.
[0095] In one embodiment, the combination number of notches / number of pairs of stator poles is 63 / 6 or In this case we have ^=63 / (2*3*3)=7 / 2.
[0096] More broadly, the combination between the number of notches Ne and the number of pairs of poles p of the stator can be one of those checked in the following table 1, for a three-phase winding.
[0097] P 5 5 s L2 15 18 II ■24 2 ? 35 33 35 35 42 45 SI 34 37 -35 £3 55 55 72 73 78 Sx 54 8? 55 1 XXXXXXXXX' XXXXX 2 XXXXXXXXX .x XX x XX XXXXXXXX' XXXXXXRXXX X. XXSX X. x: XXX 7 X. XXXXXXXXRXXRRXXXXXX X. x x. SX r T s T ir TT .X ws W. JRWW a [Table 1]
[0098] Table 1
[0099] The number of phases is in this case three, but it does not go beyond 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, 7, 9, 11 or 13. The winding is polyphase.
[0100] The series connection of the electrical conductors can be done in so-called corrugated winding or in so-called nested winding.
[0101] By "corrugated winding" is meant 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 one winding path, the electric current of the phase flows in the electrical conductors while rotating around the axis of rotation of the machine always in one direction. For one winding path, the electrical conductors of the same phase and of the same pole do not overlap when observed perpendicular to the axis of rotation of the machine.
[0102] By "nested winding" is meant a winding in which the electrical conductors of the same phase of the same pole are electrically connected to each other so that the electric current of the phase flows in the electrical conductors by rotating around the axis of rotation of the machine alternately in one direction then in the other. For a winding path, the electrical conductors of the same phase and of the same pole overlap when observed perpendicular to the axis of rotation of the machine.
[0103] The winding may comprise a single winding path or several winding paths. In an "electrical conductor" the current of the same phase flows through each winding path. By "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 may be connected together in series or in parallel or in series-parallel. In the case where there is a single path, the electrical conductors are connected in series. In the case where there are several paths, the electrical conductors of each channel are connected in series, and the channels are connected in parallel.
[0104] Electrical conductors
[0105] In an "electrical conductor" flows the current of the same phase of a winding path. Several conductors in series form a "coil". The number of coils per phase is at most equal to the number of poles of the stator or the number of pairs of poles.
[0106] In each notch, there may be one or more layers. By "layer" is meant the conductors in series belonging to the same phase arranged in the same notch. In each layer of a notch, there are the electrical conductors of the same phase. Generally, 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 houses electrical conductors of the same phase.
[0107] In the invention, the electrical conductors may be distributed in only two layers. In this case, one or more notches may accommodate electrical conductors of two different phases. This is always the case for a shortened pitch winding. In one embodiment, the winding may not comprise more than two layers. In one embodiment, it is notably devoid of four layers.
[0108] At least one 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 of said notches.
[0109] By "electrically connected" is meant any type of electrical connection, in particular by welding, with different possible welding methods, in particular laser, induction, friction, ultrasound, vibration, or brazing, or by mechanical tightening, in particular by crimping, screwing or riveting for example. The welding step can be implemented by means of a heat source, in particular a laser or an electric arc, for example an electric arc produced by means of a tungsten electrode. The welding process using a tungsten electrode can be a TIG (in English "Tungsten Inert Gas") welding. In this welding process, the electric arc is produced from a tungsten electrode and a plasma. The use of a heat source makes it possible to melt the free ends of the strands without damaging the assembly of the strands of the conductor(s). A single heat source can be used to make the same weld.Alternatively, several heat sources can be used to make the same weld.
[0110] The first and second electrical conductors may be electrically connected at the outlet of the notches, i.e. the electrical connection is formed on the electrical conductors just after they exit the two notches, at one end axial 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 removed from the stator mass by approximately 30 to 70 mm, better by approximately 40 to 60 mm.
[0111] The electrical conductors may be arranged in the notches in a distributed manner. By "distributed" it is meant that the outgoing and return electrical conductors are each housed in different and non-consecutive notches. At least one of the electrical conductors may pass successively through two non-consecutive notches.
[0112] The electrical conductors may be arranged in a row in the notches. By "row" is meant that the electrical conductors are not arranged in the notches loosely but in an orderly manner. They are stacked in the notches in a non-random manner, for example being arranged in a row of electrical conductors aligned in the radial direction.
