Transformer, electrical converter, inductor, and mobility machine
By forming the secondary winding outside the multilayer printed circuit board using surface-mounted conductive bars, the transformer design is optimized, reducing material usage and costs without compromising performance.
Patent Information
- Authority / Receiving Office
- WO · WO
- Patent Type
- Applications
- Current Assignee / Owner
- VALEO ELECTRIFICATION SAS
- Filing Date
- 2025-12-19
- Publication Date
- 2026-06-25
AI Technical Summary
Existing transformers require multilayer printed circuit boards that are oversized due to the need for multiple layers to accommodate both primary and secondary windings, leading to inefficiencies and unnecessary material usage.
The secondary winding is formed outside the multilayer printed circuit board using conductive bars mounted on its surface, reducing the need for additional layers and optimizing the transformer design.
This configuration minimizes the number of layers required for the printed circuit board, thereby reducing material usage and potentially lowering production costs while maintaining electrical performance.
Smart Images
Figure EP2025088497_25062026_PF_FP_ABST
Abstract
Description
Description TITLE: TRANSFORMER, ELECTRICAL CONVERTER, INDUCTANCE AND MOBILITY VEHICLE Technical field of the invention
[0001] The present invention relates to a transformer, an electrical converter, an inductor and a mobility device comprising such a transformer or such an electrical converter or such an inductor.
[0002] A mobility device is, for example, a motorized land vehicle, a train, an aircraft, or a drone. A motorized land vehicle is, for example, a car, a motorcycle, a motorized bicycle, or a motorized wheelchair. Technological background
[0003] A transformer is known from the prior art comprising: a multilayer printed circuit board; a magnetic core; a primary winding and a secondary winding wound around the magnetic core to be magnetically coupled to each other, the primary winding being formed in layers of the multilayer printed circuit board.
[0004] The secondary winding is also formed in layers of the multilayer printed circuit board.
[0005] Thus, such a transformer requires a multilayer printed circuit board with many layers.
[0006] Generally, the transformer is part of a larger electrical circuit, for example an electrical converter, whose components are carried by the multilayer printed circuit board.
[0007] The power converter is, for example, a dual-active bridge (DAB) converter, a widely used technology for isolated DC-DC power conversion, thanks to its wide input and output voltage range, control flexibility, and ability to implement smooth switching across its entire operating range. The power converter can thus, for example, be a dual-active bridge converter with current doubling (from the English "DAB with current doubler" or DABi2). Furthermore, the ability to implement two power conversions in a single power converter reduces costs. Thus, the power converter can be a triple-active bridge with current doubler (from the English "triple-active-bridge with current-doubler" or TABi2).
[0008] However, the components of the electrical converter may not require as many layers as the transformer to ensure their connections.
[0009] Therefore, the multilayer printed circuit board only needs to be oversized for the transformer.
[0010] It may therefore be desirable to provide a transformer that makes it possible to overcome at least some of the aforementioned problems and constraints. Summary of the invention
[0011] A transformer is therefore proposed comprising: a multilayer printed circuit board; a magnetic core; a primary winding and a secondary winding wound around the magnetic core to be magnetically coupled to each other, the primary winding being formed within layers of the multilayer printed circuit board. It is characterized in that the secondary winding is formed outside the multilayer printed circuit board, by at least one conductive bar mounted on the surface of the multilayer printed circuit board.
[0012] Thus, thanks to the invention, the secondary winding does not use layers of the multilayer printed circuit board, so that the latter can be provided with just the number of layers necessary for the connections of the components of the electrical circuit of which the transformer is a part.
[0013] "Surface mount" means that the conductive bar is attached to and fixed on an external surface of the printed circuit board, preferably by brazing or soldering onto pads designed for this purpose, in the manner of a Surface Mount Component (SMC). The printed circuit board serves as a mechanical support for the conductive bar.
[0014] According to the invention, said at least one conductive bar is attached and welded or brazed onto the surface of the multilayer printed circuit board.
[0015] The invention may further include one or more of the following optional features, in any technically feasible combination.
[0016] Optionally, the primary winding comprises several turns formed respectively in several conductive layers of the multilayer printed circuit board.
[0017] Optionally, the transformer may not have any windings other than the primary winding and the secondary winding.
[0018] Optionally, the transformer also includes a tertiary winding formed in layers of the multilayer printed circuit board.
[0019] Optionally, the primary winding has several turns formed in several conductive layers of the multilayer printed circuit board, the tertiary winding has several turns formed in several conductive layers of the multilayer printed circuit board, and the turns of the primary and tertiary windings are intertwined.
