Electromagnetic induction device

Abstract

Electromagnetic induction device (3) comprising: - a ferromagnetic core (1) having a main column (9) and four leakage columns (11) extending parallel to each other along an X axis, - first (21) and second winding (23) each having, in succession, an input connector (E1,E2), a linearly conductive element (25,27) and an output connector (S1,S2), the linearly conductive element having, in traversing it from the input connector to the output connector, an input portion (31,35), an intermediate portion (32,36) and an output portion (33,37), the input portions (31,35) and the output portions (33,37) of the first and second windings each being wound around a different leakage column (11),the intermediate portion (32) of the first winding (21) and the intermediate portion (36) of the second winding (23) being wound around the main column (9) in opposite directions. Figure for the abbreviation: Fig. 4,

Description

Title of the invention: Electromagnetic induction device

[0001] The present invention relates to an electromagnetic induction device, a power converter comprising this device and a method for transferring electrical power using this device.

[0002] In particular, the invention relates to an electromagnetic induction device having first and second windings wound in a specific manner in order to induce limited inductance losses during an electrical power transfer.

[0003] The electromagnetic induction device is advantageously implemented in a power converter, in particular for electrical transfer in the automotive field, and more specifically for charging electric motor vehicles.

[0004] In an electric vehicle, the motor is generally powered by batteries which provide it with the electrical power necessary to move the vehicle.

[0005] To date, batteries can be recharged when the vehicle is stopped, by being electrically connected to fixed electrical distribution terminals and linked to a land-based electrical distribution network.

[0006] An electrical distribution terminal comprises an electrical power converter which converts the alternating voltage (AC) of the terrestrial distribution network into a variable direct voltage (DC) necessary for recharging the batteries.

[0007] Car manufacturers aim to integrate this type of converter into the vehicle, in order to reduce the footprint of the electrical distribution terminals on the road.

[0008] Furthermore, such integration allows reversible operation of the vehicle converter. In other words, in addition to its use for charging the batteries, the converter can be used so that the vehicle batteries can supply electrical energy to the land-based electrical distribution network when the vehicle is stopped, if necessary.

[0009] However, to be integrated into a motor vehicle, such a power converter must be compact, i.e. have a power volume density greater than 2 kW / 1. To this end, it requires magnetic components and, more particularly, transformers operating at high frequency.

[0010] The power converter must also be compatible with reversible mode and its implementation must be quieter than in a distribution terminal.

[0011] Finally, the converter must have a high efficiency. Since the energy is exchanged several times between the battery and the terrestrial electricity distribution network, the inductance losses within the converter must therefore be minimized during the transfer of power.

[0012] To satisfy these constraints, converters of the resonant structure type or so-called "LLC" type and converters of the double active bridge type or so-called "DAB" type, an acronym for "Dual Active Bridge", have been proposed. These converters are for example described in S. Inoué and H. Akagi, "A Bidirectional DC-DC Converter for an Energy Storage System With Galvanic Isolation", IEEE Transactions on Power Electronics, Vol. 22, No. 6, 2007 and are known.

[0013] A converter of the LLC type, illustrated in [Fig.l], is based on the integration of a resonant type stage ("resonant tank" in English) comprising a transformer associated with capacitors of 2C capacity and inductances mounted in "series".

[0014] The inductors and capacitors are chosen to operate in resonance at a frequency equal to the nominal switching frequency of the switches. The transformer is further arranged to galvanically isolate the input and load circuits, and adapt the voltage value applied to the terminals of the load.

[0015] The converter comprises a primary winding and a secondary winding wound around a magnetic core, with a number of turns ratio n equal to the ratio of the primary and secondary voltages.

[0016] In a resonator of the LLC type, illustrated schematically in [Fig.l], the resonant series components are duplicated on either side of the same winding. The magnetizing inductance of the transformer, a function of the number of turns of the first winding and the geometry of the core, is determined to ensure the adjustment of the converter gain.

