Search

EP-4736295-A1 - AXIAL FLUX INDUCTOR OF A SYNCHRONOUS ELECTRIC MACHINE

EP4736295A1EP 4736295 A1EP4736295 A1EP 4736295A1EP-4736295-A1

Abstract

One aspect of the invention relates to an inductor (I) of a synchronous axial flux electric machine (M1'), wherein the inductor (I) comprises a first series of salient poles (1) and a second series of salient poles (1, 2) each located between two salient poles (1) of the first series, wherein each salient pole comprises a coil body (21) and an excitation coil (22) of the second series of salient poles (2) comprises windings wrapped around a covered wound portion (210) of the coil body (21) to form active portions in at least one portion of each slot (3) on either side of the coil body (21) formed between a bare portion (11n) of a base (11) of a neighbouring pole of the first series and the coil body, such that the last winding is closer to each of the two neighbouring bare portions (11n) than to the coil body.

Inventors

  • FARAH, PHILIPPE

Assignees

  • YEESMA

Dates

Publication Date
20260506
Application Date
20240628

Claims (15)

  1. 1. a coil body (21) comprising a wound covered portion (21 1 ),
  2. 2. an excitation coil (22) wound around the covered wound portion (210) of the coil body (21), 3. an axial air gap radial face (20), o notches (3), each formed between a coil body (21) of the salient poles (2) of the second series and a base (1 1 1 ) adjacent to one of the salient poles (1 ) adjacent to the first series o characterized in that each excitation coil (22) of the second series of salient poles (2) comprises turns surrounded around the wound covered part (210) of the coil body (21) forming active parts in at least a part of each notch (3) on each side of the coil body (21) formed with the bare part (11 n) of the base (1 1 ) of a salient pole (1 ) adjacent to the first series, such that the last turn is closer to each of the two bare parts (11 n) of the two bases (1 1 ) adjacent to the salient pole (1 ) of the first series, than of the coil body (21). [Claim 2] Inductor (I, I') of an axial flux synchronous electric machine (M1, M1 M2, M3) according to claim 1, wherein in each salient pole (1) of the first series, the base (11) and the beak (110) are a block of soft ferromagnetic material, the beak (110) comprising on each side a protrusion relative to the bare part (11n) of the base (11) extending towards the corresponding neighboring salient pole of the second series of salient poles (2), the protrusion axially covering turns of the excitation coil.
  3. [Claim 3] Inductor (I’) of a synchronous electric machine (M2) according to one of the preceding claims in which: - each coil body (21) comprising a bare part (21n) extending from the covered wound part, - each ferromagnetic base (1 1 ) of a salient pole (1 ) of the first series comprises a second covered wound part (1 1 ’) extending from the first bare part (1 1 n), and - in that each salient pole (1) of the first series comprises an excitation coil (12) wound around the second wound covered part (11') having a last turn closer to each bare part (21n) neighboring the coil body (21) of the two neighboring salient poles (1) of the first series than to the second wound covered part (11').
  4. [Claim 4] Inductor (I’) of a synchronous electric machine according to claim 3, in which the inductor (I’) is a central inductor in which: - the coil bodies (21) are each ferromagnetic and each comprise a first radial axial air gap surface (10) and - the ferromagnetic bases (11) and the coil bodies (21) each comprise a second radial axial air gap surface (20', 10') opposite the first radial axial air gap surface (10, 20).
  5. [Claim 5] Inductor (I) of a synchronous electric machine (M1, M1') according to one of claims 1 to 4, in which the inductor is a single-layer lateral inductor comprising a ferromagnetic frame (4) comprising a radial face relative to the central axis (X), - each salient pole (1) of the first series extending axially from the radial face of the ferromagnetic frame (4) comprising only the bare part (11 n) extending from the frame (4) to the beak (1 10) and - each coil body of the second series extending axially from the radial face of the ferromagnetic frame comprising only the covered wound portion (210) of the coil body (21) extending axially from the frame, the excitation coil entirely surrounding only the covered wound portion (210).
