Three-phase transformer for an isolated voltage converter

Abstract

The invention relates to a three-phase transformer (15) for an isolated voltage converter, comprising: - a magnetic circuit (22), comprising a first part (23) and a second part (24), each part (23, 24) comprising: a base (26) with a substantially triangular outline, and three pads (27) each extending towards the base (26) of the other part of the magnetic circuit (22), - three supports (30) of electrical conductors (31, 32), each support (30) being mounted on two facing pads (27) belonging to one and the other part (23, 24), respectively, of the magnetic circuit (22), each support (30) of electrical conductors (31, 32) carrying two electrical windings (20, 21) that are coupled inductively to one another via the magnetic circuit (22), characterized in that each pad (27) of one part (22) of the magnetic circuit defines at least one air gap (28) other than via its cooperation with the pad (27) of the other part (23) of the magnetic circuit that it faces.

Description

[0001] Description

[0002] Title of the invention: Three-phase transformer for isolated voltage converter

[0003] The present invention relates to a three-phase transformer for an isolated voltage converter, such a voltage converter being for example integrated into a component for the electrical supply of a vehicle electrical energy storage unit, also called a "charger" of this electrical energy storage unit. The electrical energy storage unit is for example a battery, which may have a nominal voltage greater than 60V, for example greater than or equal to 300V, 400V, 800V, or even 1000V. The voltage converter receives for example an alternating voltage from an electrical network and supplies the battery with a direct voltage. This converter can convey a power greater than 5kW, for example greater than 7kW, for example greater than 11kW, in particular 22kW or more. Such a converter comprises a three-phase transformer.The use of such a transformer can allow galvanic isolation and voltage adaptation.

[0004] Three-phase transformers are already known, comprising three coils, each formed by a winding around a ferrite column or core arranged in the same plane in an aluminum case. This type of transformer has several disadvantages that limit its performance. These disadvantages are high inductance drops when the transformer is arranged in the aluminum case, unbalanced currents, a non-uniform resonant frequency, and high losses in the aluminum case.

[0005] Documents FR 3 113 178, DE 102018 206 389 and JP 2019-079944 disclose multi-leg transformers with a single air gap per leg carrying electrical windings.

[0006] There is a need to address the above drawbacks.

[0007] The invention aims to meet this need and achieves this, according to one of its aspects, using a three-phase transformer for an isolated voltage converter, comprising:

[0008] - a magnetic circuit, comprising a first part and a second part, each part comprising: a base of substantially triangular outline, in particular of outline defining an equilateral triangle, and three pads each extending towards the base of the other part of the magnetic circuit,

[0009] - three electrical conductor supports, each support being mounted on two facing pads belonging respectively to one and the other of the parts of the magnetic circuit, each electrical conductor support carrying two electrical windings in inductive coupling with each other via the magnetic circuit, characterized in that each pad of a part of the magnetic circuit defines at least one air gap other than via its cooperation with the pad of the other part of the magnetic circuit with which it is facing.

[0010] Thus, in the transformer according to the invention, for each phase, the magnetic field allowing inductive coupling crosses at least three air gaps. This avoids the need for additional resonant inductances for decoupling purposes. This results in a gain in space for the converter integrating the transformer.

[0011] The magnetic circuit may include a central leg carried by one of the parts of the magnetic circuit. This central leg may reduce iron losses in the magnetic circuit.

[0012] The central leg can be made in one piece with the part of the magnetic circuit that carries it.

[0013] The central leg can extend between two ends, each in contact with one of the bases of the magnetic circuit. No air gap is then provided in the central leg. Due to the absence of an air gap in the central leg and the presence of air gaps at the pads of the magnetic circuit, the phases of the transformer are decoupled and the inductance leaks are balanced.

[0014] The central leg may have a core and three outgrowths extending from this core, each outgrowth extending between two neighboring pads carried by the same part of the magnetic circuit.

