WO2021099724A1 - Electromagnetic induction device - Google Patents

Electromagnetic induction device Download PDF

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Publication number
WO2021099724A1
WO2021099724A1 PCT/FR2020/052090 FR2020052090W WO2021099724A1 WO 2021099724 A1 WO2021099724 A1 WO 2021099724A1 FR 2020052090 W FR2020052090 W FR 2020052090W WO 2021099724 A1 WO2021099724 A1 WO 2021099724A1
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WO
WIPO (PCT)
Prior art keywords
leakage
legs
main
plates
air gap
Prior art date
Application number
PCT/FR2020/052090
Other languages
French (fr)
Inventor
Gérard DELETTE
Serge Loudot
Ulrich SOUPREMANIEN
Emmanuel CARDOUX
Original Assignee
Commissariat A L'energie Atomique Et Aux Energies Alternatives
Renault S.A.S.
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Commissariat A L'energie Atomique Et Aux Energies Alternatives, Renault S.A.S. filed Critical Commissariat A L'energie Atomique Et Aux Energies Alternatives
Priority to CN202080080611.5A priority Critical patent/CN114730654A/en
Priority to EP20823897.2A priority patent/EP4042453A1/en
Priority to JP2022529087A priority patent/JP2023502403A/en
Priority to KR1020227017012A priority patent/KR20220098742A/en
Publication of WO2021099724A1 publication Critical patent/WO2021099724A1/en

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Classifications

    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
    • H01F21/00—Variable inductances or transformers of the signal type
    • H01F21/02—Variable inductances or transformers of the signal type continuously variable, e.g. variometers
    • H01F21/08—Variable inductances or transformers of the signal type continuously variable, e.g. variometers by varying the permeability of the core, e.g. by varying magnetic bias
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
    • H01F27/00—Details of transformers or inductances, in general
    • H01F27/08—Cooling; Ventilating
    • H01F27/22—Cooling by heat conduction through solid or powdered fillings
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
    • H01F3/00—Cores, Yokes, or armatures
    • H01F3/10—Composite arrangements of magnetic circuits
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
    • H01F3/00—Cores, Yokes, or armatures
    • H01F3/10—Composite arrangements of magnetic circuits
    • H01F3/14—Constrictions; Gaps, e.g. air-gaps
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02B—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO BUILDINGS, e.g. HOUSING, HOUSE APPLIANCES OR RELATED END-USER APPLICATIONS
    • Y02B70/00—Technologies for an efficient end-user side electric power management and consumption
    • Y02B70/10—Technologies improving the efficiency by using switched-mode power supplies [SMPS], i.e. efficient power electronics conversion e.g. power factor correction or reduction of losses in power supplies or efficient standby modes

Definitions

  • the present invention belongs to the field of electronics and electricity.
  • the present invention relates to a magnetic inductance with variable inductance and for which the magnetic and thermal losses are reduced with regard to the devices known from the state of the art.
  • the magnetic inductance according to the present invention is advantageously implemented in an AC / DC or DC / DC power converter, and in particular a DAB (“Dual Active Bridge”) converter.
  • Magnetic inductors are devices well known to those skilled in the art, and implemented in a number of applications.
  • a magnetic inductor generally comprises a core, made of a ferromagnetic material, and a coil formed around a section of the core.
  • the core can also include an air gap.
  • This device is characterized by a characteristic quantity, called magnetizing inductance L, which depends on the ferromagnetic material, on the geometry of the core (and of its air gap), and of the winding, in particular on the number of turns forming this winding.
  • Certain applications in particular electronic converters, may require a high magnetizing inductance value L for nominal operation and a low magnetizing inductance for certain operating points.
  • the magnetizing inductance of the transformer of an LLC converter must be raised to the nominal operating voltage, in order to limit switching losses and guarantee good efficiency, but must be able to be greatly reduced in order to ensure the continuity of the power delivered to the load, when the input voltage drops (see the case of a server power supply system that must ensure data backup in the event of a power failure such as as described in document [1] cited at the end of the description).
  • This problem can lead to dimensioning converters of this type with low inductance values to ensure the backup function to the detriment of efficiency.
  • the transmitted power is inversely proportional to the value of series inductance L and to the phase shift between the input and output voltages set by the control.
  • the series inductance function can be implemented by a component separate from the transformer. However, in other cases, the series inductance function is performed by the leakage inductance of the same transformer.
  • a single value of series inductance restricts the operating range and proves to be less flexible for controlling the DAB converter as described in document [2] cited at the end of the description.
  • it may be considered to implement a magnetic inductor with magnetizing inductance L or series variable as a function of the magnetic flux (and consequently of the current I flowing through the winding). More particularly, it may be required to have a magnetic inductor which has a high magnetizing L or series inductance at low current I and lower at high current I.
  • a magnetic inductor is generally sized to operate in a current range I flowing in the winding less than a saturation current I sat for which the ferromagnetic core is not saturated.
  • I current flowing in the winding
  • I sat saturation current
  • the magnetizing inductance L remains independent of said current I.
  • the current I exceeds the value of the saturation current l sat
  • a magnetic saturation of the nucleus intervenes and causes a rapid decrease in its magnetic permeability and consequently of the magnetizing inductance L.
  • saturation occurs uniformly throughout the core for a value of the current I greater than the saturation current I sat .
  • saturation of the entire core, when the inductor is subjected to a current I at high frequency can be a source of significant volume magnetic losses in the inductor, and in the entire component into which it is integrated.
  • the magnetic flux lines which are no longer confined in the core, are liable to disturb the components placed near the magnetic inductance.
  • These disturbances can in particular be the source of electromagnetic incompatibilities and / or of eddy current losses.
  • An aim of the present invention is therefore to provide an electromagnetic induction device with a variable magnetizing inductance L and for which the magnetic and heating losses are reduced with regard to the devices known from the state of the art.
  • Another aim of the present invention is also to provide an electromagnetic induction device which can operate at higher frequencies than the devices known from the state of the art.
  • an electromagnetic induction device comprising:
  • the lateral protuberances interconnect the main plates in pairs so as to form secondary plates perpendicular to said main plates.
  • the ferromagnetic core, the first plates and the protuberances are made of the same ferromagnetic material.
  • the main plates are all identical.
  • a vacant volume V v of the volume V left vacant by the first plates and the protuberances is filled, at least in part, by a heat dissipating material which has a thermal conductivity greater than 10 W / m / K , advantageously the heat dissipation material comprises alumina.
  • the ferromagnetic core comprises two plane ends, essentially parallel to each other, facing one another and a surface S, the two ends delimiting the variable air gap, the main plates being arranged perpendicularly.
  • the ferromagnetic core advantageously comprises a frame of polygonal shape, and even more advantageously of rectangular shape.
  • the main plates have a cross section of a transverse area S t , the sum of the transverse areas of all the main plates being less than the area S.
  • the ferromagnetic core comprises two bases each provided with two main faces, called the inner face and outer face respectively, essentially parallel, the bases each face each other along their inner face, the variable air gap being formed in the one of the bases, the core further comprises a plurality of legs, substantially parallel to each other and which extend between the two internal faces, the plurality of legs comprises at least one main leg, at least one side leg and at least two trailing legs; the device further comprises at least one primary winding and at least one secondary winding, each comprising a main section, wound around the main leg, and a leakage section, called respectively primary leakage section and secondary leakage section each wound on a different leaking leg.
  • variable air gap being arranged between the two leakage legs, the primary plates being in the form of fins.
  • the fins are oriented in a direction defined by an axis joining the two leakage legs between which the air gap is arranged.
  • the recess opens onto the internal face of the base considered.
  • the recess opens onto the external face of the base considered.
  • the at least one main leg comprises a single main leg
  • the at least two leakage legs include four leakage legs, in which the primary leakage section comprises two primary leakage sections so that the coil primary comprises in order one of the primary leakage sections, the main section, and the other primary leakage section, the primary leakage sections each being wound around a different leakage leg, and in which the leakage section secondary comprises two secondary leakage sections so that the secondary winding comprises in order one of the secondary leakage sections, the main section, and the other secondary leakage section, the secondary leakage sections each being wound around a different leakage leg.
  • the at least one side leg comprises four side legs, the four side legs and the four trailing legs describing a circle centered on the main leg, and in which alternate, and in a regular manner, the side legs and the trailing legs, each primary trailing section being arranged diametrically opposed to a secondary trailing section with respect to the main leg.
  • the at least one lateral leg comprises two lateral legs
  • the at least two leakage legs comprise four leakage legs, forming two groups of two leakage legs, called the first group and second group respectively, the four trailing legs and the two side legs describing a circle centered on the main leg, and in which the side legs and the groups alternate in a regular manner.
  • the at least one air gap comprising a first air gap and a second air gap arranged midway between the leakage legs, respectively, of the first group and of the second group.
  • the primary leakage sections are each formed around, respectively, one and the other of the trailing legs (104) of the first group (106), and the secondary leakage sections are each formed around , respectively, of one or the other of the leakage legs (105) of the second group (107).
  • a groove is formed on one and the other of the internal faces, at a distance from and around each leakage leg, the groove being interposed between the leakage leg and the main leg.
  • FIG. 1 is a schematic perspective representation of a variable air gap according to the present invention
  • FIG. 2 is a schematic perspective representation of another configuration of a variable air gap according to the present invention.
  • FIG. 3 is a representation of a ferromagnetic core capable of being implemented within the framework of the present invention
  • FIG. 4 is a graphic representation of the evolution of the inductance L (vertical axis, unit "H") of the electromagnetic induction device as a function of an electric current I (horizontal axis, unit "A") flowing through coil;
  • FIG. 5 is a schematic representation of the electromagnetic induction device according to a first embodiment of the present invention.
  • FIGS. 6a, 6b are schematic representations of a half-core according to a side view (FIG. 6a) and a top view (FIG. 6b) capable of being implemented within the framework of the present invention
  • FIG. 7 is a schematic representation of the electromagnetic induction device according to a first embodiment of the present invention and implementing two half-cores as illustrated in FIGS. 6a and 6b;
  • FIG. 8 is a schematic representation of the electromagnetic induction device according to a first variant of the second embodiment of the present invention.
  • FIG. 9 is a schematic representation of a half-core in section, along the internal face and according to a second variant of the second embodiment of the present invention.
  • FIG. 10 is a schematic perspective representation of a half-core according to a second variant of the second embodiment of the present invention.
  • FIG. 11 is a schematic representation of a sectional half-core provided with the coils, along the internal face and according to a second variant of the second embodiment of the present invention.
  • FIG. 12 is a schematic representation of an air gap opening at the level of the external face of a base in contact with a cold source.
  • the present invention relates to an electromagnetic induction device provided with a variable air gap provided with heat dissipation means.
  • the device according to the present invention comprises a core at which the variable air gap is housed.
  • Said air gap also comprises first ferromagnetic plates intended to guide a magnetic flux liable to originate in the core and intended to operate in a saturation regime for a magnetic flux value lower than the value required for the saturation of the core, the flux being conservative throughout the magnetic circuit.
  • variable air gap according to the terms of the present invention further comprises lateral protuberances forming the heat dissipation means and which extend from lateral faces of the first plates.
  • the invention relates to an electromagnetic induction device 100 (FIGS. 1 to 3).
  • the electromagnetic induction device 100 can be a magnetic inductor of inductance L integrated in an AC / DC or DC / DC power transformer, and in particular a DAB converter.
  • the electromagnetic induction device 100 comprises a ferromagnetic core 200 (illustrated in Figures 1, 2 and 3).
  • the ferromagnetic core 200 is capable of being traversed by field lines induced by an electric current I flowing in at least one conductive coil 300 (or winding) formed around a section of the ferromagnetic core 200 and which extends along a main axis XX '.
  • main axis is meant an axis of symmetry of the conductive coil.
  • the conductive coil 300 is in particular made of a winding of a conductive wire, for example a copper wire, around a section of the ferromagnetic core 200.
  • the ferromagnetic core 200 also comprises an air gap (“Air Gap” according to Anglo-Saxon terminology), and more particularly a variable air gap 400 (FIGS. 1 and 2).
  • the air gap 400 is in particular formed by a recess or an absence of material in the ferromagnetic core 400.
  • the recess or the absence of material results in a rupture of continuity of the ferromagnetic material forming the ferromagnetic core 400.
  • variable air gap 400 defines in the ferromagnetic core 200 a volume V corresponding to the volume of material hollowed out or absent.
  • Main plates 500 made of a ferromagnetic material, are arranged in the volume V defined by the variable air gap 400.
  • a plate is understood to mean an element of generally planar shape and not very thick.
  • a plate comprises two side faces 501, essentially parallel to each other and connected by a contour.
  • the main plates 500 are moreover essentially parallel to each other and arranged in a direction parallel to field lines capable of circulating in the ferromagnetic core 200.
  • the orientation of a plate, and in particular of a main plate is defined by the orientation of its side faces 501.
  • said field lines are parallel to a direction of the planes. formed by the side faces of the main plates 500.