[0017] The topology of DAB type converters, illustrated schematically in [Fig.2], comprises arms placed on either side of the transformer and which are devoid of capacitance. The series inductances have the function of transmitting the power. The magnetizing inductance of the transformer is not constrained and only needs to be high enough to obtain a good utilization rate. However, in this bidirectional topology, it is preferable to implement four inductances connected in series with the transformer so as to have a symmetrical circuit and thus limit the low-level common mode disturbances which in fact reduce the size of the input filtering.

[0018] WO 2020 / 115389 A1 describes an electromagnetic induction device integrated within a DAB type converter, which has the advantage of being compact. However, the additional magnetic fluxes that this device can generate can contribute significantly to the magnetic losses of the core, also called "iron losses" if they are not directed adequately.

[0019] There is therefore a need for an electromagnetic induction device which makes it possible to limit these losses, in particular for an application within a converter. electrical power, in particular of the LLC type or preferably of the DAB type.

[0020] The invention relates to an electromagnetic induction device comprising: - a ferromagnetic core comprising a main column and four trailing columns which extend parallel to an X axis to each other, - a first winding and a second winding which each comprise, in succession, an input connector, a linearly conductive member and an output connector electrically connected in series, the linearly conductive member comprising, as it passes through it from the input connector to the output connector, an input portion, an intermediate portion, and an output portion, the input portions and the output portions of the first and second windings each being wound around a different leakage column, the intermediate portion of the first winding and the intermediate portion of the second winding being wound around the main column, the winding direction of the intermediate portion of the first winding being opposite to the winding direction of the intermediate portion of the second winding.

[0021] As will appear in more detail later, the inventors have found that this specific arrangement of the windings of the first and second coils makes it possible to significantly limit the inductance losses of a power converter comprising the electromagnetic induction device according to the invention.

[0022] The winding direction of each portion around the corresponding column is defined by traversing the corresponding linearly conductive member from the input connector to the output connector, with the extension axis of the main column and the extension axes of each of the trailing columns oriented in the same direction, and by observing the first and second windings from the same observation location and in an observation direction parallel to the extension axis of the main column.

[0023] Preferably, the winding direction of the intermediate portion of the first winding is opposite to the winding direction of the input portion of the first winding and / or to the winding direction of the output portion of the first winding, and the winding direction of the intermediate portion of the second winding is opposite to the winding direction of the input portion of the second winding and / or to the winding direction of the output portion of the second winding.

[0024] Preferably, the winding direction of the intermediate portion of the first winding is opposite to the winding direction of the input portion of the first winding and identical to the winding direction of the output portion of the first winding, or vice versa, and the winding direction of the intermediate portion of the second winding is opposite to the winding direction of the input portion of the second winding and identical to the winding direction of the output portion of the second winding, or vice versa.

[0025] Preferably, the winding direction of the input portion of the first winding and the winding direction of the input portion of the second winding are identical, and the winding direction of the output portion of the first winding and the winding direction of the output portion of the second winding are identical.

[0026] The linearly conductive member of the first winding and the linearly conductive member of the second winding are referred to as the first linearly conductive member and the second linearly conductive member respectively.

[0027] The linearly conductive member of the first winding and / or the linearly conductive member of the second winding are for example a solid wire, a Litz wire or a cable, for example made of a copper or aluminum-based alloy.

[0028] Each of the portions of the first and second linearly conductive members comprises at least one, preferably several, turns wound around the corresponding column.

[0029] Preferably, the ferromagnetic core comprises lower and upper plates, the leakage columns and the main column extending from the lower plate to the upper plate. In other words, the leakage columns and the main column are preferably in contact with the lower and upper plates.

[0030] Preferably, the first winding is provided with at least one identifier of the input connector of the first winding and / or at least one identifier of the output connector of the first winding and the second winding is provided with at least one identifier of the input connector of the second winding and / or at least one identifier of the output connector of the second winding. The identifier of one of said connectors facilitates the distinction between the input and output connectors of a winding and simplifies the electrical connection of the electromagnetic induction device.

[0031] At least one of the leakage columns, preferably all the leakage columns and / or the main column may each have an air gap which preferably extends transversely to the X axis.