[0015] Each outgrowth of the central leg may have a wall facing a stud whose shape is the same as that of the stud. This similarity of shape may favor the integration of these outgrowths in the space between two neighboring studs.

[0016] Each pad may have its portion extending from the base of the part of the magnetic circuit which is made in one piece with this base of the part of the magnetic circuit.

[0017] From one part of the magnetic circuit to the other, the pads may extend towards the base of the other part of the magnetic circuit over the same height. In other words, the height of the pads carried by one part of the magnetic circuit from its base may be equal to the height of the pads carried by the other part of the magnetic circuit from its base.

[0018] The magnetic field circulating between two electrical windings carried by the same support of electrical conductors can cross exactly three air gaps. In other words, two pads belonging respectively to a part of the magnetic circuit and facing each other can define a peripheral leg and this peripheral leg can have exactly three air gaps.

[0019] Each electrical conductor support may include:

[0020] - a wall around which the electrical windings are arranged, this wall defining in particular a hollow cylinder of circular cross-section, and

[0021] - three flanges offset along the longitudinal axis of the support, so that one of the electrical windings is arranged between the first and second flanges and the other of the electrical windings is arranged between the second and third flanges.

[0022] The gap between two consecutive edges can be constant or vary.

[0023] In other words, the two electrical windings carried by a support of electrical conductors can follow one another along this support, without overlapping along planes perpendicular to the longitudinal axis of this support.

[0024] Each electrical conductor support can integrate at least one of:

[0025] - a system for guiding at least one of the two electrical conductors outside the electrical winding that it defines,

[0026] - a system for holding this support on the magnetic circuit,

[0027] - a system for holding this support on a transformer housing, in particular on a body of this housing, and

[0028] - a system for holding a transformer housing cover on this support.

[0029] Such an electrical conductor support integrating all or part of the aforementioned systems can be made from a single piece, for example from plastic such as polybutylene terephthalate (PB T), or polyamide (PA).

[0030] The aforementioned guidance system may comprise at least one clamp cooperating with one of the electrical conductors beyond one end of the electrical winding that it defines.

[0031] This guidance system may comprise two additional walls extending along the longitudinal axis of the support, these two additional walls being offset and defining between them a guidance channel receiving at least one of the electrical conductors outside the winding that it defines.

[0032] The aforementioned system for holding the support on the magnetic circuit may comprise at least one pad projecting relative to the rest of the support. The pad may define a surface coming into contact with a surface of a base of the magnetic circuit.

[0033] The aforementioned system for holding the support on the transformer housing may comprise at least one pin, in particular a single pin, projecting relative to the rest of the support. The pin may have a cross-section perpendicular to the longitudinal axis of the support, which is cruciform. The pin may be force-fitted into an opening provided in the housing, in particular in the body of the housing, so as to ensure that the support is held on the housing.

[0034] The aforementioned system for holding the housing cover on the support may comprise at least one pin projecting relative to the rest of the support. The pin may have a cross-section perpendicular to the longitudinal axis of the support. The pin may be force-fitted into an opening provided in the housing cover, so as to ensure that the cover is held on the support.

[0035] The system for holding the housing cover on the support and the additional walls of the guide system may protrude from the rest of the support on the same side of the support, along the longitudinal axis of this support.

[0036] The housing cover retaining system on the bracket and the bracket retaining system on the transformer housing may protrude from the remainder of the bracket from opposite sides of the bracket along the longitudinal axis of the bracket.

[0037] In another variant, the cover can be held on the housing body by means of screws received in holes made in the wall of the housing body, in particular in holes made in a shoulder of the wall of the housing body. This holding of the cover is then not done via the support of electrical conductors. The use, with this screw fixing, of a metal cover makes it possible to ensure EMC shielding of the housing.

[0038] The magnetic circuit and the electrical conductor supports are, for example, arranged in the housing, the latter being filled in particular with a resin which is then polymerized to immobilize the interior of the housing.