  6. [Claim s] Axial flux synchronous electric machine (M1, M1’, M2, M3) comprising an inductor (I, I’) according to one of the preceding claims, comprising: - a rotor shaft having an axis of rotation (X) corresponding to the central axis (X), - a stator armature (5, 5’) comprising: o a winding (50) comprising a number Pa of active parts regularly angularly distributed around the axis of rotation (X) surrounding the rotor shaft, o a radial face of axial air gap.
  7. [Claim 7] Axial flux synchronous electric machine according to claim 6 in which the inductor (M1, M1’, M2) is integral with the rotor shaft and together forms a rotor, each axial air gap radial surface being opposite the axial air gap radial face of the armature (I, I’) forming an axial air gap between them.
  8. [Claim s] Axial flux synchronous electric machine (M1, M1’, M2) according to claim 7 in which the rotor further comprises a hoop (6) surrounding and in contact with the poles of the inductor (I, I’).
  9. [Claim 9] A compact axial flux electric machine according to claim 8, wherein the hoop comprises a housing receiving a portion of the winding, the housing having a diameter external to the diameter of the inductor.
  10. [Claim 10] Compact axial flux electric machine according to one of the preceding claims 7 to 9, in which: the inductor comprises an internal radius (r1) and an external radius (r2) measured radially respectively between an internal radial end of the beak (1 10) closest to the central axis (X) and an external radial end of the beak (1 10) furthest from the central axis (X) and in that the internal radius (r1) is equal to 60% + or - 20% of the external radius (r2) and - the rotor further comprises a device for supplying the excitation coils (20) of the inductor comprising: o a rotating part secured to the rotor shaft and electrically connected to the excitation coils (20), being located axially between an axial end of an armature (5) or inductor (i) and an axial end of another armature or another inductor axially opposite this axial end, o a stator part rotationally secured to the stator armature.
  11. [Claim 1 1 ] Axial flux synchronous electric machine (M3) according to claim 6 in which the inductor (I) is stator surrounding the rotor shaft (9), the machine further comprising a ferromagnetic rotor (90) comprising the rotor shaft (9) and a first set (90) of ferromagnetic parts (93) comprising a number Ns of parts regularly distributed around the axis of rotation (X), the number Ns is equal to the sum of or the difference between Pa/2 and Pe/2, Pe being the number of active parts of the inductor, the set (90) of ferromagnetic parts (93) being located between the first stator inductor (I) and the first stator armature (5).
  12. [Claim 12] Axial flux synchronous electric machine (M1', M3) according to one of the preceding claims 6 to 11 comprising a second inductor (I) according to claim 5 identical to the first inductor, the armature (5) being a central armature (5) located axially between the two inductors (I), the armature (5) comprising a second radial axial air gap face per tooth, and the two inductors are angularly offset from each other by one pole such that each pole of the second series of one of the inductors is axially aligned with a pole of the first series of the other inductor.
  13. [Claim 13] An axial flux electric machine according to the preceding claim, wherein the inductor is according to claim 2 and in that each magnet of the first inductor has a polarity opposite to the polarity of an axially aligned magnet of the second inductor.
  14. [Claim 14] Axial flux machine (M2) according to one of the preceding claims 6 to 12 comprising a second stator armature (5) identical to the first stator armature (5), the inductor (I') being according to claim 3 or 4 and being a central inductor located axially between the two armatures (5), each armature (5) comprising a yoke and teeth extending from the yoke towards the central inductor forming between them notches of number Pa each housing an active part.
  15. [Claim 15] A compact axial flux electrical machine according to one of the preceding claims 6 to 14, in which the rotor shaft further comprises a cooling channel comprising an axial duct extending axially in the rotor shaft and at least one projection duct extending from the axial duct to an opening opposite a coil of the armature or the inductor.