[0032] The trailing columns and the main column may be cylindrical in revolution.

[0033] The leakage columns are preferably arranged regularly, radially and / or angularly, around the extension axis of the main column.

[0034] Preferably, the leakage columns around which the first winding is wound are arranged on one side of a median plane of the ferromagnetic core, preferably containing the extension axis of the main column, the leakage columns around which the second winding is wound being arranged on the other side of the median plane.

[0035] Furthermore, the device preferably comprises return columns, extending parallel to the main column and extending from the lower plate to the upper plate. The return columns are preferably symmetrical to each other with respect to the extension axis of the main column. Each return column may be arranged between two leakage columns.

[0036] The invention also relates to an electrical power converter, preferably of the double active bridge type or of the resonant structure type, comprising the electromagnetic induction device according to the invention.

[0037] Preferably, the converter comprises a control member configured so that the phase shift between the currents flowing in the first and second windings is less than or equal to 50°.

[0038] The invention further relates to a method for transferring power between an electrical energy source and an apparatus electrically connected to each other by the electrical power converter according to the invention, the method comprising the circulation of a first electrical current coming from the electrical energy source in the first winding of the electromagnetic induction device and the induction of a second electrical current circulating in the second winding of the electromagnetic induction device with a phase shift between the first and second electrical currents less than or equal to 50°.

[0039] According to a first embodiment, the electrical energy source is an electrical production plant electrically connected to the electrical power converter via a terrestrial electrical distribution network and the device is a battery of a motor vehicle. The first winding and the second winding of the electromagnetic induction device then respectively define a primary winding and a secondary winding of the electromagnetic induction device.

[0040] According to a second embodiment, the electrical energy source is a battery of a motor vehicle and the device is electrically connected to the electrical power converter by a terrestrial electrical distribution network. The first winding and the second winding of the electromagnetic induction device then respectively define a secondary winding and a primary winding of the electromagnetic induction device.

[0041] Preferably, the converter is configured to implement the method according to the invention. Preferably, it is adapted to implement the first and second modes of implementation of the method.

[0042] The invention finally relates to a motor vehicle comprising the electric power converter according to the invention. Brief description of the drawings

[0043] Other characteristics and advantages will appear on reading the detailed description presented for illustrative and non-limiting purposes, and the attached drawing in which:

[0044] [Fig-1] and [Fig.2] schematically represent converter topologies of the LLC and DAB type of the prior art respectively;

[0045] [Fig.3] is a perspective view of the core of an exemplary electromagnetic device;

[0046] [Fig.4] are schematic top views of a section of the device of [Fig.3] along a median longitudinal plane, for three variants a) to c) of embodiment of the invention; with the first winding represented on the left and the second winding on the right;

[0047] [Fig.5] are schematic top views of a section of the device of [Fig.3] along a median longitudinal plane, for three variants a) to c) outside the invention; with the first winding represented on the left and the second winding on the right;

[0048] [Fig.6] schematically represents the equivalent electrical circuit of an example of a DAB type converter integrating the device illustrated in Figures 4 and 5;

[0049] [Fig.7] is a graph illustrating the evolution of the inductance losses, expressed in W, as a function of the phase shift between the currents flowing in the first and second windings respectively, expressed in ° for the different variants according to the invention and outside the invention illustrated in Figures 4 and 5,

[0050] [Fig.8] is a graph illustrating the evolution of the inductance losses, expressed in W, as a function of the phase shift between the currents flowing in the first and second windings respectively, expressed in ° for two preferred variants of the invention and for a device of the prior art and

[0051] [Fig.9] and [Fig. 10] are schematic top views of sections of variants of the device of [Fig.3] along a median longitudinal plane. Detailed description

[0052] Figures 1 and 2 were presented previously in the description of the prior art.

[0053] [Fig. 3] illustrates the ferromagnetic core 1 of an example of an electromagnetic device 3 according to the invention.

[0054] The electromagnetic core 1 may comprise a material chosen from MnZn, NiZn and their mixtures. It may be sintered.