[0039] The three electrical conductor supports can define a triangular pattern, including an equilateral triangle.

[0040] The invention also relates, according to another of its aspects, to a component for the electrical power supply of a vehicle electrical energy storage unit, comprising the transformer defined above. The electrical energy storage unit is for example a battery which may have one of the nominal voltages above.

[0041] The invention may be better understood by reading the following description of non-limiting examples of its implementation:

[0042] - [Fig.l] schematically represents part of the electrical circuit of a component for the electrical power supply of a vehicle electrical energy storage unit

[0043] - [Fig.2] represents in elevation an example of a three-phase transformer which can be used in the circuit of figure 1, - [Fig.3] represents in isolation the magnetic circuit of the three-phase transformer of figure 2,

[0044] - [Fig.4] partially represents the three-phase transformer of figures 2 and 3 when the housing cover is removed

[0045] - [Fig.5] shows a detail of an example of a system for holding the transformer housing cover on the support,

[0046] - [Fig.6] represents the cover of the housing of figure 4,

[0047] - [Fig.7] represents in isolation the body of the terminal block visible in figure 2,

[0048] - [Fig.8] represents the body of figure 7 in which inserts are arranged,

[0049] - [Fig.9] represents the terminal block of figures 7 and 8 with electrically conductive bar and screws,

[0050] - [Fig.10] represents the face of the transformer opposite to that shown in figure 4,

[0051] - [Fig.11] is a view of the transformer electrical conductor support from the same side as Fig.10, and shows the support holding system on the magnetic circuit and the support holding system on the transformer housing body carried by this support

[0052] - [Fig.12] represents the body of the transformer housing on which the electrical conductor support of figure 11 is held,

[0053] - [Fig.13] is a view similar to Figure 11 and also shows ribs allowing the distance of this support from the portion of the magnetic circuit on which it is mounted,

[0054] - [Fig.14], [Fig.15] and [Fig.16] are views similar to that of figure 13, when the electrical conductor support is mounted on the portion of the magnetic circuit,

[0055] - [Fig.17] is a side sectional view of Figure 16,

[0056] - [Fig.18] represents three supports of electrical conductors of the transformer and their electrical conductors, in the absence of the magnetic circuit,

[0057] - [Fig.19] represents in isolation one of the three electrical conductor supports of figure 18 with its electrical conductors,

[0058] - [Fig.20] represents the electrical conductor support of figure 19 without its electrical conductors, and

[0059] - [Fig.21] represents, in a similar way to figure 2, another example of a three-phase transformer differing among other things by the way in which the cover is held.

[0060] Figure 1 shows a part of the electrical circuit 1 of a component for the electrical power supply of a vehicle electrical energy storage unit. This component is also called a “charger”. The electrical energy storage unit, not shown in this figure 1, is for example a battery, which may have a nominal voltage greater than 60V, for example greater than or equal to 300V, 400V, 800V, or even 1000V.

[0061] The circuit 10 receives as input an alternating voltage from a network (not shown) which is three-phase here. A rectifier for converting this alternating voltage into a direct voltage, and also performing a power factor correction function (power factor correction in English) if necessary, is arranged upstream of a direct bus 11. Downstream of this direct bus, from the electrical network, is arranged an isolated voltage converter 12, here being a DC / DC. This converter 12 comprises in a known manner an inverter 14, a three-phase transformer 15, and a rectifier 16 supplying the vehicle with a direct voltage isolated from the electrical network. As can be seen in FIG. 1, the three-phase transformer 15 is connected to each of the rectifier 16 and the inverter 14 by an inductor block 17 and a capacitor block 18, so as to define a CLLLC structure.Other structures are of course possible, such as an LLC, CLLC, LC or even CL structure.

[0062] As can be seen in Figure 1, each phase has a primary winding 20 and a secondary winding 21 in inductive coupling with each other, and the primary windings 20 are connected in star and the secondary windings 21 are also connected in star.