[0113] The electrical conductors may have a generally rectangular cross-section, in particular with rounded edges. The circumferential dimension of an electrical conductor may correspond substantially to the width of a notch. Thus, 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.
[0114] The electrical conductors may be adjacent to each other by their long sides, otherwise called the flat.
[0115] Optimizing the stacking can allow a greater quantity of electrical conductors to be placed in the notches.
[0116] The stator may include a sensor for measuring the temperature of the electrical conductors, for example a thermocouple. The sensor may be arranged in the notch, or alternatively at the welding portions.
[0117] At least one tooth, better all the teeth, may be of generally trapezoidal cross-section. At least one tooth, better all the teeth, may have edges that diverge away from the axis of rotation of the machine.
[0118] The stator mass can be made by stacking sheets. The teeth are connected to each other by bridges of material, and on the opposite side by a yoke. The closed notches can be made entirely by cutting into the sheets. Each sheet of the stack of sheets can be a single piece.
[0119] 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 their assembly within the stack. The electrical insulation can also be obtained by heat treatment of the sheets, if applicable.
[0120] Alternatively, the stator mass may be manufactured from a compacted or agglomerated magnetic powder. Machine and rotor
[0121] The invention also relates to a rotating electrical machine, such as a synchronous motor or a synchronous generator, comprising a stator as defined above. The machine may be synchronous or asynchronous. The machine may be reluctance. It may constitute a synchronous motor.
[0122] The maximum rotational speed of the machine may be high, for example greater than 10,000 rpm, better still greater than 12,000 rpm, for example of the order of 14,000 rpm to 15,000 rpm, or even 20,000 rpm or 25,000 rpm. The maximum rotational speed of the machine may be less than 100,000 rpm, or even 60,000 rpm, or even less than 40,000 rpm, better still less than 30,000 rpm.
[0123] The rotating electrical machine may comprise a rotor. The rotor may have permanent magnets, surface magnets or buried magnets. The rotor may be flux concentrating. It may comprise one or more layers of magnets arranged in an I, U or V shape. Alternatively, it may be a wound or squirrel cage rotor, or a variable reluctance rotor.
[0124] 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, for example being between 100 and 200 mm.
[0125] The rotor may comprise a rotor mass extending along the axis of rotation and arranged around a shaft. The shaft may comprise torque transmission means for driving the rotor mass in rotation.
[0126] The rotor may be mounted cantilevered or not.
[0127] The machine can be inserted alone in a housing or inserted in a box housing gear. In this case, it is inserted into a casing which also houses a gearbox. Manufacturing process
[0128] The invention also relates, independently or in combination with the above, to a method of manufacturing a stator of a rotating electrical machine, in particular a stator as defined above, in which electrical conductors are arranged in the notches of a stator mass of the stator by introducing them into the corresponding notches via one or both axial ends of the stator.
[0129] At least one electrical conductor, or a majority of the electrical conductors, introduced into the notches, are U-shaped. They can be placed in pin shape prior to their introduction into the slots. All U-shaped electrical conductors can be shaped, simultaneously or successively, then introduced into the stator mass simultaneously or successively.
[0130] The shaping may include a first step of assembling the strands of the same electrical conductor.
[0131] A second shaping step can be implemented after their introduction into the notches. This can notably involve the inclination of the welding portions.
[0132] The same U-shaped electrical conductor can be arranged in two different non-consecutive notches of the stator mass of the stator. In the case where an electrical conductor is U-shaped, it can be welded to two other electrical conductors on the same side of the machine. Brief description of the drawings
[0133] The invention may be better understood by reading the detailed description which follows, non-limiting examples of its embodiment, and by examining the attached drawing, in which:
[0134] [fig. 1] Figure 1 is a schematic and partial perspective view of a stator made in accordance with the invention.
[0135] [fig.2] Figure 2 is a schematic and partial perspective view of the stator of the Figure 1.
[0136] [fig.3] Figure 3 is a detailed perspective view of the stator of figure 1.
[0137] [fig.4a] Figure 4a is a schematic and partial perspective view of the electrical conductors of a phase of the stator of figure 1.
[0138] [fig.4b] Figure 4b is a schematic and partial perspective view of the electrical conductors of a phase of the stator of figure 1.
[0139] [fig.4c] Figure 4c is a schematic and partial perspective view of the electrical conductors of a phase of the stator of figure 1.
[0140] [fig.5a] Figure 5a is a schematic and partial perspective view of a conductor electrical of the stator of figure 1.