[0055] The core 1 comprises a lower plate 5 and an upper plate 7 which preferably extend parallel to each other and which are arranged face to face. The lower and upper plates are for example plates. They may have a generally parallelepiped shape, or a disc shape, as illustrated in the [Fig.8]. The lower and / or upper plates may have one or more notches 10, as illustrated in [Fig. 10], in particular to reduce the mass of the core.

[0056] The core 1 further comprises a plurality of columns which extend from one side of the lower plate 5 to the upper plate 7. The plurality of columns is perpendicular to the lower and upper plates.

[0057] The plurality of columns comprises a main column 9, four trailing columns 11 and two return columns 13 which are parallel to each other and to an X axis.

[0058] The columns each have an elongated shape, for example a bar. They can be solid or hollow.

[0059] Preferably, the main column and / or the trailing columns have a general cylindrical shape of revolution.

[0060] The main column 9 is arranged in the center of the ferromagnetic core 1. The leakage columns 11 are arranged radially at the same distance from the main column. The radial distance between the main column 9 and a leakage column 11 is the distance between the extension axes of said columns, measured perpendicular to said columns.

[0061] The leakage columns 11 are further symmetrical to each other with respect to two transverse median planes of the core which each contain the extension axis of the main column and which are perpendicular. In a variant, the leakage columns may be arranged in a regular angular manner. In other words, the angle between two radii joining each pair of two leakage columns adjacent to the main column may be constant.

[0062] The leakage columns 11 each comprise an air gap 15. The air gap may be arranged in the center of the corresponding leakage column 11. Preferably, it is arranged closer to the lower plate 5 or the upper plate 7, so as to provide a sufficient winding surface for a coil and / or to limit the impact of radiating electromagnetic fluxes which can lead to an increase in the electrical resistance of the electrical conductors forming the coil. In a variant not shown, the main column may comprise an air gap.

[0063] The ferromagnetic core 1 preferably comprises two half-cores 17, which can be separated from each other by a longitudinal plane P.

[0064] The longitudinal plane P can be median as illustrated in [Fig.3]. Each of the half-cores can thus be obtained separately, for example by sintering and the parts are assembled, for example clamped against each other using an external clamping clip.

[0065] The return columns 13 are arranged diametrically opposite the main column 9.

[0066] The electromagnetic induction device further comprises a first winding 21 and a second winding 23.

[0067] The first 21 and second 23 windings respectively comprise first 25 and second 27 electrically conductive linear members.

[0068] [Fig.4] is a view along the X axis of the section along the longitudinal median plane P of different configurations a) to c) of winding of the first 21 and second 23 windings according to the invention.

[0069] To facilitate the visualization of the windings, for each of the configurations a) to c), only the winding of the first winding 21 on the left and only the winding of the second winding 23 on the right have been illustrated. Obviously, the electromagnetic induction device 3 according to the invention jointly comprises these two windings.

[0070] The first winding comprises an input connector El and an output connector SI which are attached to each of the opposite ends of the first electrically conductive linear member 23. The second winding comprises an input connector E2 and an output connector S2 which are attached to each of the opposite ends of the second electrically conductive linear member 27.

[0071] Each of the first and second windings preferably comprises an identifier which makes it possible to easily identify the input connector of the corresponding output connector. The identifier is for example a colored mark applied to at least one of the connectors, for example a green mark on the input connector and a red mark on the output connector. Alternatively, it may be a letter, for example an “I”, the initial of the word “input” in English (the translation of which into French is the word “entrée”), for the input connector and an “O”, the initial of the word “output” in English (the translation of which into French is the word “sortie”), for the output connector. According to yet another variant, the input connector and / or the output connector of one of the first and second windings may comprise a key to prevent improper connection. Obviously, these different types of identifier may be combined together.