[0063] The three-phase transformer 15 comprises in the example considered a magnetic circuit 22, comprising a first part 23 and a second part 24. Each part 23, 24 comprises: a base 26 of substantially triangular outline, and three pads 27 each extending in the direction of the base 26 of the other part of the magnetic circuit 22. Each base 26 here has an outline defining an equilateral triangle.

[0064] The transformer 15 further comprises three supports 30 of electrical conductors 31, 32, each support 30 being here mounted on two facing pads 27 belonging respectively to one and the other of the parts 23, 24 of the magnetic circuit. Two electrical conductors 31, 32 associated with the same support 30 respectively have a portion defining a primary winding 20 and a portion defining a secondary winding 21. These electrical conductors 31, 32 are for example Litz wire.

[0065] As can be seen in Figure 2, the three supports 30 of electrical conductors 31, 32 are positioned so as to define an equilateral triangle. The transformer 15 further comprises a housing 50 comprising a body 51 closed by a cover 52, which are visible in Figures 4 and 6. This body 51 and this cover 52 are for example made of metal, for example aluminum. The supports 30 and the magnetic circuit 22 are arranged inside the housing 50. The body 51 is filled with a resin capable of being polymerized to harden and immobilize the components arranged inside the body ("potting" in English).

[0066] As can be seen in Figures 4 and 6, the housing 50 also has a triangular outline, being more precisely here an equilateral triangle. The housing is in the example considered exclusively formed by the body 51 and the cover 52, but the invention is not limited to a housing 50 consisting of two parts.

[0067] As can be seen in Figure 3, each pad 27 defines its own air gap 28, for example via an area of ​​the pad 27 filled with non-magnetic material such as a fiberglass-reinforced epoxy resin composite (FR4) or ceramic. This area occupied by this non-magnetic material defines, for example, an entire slice of the pad. Several sections are, for example, assembled with this area of ​​the pad 27 to constitute this pad 27. As can be seen in Figure 3, an additional air gap 29 is present between the facing ends of two pads 27 belonging respectively to different parts 23, 24 of the magnetic circuit 22. Thus, in the example of magnetic circuit 22 considered, each magnetic field allowing the inductive coupling between a primary winding 20 and a secondary winding 21 crosses exactly three air gaps.

[0068] Still in Figure 3, it can be seen that the magnetic circuit 22 of the example considered comprises a central leg 40 carried by one of the parts 23, 24 of the magnetic circuit 22. This central leg 40 is here made in a single piece with the part 23 of the magnetic circuit 22 which carries it.

[0069] It can be seen in Figure 3 that the central leg 40 extends in this example continuously between two ends each being in contact with one of the bases 26 of the magnetic circuit 22, so that no air gap is provided in the central leg 40.

[0070] It can also be seen in Figure 3 or in Figure 16 that the central leg 40 has a core 41 and three protrusions 42 extending from this core 41, each protrusion 42 extending between two neighboring pads 27 carried by the same part of the magnetic circuit.

[0071] As can be seen in Figure 3, in the example considered, each pad 27 has a circular outer contour, and each protrusion 42 of the central leg 40 here has a wall facing the pads 27 of rounded shape. As can be seen in Figure 2, the three-phase transformer 15 comprises a connection terminal block 45. This connection terminal block 45 is fixed to one side of the housing 50 of the three-phase transformer 15. As can be seen in Figure 2, the terminal block 45 here defines six terminals 60 for connecting the three-phase transformer 15 to the rest of the electrical circuit 10, these terminals 60 being shown schematically in Figure 1. These terminals 60 here come into contact with electrical tracks of an electronic card not shown.

[0072] The connection terminal block 45 has, as can be seen in FIG. 2, an elongated shape, and the six terminals 60 are here arranged in a row.