[0141] [fig.5b] Figure 5b is a schematic and partial perspective view of two electrical conductors of the stator of figure 1.
[0142] [fig.6] Figure 6 is a view similar to Figure 1 of an alternative embodiment.
[0143] [fig.7] Figure 7 is a schematic and partial perspective view of the stator of the Figure 6.
[0144] [fig.8] Figure 8 is a schematic and partial top view of the stator of the Figure 6.
[0145] [fig.9] Figure 9 is a top view, similar to figure 8, of the winding of the stator of figure 6.
[0146] [fig.10] Figure 10 is a detailed perspective view of the stator of figure 6.
[0147] [fig.l 1] Figure 11 is a detailed perspective view of the stator winding of the Figure 6.
[0148] [fig. 12] Figure 12 is a schematic and partial perspective view of the electrical conductors of a phase of the stator of figure 6.
[0149] [fig. 13a] Figure 13a is a schematic and partial perspective view of an electrical conductor of the stator of figure 6.
[0150] [fig. 13b] Figure 13b is a schematic and partial perspective view of the same electrical conductor of the stator of figure 6.
[0151] [fig. 13c] Figure 13c is a schematic and partial perspective view of two electrical conductors of the stator of figure 6. Detailed description
[0152] Figures 1 to 5b illustrate a stator 2 of a rotating electrical machine 1 also comprising a rotor, not shown. The stator makes it possible to generate a rotating magnetic field for driving the rotor in rotation, in the case 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.
[0153] The examples illustrated below are schematic and the relative dimensions of the different constituent elements have not necessarily been respected.
[0154] 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 air gap side by material bridges 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 electrical conductors 22 may be for the most part in the shape of pins, namely U or I, and extending axially in the notches.
[0155] In the example described, all the electrical conductors 22 of the stator 2 are identical, all being U-shaped, with the same pitch Np for all the electrical conductors of the stator which are U-shaped. Each U-shaped electrical conductor has first 22e and second 22f legs extending axially respectively in first A and second R notches. The first A and second R notches are separated by a number Np of notches and by a number Nd of teeth. The number Np of notches is the same for all the U-shaped electrical conductors of the stator. In the example described, Np is 11. The number Nd of teeth is the same for all the U-shaped electrical conductors. U-shaped pin of the stator. In the example described, Nd is 10.
[0156] Given the constant spacing between the legs of all the electrical conductors 22, the invention makes it possible to reduce the height of the buns 22d on the side opposite the welds, as visible in FIG. 2, as well as to have a more regular spacing between each of the buns 22d.
[0157] Space is also freed up on either side of the pins at the outlet of the notch, which can allow the connections to the other phases or to an inverter to be positioned there, on the side of the stator yoke, as illustrated in Figures 1 and 3.
[0158] The stator may comprise for this purpose a phase connector 12 comprising metal elements 16 connected to electrical conductors 22 of the stator. The metal elements 16 are arranged radially externally relative to the electrical conductors 22 to which they are connected. The metal elements 16 connected to conductors are held by an insulating support 14. Furthermore, the phase connector may have connection lugs to a power supply bus. The machine 1 may thus be connected to an inverter (not shown), electrically connected to the connection lugs 17 of the connector 12.
[0159] In the example described, 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 of said notches. The first and second notches are non-consecutive. In the example illustrated, they are separated by 12 other notches and by 11 teeth. Alternatively, the first and second notch are separated by 3, 4, 5, 6, 7, 8, 9, 10, 11 or 13 other notches, for example, and by 2, 3, 4, 5, 6, 7, 8, 9, 10, 12 or 13 teeth.
[0160] In particular, Figures 4a to 4c show the end surfaces 22a of the 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 plane of the electrical connection can be 40 to 60 mm away from the stator mass.
[0161] The electrical conductors are arranged in the slots in a distributed manner, and they form a distributed winding, which is in the example described fractional. In this example, the number of slots is 63. The number of stator poles is 6. Thus, the combination number of slots / number of stator poles is 63 / 6.
[0162] The electrical conductors form a fractional winding, for which the ratio q defined by <?=Ne / (2pm) s’écrit sous la forme d’une fraction irréductible zln, zetn étant deux nombres entiers non nuis, n étant différent de 1, où Ne est le nombre d’encoches du stator, m le nombre de phases du bobinage etp le nombre de paires de pôles du stator. On voit notamment sur la figure 4 isolément une bobine d'une phase dans le cas d'un bobinage fractionnaire triphasé. On a alors q=63 / (3x6)=7 / 2 pour cette machine à 63 encoches et 6 pôles. Une bobine est formée par les conducteurs electrical conductors of the same phase passing through adjacent slots, and by electrical conductors returning from the same phase passing through adjacent slots.