  • the main plates 500 also have a cross section of surface S t adapted so that all of said main plates 500 have a saturation magnetic field B sati , called first magnetic field B sati , less than that of the ferromagnetic core 200, called second field magnetic B sat 2.
  • cross section is understood to mean a section along a section plane perpendicular to the field lines crossing the main plates.
  • the amplitude of the magnetic field B passing through the ferromagnetic core 200 depends on the electric current I flowing in the coil 300.
  • the first magnetic field B sati and the second magnetic field B sat 2 are reached when the electric current I flowing in the coil 300 is equal, respectively, to a first saturation current I sati , and to a second saturation current I sat 2.
  • the behavior of the electromagnetic induction device 100, and more particularly its magnetizing inductance L will depend on the electric current I flowing in the coil 300.
  • FIG. 4 is a graphical representation of the different operating regimes of an electromagnetic induction device 100, the main plates 500 of which are all identical.
  • identical main plates plates of the same shape, same dimensions and same material.
  • Such a device 100 has three operating modes or stages “A”, “B” and “C” associated with an electric current I flowing in the coil 300, respectively, less than the first saturation current I sati , between the first current saturation current I sati and the second saturation current I sat 2, and greater than the second saturation current I sat 2.
  • the “A” regime corresponding to a linear regime for which the ferromagnetic core 200 and the main plates 500 are unsaturated.
  • the permeabilities of the ferromagnetic core 200 and of the main plates 500 are little or not dependent on the magnetic field circulating in the core so that the induction L is also essentially constant and equal to a first induction Li.
  • the "B” regime is characterized by a drop in inductance L to a second induction L2.
  • the "C” regime corresponds to a saturation regime of the ferromagnetic core 200 and of the main plates 500 caused by an electric current. circulating in the coil 300 greater than the second saturation current I sat 2. In this regime, the inductance L drops again to a value L3.
  • the main plates 500 are also provided with lateral ferromagnetic protrusions 600.
  • protuberance is understood to mean members projecting at the level of the surface on which they are placed.
  • the lateral protuberances 600 are intended in particular to diffuse a heat capable of being produced within the main plates 500 when the latter are traversed by a magnetic field greater than their magnetic field of saturation B sati .
  • the lateral protuberances 600 extend in particular from the lateral faces 501 of said main plates 500 in a direction essentially orthogonal to said lateral faces 501 (FIGS. 1 and 2).
  • the lateral protuberances 600 can have a rectangular, circular, square, triangular section.
  • the lateral protrusions 600 can interconnect the main plates 500 two by two so as to form secondary plates 700 perpendicular to said main plates 600 (FIG. 2).
  • the secondary plates 700 are dimensioned so as not to saturate when the magnetic field circulating in the core is less than the second magnetic field B sat 2.
  • the secondary plates 700 limit the overflow of the core. magnetic flux around the air gap area.
  • the secondary plates 700 ensure the guidance of the magnetic flux in the air gap, and de facto limit any lateral radiation of the magnetic field.
  • the lateral protuberances can be limited to the volume V defined by the variable air gap.
  • the ferromagnetic core 200, the first plates 500 and the lateral protuberances 600 are made of the same ferromagnetic material. Still advantageously, the vacant volume V v of the volume V left vacant by the first plates 500 and the protuberances 600 can be filled, at least in part, by a heat dissipating material 601 (FIG. 5) which has a higher thermal conductivity. at 10 W / m / K, advantageously the heat dissipating material comprises alumina.
  • the presence of the heat dissipation material makes it possible to assist the cooling by the lateral protuberances 600 by draining the heat produced in the air gap towards a heat sink.
  • the ferromagnetic core 200 comprises two flat ends 200a and 202b of surface S, essentially parallel to each other, facing each other.
  • the ends 200a and 200b define the variable air gap 400, and the main plates 500 are arranged perpendicular to the latter.
  • the main plates 500 have a cross section of a transverse area S t , the sum of the transverse areas of all the main plates 500 being less than the area S.
  • the ferromagnetic core can comprise a frame of polygonal shape, and even more advantageously of rectangular shape.
  • the magnetic core 200 comprises five parallelepipedal sections 201-205 composed of ferromagnetic materials joined two by two by their ends in order to form a rectangular frame.
  • Two sections 204 and 205 form one side of the rectangular frame and are spaced at their ends 200a and 200b by the air gap 400 (spacing g).
  • the sizing principle of a device according to the present invention is presented below on the basis of the core forming a side square frame / and illustrated in FIG. 5. This sizing principle is not however limited to this single configuration, and those skilled in the art can easily adapt it to other types of core geometries.
  • the primary plates 500 identical, connect the ends 200a and 200b which have a spacing g. The fraction of the end surface 200a and 200b covered by the sections of the primary plates is noted /.
  • the reluctance R e of the air gap structure provided only with the primary plates made of a ferromagnetic material of permeability p s is then expressed as follows:
  • the reluctance of the air gap structure is calculated simply by applying a reluctance network method to each of the constituents of the structure.
  • the thickness of these plates, denoted e p is small compared to the spacing g (e p “g).
  • the secondary plates furthermore comprise a ferromagnetic material of permeability m r and divide the air gap into several secondary air gaps placed in series.
  • the reluctance R es of each secondary air gap is therefore expressed as follows:
  • the total reluctance of the air gap structure comprising the primary and secondary plates is the sum of the N p secondary reluctances separating the plates:
  • This term therefore makes it possible to modulate the air gap distance which intervenes in the value of the inductance without modifying the geometry of the magnetic circuit. For this, it is necessary to produce, as a function of the applied current, a variation in the permeability p s of the primary plates.
  • the primary plates which have a relatively small cross section of surface S t compared to surface S, are traversed by a magnetic induction greater than that traversing the core according to the principle of conservation of magnetic flux. Such a consideration makes it possible to produce locally, in particular at the level of the primary plates 500, a saturation effect.
  • the magnetic induction in the primary plates B st corresponds to an amplification of the magnetic induction B c in the ferromagnetic core.
  • This amplification is a function of the surface fraction f and is given by the following relation:
  • the value of the saturation current is in this regard given by the following relation: For a current I greater than the saturation current l sat , the permeability of the primary plates p s is equal to 1.
  • nominal operation at low induction l "l sat )
  • high induction operation l" l sat
  • Figures 6a, 6b, and 7 propose another configuration of the ferromagnetic core in connection with the first embodiment of the electromagnetic induction device 100.
  • the ferromagnetic core comprises two half-cores 200i and 200 2 is of the ETD type (double E with cylindrical central leg), well known to those skilled in the art.
  • the two identical half-cores are mounted opposite each other with an air gap formed at a central column 207 (FIG. 7).
  • the spacing g of the air gap is in this example equal to 5 mm.
  • the air gap structure comprises 5 primary plates (21.65 mm x 5mm) 0.41mm thick and 2 secondary plates (21.65mm x 21.65mm) 1mm thick evenly spaced.
  • the permeability of the ferromagnetic material is 1500 and the saturation induction is 430 mT.
  • the central column 207 is wound with a winding of 5 turns of conductive wire.
  • the saturation current is 6 A.
  • the core inductance is 16 mH and decreases to 3 mH after saturation of the primary plates.
  • the heat exchange surface developed by the secondary plates improves cooling by natural air convection and limits heating to 100 ° C in the structure.
  • the remainder of the description relates to a second embodiment of the electromagnetic induction device 100.
  • the electromagnetic induction device 100 corresponding to this second mode can in particular be implemented as a component of a power converter of the “Dual Active Bridge” (DAB) type, and essentially uses the elements described above.
  • DAB Double Active Bridge
  • Figures 8 and 9-11 are in this regard schematic representations, in top view, of a half-cores 2OO 3 and 2OO 4 capable of being implemented according respectively to a first variant and a second variant of this second of achievement.
  • the ferromagnetic core 200 comprises an assembly of the two half-cores 2OO 3 and 2OO 4 .
  • the ferromagnetic core 200 comprises two bases 101 each provided with two main faces, called the inner face 101a and outer face 101b, respectively, essentially parallel.
  • the bases each face each other according to their internal face 101a, and the variable air gap 400 is in one of the bases, more particularly in its volume.
  • the core further comprises a plurality of legs, substantially parallel to each other and which extend between the two internal faces 101a.
  • the plurality of legs include at least one main leg 102, at least one side leg 103, and at least two leakage legs 104 and 105.
  • the device further comprises at least one primary winding 301 and at least one secondary winding 302.
  • Each of the primary 301 and secondary 302 coils comprises a main section, wound around the main leg 102, and a trailing section, called the primary trailing section and the secondary trailing section, respectively, each wound on a different leakage leg 104 and 105.
  • variable air gap 400 being disposed between the two leakage legs, and the primary plates are in the form of fins.
  • the fins are oriented in a direction defined by an axis joining the two leakage legs between which the air gap is arranged.
  • the recess may open onto one and / or the other of the internal face and the external face of the base which includes the air gap.
  • FIG. 12 is a schematic representation of an air gap 400 opening out at the level of the external face 101b of a base 101 in contact with a cold source.
  • the ferromagnetic core can include a single main leg 102 and four leak legs 104 and 105.
  • the primary leakage section comprises two primary leakage sections so that the primary coil 301 comprises in order one of the primary leakage sections 301a, the main section 301b, and the other primary leakage section 301c, the primary leak sections each being wrapped around a different leak leg.
  • the secondary leakage section comprises two secondary leakage sections so that the secondary winding 302 comprises in order one of the secondary leakage sections 302a, the main section 302b, and the other secondary leakage section 302c, the secondary leakage sections each being wound around a different leakage leg.
  • at least one side leg 103 comprises four side legs 103.
  • the four lateral legs 103 and the four trailing legs 104, 105 describe a circle centered on the main leg 102 and in which the side legs and the trailing legs alternate in a regular manner.
  • Each primary leakage section is further arranged diametrically opposed to one of the secondary leakage sections with respect to the main leg.
  • the device thus described comprises a transformer function and a series inductance function.
  • the transformer function is performed by the main sections 301b and 302b, respectively, of the primary winding 301 and the secondary winding 302, surrounded around the main leg.
  • the series inductances created at the primary and secondary windings are provided by the primary leakage sections 301a and 301c and by the secondary leakage sections 302a and 302c.
  • a magnetic flux created at the level of the main leg by the passage of a current in the primary winding follows a loop path successively crossing the base, the side legs, the other base, and crosses the main leg again.
  • a primary “leakage” flow follows a different contour connecting two trailing legs of the primary circuit and crossing the cylindrical base in its thickness along a line connecting the base of the two primary leakage legs.
  • the secondary leakage flow follows a similar contour described by the two secondary leakage legs.
  • variable air gap between two primary trailing legs makes it possible to confer a variable leak inductance character on the device.
  • the implementation of the variable air gap between two secondary trailing legs makes it possible to confer a variable leak inductance character on the device.
  • the ferromagnetic core comprises two lateral legs 103, and four leakage legs 104 and 105.
  • the two leakage legs 104 and the two leakage legs 105 form two groups of two leakage legs, called the first group 106 and second group 107, respectively.
  • the four trailing legs and the two side legs describe a circle centered on the main leg, and in which the side legs and the groups alternate in a regular manner.
  • the at least one air gap 400 comprises a first air gap 401 and a second air gap 402 arranged midway between the leakage legs, respectively, of the first group 106 and of the second group 107.
  • each of the primary trailing sections is formed around, respectively, one of the trailing legs and the other of the trailing legs of the first group.
  • each of the secondary leakage sections is formed around, respectively, one of the leakage legs and the other of the leakage legs of the second group 107.
  • the proximity between the leakage legs of the same group of leakage legs allows more precise control of the leaks.
  • a flux barrier 800 can also be formed in the bases 101 so as to limit the magnetic flux between the leakage legs and the side legs.
  • These flow barriers 800 may in particular include a recessed area between each of the elements of the first group 106 and those of the second group 107 and the side legs.
  • the hollowed out zone can in particular extend from the edge and along a radius of the base considered.
  • a bleeding can be formed on one and the other of the internal faces, at a distance from and around each leakage leg, and which is interposed between the leakage leg and the main leg.
  • the process for manufacturing the core according to the present invention may make use of an injection molding technique (“PIM” or “Powder Injection Molding” according to Anglo-Saxon terminology). This technique is particularly well suited for the production of large series parts of complex geometry. Injection molding initially implements a step of forming a masterbatch (“feedstock” according to Anglo-Saxon terminology).
  • the masterbatch comprises in particular a mixture of organic material (or polymeric binder) and inorganic powders (metallic or ceramic) intended to form the final part.
  • the masterbatch is injected into an injection molding machine, the technology of which is known to those skilled in the art.
  • the injection press makes it possible to melt the polymers injected with the powder in a cavity, and to give said powder the desired shape.
  • the masterbatch, thus shaped and melted, is subjected to cooling so as to solidify it and fix it in a shape imposed by the injection molding machine.
  • the part formed by the masterbatch is then unmolded and unbound in order to eliminate the organic matter.
  • the part can then be consolidated by sintering.