[0073] The various elements of the terminal block 45 according to the embodiment shown will now be described with reference to figures 7 to 9

[0074] The terminal block 45 here comprises a body 61 and a plurality of electrically conductive bars 62, each terminal 60 being defined by a portion 63 of a bar. Each portion 63 is here flat, so as to come into contact with an electrical track of the electronic card mentioned above. The body 61 can be made of plastic, for example PBT, PA, etc.

[0075] Each electrically conductive bar 62 has, for example, a portion 65, opposite the portion 63 defining the terminal, which is electrically connected to one of the electrical conductors 31, 32, here via a hollow sleeve 66 inside which the conductor 31, 32 is inserted, for example fixed by crimping or welding.

[0076] Each electrically conductive bar 62 locally comprises a hole 67 and the fixing of this electrically conductive bar 62 on the body 61 is carried out by means of a screw 68 received in this hole 67. The body 61 here comprises six housings 69, and each of these housings receives an insert 70 forming a hole 71, the aforementioned screw 68 being received in an insert hole 71. Thus, the fixing of the electrically conductive bar 62 on the body 61 is carried out via the screw 68 and the insert 70 received in the housing 69. Each insert 70 can be made of metal, in particular steel. Alternatively, each insert is made of composite material. Six inserts are for example provided, and all these inserts 70 have in the example considered the same shape and the same dimensions. Each screw 68 can, in addition to ensuring the fixing of an electrically conductive bar 62 on the body 61, also ensure the fixing of the electrically conductive bar 62 on the electronic card not shown.

[0077] As can be seen in Figure 8, each insert 70 can define a positioning relief 73 of the portion 63 of the electrically conductive bar defining the hole 67. This positioning relief 73 is for example a circular-shaped flat. As can be seen in Figures 2, 7 and 8, the outer wall of each housing 69 can provide a recess 75 capable of receiving an end portion 64 of the electrically conductive bar 62, in order to ensure correct positioning of this bar on the body 61 and to avoid any relative rotation between this bar and this body.

[0078] In another example of implementation not shown, the body 61 comprises a plurality of housings 69 which directly receive the screws 68, in the absence of an insert 70. In this other example of implementation, the fixing of the electrically conductive bar 62 on the body 61 is done directly via the screw 68, without an intermediate part.

[0079] As can be seen in Figures 4 and 5, each support 30 for electrical conductors can integrate a system 80 for holding the cover 52 on this support 30.

[0080] Each support 30 comprises, for example, a single pin 81 projecting relative to the rest of the support 30 along the longitudinal axis of the latter. Alternatively, only two of the three supports of the transformer 15 comprise a pin 81, the third support 30 being devoid of one.

[0081] Figure 5 shows in detail a pin 81, the latter being able to have a section perpendicular to the longitudinal axis of the support which is cruciform. Each pin 81 of a support 30 of electrical conductors is in the example considered force-fitted into an opening made in the cover 52, as can be seen in Figure 4. The relative arrangement of the pins 81 of the supports 30 makes it possible to immobilize the cover 52.

[0082] As can be seen in Figure 5, the holding system 80 of the cover 52 on the support 30 can extend along the longitudinal axis of the support 30 on the same side of the support 30 as a guiding system 85 of electrical conductors which will be described with reference to Figures 18 to 20.

[0083] In these figures 18 to 20, the holding system 80 is not shown, the guide system 85 being able to be present without necessarily the holding system 80 being there, other ways of holding the cover 52 being possible, as described in particular with reference to figure 21.

[0084] As can be seen in Figure 18, each electrical conductor 31, 32 carried by a support 30 of the transformer 15 can be guided outside the winding 20, 21 which it defines.

[0085] In the example considered, each of these conductors 31, 32 is guided by the guiding system 85 beyond each of the ends of the electrical winding 20, 21 that it defines. As already mentioned previously and as can be seen in Figures 2 and 21, the first ends of the electrical conductors may constitute an output to the electrical circuit 10 outside the transformer 15, and three of the second ends of the electrical conductors may lead to a common point via a star connection to the primary, and three other of these second ends of the electrical conductors may lead to a common point via another star connection to the secondary.