[0072] For each of the configurations a) to c) of [Fig. 3], the first winding 21 comprises an input portion 31, fixed to the input connector E1 and which is wound around a leakage column 11. The input portion 31 is extended by an intermediate portion 32 wound around the main column 9. The intermediate portion 32 is extended by an output portion 33 wound around another leakage column and which is connected to the output connector SL. As regards the second winding, it comprises an input portion 35, fixed to the input connector E2 and which is wound around a leakage column 11, different from those around which the first winding 21 is wound. The input portion 35 is extended by an intermediate portion 36 wound around the main column 9. The intermediate portion 36 is extended by an output portion 37 wound around a leakage column 11 different from that on which the input portion 35 of the second winding is wound and different from those on which the first winding 21 is wound. The output portion 37 of the second conductive linear member is connected to the output connector S2.

[0073] Furthermore, the following convention has been adopted by traversing the first winding 21 and the second winding 23 from their respective input connectors E1, E2 to their respective output connectors S1, S2, and by orienting all the extension axes of the trailing columns and the main column in the same direction.

[0074] In the example illustrated in Figures 4 and 5, the winding direction of each portion is indicated by the arrows along the first 25 and second 27 electrically conductive members starting from the respective input connectors E1, E2, to the respective output connectors S1, S2. Furthermore, when a portion among the input, intermediate and output portions of one of the first or second windings is shown wound in the clockwise direction, it will be indicated as being wound in the “S” direction and in the “N” direction if it is wound in the counterclockwise direction. At the center of each leakage column and in the main column, the direction of the induced magnetic flux has been materialized by traveling through the corresponding portion of the electrically conductive member from the input to the output of the winding.

[0075] According to this nomenclature, the succession of three letters among N and S indicates the winding direction of each of the input, intermediate and output portions of the winding.

[0076] For example, assigning "NSN" to a winding means that when traversing the latter from the input connector to the output connector, the input portion is wound counterclockwise, the intermediate portion is oriented clockwise and the output portion is oriented counterclockwise.

[0077] The examples illustrated in [Fig. 4] are all according to the invention. In particular, as can be seen in these figures, they all have an intermediate portion 32 of the first winding 21 which is wound around the main column 9 in a winding direction opposite to that of the intermediate portion 36 of the second winding 23.

[0078] [Fig. 5] shows three comparative configurations of winding of the first and second windings in which the intermediate portions 32, 36 of the first 21 and second 23 windings are wound in the same direction by traveling through the first and second windings from their input connector to their respective output connector.

[0079] In operation, part of the magnetic flux generated by the currents flowing in the first and second windings circulates from the main column 9 to the lower 5 and upper 7 plates before returning to the main column. Furthermore, the magnetic flux generated by each of the leakage columns 11 can circulate towards the main column 9 and / or in a return column 13, whether or not crossing the air gap 15 depending on the direction of the winding. Each leakage column can therefore induce two paths of circulation of the magnetic flux, the generation of which can be coupled to the magnetic fluxes generated by the other leakage columns. Examples

[0080] The following example shows a dimensioning of a device as described in Figures 3 and 4 and the properties of this device have been numerically simulated.

[0081] In particular, Table 1 presents the specifications of an electrical power converter 38 of the DAB type, in which the device is integrated. [Fig.6] schematically illustrates the equivalent electrical circuit of the converter.

[0082] [Tables 1] Quantity Target value Unit Input voltage (rms) 230 V Output voltage at rated power (rms) 690 V Rated power from 2 to 7 kW Transformation ratio nt 3 Resonant series inductance LrPi = LrP2 5 + / - 5% pH Resonant series inductance LrS[ = LrS2 5 + / - 5% pH Resonant series inductance Lr= 2*LrP[ + 2*LrP2 / nt2 11 + / -5% pH Magnetizing inductance Lm 900 + / - 5% pH Frequency range at rated power 100 kHz Table 1

[0083] The ferromagnetic core is formed from the 3C95 alloy marketed by the company Ferroxcube®. The inductance losses were calculated at an average temperature of 80°.

[0084] The core has a volume of 63 cm3 and has a mass of 300 g. The bulk volume of the core, including the volume of air between the columns, is 100 cm3. Such a core has a mass saving of approximately 50% compared to a reference prior art device in which the series inductances are arranged outside the core.