[0163] The electrical conductors 22 are made of copper or aluminum, or any other conductive material enameled or coated with any other suitable insulating coating.
[0164] The electrical conductors 22 are arranged in a row in the notches 21, in a row of aligned electrical conductors.
[0165] The electrical conductors may have a generally rectangular cross-section, in particular with rounded corners. In the example described, they are superimposed radially in a single row. The circumferential dimension of an electrical conductor corresponds substantially to the width of a notch. Thus, the notch only has one electrical conductor across its width. It may have several electrical conductors across its radial dimension. It has two in the example described.
[0166] Furthermore, the hairpin electrical conductors each have first 22e and second 22f legs which extend outside the notches by a welding portion 22b inclined relative to a plane perpendicular to a longitudinal axis of the stator to overhang the stator mass circumferentially at the level of a notch, this notch being separated from the first A or the second R notch respectively by a number NI and / or N2 of teeth.
[0167] In the example described with reference to Figures 1 to 5b, we have the welding portion 22b of the second leg 22f of the electrical conductor 22 which is aligned with the latter, as clearly visible in Figure 5b. In this case, we have N2 which is zero. The first leg 22e is arranged closer to the rotor than the second leg 22f. The second leg 22f is arranged closer to the stator yoke than the first leg 22e. Thus, in this example, we have NI which is equal to 11.
[0168] For each electrical conductor, the innermost welding portion 22b relative to the longitudinal axis of the stator, which is arranged closer to the rotor, is inclined with the same inclination relative to the plane perpendicular to the longitudinal axis of the stator as the other innermost welding portions.
[0169] For each electrical conductor, the outermost welding portion relative to the longitudinal axis of the stator, which is arranged further from the rotor, is inclined with an inclination which may be different relative to the plane perpendicular to the longitudinal axis of the stator than the other outermost welding portions. The outermost welding portions are not necessarily all inclined with the same inclination relative to the plane perpendicular to the longitudinal axis of the stator. They may be inclined with at least two, or even three or four, different inclinations relative to the plane perpendicular to the longitudinal axis of the stator.
[0170] Between two rectilinear welding portions 22b of two consecutive second legs 22f of two adjacent electrical conductors 22, it is possible to arrange, for example, a temperature probe or any other sensor, the two welding portions being well spaced apart. In one embodiment, the sensor can be threaded onto the rectilinear electrical conductor before welding it.
[0171] Furthermore, the electrical conductor illustrated in Figure 5a has a second leg 22f extending out of the notch by a welding portion 22b forming a step relative to the notch, while extending in the same radial plane as the second leg. This welding portion 22b is radially even further from the axis of rotation of the machine. This step of the electrical conductor makes it possible to reach the metal elements 16 of the phase connector 12.
[0172] Of course, it does not go beyond the scope of the present invention if the values of the numbers NI and N2 are different or equal. In the example just described, N1 is equal to Nd and N2 is equal to 0. N1 and N2 may be equal or substantially equal, being equal to Nd / 2 or Nd / 2 + 0.5 or Nd / 2 - 0.5 or Nd / 2 + / - 1 or Nd / 2 + 1.5, depending on the value of Nd.
[0173] In the embodiment illustrated in Figures 6 to 13c, the numbers NI and N2 are substantially equal. In the example illustrated, Np being equal to 11 and Nd to 10, NI is equal to 6 and N2 is equal to 5. For certain hairpin electrical conductors, N2 may be equal to 6, in particular in the case where this electrical conductor is connected to the metal elements 16 of the phase connector 12.
[0174] Each of the first 22e and second 22f legs of the electrical conductors 22 extend outside the notches by a welding portion 22b inclined relative to a plane perpendicular to a longitudinal axis of the stator to overhang the stator mass circumferentially at the level of a notch, this notch being separated from the first A or the second R notch respectively by a number NI and N2 of notches.
[0175] In the example described, as illustrated in FIGS. 13a to 13c, the two welding portions 22b of each of the first 22e and second 22f legs of the electrical conductors 22 are oriented away from each other.