[0086] The support 30 of the two electrical windings 31, 32 comprises:

[0087] - a wall 90 around which the electrical windings 20, 21 are arranged, and this wall 90 defines in the example considered but in a non-limiting manner a hollow cylinder of circular cross-section, and

[0088] - three flanges 92, 93, 94 offset along the longitudinal axis of the support, so that one of the electrical windings 31 is arranged between the first 92 and the second flange 92 and the other of the electrical windings 32 is arranged between the second 93 and the third 94 flange, as is clearly visible in FIG. 2 for example. The distance between two consecutive flanges 92, 93 and 93, 94 remains constant in the example considered.

[0089] The guidance system 85 acts on the electrical conductors on the one hand via clamps 97 and 98, and on the other hand via additional walls 105 and 106.

[0090] In the example of Figures 18 to 20, the guidance system 85 comprises, for each electrical conductor 31, 32, on the one hand a first clamp 97 cooperating with this electrical conductor 31, 32 beyond the first end of the electrical winding 20, 21 that it defines. Such a clamp 97 has for example two arms 99 curved so as to match an area of ​​the contour of this end of the electrical conductor, as shown in Figure 18 or 20. This is a circular contour. Each clamp 97 is for example, but in a non-limiting manner, made in a single piece with the rest of the support 30 of electrical conductors. As already explained, each first clamp 97 cooperates for example with a portion of electrical conductor 31, 32 on the way to a connection terminal 60.

[0091] The guidance system 85 further comprises a second clamp 98 cooperating with the electrical conductor beyond the second end of the electrical winding that it defines, these first 97 and second 98 clamps succeeding one another along one of the first 92, second 93 and third 94 edges. As already explained, each second clamp 98 cooperates for example with a portion of electrical conductor 31, 32 on the way to a common point of a star connection.

[0092] More precisely, in the example considered:

[0093] - the first rim 92 comprises two first clamps 97 which each cooperate respectively with one of the electrical conductors 31, 32 beyond the first end of the electrical winding 20, 21 which it defines, and two second clamps 98 which each cooperate respectively with an electrical conductor beyond the second end of this electrical winding 20, 21, and - the second rim 93 comprises a first clamp 97, arranged under a first clamp

[0094] 97 of the first rim 92, and a second clamp 98, arranged under a second clamp 98 of the first rim. The clamps carried by the second rim 94 make it possible to guide the electrical conductor 32 outside the electrical winding arranged between the second rim 93 and the third rim 94.

[0095] It can be seen in Figures 18 to 20 that, along the edge 92, there are two pairs of clamps each formed of a first clamp 97 and a second clamp 98, and that the distance between two pairs of clamps is greater than the distance between two clamps of the same pair.

[0096] It can also be seen in these figures 19 and 20 that the clamps 97, 98 carried by the second rim 93 are aligned along the axis of the cylindrical wall 90 with clamps 97,

[0097] 98 carried by the first rim 92.

[0098] The two additional walls 105 and 106 of the guidance system 85 will now be described. These two additional walls 105 and 106 are here offset so as to define between them a guide channel 108 receiving in a stacked manner the electrical conductors 31, 32 outside the windings 20, 21 that they define. The channel 108 here has a constant dimension. These additional walls extend in the example considered on either side of an arcuate portion of the first rim 92, projecting axially beyond this first rim 92. In the overlapping zone of this first rim 92, the additional walls 105 and 106 each define an arcuate portion, the wall 106 having a radius greater than the wall 105, as is also visible in FIG. 17.

[0099] It can be seen in Figures 18 to 20 that the wall 106 comprises first openings 110 for the passage of the electrical conductors 31, 32 towards the electrical winding 20, 21 which it defines, and second openings 111 in which no electrical winding passes. It can be seen that the first openings 110 are arranged radially opposite a clamp 97, 98.