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  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Chemical & Material Sciences (AREA)
  • Composite Materials (AREA)
  • Transformer Cooling (AREA)
  • Soft Magnetic Materials (AREA)
  • Coils Or Transformers For Communication (AREA)
  • Iron Core Of Rotating Electric Machines (AREA)
  • Cooling Or The Like Of Electrical Apparatus (AREA)

Abstract

The invention relates to an electromagnetic induction device provided with a variable air gap equipped with heat dissipation means. In particular, the device according to the present invention comprises a core in which the variable air gap is housed. Said air gap further comprises first ferromagnetic plates intended to guide a magnetic flux that can originate in the core and can collectively have a saturation magnetic field less than that of the core. The variable air gap according to the terms of the present invention further comprises lateral protuberances which form the heat dissipation means and extend from lateral faces of the first plates.

Description

Description Description
Titre : DISPOSITIF D'INDUCTION ELECTROMAGNETIQUE DOMAINE TECHNIQUE Title: ELECTROMAGNETIC INDUCTION DEVICE TECHNICAL FIELD
La présente invention appartient au domaine de l'électronique et de l'électricité. En particulier, la présente invention concerne une inductance magnétique à inductance variable et pour laquelle les pertes magnétiques et thermiques sont réduites au regard des dispositifs connus de l'état de la technique. The present invention belongs to the field of electronics and electricity. In particular, the present invention relates to a magnetic inductance with variable inductance and for which the magnetic and thermal losses are reduced with regard to the devices known from the state of the art.
L'inductance magnétique selon la présente invention est avantageusement mise en œuvre dans un convertisseur de puissance AC/DC ou DC/DC, et notamment un convertisseur DAB (« Dual Active Bridge »). The magnetic inductance according to the present invention is advantageously implemented in an AC / DC or DC / DC power converter, and in particular a DAB (“Dual Active Bridge”) converter.
ÉTAT DE LA TECHNIQUE ANTÉRIEURE STATE OF THE PRIOR ART
Les inductances magnétiques sont des dispositifs bien connus de l'homme du métier, et mis œuvre dans nombre d'applications. Magnetic inductors are devices well known to those skilled in the art, and implemented in a number of applications.
Une inductance magnétique comprend en général un noyau, fait d'un matériau ferromagnétique, et d'un bobinage formé autour d'une section du noyau. Le noyau peut également comprendre un entrefer. Ce dispositif est caractérisé par une grandeur caractéristique, dite inductance magnétisante L, qui dépend du matériau ferromagnétique, de la géométrie du noyau (et de son entrefer), et du bobinage, en particulier du nombre de spires formant ce bobinage. A magnetic inductor generally comprises a core, made of a ferromagnetic material, and a coil formed around a section of the core. The core can also include an air gap. This device is characterized by a characteristic quantity, called magnetizing inductance L, which depends on the ferromagnetic material, on the geometry of the core (and of its air gap), and of the winding, in particular on the number of turns forming this winding.
Certaines applications, notamment les convertisseurs électroniques, peuvent nécessiter une valeur d'inductance magnétisante L élevée pour un fonctionnement nominal et une inductance magnétisante faible pour certains points de fonctionnement. Certain applications, in particular electronic converters, may require a high magnetizing inductance value L for nominal operation and a low magnetizing inductance for certain operating points.
C'est notamment le cas des topologies de convertisseurs résonants ditThis is particularly the case for topologies of so-called resonant converters.
LLC. LLC.
En effet, l'inductance magnétisante du transformateur d'un convertisseur LLC doit être élevée à la tension nominale de fonctionnement, afin de limiter les pertes par commutations et garantir un bon rendement, mais doit pouvoir être fortement réduite afin assurer la continuité de la puissance délivrée dans la charge, lorsque la tension d'entrée chute (cf. le cas d'un système d'alimentation de serveur devant assurer la sauvegarde des données en cas de coupure de l'alimentation tel que décrit dans le document [1] cité à la fin de la description). Cette problématique peut conduire à dimensionner les convertisseurs de ce type avec de faibles valeurs inductance pour assurer la fonction de sauvegarde au détriment du rendement. Indeed, the magnetizing inductance of the transformer of an LLC converter must be raised to the nominal operating voltage, in order to limit switching losses and guarantee good efficiency, but must be able to be greatly reduced in order to ensure the continuity of the power delivered to the load, when the input voltage drops (see the case of a server power supply system that must ensure data backup in the event of a power failure such as as described in document [1] cited at the end of the description). This problem can lead to dimensioning converters of this type with low inductance values to ensure the backup function to the detriment of efficiency.
Dans le cas des topologies de convertisseur DAB, la valeur d'inductance dite « série » car placée en série avec l'inductance magnétisante du transformateur détermine la plage de fonctionnement du convertisseur. In the case of DAB converter topologies, the so-called “series” inductance value because it is placed in series with the magnetizing inductance of the transformer determines the operating range of the converter.
La puissance transmise est inversement proportionnelle à la valeur d'inductance série L et au déphasage entre les tensions d'entrée et de sortie réglées par le pilotage. The transmitted power is inversely proportional to the value of series inductance L and to the phase shift between the input and output voltages set by the control.
Dans certains cas, la fonction d'inductance série peut être mise en œuvre par un composant distinct du transformateur. Toutefois, dans d'autres cas, la fonction d'inductance série est assurée par l'inductance de fuite du même transformateur. In some cases, the series inductance function can be implemented by a component separate from the transformer. However, in other cases, the series inductance function is performed by the leakage inductance of the same transformer.
Dans ces deux cas, une valeur unique d'inductance série restreint la plage de fonctionnement et s'avère moins souple pour le pilotage du convertisseur DAB tel que décrit dans le document [2] cité à la fin de la description. Afin de pallier ces problèmes, il peut être considéré de mettre en œuvre une inductance magnétique à inductance magnétisante L ou série variable en fonction du flux magnétique (et par conséquent du courant I parcourant le bobinage). Plus particulièrement, il peut être requis de disposer d'une inductance magnétique qui présente une inductance magnétisante L ou série élevée à faible courant I et plus faible à fort courant I. In these two cases, a single value of series inductance restricts the operating range and proves to be less flexible for controlling the DAB converter as described in document [2] cited at the end of the description. In order to alleviate these problems, it may be considered to implement a magnetic inductor with magnetizing inductance L or series variable as a function of the magnetic flux (and consequently of the current I flowing through the winding). More particularly, it may be required to have a magnetic inductor which has a high magnetizing L or series inductance at low current I and lower at high current I.
Cependant, une inductance magnétique est généralement dimensionnée pour fonctionner dans un domaine de courant I circulant dans le bobinage inférieur à un courant de saturation lsat pour lequel le noyau ferromagnétique n'est pas saturé. Dans ce domaine, tant que le courant I est inférieur au courant de saturation lsat, l'inductance magnétisante L reste indépendante dudit courant I. Toutefois, dès lors que le courant I dépasse la valeur du courant de saturation lsat, une saturation magnétique du noyau intervient et provoque une diminution rapide de sa perméabilité magnétique et par voie de conséquence de l'inductance magnétisante L. However, a magnetic inductor is generally sized to operate in a current range I flowing in the winding less than a saturation current I sat for which the ferromagnetic core is not saturated. In this range, as long as the current I is less than the saturation current l sat , the magnetizing inductance L remains independent of said current I. However, as soon as the current I exceeds the value of the saturation current l sat , a magnetic saturation of the nucleus intervenes and causes a rapid decrease in its magnetic permeability and consequently of the magnetizing inductance L.
Ainsi, dès lors qu'une variabilité de l'inductance magnétisante L est requise lors du fonctionnement de l'inductance magnétique, différentes solutions peuvent être considérées. De manière générale, ces solutions proposent d'étendre le domaine de fonctionnement de l'inductance magnétique à un régime non linéaire précédent la saturation complète du matériau ferromagnétique. A cet effet, il est donc possible de considérer une perméabilité magnétique plus faible et/ou un redimensionnement de l'entrefer. Thus, when a variability of the magnetizing inductance L is required during the operation of the magnetic inductance, different solutions can be considered. In general, these solutions propose to extend the operating range of the magnetic inductance to a nonlinear regime preceding the complete saturation of the ferromagnetic material. For this purpose, it is therefore possible to consider a lower magnetic permeability and / or a resizing of the air gap.
Dès lors que l'une et/ou l'autre de ces deux solutions est mise en œuvre, la saturation se produit uniformément dans l'ensemble du noyau pour une valeur du courant I supérieure au courant de saturation lsat. As soon as one and / or the other of these two solutions is implemented, saturation occurs uniformly throughout the core for a value of the current I greater than the saturation current I sat .
Toutefois ces solutions ne sont pas satisfaisantes. However, these solutions are not satisfactory.
En effet, une saturation de l'intégralité du noyau, lorsque l'inductance est soumise à une courant I à haute fréquence (typiquement supérieure à 10 kHz), peut être une source de pertes magnétiques volumiques importantes dans l'inductance, et dans l'ensemble du composant lequel elle est intégrée. Indeed, saturation of the entire core, when the inductor is subjected to a current I at high frequency (typically greater than 10 kHz), can be a source of significant volume magnetic losses in the inductor, and in the entire component into which it is integrated.
Par ailleurs, ces pertes peuvent entraîner un échauffement du noyau.Moreover, these losses can lead to heating of the core.
En outre, en régime de saturation, les lignes de flux magnétique, qui ne sont plus confinées dans le noyau, sont susceptibles de perturber les composants disposés à proximité de l'inductance magnétique. Ces perturbations peuvent notamment être à la source d'incompatibilités électromagnétiques et/ou de pertes par courants de Foucault. In addition, in the saturation regime, the magnetic flux lines, which are no longer confined in the core, are liable to disturb the components placed near the magnetic inductance. These disturbances can in particular be the source of electromagnetic incompatibilities and / or of eddy current losses.
Il a donc pu être proposé, dans les documents [3] à [7] cités à la fin de la description, des dimensionnements du noyau, et notamment de l'entrefer, permettant de localiser la saturation du noyau audit entrefer. It has therefore been possible to propose, in documents [3] to [7] cited at the end of the description, dimensioning of the core, and in particular of the air gap, making it possible to locate the saturation of the core in said air gap.
Les dimensionnements proposés ne sont toutefois pas satisfaisant. En effet, quand bien même la saturation du noyau reste localisée au voisinage de l'entrefer, ce dernier reste le siège de pertes magnétiques et d'échauffements susceptibles de perturber le fonctionnement de l'ensemble du composant. However, the proposed sizing is not satisfactory. Indeed, even though the saturation of the core remains localized in the vicinity of the air gap, the latter remains the site of magnetic losses and overheating liable to disturb the operation of the entire component.
Par surcroît, ces pertes magnétiques et par échauffement limitent la mise en œuvre de telles inductances magnétiques à des courants I de fréquences élevées et notamment pouvant atteindre 500 kHz. In addition, these magnetic and heating losses limit the use of such magnetic inductors at currents I of high frequencies and in particular up to 500 kHz.
Un but de la présente invention est donc de proposer un dispositif d'induction électromagnétique d'inductance magnétisante L variable et pour laquelle les pertes magnétiques et réchauffement sont réduits au regard des dispositifs connus de l'état de la technique. An aim of the present invention is therefore to provide an electromagnetic induction device with a variable magnetizing inductance L and for which the magnetic and heating losses are reduced with regard to the devices known from the state of the art.
Un autre but de la présente invention est également de proposer un dispositif d'induction électromagnétique qui peut fonctionner à des fréquences plus élevées que les dispositifs connus de l'état de la technique. Another aim of the present invention is also to provide an electromagnetic induction device which can operate at higher frequencies than the devices known from the state of the art.
EXPOSÉ DE L'INVENTION DISCLOSURE OF THE INVENTION
Les buts de la présente invention sont, au moins en partie, atteints par un dispositif d'induction électromagnétique comprenant : The aims of the present invention are, at least in part, achieved by an electromagnetic induction device comprising:
- un noyau ferromagnétique ; - a ferromagnetic core;
- au moins un entrefer, dit entrefer variable, et définissant dans le noyau un volume V, dans lequel sont disposées des plaques principales ferromagnétiques, essentiellement parallèles et agencées selon une direction parallèle à des lignes de champ susceptibles de circuler dans le noyau, les plaques principales présentant une section transversale configurée pour que l'ensemble desdites plaques présente un champ magnétique de saturation inférieur à celui du noyau ferromagnétique, les plaques principales étant également pourvues de protubérances latérales destinées à diffuser une chaleur susceptible d'être produite au sein des plaques principales lorsque ces dernières sont parcourues par un champ magnétique supérieur à leur champ magnétique de saturation, lesdites protubérances latérales s'étendant à partir de faces latérales desdites plaques selon une direction essentiellement orthogonale auxdites faces latérales. Selon un mode de réalisation, les protubérances latérales relient entre elles les plaques principales deux à deux de manière à former des plaques secondaires perpendiculaires auxdites plaques principales. - at least one air gap, called a variable air gap, and defining in the core a volume V, in which are arranged main ferromagnetic plates, essentially parallel and arranged in a direction parallel to field lines capable of circulating in the core, the plates main having a cross section configured so that all of said plates have a saturation magnetic field lower than that of the ferromagnetic core, the main plates also being provided with lateral protuberances intended to diffuse a heat capable of being produced within the main plates when the latter are traversed by a magnetic field greater than their saturation magnetic field, said lateral protuberances extending from lateral faces of said plates in a direction essentially orthogonal to said lateral faces. According to one embodiment, the lateral protuberances interconnect the main plates in pairs so as to form secondary plates perpendicular to said main plates.