[0176] Furthermore, most electrical conductors 22 have a second leg 22f extending out of the notch by a circumferentially extending welding portion 22b, while some electrical conductors 22 have a second leg 22f extending out of the notch by a welding portion 22b extending outside a circumferential surface, as clearly visible in FIGS. 8 and 9. The welding portions 22b outside a circumferential surface may allow a phase connector to be reached which may be disposed around the welding portions, rather than above them, relative to a longitudinal axis of the stator, as visible in FIGS. Figures 6, 10 and 11.
[0177] In another embodiment, the machine could have 60 notches, 60 teeth, 8 poles, hairpin electrical conductors each having first 22nd and second 22f legs separated by 8 other notches and 7 teeth. In this example, NI can be between 3 and 8 and N2 between 0 and 4.
[0178] In the preceding examples, the winding is corrugated. It is not outside the scope of the present invention when the winding is nested.
Claims
Claims
1. Stator (2) of a rotating electrical machine (1), comprising a stator mass (25) comprising notches (21) formed between teeth (23), electrical conductors (22) being housed in the notches (21), at least a portion of the electrical conductors, or even a majority of the electrical conductors, being in the shape of a U-shaped pin, each comprising first (22e) and second (22f) legs extending axially respectively in first (A) and second (R) notches, at least one of the first (22e) and second (22f) legs of the electrical conductors (22) extending outside the notches by a weld portion inclined relative to a plane perpendicular to a longitudinal axis of the stator to overhang the stator mass circumferentially at the level of a notch or a tooth, this notch or tooth being separated from the first (A) or the second (R) notch respectively by a number NI and / or N2 of teeth,at least a portion of the electrical conductors each having a welding portion that is the innermost relative to the longitudinal axis of the stator, or even a majority, better still all the electrical conductors each having a welding portion that is the innermost relative to the longitudinal axis of the stator, said innermost welding portions being inclined with the same inclination relative to the plane perpendicular to the longitudinal axis of the stator.,
2. Stator according to the preceding claim, the first leg being arranged closer to the rotor than the second leg.
3. Stator according to one of the two preceding claims, at least a portion of the electrical conductors (22) having a second leg (22f) extending out of the notch by a welding portion extending in the same radial plane as the second leg, or even being aligned with it.
4. Stator according to any one of the preceding claims, at least a portion of the electrical conductors (22) having a second leg (22f) extending out of the notch by a welding portion forming a step relative to the notch, while extending in the same radial plane as the second leg.
5. A stator according to any preceding claim, at least a portion of the electrical conductors (22) having a second leg (22f) extending out of the notch by a welding portion extending circumferentially.
6. A stator according to any preceding claim, at least a portion of the electrical conductors (22) having a second leg (221) extending out of the notch by a weld portion extending out of a circumferential surface.
7. Stator according to any one of the preceding claims, the first (A) and second (R) notches being separated by a number Nd of teeth, the number Nd of teeth being the same for all the U-shaped electrical conductors (22) of the stator.
8. Stator according to any one of the preceding claims, comprising two electrical conductors per notch.
9. Stator according to the preceding claim, the electrical conductors (22) forming a distributed winding.
10. Stator according to any one of the preceding claims, the electrical conductors (22) housed in the notches (21) forming a multi-phase winding having at least a first phase (a) and a second phase (b), an input electrical conductor (A) of the first phase (a) being located in a first notch (notch number 1), one or more electrical conductors of the second phase (b) being located in a second notch (notch number 2), the second notch immediately following the first notch when moving circumferentially around the axis of rotation of the machine, in the direction of circulation of the electric current around the axis of rotation of the machine.
11. Stator according to any one of the preceding claims, the second notch comprising one or more electrical conductors of the same phase only.
12. Stator according to any one of the preceding claims, at least a first electrical conductor housed in a first notch being electrically connected to a second electrical conductor housed in a second notch, at the outlet of said notches.
13. Stator according to any one of the preceding claims, in which all the electrical conductors (22) having a free end (22a) located at the same circumferential position around the axis of rotation of the machine, whatever their radial position, are electrically connected together.
14. Stator according to any one of the preceding claims, comprising a phase connector (12) comprising me- metal elements (16) connected to electrical conductors of the stator, the metal elements being arranged radially externally or internally relative to the electrical conductors to which they are connected.
15. A rotating electrical machine (1) comprising a stator (2) according to any one of the preceding claims and a rotor.