[0085] The main column has a diameter of 26 mm. The diameter of each trailing column is equal to 14 mm. The first winding has 5 turns around each of the trailing columns around which it is wound, and 7 turns on the main column. The second winding has 5 turns around each of the trailing columns around which it is wound and 21 turns on the main column.

[0086] The electromagnetic properties were simulated by fixing the desired phase shift between the current flowing in the first winding, acting as primary, and the second winding, acting as secondary, for a power converter in which the devices according to the invention illustrated in [Fig.4] a) to c) and the devices outside the invention illustrated in [Fig.5] a) to c) have been integrated.

[0087] The inductance losses were measured for different fixed phase shifts between the currents flowing in the first and second windings, between 15° and 90°, and in particular for phase shifts less than or equal to 70°, which are characteristic of the phase shifts generally implemented within a DAB type converter. They are illustrated in [Fig.7].

[0088] It is observed for the examples outside the invention (winding configuration of NNN-NNN, NSN-NSN and NSS-NSS coils), that the inductance losses are higher than for the examples according to the invention (winding configuration NNN-SSS, NSN-SNS and NSS-SNN), over the phase shift range considered between 15° and 70°.

[0089] Differences in inductance losses exist for the winding configurations of coils according to the invention. Without being bound by any theory, the inventors are of the opinion that these differences result from local magnetic flux concentrations in the core, the intensity of which depends on the winding configuration of the trailing legs. For example, the “NSN-NSN” winding configuration, presented as a comparative example, is less efficient than the other winding configurations because it concentrates approximately twice as many inductance losses in the lower 5 and upper 7 plates as the examples of winding configurations according to the invention in which the winding directions of the intermediate portions of the first and second windings are opposite, for a phase shift of 90°.Furthermore, for a phase shift of 90°, in the return legs 13 it concentrates approximately eight times more inductance losses than the example of winding configuration “NSS-SNN” according to the invention, and approximately three times more inductance losses than the example of winding configuration “NNN-SSS” according to the invention.

[0090] The example of a winding configuration “NNN-SSS” according to the invention is less efficient than the example of a configuration “NSS-SNN” according to the invention, because it generates more inductance losses in the return legs 13 (approximately 2.4 times). Another example of an advantageous winding configuration, not shown, is the confi- “SNN-SSN” configuration according to the invention, in which: - the winding directions of the input portions of the primary and secondary windings are identical, - the winding directions of the output portions of the primary and secondary windings are identical, and - the winding directions of the intermediate portions of the primary and secondary windings are opposite. This example would allow to obtain a gain of about 3% compared to the example of the “NSS-SNN” configuration thanks to a reduction of the inductance losses of about 20% in the return legs (13) (where the losses are quite low overall -3-4W compared to the ~45W of total losses). The phase shift considered in these comparisons is always 90°.

[0091] The device according to the invention thus makes it possible to reduce inductance losses with winding configurations which induce magnetic fluxes which are in opposite directions in the main column.

[0092] The most favorable winding configurations of the first and second windings according to the invention are of the NNN-SSS and NSS-SNN type. These configurations are compared to the reference electromagnetic induction device, comprising a core in which the main column and the four external inductances are wound and spaced from the core. The main column is wound with 7 turns in the primary and 21 turns in the secondary. The external inductances of 5pH define the inductances LrPl, LrPl, LrSl and LrS2 of [Fig. 3]. The phase shift between the primary and secondary voltages has been set at different values ​​between 15° and 90°.

[0093] As can be seen in [Fig.8], up to a phase shift of about 50°, the conversion of electrical power by means of the device according to the invention according to the winding configurations of the first and second windings NNN-SSS and NSS-SNN is carried out with less inductance losses than with the reference device. The device according to the invention is therefore particularly well suited for application within a DAB type power converter, in which the phase shift is generally controlled to an optimal value of about 30°, as defined in "Design Optimization of High Frequency Transformer for Dual Active Bridge DC-DC Converter", KD Hoang and J. Wang, DOI: 10.1109 / ICElMach.2012.6350205.

[0094] Furthermore, even if the losses are higher for phase shifts greater than 50°, the device according to the invention is nevertheless more compact than the reference device, and therefore has an advantage over the latter when it has to be installed in a confined space.