[0100] In the example of figures 10 to 12, each support 30 of electrical conductors 31, 32 also integrates a holding system 120 on the body 51 of the housing 50. This holding system 120 here comprises a pin 121, having in this example a section perpendicular to the longitudinal axis of the support which is cruciform. This pin 121 extends axially away from the rest of the support 30 from the third rim 94. As can be seen in Figures 10 and 12, each pin 121 is force-fitted into an opening 122 formed in the body 51 of the housing 50. This holding system can ensure immobilization of the magnetic circuit 22 on the body 51 of the housing before polymerization of the resin contained in this housing 50. When such holding systems 120 exist, they may or may not be combined with the holding systems 80 and the guidance systems 85 mentioned above.As can be seen in Figures 10 to 12, each holding system 120 can then extend axially on one side of the support 30 while the holding system 80 and the guide system 85 extend axially on the opposite side of the support 30.

[0101] We will now describe with reference to Figures 13 to 15, a functionality that can be integrated into all or part of the supports 30 of electrical conductors 31, 32. A system 130 for holding the support 30 of electrical conductors 31, 32 on the magnetic circuit 22 is thus provided. This holding system 130 is in the form of two pads 132 projecting relative to the rest of the support 30. When the holding system 120 is provided, these systems 130 and 120 can extend axially on the same side of the support, the pin 121 and a pad 132 being arranged in particular side by side as can be seen in the example of Figure 11.

[0102] Each pad 132 here defines a surface 135 coming into contact with a surface 136 of a base 26 of the magnetic circuit 22. The surfaces 135 and 136 are here flat. Each pad 132 is for example supported by a reinforcement 133, as visible in FIG. 11.

[0103] As can be deduced from Figure 15, the cooperation between the two pads 132 of a support 30 and the base 26 can ensure rotational immobilization of the support 30 on the magnetic circuit 22.

[0104] We will now describe with reference to figures 13 to 16 another functionality which can be integrated into all or part of the supports 30 of electrical conductors 31, 32. It can be seen in these figures that the cylindrical wall 90 of the support 30 comprises ribs 142 extending away from the wall 90 in the direction of the pad 27 on which this support is mounted.

[0105] In the example considered, six ribs 142 are provided, but the invention is not limited to a precise number of ribs 142. These six ribs 142 thus constitute a spacing system 140 of the cylindrical wall 90, and therefore of the electrical windings 20, 21 which it carries, of the pad 27.

[0106] It can be seen in Figures 13 to 16 that all the ribs 142 can have the same shape and be distributed uniformly around the pad 27.

[0107] It can also be seen in these figures that each rib 142 can extend continuously along the axis of the support 30 from the first edge 92 to the third edge 94.

[0108] In a variant not shown, all or part of the ribs extend discontinuously along the axis of the support 30. As can be seen in FIG. 16, each rib 142 does not, for example, extend as far as the pad 27 on which the support 30 is mounted. An empty space ensuring easy mounting thus remains present between each end of a rib opposite the pad 27 and this pad 27.

[0109] As already mentioned, each support 30 of electrical conductors 31, 32 can be made from a single piece.

[0110] When this support 30 integrates:

[0111] -ribs 142, and / or

[0112] - the holding system 80 of the cover 52 on the support, and / or

[0113] - the guidance system 85 of electrical conductors, and / or

[0114] - the holding system 120 of the support on the body 51 of the housing, and / or

[0115] - the system 130 for holding the support on the magnetic circuit 22, all these systems can be made in one piece or not with the rest of the support 30. In a particular example, the support 30 is thus in one piece and has all or part of the aforementioned functionalities.

[0116] The invention is not limited to the examples which have just been described.

[0117] In the example of figure 21, the cover 52 is held directly on the body 51 of the housing 50 by means of screws 56 received in a shoulder 57 of the wall of the body 51. The cover 52, which is shown transparently in this figure 21, can close the body 51, thus ensuring EMC shielding of the housing 50.