Description

DESCRIPTION TITLE: Axial flux inductor of a synchronous electric machine TECHNICAL FIELD OF THE INVENTION [0001] The technical field of the invention is that of axial flux synchronous electrical machines, in particular the axial flux inductor. [0002] The present invention relates to the axial flux inductor and in particular to different embodiments of axial flux synchronous electrical machines comprising such an axial flux inductor. TECHNOLOGICAL BACKGROUND OF THE INVENTION [0003] The synchronous machine comprises, like any electric motor, a rotor and a stator, mainly the rotor forms the inductor and the stator forms the armature. In the state of the art, inductors of synchronous electric machines are known, wound and/or with magnets. The inductor may have an advantage in being wound. Indeed, a machine with a wound iron core can produce a higher induction than those with magnets which are also more expensive and thermally limited by their characteristics than a coil. Thus at iso volume, a synchronous electric machine comprising an inductor with magnet will be more expensive, more thermally limited and less efficient (torque) particularly at high rotation speed than a machine compared to an electric machine comprising a wound inductor. [0004] There are also mainly two main families of air gaps known in electrical machines. [0005] A first family of synchronous electric machine has a radial air gap, the flux of which is mainly radial, also called a field, the air gap volume of which between a stator comprising coils forming the armature and the rotor forming an inductor (with magnet or wound) is cylindrical in shape surrounding the axis of rotation of the rotor. [0006] A second family of synchronous electric machine has an axial air gap, the flux of which is mainly axial, also called an axial field, and the air gap volume of which between a stator comprising coils forming the armature and the rotor forming the inductor (with magnet or wound) is in the form of a disk perpendicular to the axis of rotation of the rotor. [0007] A transverse flux family is also known, having an axial air gap part and a radial air gap part. [0008] The advantage of the axial air gap machine is to use the maximum diameter of the machine for the air gap surface, but the larger the useful air gap diameter, the greater the torque. In addition, these machines can also be chosen for reasons of axial bulkiness which is much smaller than those of radial air gap machines which have the advantage of radial bulkiness. [0009] there are also salient pole or claw inductor rotors. [0010] Claw rotors comprise a single coil wound around the axis of rotation passing through the claws. This makes it possible to have ampere turns produced by this coil passing through each pole having the advantage of improving the conductor rate per notch and therefore increasing the torque as well as reducing joule losses. However, the disadvantage is that the claws are subjected to a concentration of deformation stress at the foot of the claws by centrifugal force requiring a sufficiently large air gap according to the manufacturing tolerances of the internal diameter of the armature and the external diameter of the claws. However, the larger the air gap, the lower the performance of the synchronous electrical machine. In addition, these claws have the disadvantage of having leakage fluxes not crossing the air gap and not contributing to the supply of torque. [0011] Among the synchronous machines, there is the electric machine with a salient pole inductor comprising a ferromagnetic frame, a plurality of ferromagnetic bodies distributed angularly extending axially from the frame and a coil per ferromagnetic body. Each coil is wound around one of the ferromagnetic bodies. [0012] There is therefore a need to have a synchronous electric machine architecture of an axial flux wound inductor that is simpler to manufacture in order to reduce the cost while improving the efficiency and torque. SUMMARY OF THE INVENTION [0013] The invention provides a solution to the problems discussed above by allowing an excitation coil surrounding a portion of a coil body to have more turns than in the prior art. [0014] One aspect of the invention relates to an inductor of an axial flux synchronous electrical machine, the inductor being of the salient pole type comprising: a first series of salient poles each comprising a ferromagnetic base regularly distributed angularly around the central axis, and a nose extending from the ferromagnetic base comprising a radial axial air gap surface, each ferromagnetic base comprising at least one bare portion, a second series of salient poles, each located between two salient poles of the first series, each salient pole of the second series comprising at least: a coil body comprising a wound covered portion, an excitation coil wound around the wound covered portion of the coil body, an axial air gap radial face. notches, each formed between a coil body