Selon un mode de réalisation, le noyau ferromagnétique, les premières plaques et les protubérances sont faites d'un même matériau ferromagnétique. According to one embodiment, the ferromagnetic core, the first plates and the protuberances are made of the same ferromagnetic material.
Selon un mode de réalisation, les plaques principales sont toutes identiques. According to one embodiment, the main plates are all identical.
Selon un mode de réalisation, un volume vacant Vv du volume V laissé vacant par les premières plaques et les protubérances est comblé, au moins en partie, par un matériau de dissipation thermique qui présente une conductivité thermique supérieure à 10 W/m/K, avantageusement le matériau de dissipation thermique comprend de l'alumine. According to one embodiment, a vacant volume V v of the volume V left vacant by the first plates and the protuberances is filled, at least in part, by a heat dissipating material which has a thermal conductivity greater than 10 W / m / K , advantageously the heat dissipation material comprises alumina.
Selon un mode de réalisation, le noyau ferromagnétique comprend un matériau ferromagnétique choisi parmi : un alliage métallique du type FeX où X comprend l'un des éléments choisi parmi Si, Al, Co, Ni, oxyde ferrite de structure spinelle du type A(Fe,B) 04 avec A = (Mn, Ni) B=(Co, Cu, Al,..). According to one embodiment, the ferromagnetic core comprises a ferromagnetic material chosen from: a metal alloy of the FeX type where X comprises one of the elements chosen from Si, Al, Co, Ni, ferrite oxide of type A spinel structure (Fe , B) 0 4 with A = (Mn, Ni) B = (Co, Cu, Al, ..).
Selon un mode de réalisation, le noyau ferromagnétique comprend deux extrémités planes, essentiellement parallèles entre elles, en regard l'une de l'autre et d'une surface S, les deux extrémités délimitent l'entrefer variable, les plaques principales étant disposées perpendiculairement aux extrémités, avantageusement le noyau ferromagnétique comprend un cadre de forme polygonale, et encore plus avantageusement de forme rectangulaire. According to one embodiment, the ferromagnetic core comprises two plane ends, essentially parallel to each other, facing one another and a surface S, the two ends delimiting the variable air gap, the main plates being arranged perpendicularly. at the ends, the ferromagnetic core advantageously comprises a frame of polygonal shape, and even more advantageously of rectangular shape.
Selon un mode de réalisation, les plaques principales présentent une section transversale d'une surface transversale St, la somme des surfaces transversales de l'ensemble des plaques principales étant inférieure à la surface S. According to one embodiment, the main plates have a cross section of a transverse area S t , the sum of the transverse areas of all the main plates being less than the area S.
Selon un mode de réalisation, le noyau ferromagnétique comprend deux bases pourvues chacune de deux faces principales, dites respectivement face interne et face externe, essentiellement parallèles, les bases se font face chacune selon leur face interne, l'entrefer variable étant formé dans l'une des bases, le noyau comprend en outre une pluralité de jambes, essentiellement parallèles entre elles et qui s'étendent entre les deux faces internes, la pluralité de jambes comprend au moins une jambe principale, au moins une jambe latérale et au moins deux jambes de fuites ; le dispositif comprend en outre au moins un bobinage primaire et au moins un bobinage secondaire, comprenant chacun une section principale, enroulée autour de la jambe principale, et une section de fuite, dites respectivement section de fuite primaire et section de fuite secondaire enroulées chacune sur une jambe de fuites différente. According to one embodiment, the ferromagnetic core comprises two bases each provided with two main faces, called the inner face and outer face respectively, essentially parallel, the bases each face each other along their inner face, the variable air gap being formed in the one of the bases, the core further comprises a plurality of legs, substantially parallel to each other and which extend between the two internal faces, the plurality of legs comprises at least one main leg, at least one side leg and at least two trailing legs; the device further comprises at least one primary winding and at least one secondary winding, each comprising a main section, wound around the main leg, and a leakage section, called respectively primary leakage section and secondary leakage section each wound on a different leaking leg.
Selon un mode de réalisation, l'entrefer variable étant disposé entre les deux jambes de fuites, les plaques primaires étant en forme d'ailettes. According to one embodiment, the variable air gap being arranged between the two leakage legs, the primary plates being in the form of fins.
Selon un mode de réalisation, les ailettes sont orientées selon une direction définie par un axe joignant les deux jambes de fuites entre lesquelles l'entrefer est disposé. According to one embodiment, the fins are oriented in a direction defined by an axis joining the two leakage legs between which the air gap is arranged.
Selon un mode de réalisation, l'évidement débouche sur la face interne de la base considérée. According to one embodiment, the recess opens onto the internal face of the base considered.
Selon un mode de réalisation, l'évidement débouche sur la face externe de la base considérée. According to one embodiment, the recess opens onto the external face of the base considered.
Selon un mode de réalisation, l'au moins une jambe principale comprend une unique jambe principale, les au moins deux jambes de fuites comprennent quatre jambes de fuites, dans lequel la section de fuite primaire comprend deux sections de fuites primaires de sorte que le bobinage primaire comprenne dans l'ordre une des sections de fuites primaire, la section principale, et l'autre section de fuite primaire, les sections de fuites primaires étant enroulées chacune autour d'une jambe de fuites différente, et dans lequel la section de fuite secondaire comprend deux sections de fuites secondaire de sorte que le bobinage secondaire comprenne dans l'ordre une des sections de fuites secondaire, la section principale, et l'autre section de fuites secondaire, les sections de fuites secondaire étant enroulées chacune autour d'une jambe de fuites différente. According to one embodiment, the at least one main leg comprises a single main leg, the at least two leakage legs include four leakage legs, in which the primary leakage section comprises two primary leakage sections so that the coil primary comprises in order one of the primary leakage sections, the main section, and the other primary leakage section, the primary leakage sections each being wound around a different leakage leg, and in which the leakage section secondary comprises two secondary leakage sections so that the secondary winding comprises in order one of the secondary leakage sections, the main section, and the other secondary leakage section, the secondary leakage sections each being wound around a different leakage leg.
Selon un mode de réalisation, l'au moins une jambe latérale comprend quatre jambes latérales, les quatre jambes latérales et les quatre jambes de fuites décrivant un cercle centré sur la jambe principale, et dans lequel s'alternent, et de manière régulière, les jambes latérales et les jambes de fuites, chaque section de fuite primaire étant disposée de manière diamétralement opposée à une section de fuite secondaire par rapport à la jambe principale. According to one embodiment, the at least one side leg comprises four side legs, the four side legs and the four trailing legs describing a circle centered on the main leg, and in which alternate, and in a regular manner, the side legs and the trailing legs, each primary trailing section being arranged diametrically opposed to a secondary trailing section with respect to the main leg.
Selon un mode de réalisation, l'au moins une jambe latérale comprend deux jambes latérales, les au moins deux jambes de fuites comprennent quatre jambes de fuites, formant deux groupes de deux jambes de fuites, dits respectivement premier groupe et deuxième groupe, les quatre jambes de fuites et les deux jambes latérales décrivant un cercle centré sur la jambe principale, et dans lequel s'alternent, de manière régulière, les jambes latérales et les groupes. According to one embodiment, the at least one lateral leg comprises two lateral legs, the at least two leakage legs comprise four leakage legs, forming two groups of two leakage legs, called the first group and second group respectively, the four trailing legs and the two side legs describing a circle centered on the main leg, and in which the side legs and the groups alternate in a regular manner.
Selon un mode de réalisation, l'au moins un entrefer comprenant un premier entrefer et un deuxième entrefer disposés à mi-distance entre les jambes de fuites, respectivement, du premier groupe et du deuxième groupe. According to one embodiment, the at least one air gap comprising a first air gap and a second air gap arranged midway between the leakage legs, respectively, of the first group and of the second group.
Selon un mode de réalisation, les sections de fuites primaire sont chacune formées autour, respectivement, de l'une et l'autre des jambes de fuite (104) du premier groupe (106), et les sections de fuites secondaire sont chacune formées autour, respectivement, de l'une ou l'autre des jambes de fuites (105) du deuxième groupe (107). According to one embodiment, the primary leakage sections are each formed around, respectively, one and the other of the trailing legs (104) of the first group (106), and the secondary leakage sections are each formed around , respectively, of one or the other of the leakage legs (105) of the second group (107).
Selon un mode de réalisation, une saignée est formée sur l'une et l'autre des faces internes, à distance et autour de chaque jambe de fuites, la saignée s'interposant entre la jambe de fuites et la jambe principale. According to one embodiment, a groove is formed on one and the other of the internal faces, at a distance from and around each leakage leg, the groove being interposed between the leakage leg and the main leg.
BRÈVE DESCRIPTION DES DESSINS BRIEF DESCRIPTION OF THE DRAWINGS
D'autres caractéristiques et avantages apparaîtront dans la description qui va suivre d'un dispositif d'induction électromagnétique selon l'invention, donnés à titre d'exemples non limitatifs, en référence aux dessins annexés dans lesquels : Other characteristics and advantages will appear in the following description of an electromagnetic induction device according to the invention, given by way of nonlimiting examples, with reference to the appended drawings in which:
La figure 1 est une représentation schématique en perspective d'un entrefer variable selon la présente invention ; FIG. 1 is a schematic perspective representation of a variable air gap according to the present invention;
La figure 2 est représentation schématique en perspective d'une autre configuration d'un entrefer variable selon la présente invention ; FIG. 2 is a schematic perspective representation of another configuration of a variable air gap according to the present invention;
La figure 3 est une représentation d'un noyau ferromagnétique susceptible d'être mis en œuvre dans le cadre de la présente invention ; La figure 4 est une représentation graphique de l'évolution de l'inductance L (axe vertical, unité « H ») du dispositif d'induction électromagnétique en fonction d'un courant électrique I (axe horizontal, unité « A ») circulant la bobine ; FIG. 3 is a representation of a ferromagnetic core capable of being implemented within the framework of the present invention; FIG. 4 is a graphic representation of the evolution of the inductance L (vertical axis, unit "H") of the electromagnetic induction device as a function of an electric current I (horizontal axis, unit "A") flowing through coil;
La figure 5 est une représentation schématique du dispositif d'induction électromagnétique selon un premier mode de réalisation de la présente invention ; FIG. 5 is a schematic representation of the electromagnetic induction device according to a first embodiment of the present invention;
Les figures 6a, 6b sont des représentations schématiques d'un demi- noyau selon une vue de côté (figure 6a) et une vue de dessus (figure 6b) susceptible d'être mis en œuvre dans le cadre de la présente invention ; FIGS. 6a, 6b are schematic representations of a half-core according to a side view (FIG. 6a) and a top view (FIG. 6b) capable of being implemented within the framework of the present invention;
La figure 7 est une représentation schématique du dispositif d'induction électromagnétique selon un premier mode de réalisation de la présente invention et mettant en œuvre deux demi-noyau tels qu'illustrés aux figures 6a et 6b ; FIG. 7 is a schematic representation of the electromagnetic induction device according to a first embodiment of the present invention and implementing two half-cores as illustrated in FIGS. 6a and 6b;
La figure 8 est une représentation schématique du dispositif d'induction électromagnétique selon une première variante du deuxième mode de réalisation de la présente invention ; FIG. 8 is a schematic representation of the electromagnetic induction device according to a first variant of the second embodiment of the present invention;
La figure 9 est une représentation schématique d'un demi-noyau en coupe, selon la face interne et selon une deuxième variante du deuxième mode de réalisation de la présente invention ; FIG. 9 is a schematic representation of a half-core in section, along the internal face and according to a second variant of the second embodiment of the present invention;
La figure 10 est une représentation schématique en perspective d'un demi-noyau selon une deuxième variante du deuxième mode de réalisation de la présente invention ; FIG. 10 is a schematic perspective representation of a half-core according to a second variant of the second embodiment of the present invention;
La figure 11 est une représentation schématique d'un demi-noyau en coupe pourvu des bobinages, selon la face interne et selon une deuxième variante du deuxième mode de réalisation de la présente invention ; FIG. 11 is a schematic representation of a sectional half-core provided with the coils, along the internal face and according to a second variant of the second embodiment of the present invention;
La figure 12 est une représentation schématique d'un entrefer débouchant au niveau la face externe d'une base au contact d'une source froide. FIG. 12 is a schematic representation of an air gap opening at the level of the external face of a base in contact with a cold source.