[0118] It can be seen in this figure 21 that the wall 105 of the guide system 85 can have additional projections 115, received in openings made in the cover 52. These additional projections 115 define for example two slots per side of the transformer 15, and they can facilitate the introduction of the magnetic circuit 22 provided with the supports 30 inside the body 51 of the housing 50.

Claims

Claims 1. Three-phase transformer (15) for isolated voltage converter (12), comprising: - a magnetic circuit (22), comprising a first part (23) and a second part (24), each part (23, 24) comprising: a base (26) of substantially triangular outline, this outline defining in particular an equilateral triangle, and three pads (27) each extending in the direction of the base (26) of the other part of the magnetic circuit (22), - three supports (30) for electrical conductors (31, 32), each support (30) being mounted on two facing pads (27) belonging respectively to one and the other of the parts (23, 24) of the magnetic circuit (22), each support (30) for electrical conductors (31, 32) carrying two electrical windings (20, 21) in inductive coupling with each other via the magnetic circuit (22), the three supports (30) defining in particular a triangular pattern, in particular an equilateral triangle, characterized in that each pad (27) of a part (22) of the magnetic circuit defines at least one air gap (28) other than via its cooperation with the pad (27) of the other part (23) of the magnetic circuit with which it is facing.

2. Transformer according to claim 1, the magnetic circuit (22) comprising a central leg (40) carried by one of the parts (23, 24) of the magnetic circuit (22).

3. Transformer according to claim 2, the central leg (40) being made in one piece with the part (23, 24) of the magnetic circuit which carries it.

4. Transformer according to claim 2 or 3, the central leg (40) extending between two ends each being in contact with one of the bases (26) of the magnetic circuit, the central leg (40) being in particular devoid of an air gap.

5. Transformer according to any one of claims 2 to 4, the central leg (40) having a core (41) and three protrusions (42) extending from this core (41), each protrusion (42) extending between two neighboring pads (27) carried by the same part (23, 24) of the magnetic circuit (22).

6. Transformer according to claim 5, each protrusion (42) having a wall facing a stud (27) whose shape is the same as that of the stud (27).

7. Transformer according to any one of the preceding claims, the magnetic field circulating between two electrical windings (20, 21) carried by the same support (30) of electrical conductors (31, 32) crossing exactly three air gaps (28, 29).

8. Transformer according to any one of the preceding claims, each support (30) of electrical conductors integrating at least one: - a guidance system (85) for at least one of the two electrical conductors (31, 32) to the exterior of the electrical winding (20, 21) which it defines, - a holding system (130) on the magnetic circuit (22), - a holding system (120) on a housing (50) of the transformer, and - a system (80) for holding a cover (52) of the transformer housing.

9. Transformer according to any one of the preceding claims, each support (30) of electrical conductors (31, 32) being made in one piece.

10. Transformer according to any one of the preceding claims, each stud (27) having its portion extending from the base (26) of the part (23, 24) of the magnetic circuit which is made in one piece with this base (26) of the part of the magnetic circuit.

11. Transformer according to any one of the preceding claims, from one part (23, 24) of the magnetic circuit (22) to the other, the pads (27) extending towards the base (26) of the other part (23, 24) of the magnetic circuit (22) over the same height.

12. Transformer according to any one of the preceding claims, the two electrical windings (20, 21) carried by the support (30) of electrical conductors (31, 32) succeeding one another along this support, without overlapping along planes perpendicular to the longitudinal axis of this support (30).

13. Transformer according to any one of the preceding claims, comprising a housing (50) comprising a body (51) and a cover (52), the magnetic circuit (22) and the supports (30) of electrical conductors being arranged in this housing (50), the cover (52) being held on the body (51) by means of screws (56) received in holes (57) provided in the wall of the body (51).

14. Component (10) for the electrical power supply of a vehicle electrical energy storage unit, comprising the transformer (15) according to any one of the preceding claims.

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