Claims

Claims

1. Electromagnetic induction device (3) comprising: - a ferromagnetic core (1) comprising a main column (9) and four leakage columns (11) which extend parallel to an axis X to each other, - a first winding (21) and a second winding (23) which each comprise, in succession, an input connector (E1, E2), a linearly conductive member (25, 27) and an output connector (S1, S2) electrically connected in series, the linearly conductive member comprising, as it passes through it from the input connector to the output connector, an input portion (31, 35), an intermediate portion (32, 36) and an output portion (33, 37), the input portions (31, 35) and the output portions (33, 37) of the first and second windings each being wound around a different leakage column (11),the intermediate portion (32) of the first winding (21) and the intermediate portion (36) of the second winding (23) being wound around the main column (9), the winding direction of the intermediate portion (32) of the first winding being opposite to the winding direction of the intermediate portion (36) of the second winding.,

2. Device according to claim 1, the winding direction of the intermediate portion (32) of the first winding being opposite to the winding direction of the input portion (31) of the first winding and / or to the winding direction of the output portion (33) of the first winding, and the winding direction of the intermediate portion (36) of the second winding being opposite to the winding direction of the input portion (35) of the second winding and / or to the winding direction of the output portion (37) of the second winding.

3. Device according to claim 1, the winding direction of the intermediate portion (32) of the first winding being opposite to the winding direction of the input portion (31) of the first winding and identical to the winding direction of the output portion (33) of the first winding, or vice versa, and the winding direction of the intermediate portion (36) of the second winding being opposite to the winding direction of the input portion (35) of the second winding and identical to the winding direction of the output portion (37) of the second winding, or vice versa.

4. Device according to claim 3, the winding direction of the input portion (31) of the first winding and the winding direction of the input portion (35) of the second winding being identical, and the winding direction of the output portion (33) of the first winding and the winding direction of the output portion (37) of the second winding being identical.

5. Device according to any one of the preceding claims, the first winding being provided with at least one identifier of the input connector of the first winding and / or at least one identifier of the output connector of the first winding and the second winding being provided with at least one identifier of the input connector of the second winding and / or at least one identifier of the output connector of the second winding.

6. Device according to any one of the preceding claims, the ferromagnetic core (1) comprising lower (5) and upper (7) plates, the leakage columns (11) and the main column (9) extending from the lower plate to the upper plate.

7. Device according to any one of the preceding claims, at least one of the leakage columns (11), preferably all the leakage columns, and / or the main column (9) each having an air gap (15) which preferably extends transversely to the X axis.

8. Device according to any one of the preceding claims, the leakage columns and the main column being cylindrical in revolution.

9. Device according to any one of the preceding claims, the leakage columns being arranged regularly, radially and / or angularly, around the axis of extension of the main column.

10. Device according to any one of the preceding claims, the leakage columns around which the first winding is wound being arranged on one side of a median plane of the ferromagnetic core, preferably containing the extension axis of the main column, the leakage columns around which the second winding is wound being arranged on the other side of the median plane.

11. An electrical power converter (38), preferably of the double active bridge type or of the resonant structure type, comprising the electromagnetic induction device (3) according to any one of claims 1 to 10.

12. A method of transferring electrical power between a power source electrical (40) and an apparatus (42) electrically connected to each other by the electrical power converter (38) according to the preceding claim, the method comprising the circulation of a first electric current (IJ) coming from the electrical energy source in the first winding of the electromagnetic induction device (3) and the induction of a second electric current (I2) circulating in the second winding of the electromagnetic induction device (3) with a phase shift between the first and second electric currents less than or equal to 50°.

13. A method according to claim 12, the electrical energy source being an electrical production plant electrically connected to the electrical power converter via a land-based electrical distribution network and the apparatus being a battery of a motor vehicle.

14. A method according to claim 12, the electrical energy source being a battery of a motor vehicle and the apparatus being electrically connected to the electrical power converter by a land-based electrical distribution network.

15. A motor vehicle comprising the electric power converter according to claim 11.

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