EXPOSÉ DÉTAILLÉ DE MODES DE RÉALISATION PARTICULIERS DETAILED PRESENTATION OF PARTICULAR EMBODIMENTS
La présente invention concerne un dispositif d'induction électromagnétique pourvu d'un entrefer variable doté de moyens de dissipation de chaleur. En particulier, le dispositif selon la présente invention comprend un noyau au niveau duquel est logé l'entrefer variable. Ledit entrefer comprend par ailleurs des premières plaques ferromagnétiques destinées à guider un flux magnétique susceptible de prendre naissance dans le noyau et destinées à fonctionner dans un régime de saturation pour une valeur de flux magnétique inférieure à la valeur requise pour la saturation du noyau, le flux étant conservatif dans tout le circuit magnétique. The present invention relates to an electromagnetic induction device provided with a variable air gap provided with heat dissipation means. In particular, the device according to the present invention comprises a core at which the variable air gap is housed. Said air gap also comprises first ferromagnetic plates intended to guide a magnetic flux liable to originate in the core and intended to operate in a saturation regime for a magnetic flux value lower than the value required for the saturation of the core, the flux being conservative throughout the magnetic circuit.
L'entrefer variable selon les termes de la présente invention comprend en outre, des protubérances latérales formant les moyens de dissipation de chaleur et qui s'étendent à partir de faces latérales des premières plaques. The variable air gap according to the terms of the present invention further comprises lateral protuberances forming the heat dissipation means and which extend from lateral faces of the first plates.
Plus particulièrement, l'invention concerne un dispositif d'induction électromagnétique 100 (figures 1 à 3). More particularly, the invention relates to an electromagnetic induction device 100 (FIGS. 1 to 3).
Le dispositif d'induction électromagnétique 100 peut être une inductance magnétique d'inductance L intégrée dans un transformateur de puissance AC/DC ou DC/DC, et notamment un convertisseur DAB. The electromagnetic induction device 100 can be a magnetic inductor of inductance L integrated in an AC / DC or DC / DC power transformer, and in particular a DAB converter.
Le dispositif d'induction électromagnétique 100 comprend un noyau ferromagnétique 200 (illustré aux figures 1, 2 et 3). The electromagnetic induction device 100 comprises a ferromagnetic core 200 (illustrated in Figures 1, 2 and 3).
Le noyau ferromagnétique 200 peut comprendre au moins un matériau ferromagnétique choisi parmi : un alliage métallique du type FeX où X comprend l'un des éléments choisi parmi Si, Al, Co, Ni, un oxyde ferrite de structure spinelle du type A(Fe,B) 04 avec A = (Mn, Ni) B=(Co, Cu, Al,..). The ferromagnetic core 200 may comprise at least one ferromagnetic material chosen from: a metal alloy of the FeX type where X comprises one of the elements chosen from Si, Al, Co, Ni, a ferrite oxide of spinel structure of the type A (Fe, B) 0 4 with A = (Mn, Ni) B = (Co, Cu, Al, ..).
Le noyau ferromagnétique 200 est susceptible d'être parcouru par des lignes de champ induites par un courant électrique I circulant dans au moins une bobine 300 (ou bobinage) conductrice formée autour d'une section du noyau ferromagnétique 200 et qui s'étend selon un axe principal XX'. The ferromagnetic core 200 is capable of being traversed by field lines induced by an electric current I flowing in at least one conductive coil 300 (or winding) formed around a section of the ferromagnetic core 200 and which extends along a main axis XX '.
Par « axe principal », on entend un axe de symétrie de la bobine conductrice. By “main axis” is meant an axis of symmetry of the conductive coil.
La bobine conductrice 300 est notamment faite d'un enroulement d'un fil conducteur, par exemple un fil en cuivre, autour d'une section du noyau ferromagnétique 200. Le noyau ferromagnétique 200 comprend également un entrefer (« Air Gap » selon la terminologie Anglo-Saxonne), et plus particulièrement un entrefer variable 400 (figures 1 et 2). The conductive coil 300 is in particular made of a winding of a conductive wire, for example a copper wire, around a section of the ferromagnetic core 200. The ferromagnetic core 200 also comprises an air gap (“Air Gap” according to Anglo-Saxon terminology), and more particularly a variable air gap 400 (FIGS. 1 and 2).
L'entrefer 400 est notamment formé par un évidement ou une absence de matière dans le noyau ferromagnétique 400. The air gap 400 is in particular formed by a recess or an absence of material in the ferromagnetic core 400.
L'évidement ou l'absence de matière se traduit par une rupture de continuité du matériau ferromagnétique formant le noyau ferromagnétique 400. The recess or the absence of material results in a rupture of continuity of the ferromagnetic material forming the ferromagnetic core 400.
L'entrefer variable 400 définit dans le noyau ferromagnétique 200 un volume V correspondant au volume de matière évidé ou absent. The variable air gap 400 defines in the ferromagnetic core 200 a volume V corresponding to the volume of material hollowed out or absent.
Des plaques principales 500, faites d'un matériau ferromagnétique, sont disposées dans le volume V défini par l'entrefer variable 400. Main plates 500, made of a ferromagnetic material, are arranged in the volume V defined by the variable air gap 400.
Par « plaque », on entend un élément de forme généralement plane et peu épais. En particulier, une plaque comprend deux faces latérales 501, essentiellement parallèles entre elles et reliées par un contour. The term “plate” is understood to mean an element of generally planar shape and not very thick. In particular, a plate comprises two side faces 501, essentially parallel to each other and connected by a contour.
Les plaques principales 500 sont par ailleurs essentiellement parallèles entre elles et agencées selon une direction parallèle à des lignes de champ susceptibles de circuler dans le noyau ferromagnétique 200. The main plates 500 are moreover essentially parallel to each other and arranged in a direction parallel to field lines capable of circulating in the ferromagnetic core 200.
Selon la présente invention, l'orientation d'une plaque, et notamment d'une plaque principale, est définie par l'orientation de ses faces latérales 501. En d'autres termes, lesdites lignes de champ sont parallèles à une direction des plans formés par les faces latérales des plaques principales 500. According to the present invention, the orientation of a plate, and in particular of a main plate, is defined by the orientation of its side faces 501. In other words, said field lines are parallel to a direction of the planes. formed by the side faces of the main plates 500.
Les plaques principales 500 ont également une section transversale de surface St adaptée pour que l'ensemble desdites plaques principales 500 présente un champ magnétique de saturation Bsati, dit premier champ magnétique Bsati, inférieur à celui du noyau ferromagnétique 200, dit deuxième champ magnétique Bsat2. The main plates 500 also have a cross section of surface S t adapted so that all of said main plates 500 have a saturation magnetic field B sati , called first magnetic field B sati , less than that of the ferromagnetic core 200, called second field magnetic B sat 2.
Par « section transversale », on entend une section selon un plan de coupe perpendiculaire aux lignes de champ traversant les plaques principales. The term “cross section” is understood to mean a section along a section plane perpendicular to the field lines crossing the main plates.
L'amplitude du champ magnétique B traversant le noyau ferromagnétique 200 dépend du courant électrique I circulant dans la bobine 300. Notamment, le premier champ magnétique Bsati et le deuxième champ magnétique Bsat2 sont atteints lorsque le courant électrique I circulant dans la bobine 300 est égal, respectivement, à un premier courant de saturation lsati, et à un deuxième courant de saturation Isat2. The amplitude of the magnetic field B passing through the ferromagnetic core 200 depends on the electric current I flowing in the coil 300. In particular, the first magnetic field B sati and the second magnetic field B sat 2 are reached when the electric current I flowing in the coil 300 is equal, respectively, to a first saturation current I sati , and to a second saturation current I sat 2.
Ainsi, le comportement du dispositif d'induction électromagnétique 100, et plus particulièrement son inductance magnétisante L, va dépendre du courant électrique I circulant dans la bobine 300. Thus, the behavior of the electromagnetic induction device 100, and more particularly its magnetizing inductance L, will depend on the electric current I flowing in the coil 300.
À cet égard, la figure 4 est une représentation graphique des différents régimes de fonctionnement d'un dispositif d'induction électromagnétique 100 dont les plaques principales 500 sont toutes identiques. In this regard, FIG. 4 is a graphical representation of the different operating regimes of an electromagnetic induction device 100, the main plates 500 of which are all identical.
Par « plaques principales identiques », on entend des plaques de même forme, mêmes dimensions et même matériau. By “identical main plates” is meant plates of the same shape, same dimensions and same material.
Un tel dispositif 100 présente trois régimes ou paliers de fonctionnement « A », « B » et « C » associés à un courant électrique I circulant dans la bobine 300, respectivement, inférieur au premier courant de saturation lsati, compris entre le premier courant de saturation lsati et le deuxième courant de saturation Isat2, et supérieur au deuxième courant de saturation Isat2. Such a device 100 has three operating modes or stages “A”, “B” and “C” associated with an electric current I flowing in the coil 300, respectively, less than the first saturation current I sati , between the first current saturation current I sati and the second saturation current I sat 2, and greater than the second saturation current I sat 2.
Plus particulièrement, le régime « A » correspondant à un régime linéaire pour lequel le noyau ferromagnétique 200 et les plaques principales 500 sont non saturés. Dans ce régime, les perméabilités du noyau ferromagnétique 200 et des plaques principales 500 sont peu ou pas dépendantes du champ magnétique circulant dans le noyau de sorte que l'induction L est également essentiellement constante et égale à une première induction Li. More particularly, the “A” regime corresponding to a linear regime for which the ferromagnetic core 200 and the main plates 500 are unsaturated. In this regime, the permeabilities of the ferromagnetic core 200 and of the main plates 500 are little or not dependent on the magnetic field circulating in the core so that the induction L is also essentially constant and equal to a first induction Li.
Le régime « B » se caractéristique par une chute de l'inductance L à une deuxième induction L2. The "B" regime is characterized by a drop in inductance L to a second induction L2.
Cette chute est notamment due à une saturation des plaques principales 500 qui, sous l'effet d'un champ magnétique supérieur au premier champ magnétique Bsati, voient leur perméabilité diminuer fortement pour atteindre une valeur voisine de 1. This drop is in particular due to saturation of the main plates 500 which, under the effect of a magnetic field greater than the first magnetic field B sati , see their permeability decrease sharply to reach a value close to 1.
Enfin, le régime « C » correspond à un régime de saturation du noyau ferromagnétique 200 et des plaques principales 500 provoqué par un courant électrique circulant dans la bobine 300 supérieur au deuxième courant de saturation Isat2. Dans ce régime, l'inductance L chute à nouveau à une valeur L3. Finally, the "C" regime corresponds to a saturation regime of the ferromagnetic core 200 and of the main plates 500 caused by an electric current. circulating in the coil 300 greater than the second saturation current I sat 2. In this regime, the inductance L drops again to a value L3.
Selon la présente invention, les plaques principales 500 sont également pourvues de protubérances latérales 600 ferromagnétiques. According to the present invention, the main plates 500 are also provided with lateral ferromagnetic protrusions 600.
Par « protubérance », on entend des organes faisant saillie au niveau de la surface sur laquelle ils sont disposés. The term “protuberance” is understood to mean members projecting at the level of the surface on which they are placed.
Les protubérances latérales 600 sont notamment destinées à diffuser une chaleur susceptible d'être produite au sein des plaques principales 500 lorsque ces dernières sont parcourues par un champ magnétique supérieur à leur champ magnétique de saturation Bsati. The lateral protuberances 600 are intended in particular to diffuse a heat capable of being produced within the main plates 500 when the latter are traversed by a magnetic field greater than their magnetic field of saturation B sati .
Les protubérances latérales 600 s'étendent notamment à partir des faces latérales 501 desdites plaques principales 500 selon une direction essentiellement orthogonale auxdites faces latérales 501 (figure 1 et 2). The lateral protuberances 600 extend in particular from the lateral faces 501 of said main plates 500 in a direction essentially orthogonal to said lateral faces 501 (FIGS. 1 and 2).
Les protubérances latérales 600 peuvent présenter une section rectangulaire, circulaire, carrée, triangulaire. The lateral protuberances 600 can have a rectangular, circular, square, triangular section.
Les protubérances latérales 600 peuvent relier entre elles les plaques principales 500 deux à deux de manière à former des plaques secondaires 700 perpendiculaires auxdites plaques principales 600 (figure 2). The lateral protrusions 600 can interconnect the main plates 500 two by two so as to form secondary plates 700 perpendicular to said main plates 600 (FIG. 2).
De manière particulièrement avantageuse, les plaques secondaires 700 sont dimensionnées pour ne pas saturer lorsque le champ magnétique circulant dans le noyau est inférieur au deuxième champ magnétique Bsat2. Ainsi, lorsque les plaques principales 500 saturent, les plaques secondaires 700 limitent le débordement du flux magnétique autour de la zone de l'entrefer. En d'autres termes, les plaques secondaires 700 assurent le guidage du flux magnétique dans l'entrefer, et limitent de facto tout rayonnement latéral du champ magnétique. Particularly advantageously, the secondary plates 700 are dimensioned so as not to saturate when the magnetic field circulating in the core is less than the second magnetic field B sat 2. Thus, when the main plates 500 saturate, the secondary plates 700 limit the overflow of the core. magnetic flux around the air gap area. In other words, the secondary plates 700 ensure the guidance of the magnetic flux in the air gap, and de facto limit any lateral radiation of the magnetic field.
Par ailleurs, les protubérances latérales peuvent être limitées au volume V défini par l'entrefer variable. Furthermore, the lateral protuberances can be limited to the volume V defined by the variable air gap.
Avantageusement, le noyau ferromagnétique 200, les premières plaques 500 et les protubérances latérales 600 sont faites d'un même matériau ferromagnétique. Toujours de manière avantageuse, le volume vacant Vv du volume V laissé vacant par les premières plaques 500 et les protubérances 600 peut être comblé, au moins en partie, par un matériau de dissipation thermique 601 (figure 5) qui présente une conductivité thermique supérieure à 10 W/m/K, avantageusement le matériau de dissipation thermique comprend de l'alumine. Advantageously, the ferromagnetic core 200, the first plates 500 and the lateral protuberances 600 are made of the same ferromagnetic material. Still advantageously, the vacant volume V v of the volume V left vacant by the first plates 500 and the protuberances 600 can be filled, at least in part, by a heat dissipating material 601 (FIG. 5) which has a higher thermal conductivity. at 10 W / m / K, advantageously the heat dissipating material comprises alumina.
La présence du matériau de dissipation thermique permet d'assister le refroidissement par les protubérances latérales 600 en drainant la chaleur produite dans l'entrefer vers un puits de chaleur. The presence of the heat dissipation material makes it possible to assist the cooling by the lateral protuberances 600 by draining the heat produced in the air gap towards a heat sink.
Selon un premier mode de réalisation du dispositif d'induction électromagnétique 100, le noyau ferromagnétique 200 comprend deux extrémités planes 200a et 202b de surface S, essentiellement parallèles entre elles, en regard l'une de l'autre. According to a first embodiment of the electromagnetic induction device 100, the ferromagnetic core 200 comprises two flat ends 200a and 202b of surface S, essentially parallel to each other, facing each other.
Les extrémités 200a et 200b délimitent l'entrefer variable 400, et les plaques principales 500 sont disposées perpendiculairement à ces dernières. The ends 200a and 200b define the variable air gap 400, and the main plates 500 are arranged perpendicular to the latter.
Les plaques principales 500 présentent une section transversale d'une surface transversale St, la somme des surfaces transversales de l'ensemble des plaques principales 500 étant inférieure à la surface S. The main plates 500 have a cross section of a transverse area S t , the sum of the transverse areas of all the main plates 500 being less than the area S.
Le noyau ferromagnétique peut comprendre un cadre de forme polygonale, et encore plus avantageusement de forme rectangulaire. The ferromagnetic core can comprise a frame of polygonal shape, and even more advantageously of rectangular shape.
Par exemple, tel qu'illustré à la figure 5, le noyau magnétique 200 comprend par cinq tronçons parallélépipédiques 201-205 composés de matériaux ferromagnétiques joints deux à deux par leurs extrémités afin de former un cadre rectangulaire. Deux tronçons 204 et 205 forment un côté du cadre rectangulaire et sont espacés, au niveau de leurs extrémités 200a et 200b par l'entrefer 400 (d'espacement g). For example, as illustrated in FIG. 5, the magnetic core 200 comprises five parallelepipedal sections 201-205 composed of ferromagnetic materials joined two by two by their ends in order to form a rectangular frame. Two sections 204 and 205 form one side of the rectangular frame and are spaced at their ends 200a and 200b by the air gap 400 (spacing g).
Le principe de dimensionnement d'un dispositif selon la présente invention est présenté ci-après sur la base du noyau formant un cadre carré de côté / et illustré à la figure 5. Ce principe de dimensionnement n'est toutefois pas limité cette seule configuration, et l'homme du métier pourra aisément l'adapter à d'autres types de géométries de noyaux. Dans cet exemple, les plaques primaires 500, identiques, relient les extrémités 200a et 200b qui présentent un espacement g. La fraction de la surface d'extrémité 200a et 200b couverte par les sections des plaques primaires est noté/. The sizing principle of a device according to the present invention is presented below on the basis of the core forming a side square frame / and illustrated in FIG. 5. This sizing principle is not however limited to this single configuration, and those skilled in the art can easily adapt it to other types of core geometries. In this example, the primary plates 500, identical, connect the ends 200a and 200b which have a spacing g. The fraction of the end surface 200a and 200b covered by the sections of the primary plates is noted /.
La réluctance Re de la structure d'entrefer pourvue uniquement des plaques primaires faite d'un matériau ferromagnétique de perméabilité ps s'exprime alors de la manière suivante :
Figure imgf000016_0001
The reluctance R e of the air gap structure provided only with the primary plates made of a ferromagnetic material of permeability p s is then expressed as follows:
Figure imgf000016_0001
Dès lors que Np plaques secondaires sont considérées, la réluctance de la structure d'entrefer se calcule simplement en appliquant une méthode du réseau de réluctances à chacun des constituants de la structure. L'épaisseur de ces plaques, notée ep, est faible devant l'espacement g (ep « g). As soon as N p secondary plates are considered, the reluctance of the air gap structure is calculated simply by applying a reluctance network method to each of the constituents of the structure. The thickness of these plates, denoted e p , is small compared to the spacing g (e p “g).
Les plaques secondaires comprennent par ailleurs un matériau ferromagnétique de perméabilité mr et divisent l'entrefer en plusieurs entrefers secondaires placés en série. La réluctance Res de chaque entrefer secondaire s'exprime donc de la manière suivante :
Figure imgf000016_0002
The secondary plates furthermore comprise a ferromagnetic material of permeability m r and divide the air gap into several secondary air gaps placed in series. The reluctance R es of each secondary air gap is therefore expressed as follows:
Figure imgf000016_0002
La réluctance totale de la structure d'entrefer comprenant les plaques primaires et secondaires est la somme des Np réluctances secondaires séparant les plaques :
Figure imgf000016_0003
The total reluctance of the air gap structure comprising the primary and secondary plates is the sum of the N p secondary reluctances separating the plates:
Figure imgf000016_0003
Ces expressions permettent de déduire l'inductance L(pC m5) du dispositif illustré à la figure 5 et qui s'exprime de la manière suivante :
Figure imgf000017_0001
These expressions make it possible to deduce the inductance L (p C m 5 ) of the device illustrated in FIG. 5 and which is expressed as follows:
Figure imgf000017_0001
Cette expression de l'inductance est identique à celle obtenue avec un entrefer constant dont l'espacement g est pondéré par le terme F(^s, f). This expression of the inductance is identical to that obtained with a constant air gap whose spacing g is weighted by the term F (^ s , f).
Ce terme permet donc de moduler la distance d'entrefer qui intervient dans la valeur de l'inductance sans modifier la géométrie du circuit magnétique. Pour cela, il est nécessaire de produire en fonction du courant appliqué une variation de la perméabilité ps des plaques primaires. This term therefore makes it possible to modulate the air gap distance which intervenes in the value of the inductance without modifying the geometry of the magnetic circuit. For this, it is necessary to produce, as a function of the applied current, a variation in the permeability p s of the primary plates.
Les plaques primaires, qui présentent une section transversale de surface St relativement faible au regard de la surface S, sont parcourues par une induction magnétique supérieure à celle parcourant le noyau selon le principe de conservation du flux magnétique. Une telle considération permet de produire localement, notamment au niveau des plaques primaires 500, un effet de saturation. The primary plates, which have a relatively small cross section of surface S t compared to surface S, are traversed by a magnetic induction greater than that traversing the core according to the principle of conservation of magnetic flux. Such a consideration makes it possible to produce locally, in particular at the level of the primary plates 500, a saturation effect.
L'induction magnétique dans les plaques primaires Bst correspond à une amplification de l'induction magnétique Bc dans le noyau ferromagnétique. Cette amplification est fonction de la fraction de surface f et est donnée par la relation suivante :
Figure imgf000017_0002
The magnetic induction in the primary plates B st corresponds to an amplification of the magnetic induction B c in the ferromagnetic core. This amplification is a function of the surface fraction f and is given by the following relation:
Figure imgf000017_0002
Lorsque le courant I circulant dans la bobine augmente, l'induction magnétique augmente également. Toutefois, dès que le courant I circulant dans la bobine atteint le courant de saturation lsat, l'induction magnétique dans les plaques primaires atteint la valeur de saturation Bsat, tandis que le noyau ferromagnétique reste en régime linéaire. When the current I flowing through the coil increases, the magnetic induction also increases. However, as soon as the current I flowing in the coil reaches the saturation current l sat , the magnetic induction in the primary plates reaches the saturation value B sat , while the ferromagnetic core remains in linear regime.
La valeur du courant de saturation est à cet égard donnée par la relation suivante :
Figure imgf000017_0003
Pour un courant I supérieur au courant de saturation lsat, la perméabilité des plaques primaires ps est égale à 1. Afin de déterminer l'amplitude de la variation d'inductance atteignable par un pilotage en courant, il est considéré un fonctionnement nominal à faible induction (l«lsat), hors saturation, suivi d'un fonctionnement à forte induction (l»lsat) où la saturation se produit dans les plaques primaires (ps=l). La variation d'inductance entre ces deux cas limites est donnée par :
Figure imgf000018_0001
The value of the saturation current is in this regard given by the following relation:
Figure imgf000017_0003
For a current I greater than the saturation current l sat , the permeability of the primary plates p s is equal to 1. In order to determine the amplitude of the variation in inductance attainable by current control, nominal operation at low induction (l "l sat ), excluding saturation, followed by high induction operation (l" l sat ) where saturation occurs in the primary plates (p s = l). The variation of inductance between these two borderline cases is given by:
Figure imgf000018_0001
Les figures 6a, 6b, et 7 proposent une autre configuration du noyau ferromagnétique en lien avec le premier mode de réalisation du dispositif d'induction électromagnétique 100. Dans cette autre configuration, le noyau ferromagnétique comprend deux demi-noyaux 200i et 2002 est du type ETD (en double E avec jambe centrale cylindrique), bien connu de l'homme du métier. Figures 6a, 6b, and 7 propose another configuration of the ferromagnetic core in connection with the first embodiment of the electromagnetic induction device 100. In this other configuration, the ferromagnetic core comprises two half-cores 200i and 200 2 is of the ETD type (double E with cylindrical central leg), well known to those skilled in the art.
Les cotes des demi-noyaux ferromagnétiques sont données en relation avec les figures 6a et 6b et reprises dans le tableau suivant :
Figure imgf000018_0002
The dimensions of the ferromagnetic half-cores are given in relation to figures 6a and 6b and repeated in the following table:
Figure imgf000018_0002
Les deux demi-noyaux identiques sont montés en vis-à-vis avec un entrefer ménagé au niveau d'une colonne centrale 207 (figure 7). L'espacement g de l'entrefer est dans cet exemple égal à 5 mm. La structure d'entrefer comprend 5 plaques primaires (21,65 mm x 5mm) de 0,41 mm d'épaisseur et 2 plaques secondaires (21.65 mm x 21.65 mm) de 1 mm d'épaisseur régulièrement espacées. The two identical half-cores are mounted opposite each other with an air gap formed at a central column 207 (FIG. 7). The spacing g of the air gap is in this example equal to 5 mm. The air gap structure comprises 5 primary plates (21.65 mm x 5mm) 0.41mm thick and 2 secondary plates (21.65mm x 21.65mm) 1mm thick evenly spaced.
La perméabilité du matériau ferromagnétique est de 1500 et l'induction à saturation est de 430 mT. La colonne centrale 207 est bobinée avec un enroulement de 5 tours de fil conducteur. The permeability of the ferromagnetic material is 1500 and the saturation induction is 430 mT. The central column 207 is wound with a winding of 5 turns of conductive wire.
Dans ces conditions, le courant de saturation est de 6 A. Pour un courant inférieur à lsat, l'inductance du noyau est de 16 mH et diminue à 3 mH après saturation des plaques primaires. La surface d'échange thermique développée par les plaques secondaires permet d'améliorer le refroidissement par convection naturelle d'air et de limiter réchauffement à 100°C dans la structure. Under these conditions, the saturation current is 6 A. For a current less than 1 sat , the core inductance is 16 mH and decreases to 3 mH after saturation of the primary plates. The heat exchange surface developed by the secondary plates improves cooling by natural air convection and limits heating to 100 ° C in the structure.
La suite de la description concerne un deuxième mode de réalisation du dispositif d'induction électromagnétique 100. The remainder of the description relates to a second embodiment of the electromagnetic induction device 100.
Le dispositif d'induction électromagnétique 100 correspondant à ce deuxième mode peut notamment être mis en œuvre comme composant d'un convertisseur de puissance du type « Dual Active Bridge » (DAB), et reprend pour l'essentiel les éléments décrit précédemment. The electromagnetic induction device 100 corresponding to this second mode can in particular be implemented as a component of a power converter of the “Dual Active Bridge” (DAB) type, and essentially uses the elements described above.
Les figures 8 et 9-11 sont à cet égard des représentations schématiques, en vue de dessus, d'un demi-noyaux 2OO3 et 2OO4 susceptibles d'être mis en œuvre selon respectivement une première variante et une deuxième variante de ce deuxième de réalisation. Figures 8 and 9-11 are in this regard schematic representations, in top view, of a half-cores 2OO 3 and 2OO 4 capable of being implemented according respectively to a first variant and a second variant of this second of achievement.
Selon ce deuxième mode de réalisation, le noyau ferromagnétique 200 comprend un assemblage des deux demi-noyaux 2OO3 et 2OO4. According to this second embodiment, the ferromagnetic core 200 comprises an assembly of the two half-cores 2OO 3 and 2OO 4 .
A cet égard, le noyau ferromagnétique 200 comprend deux bases 101 pourvues chacune de deux faces principales, dites respectivement face interne 101a et face externe 101b, essentiellement parallèles. In this regard, the ferromagnetic core 200 comprises two bases 101 each provided with two main faces, called the inner face 101a and outer face 101b, respectively, essentially parallel.
Les bases se font face chacune selon leur face interne 101a, et l'entrefer variable 400 est dans l'une des bases, plus particulièrement dans son volume. The bases each face each other according to their internal face 101a, and the variable air gap 400 is in one of the bases, more particularly in its volume.
Le noyau comprend en outre une pluralité de jambes, essentiellement parallèles entre elles et qui s'étendent entre les deux faces internes 101a. La pluralité de jambes comprend au moins une jambe principale 102, au moins une jambe latérale 103 et au moins deux jambes de fuites 104 et 105. The core further comprises a plurality of legs, substantially parallel to each other and which extend between the two internal faces 101a. The plurality of legs include at least one main leg 102, at least one side leg 103, and at least two leakage legs 104 and 105.
Le dispositif comprend en outre au moins un bobinage primaire 301 et au moins un bobinage secondaire 302. The device further comprises at least one primary winding 301 and at least one secondary winding 302.
Chacun des bobinages primaire 301 et secondaire 302 comprend une section principale, enroulée autour de la jambe principale 102, et une section de fuite, dites respectivement section de fuite primaire et section de fuite secondaire enroulées chacune sur une jambe de fuites différente 104 et 105. Each of the primary 301 and secondary 302 coils comprises a main section, wound around the main leg 102, and a trailing section, called the primary trailing section and the secondary trailing section, respectively, each wound on a different leakage leg 104 and 105.
De manière avantageuse, l'entrefer variable 400 étant disposé entre les deux jambes de fuites, et les plaques primaires sont en forme d'ailettes. Advantageously, the variable air gap 400 being disposed between the two leakage legs, and the primary plates are in the form of fins.
Toujours de manière avantageuse, les ailettes sont orientées selon une direction définie par un axe joignant les deux jambes de fuites entre lesquelles l'entrefer est disposé. Still advantageously, the fins are oriented in a direction defined by an axis joining the two leakage legs between which the air gap is arranged.
Par ailleurs, l'évidement peut déboucher sur l'une et/ou l'autre de la face interne et de la face externe de la base qui comprend l'entrefer. Furthermore, the recess may open onto one and / or the other of the internal face and the external face of the base which includes the air gap.
A cet égard, la figure 12 est une représentation schématique d'un entrefer 400 débouchant au niveau la face externe 101b d'une base 101 au contact d'une source froide. In this regard, FIG. 12 is a schematic representation of an air gap 400 opening out at the level of the external face 101b of a base 101 in contact with a cold source.
Le noyau ferromagnétique peut comprendre une unique jambe principale 102 et quatre jambes de fuites 104 et 105. The ferromagnetic core can include a single main leg 102 and four leak legs 104 and 105.
A cet égard, la section de fuite primaire comprend deux sections de fuites primaires de sorte que le bobinage primaire 301 comprenne dans l'ordre une des sections de fuites primaire 301a, la section principale 301b, et l'autre section de fuites primaire 301c, les sections de fuites primaires étant enroulées chacune autour d'une jambe de fuites différente. In this regard, the primary leakage section comprises two primary leakage sections so that the primary coil 301 comprises in order one of the primary leakage sections 301a, the main section 301b, and the other primary leakage section 301c, the primary leak sections each being wrapped around a different leak leg.
De manière équivalente, la section de fuite secondaire comprend deux sections de fuites secondaire de sorte que le bobinage secondaire 302 comprenne dans l'ordre une des sections de fuites secondaire 302a, la section principale 302b, et l'autre section de fuites secondaire 302c, les sections de fuites secondaire étant enroulées chacune autour d'une jambe de fuites différente. Selon la première variante (figure 8), l'au moins une jambe latérale 103 comprend quatre jambes latérales 103. Equivalently, the secondary leakage section comprises two secondary leakage sections so that the secondary winding 302 comprises in order one of the secondary leakage sections 302a, the main section 302b, and the other secondary leakage section 302c, the secondary leakage sections each being wound around a different leakage leg. According to the first variant (Figure 8), at least one side leg 103 comprises four side legs 103.
Plus particulièrement, les quatre jambes latérales 103 et les quatre jambes de fuites 104, 105 décrivant un cercle centré sur la jambe principale 102 et dans lequel s'alternent, et de manière régulière, les jambes latérales et les jambes de fuites. Chaque section de fuite primaire est en outre disposée de manière diamétralement opposée à une des sections de fuite secondaire par rapport à la jambe principale. More particularly, the four lateral legs 103 and the four trailing legs 104, 105 describe a circle centered on the main leg 102 and in which the side legs and the trailing legs alternate in a regular manner. Each primary leakage section is further arranged diametrically opposed to one of the secondary leakage sections with respect to the main leg.
Le dispositif ainsi décrit comprend une fonction de transformateur et une fonction d'inductance série. The device thus described comprises a transformer function and a series inductance function.
La fonction de transformateur est assurée par les sections principales 301b et 302b, respectivement, du bobinage primaire 301 et du bobinage secondaire 302, entourées autour de la jambe principale. The transformer function is performed by the main sections 301b and 302b, respectively, of the primary winding 301 and the secondary winding 302, surrounded around the main leg.
Les inductances série créées au niveau des bobinages primaire et secondaire sont assurées par les sections de fuites primaires 301a et 301c et par les sections fuites secondaires 302a et 302c. The series inductances created at the primary and secondary windings are provided by the primary leakage sections 301a and 301c and by the secondary leakage sections 302a and 302c.
Ainsi, un flux magnétique, dit « flux de transformateur », créé au niveau de la jambe principale par le passage d'un courant dans le bobinage primaire suit un parcours en boucle traversant successivement la base, les jambes latérales, l'autre base, et traverse à nouveau la jambe principale. Thus, a magnetic flux, called "transformer flux", created at the level of the main leg by the passage of a current in the primary winding follows a loop path successively crossing the base, the side legs, the other base, and crosses the main leg again.
De manière équivalente, un flux de « fuite » primaire suit un contour différent reliant deux jambes de fuite du circuit primaire et traversant la base cylindrique dans son épaisseur selon une ligne reliant la base des deux jambes de fuites primaires. Le flux de fuite secondaire suit un contour similaire décrit par les deux jambes de fuites secondaires. Equivalently, a primary “leakage” flow follows a different contour connecting two trailing legs of the primary circuit and crossing the cylindrical base in its thickness along a line connecting the base of the two primary leakage legs. The secondary leakage flow follows a similar contour described by the two secondary leakage legs.
La mise en œuvre de l'entrefer variable entre deux jambes de fuite primaire permet de conférer un caractère d'inductance de fuite variable au dispositif. The implementation of the variable air gap between two primary trailing legs makes it possible to confer a variable leak inductance character on the device.
De manière équivalente, La mise en œuvre de l'entrefer variable entre deux jambes de fuite secondaire permet de conférer un caractère d'inductance de fuite variable au dispositif. Selon la deuxième variante (figure 9 à 11), le noyau ferromagnétique comprend deux jambes latérales 103, et quatre jambes de fuites 104 et 105. In an equivalent manner, the implementation of the variable air gap between two secondary trailing legs makes it possible to confer a variable leak inductance character on the device. According to the second variant (FIG. 9 to 11), the ferromagnetic core comprises two lateral legs 103, and four leakage legs 104 and 105.
Les deux jambes de fuites 104 et les deux jambes de fuites 105 forment deux groupes de deux jambes de fuites, dits respectivement premier groupe 106 et deuxième groupe 107. The two leakage legs 104 and the two leakage legs 105 form two groups of two leakage legs, called the first group 106 and second group 107, respectively.
Par ailleurs, les quatre jambes de fuites et les deux jambes latérales décrivent un cercle centré sur la jambe principale, et dans lequel s'alternent, de manière régulière, les jambes latérales et les groupes. Furthermore, the four trailing legs and the two side legs describe a circle centered on the main leg, and in which the side legs and the groups alternate in a regular manner.
De manière avantageuse, l'au moins un entrefer 400 comprend un premier entrefer 401 et un deuxième entrefer 402 disposés à mi-distance entre les jambes de fuites, respectivement, du premier groupe 106 et du deuxième groupe 107. Advantageously, the at least one air gap 400 comprises a first air gap 401 and a second air gap 402 arranged midway between the leakage legs, respectively, of the first group 106 and of the second group 107.
En particulier, chacune des sections de fuite primaire est formées autour, respectivement, d'une des jambes de fuites et de l'autre des jambes de fuites du premier groupe. In particular, each of the primary trailing sections is formed around, respectively, one of the trailing legs and the other of the trailing legs of the first group.
De manière équivalente, chacune des sections de fuite secondaire est formée autour, respectivement, d'une des jambes de fuites et de l'autre des jambes de fuites du deuxième groupe 107. Equivalently, each of the secondary leakage sections is formed around, respectively, one of the leakage legs and the other of the leakage legs of the second group 107.
Selon cette deuxième variante, la proximité entre les jambes de fuites d'un même groupe de jambes de fuites permet un contrôle plus précis des fuites. According to this second variant, the proximity between the leakage legs of the same group of leakage legs allows more precise control of the leaks.
Une barrière de flux 800 peut également être formée dans les bases 101 de manière à limiter le flux magnétique entre les jambes de fuites et les jambes latérales. Ces barrières de flux 800 peuvent notamment comprendre une zone évidée entre chacun des éléments du premier groupe 106 et ceux du deuxième groupe 107 et les jambes latérales. A flux barrier 800 can also be formed in the bases 101 so as to limit the magnetic flux between the leakage legs and the side legs. These flow barriers 800 may in particular include a recessed area between each of the elements of the first group 106 and those of the second group 107 and the side legs.
La zone évidée peut notamment s'étendre à partir du bord et selon un rayon de la base considérée. The hollowed out zone can in particular extend from the edge and along a radius of the base considered.
Enfin quelle que soit la variante considérée, une saignée peut être formée sur l'une et l'autre des faces internes, à distance et autour de chaque jambe de fuites, et qui s'interpose entre la jambe de fuites et la jambe principale. Le procédé de fabrication du noyau selon la présente invention peut faire appel à une technique de moulage par injection (« PIM » ou « Powder Injection Molding » selon la terminologie Anglo-Saxonne). Cette technique est particulièrement bien adaptée pour la production de pièces en grande série de géométrie complexe. Le moulage par injection met en œuvre dans un premier temps une étape de formation d'un mélange maître (« feedstock » selon la terminologie Anglo- Saxonne). Finally, whatever the variant considered, a bleeding can be formed on one and the other of the internal faces, at a distance from and around each leakage leg, and which is interposed between the leakage leg and the main leg. The process for manufacturing the core according to the present invention may make use of an injection molding technique (“PIM” or “Powder Injection Molding” according to Anglo-Saxon terminology). This technique is particularly well suited for the production of large series parts of complex geometry. Injection molding initially implements a step of forming a masterbatch (“feedstock” according to Anglo-Saxon terminology).
Le mélange-maître comprend en particulier un mélange de matière organique (ou liant polymérique) et des poudres inorganiques (métalliques ou céramiques) destinées à former la pièce finale. The masterbatch comprises in particular a mixture of organic material (or polymeric binder) and inorganic powders (metallic or ceramic) intended to form the final part.
Le mélange-maître est injecté dans une presse à injecter, dont la technologie est connue de l'homme du métier. La presse à injecter permet de faire fondre les polymères injectés avec la poudre dans une cavité, et conférer à ladite poudre la forme désirée. Le mélange-maître, ainsi mis en forme et fondu, est soumis à un refroidissement de manière à le solidifier et le figer dans une forme imposée par la presse à injecter. The masterbatch is injected into an injection molding machine, the technology of which is known to those skilled in the art. The injection press makes it possible to melt the polymers injected with the powder in a cavity, and to give said powder the desired shape. The masterbatch, thus shaped and melted, is subjected to cooling so as to solidify it and fix it in a shape imposed by the injection molding machine.
La pièce formée par le mélange-maître est alors démoulée, et déliantée afin d'éliminer la matière organique. La pièce peut ensuite être consolidée par frittage. The part formed by the masterbatch is then unmolded and unbound in order to eliminate the organic matter. The part can then be consolidated by sintering.
RÉFÉRENCES REFERENCES
[1] Jeong et al., "Analysis on Half-Bridge LLC Résonant Converter by Using Varaible Inductance for High Efficiency and Power Density Server Power Supply”, 2017 IEEE Applied Power Electronics Conférence and Exposition, 26-30 Mars 2017, [2] Saeed et al., "Extended Operational Range of Dual-Active-Bridge[1] Jeong et al., "Analysis on Half-Bridge LLC Resonant Converter by Using Varaible Inductance for High Efficiency and Power Density Server Power Supply", 2017 IEEE Applied Power Electronics Conference and Exposition, March 26-30, 2017, [2] Saeed et al., "Extended Operational Range of Dual-Active-Bridge
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[6] US2015/0109086, [6] US2015 / 0109086,
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Claims

Revendications Claims
1. Dispositif d'induction électromagnétique (100) comprenant : 1. Electromagnetic induction device (100) comprising:
-un noyau ferromagnétique (200) ; -a ferromagnetic core (200);
- au moins un entrefer, dit entrefer variable (400), et définissant dans le noyau un volume V, dans lequel sont disposées des plaques principales (500) ferromagnétiques, essentiellement parallèles et agencées selon une direction parallèle à des lignes de champ susceptibles de circuler dans le noyau, les plaques principales (500) présentant une section transversale configurée pour que l'ensemble desdites plaques présente un champ magnétique de saturation inférieur à celui du noyau ferromagnétique (200), les plaques principales (500) étant également pourvues de protubérances latérales (600) destinées à diffuser une chaleur susceptible d'être produite au sein des plaques principales (500) lorsque ces dernières sont parcourues par un champ magnétique supérieur à leur champ magnétique de saturation, lesdites protubérances latérales (600) s'étendant à partir de faces latérales (501) desdites plaques selon une direction essentiellement orthogonale auxdites faces latérales (501). - at least one air gap, called a variable air gap (400), and defining in the core a volume V, in which are arranged the main ferromagnetic plates (500), essentially parallel and arranged in a direction parallel to the field lines capable of circulating in the core, the main plates (500) having a cross section configured so that all of said plates have a saturation magnetic field lower than that of the ferromagnetic core (200), the main plates (500) also being provided with lateral protuberances (600) intended to diffuse a heat capable of being produced within the main plates (500) when the latter are traversed by a magnetic field greater than their saturation magnetic field, said lateral protuberances (600) extending from side faces (501) of said plates in a direction essentially orthogonal to said side faces (501).
2. Dispositif selon la revendication 1, dans lequel les protubérances latérales (600) relient entre elles les plaques principales (500) deux à deux de manière à former des plaques secondaires (700) perpendiculaires auxdites plaques principales (500). 2. Device according to claim 1, wherein the lateral protrusions (600) interconnect the main plates (500) in pairs so as to form secondary plates (700) perpendicular to said main plates (500).
3. Dispositif selon la revendication 1 ou 2, dans lequel le noyau ferromagnétique (200), les plaques principales (500) et les protubérances latérales sont faites d'un même matériau ferromagnétique. 3. Device according to claim 1 or 2, wherein the ferromagnetic core (200), the main plates (500) and the side protrusions are made of the same ferromagnetic material.
4. Dispositif selon l'une des revendications 1 à 3, dans lequel les plaques principales (500) sont toutes identiques. 4. Device according to one of claims 1 to 3, wherein the main plates (500) are all identical.
5. Dispositif selon l'une des revendications 1 à 4, dans lequel un volume vacant Vv du volume V laissé vacant par les plaques principales (500) et les protubérances latérales est comblé, au moins en partie, par un matériau de dissipation thermique qui présente une conductivité thermique supérieure à 10 W/m/K, avantageusement le matériau de dissipation thermique comprend de l'alumine. 5. Device according to one of claims 1 to 4, wherein a vacant volume V v of the volume V left vacant by the main plates (500) and the protuberances sides is filled, at least in part, with a heat dissipation material which has a thermal conductivity greater than 10 W / m / K, advantageously the heat dissipation material comprises alumina.
6. Dispositif selon l'une des revendications 1 à 5, dans lequel le noyau ferromagnétique (200) comprend un matériau ferromagnétique choisi parmi : un alliage métallique du type FeX où X comprend l'un des éléments choisi parmi Si, Al, Co, Ni, oxyde ferrite de structure spinelle du type A(Fe,B)2Û4 avec A = (Mn, Ni) B=(Co, Cu, Al,..). 6. Device according to one of claims 1 to 5, wherein the ferromagnetic core (200) comprises a ferromagnetic material chosen from: a metal alloy of the FeX type where X comprises one of the elements chosen from Si, Al, Co, Ni, ferrite oxide of spinel structure of the type A (Fe, B) 2O4 with A = (Mn, Ni) B = (Co, Cu, Al, ..).
7. Dispositif selon l'une des revendications 1 à 6, dans lequel le noyau ferromagnétique (200) comprend deux extrémités (200a, 200b) planes, essentiellement parallèles entre elles, en regard l'une de l'autre et d'une surface S, les deux extrémités délimitent l'entrefer variable (400), les plaques principales (500) étant disposées perpendiculairement aux extrémités, avantageusement le noyau ferromagnétique (200) comprend un cadre de forme polygonale, et encore plus avantageusement de forme rectangulaire. 7. Device according to one of claims 1 to 6, wherein the ferromagnetic core (200) comprises two ends (200a, 200b) planar, substantially parallel to each other, facing each other and a surface. S, the two ends define the variable air gap (400), the main plates (500) being arranged perpendicular to the ends, advantageously the ferromagnetic core (200) comprises a frame of polygonal shape, and even more advantageously of rectangular shape.
8. Dispositif selon la revendication 7, dans lequel les plaques principales (500) présentent une section transversale d'une surface transversale St, la somme des surfaces transversales de l'ensemble des plaques principales (500) étant inférieure à la surface S. 8. Device according to claim 7, wherein the main plates (500) have a cross section of a transverse area S t , the sum of the transverse areas of all the main plates (500) being less than the area S.
9. Dispositif selon l'une des revendications 1 à 6, dans lequel le noyau ferromagnétique (200) comprend deux bases (101) pourvues chacune de deux faces principales, dites respectivement face interne (101a) et face externe (101b), essentiellement parallèles, les bases (101) se font face chacune selon leur face interne (101a), l'entrefer variable (400) étant formé dans l'une des bases, le noyau (200) comprend en outre une pluralité de jambes, essentiellement parallèles entre elles et qui s'étendent entre les deux faces internes, la pluralité de jambes comprend au moins une jambe principale (102), au moins une jambe latérale (103) et au moins deux jambes de fuites (104, 105) ; le dispositif comprend en outre au moins un bobinage primaire (301) et au moins un bobinage secondaire (302), comprenant chacun une section principale (301b, 302b), enroulée autour de la jambe principale (102), et une section de fuite, dites respectivement section de fuite primaire (301a, 301c) et section de fuite secondaire (302a, 302c) enroulées chacune sur une jambe de fuites différente. 9. Device according to one of claims 1 to 6, wherein the ferromagnetic core (200) comprises two bases (101) each provided with two main faces, said respectively inner face (101a) and outer face (101b), essentially parallel. , the bases (101) each face each other along their internal face (101a), the variable air gap (400) being formed in one of the bases, the core (200) further comprises a plurality of legs, essentially parallel between them and which extend between the two internal faces, the plurality of legs comprises at least one main leg (102), at least one side leg (103) and at least two trailing legs (104, 105); the device further comprises at least one primary coil (301) and at least one secondary coil (302), each comprising a main section (301b, 302b), wound around the main leg (102), and a trailing section, said respectively primary leakage section (301a, 301c) and secondary leakage section (302a, 302c) each wound on a different leakage leg.
10. Dispositif selon la revendication 9, dans lequel l'entrefer variable (400) étant disposé entre les deux jambes de fuites, les plaques primaires étant en forme d'ailettes. 10. Device according to claim 9, wherein the variable air gap (400) being disposed between the two leakage legs, the primary plates being in the form of fins.
11. Dispositif selon la revendication 10, dans lequel les ailettes sont orientées selon une direction définie par un axe joignant les deux jambes de fuites entre lesquelles l'entrefer est disposé. 11. Device according to claim 10, wherein the fins are oriented in a direction defined by an axis joining the two leakage legs between which the air gap is disposed.
12. Dispositif selon l'une des revendications 9 à 11, dans lequel l'évidement débouche sur la face interne (101a) de la base considérée. 12. Device according to one of claims 9 to 11, wherein the recess opens onto the internal face (101a) of the base considered.
13. Dispositif selon l'une des revendications 9 à 12, dans lequel l'évidement débouche sur la face externe (101b) de la base considérée. 13. Device according to one of claims 9 to 12, wherein the recess opens onto the outer face (101b) of the base considered.
14. Dispositif selon l'une des revendications 9 à 13, dans lequel l'au moins une jambe principale (102) comprend une unique jambe principale (102), les au moins deux jambes de fuites comprennent quatre jambes de fuites, dans lequel la section de fuite primaire comprend deux sections de fuites primaires de sorte que le bobinage primaire comprenne dans l'ordre une des sections de fuites primaire (301a), la section principale (301b), et l'autre section de fuites primaire (301c), les sections de fuites primaires étant enroulées chacune autour d'une jambe de fuites différente, et dans lequel la section de fuite secondaire comprend deux sections de fuites secondaire de sorte que le bobinage secondaire comprenne dans l'ordre une des sections de fuites secondaire (302a), la section principale (302b), et l'autre section de fuites secondaire (302c), les sections de fuites secondaire étant enroulées chacune autour d'une jambe de fuites différente. 14. Device according to one of claims 9 to 13, wherein the at least one main leg (102) comprises a single main leg (102), the at least two leakage legs comprise four leakage legs, wherein the primary leakage section comprises two primary leakage sections so that the primary winding comprises in order one of the primary leakage sections (301a), the main section (301b), and the other primary leakage section (301c), the primary leakage sections each being wrapped around a different leakage leg, and wherein the secondary leakage section comprises two secondary leakage sections of so that the secondary winding comprises in order one of the secondary leakage sections (302a), the main section (302b), and the other secondary leakage section (302c), the secondary leakage sections each being wound around a different leaking leg.
15. Dispositif selon la revendication 14, dans lequel l'au moins une jambe latérale comprend quatre jambes latérales, les quatre jambes latérales et les quatre jambes de fuites décrivant un cercle centré sur la jambe principale (102), et dans lequel s'alternent, et de manière régulière, les jambes latérales et les jambes de fuites, chaque section étant disposée de manière diamétralement opposée à une section de fuite secondaire par rapport à la jambe principale (102). 15. Device according to claim 14, wherein the at least one side leg comprises four side legs, the four side legs and the four trailing legs describing a circle centered on the main leg (102), and in which alternate , and regularly, the side legs and the trailing legs, each section being disposed diametrically opposed to a secondary trailing section with respect to the main leg (102).
16. Dispositif selon la revendication 14, dans lequel l'au moins une jambe latérale comprend deux jambes latérales, les au moins deux jambes de fuites comprennent quatre jambes de fuites, formant deux groupes de deux jambes de fuites, dits respectivement premier groupe (106) et deuxième groupe (107), les quatre jambes de fuites et les deux jambes latérales décrivant un cercle centré sur la jambe principale (102), et dans lequel s'alternent, de manière régulière, les jambes latérales et les groupes (106, 107). 16. Device according to claim 14, wherein the at least one lateral leg comprises two lateral legs, the at least two leakage legs comprise four leakage legs, forming two groups of two leakage legs, respectively called the first group (106 ) and second group (107), the four trailing legs and the two side legs describing a circle centered on the main leg (102), and in which alternate, in a regular manner, the side legs and the groups (106, 107).
17. Dispositif selon la revendication 16, dans lequel l'au moins un entrefer comprenant un premier entrefer (401) et un deuxième entrefer (402) disposés à mi-distance entre les jambes de fuites, respectivement, du premier groupe (106) et du deuxième groupe (107). 17. Device according to claim 16, wherein the at least one air gap comprising a first air gap (401) and a second air gap (402) arranged midway between the leakage legs, respectively, of the first group (106) and of the second group (107).
18. Dispositif selon la revendication 17, dans lequel les sections de fuites primaire sont chacune formées autour, respectivement, de l'une et l'autre des jambes de fuite (104) du premier groupe (106), et les sections de fuites secondaire sont chacune formées autour, respectivement, de l'une ou l'autre des jambes de fuites (105) du deuxième groupe (107). 18. Device according to claim 17, wherein the primary leakage sections are each formed around, respectively, one and the other of the trailing legs (104) of the first group (106), and the secondary leakage sections. are each formed around, respectively, one or the other of the leakage legs (105) of the second group (107).
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FR3103624B1 (en) 2021-12-17
CN114730654A (en) 2022-07-08

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