[0020] An electrical converter is also proposed comprising: a transformer according to the invention; a first active bridge comprising four transistors mounted on the multilayer printed circuit board, the first active bridge being connected to the primary winding; and a second active bridge comprising four transistors mounted on the multilayer printed circuit board, the second active bridge being connected to the secondary winding.
[0021] Optionally, the electrical converter also includes a third active bridge comprising four transistors mounted on the multilayer printed circuit board, the third active bridge being connected to the tertiary winding.
[0022] An inductance is also proposed comprising: a multilayer printed circuit board; a magnetic core; a winding wound around the magnetic core, the winding comprising at least one turn formed in at least one of the layers of the multilayer printed circuit board; characterized in that the winding comprises at least one turn formed outside the multilayer printed circuit board, by at least one conductive bar mounted on the surface of the multilayer printed circuit board. According to the invention, said at least one conductive bar forms an additional turn of the winding.
[0023] Optionally, the winding includes a loop formed in several conductive layers of the multilayer printed circuit board, these conductive layers being connected in parallel to each other by vias.
[0024] A mobility device is also proposed comprising a transformer according to the invention, or an electrical converter according to the invention, or an inductor according to the invention. Brief description of the figures
[0025] The invention will be better understood with the aid of the following description, given solely by way of example and made with reference to the accompanying drawings in which: Figure 1 is an electrical circuit of a first electrical converter according to the invention, Figure 2 is a cross-sectional view of a transformer of the first electrical converter, Figure 3 is an exploded three-dimensional view of the transformer, Figure 4 is a cross-sectional view of two coupled inductors of the first electrical converter, Figure 5 is an electrical circuit of a second electrical converter according to the invention, and Figure 6 is a cross-sectional view of a transformer of the second electrical converter. Detailed description of the invention
[0026] With reference to Figure 1, a first electrical converter 100 according to the invention will now be described.
[0027] In the illustrated example, the first 100 power converter is an active double bridge converter and current doubler.
[0028] The first electrical converter 100 initially comprises a multilayer printed circuit board 102.
[0029] The first electrical converter 100 further includes, on the multilayer printed circuit board 102, two input terminals IN+, IN- designed to receive between them a DC input voltage VIN and an output terminal OUT designed to provide an output current IOUT.
[0030] The first electrical converter 100 also includes a first active bridge 104 comprising four transistors 104A-D mounted on the multilayer printed circuit board 102.
[0031] The first electrical converter 100 also includes a second active bridge 106 comprising four transistors 106A-D mounted on the multilayer printed circuit board 102.
[0032] The first electrical converter 100 further includes a control device 108, such as a microcontroller, mounted on the multilayer printed circuit board 102 and designed to control the transistors 104A-D, 106A-D of the first and second active bridges 104, 106.
[0033] Each 104A-D, 106A-D transistor is, for example, a metal-oxide gate field-effect transistor (MOSFET), a silicon metal-oxide gate field-effect transistor (SiMOSFET), a silicon carbide metal-oxide gate field-effect transistor (SiCMOSFET), an insulated gate bipolar transistor (IGBT), or a gallium nitride field-effect transistor (GaNFET).
[0034] The first electrical converter 100 further comprises a transformer 110 having a magnetic core 112, as well as a primary winding 114 and a secondary winding 116 wound around the magnetic core 112 to be magnetically coupled to each other.
[0035] The first electrical converter 100 further comprises first and second coupled inductors 118, 120 and a magnetic core 122 for magnetic coupling of the coupled inductors 118, 120. The coupled inductors 118, 120 and their magnetic core 122 are mounted on the multilayer printed circuit board 102. The coupled inductors 118, 120 are connected to each other at a midpoint connected to the output terminal OUT, and both to the second active bridge 106.
[0036] As previously stated, the first power converter 100 is designed to receive the DC input voltage VIN between the two input terminals IN+ and IN-. The control device 108 is then designed to drive the transistors of the first active bridge 104 so that it supplies a primary AC voltage VP~ to the primary winding 114. By magnetic coupling, the secondary winding 116 is then designed to present a secondary AC voltage VS~. The control device 108 is then designed to drive the transistors of the second active bridge 106 so that it supplies a DC output voltage VOUT. The coupled inductors 118 and 120 are then designed to supply a current IOUT to the output terminal OUT from the output voltage VOUT.
[0037] With reference to Figure 2, transformer 110 will now be described in more detail.
[0038] The 102 multilayer printed circuit board has several layers stacked in a stack, including conductive layers (four in the example shown, labeled TOP, INT1, INT2, and BOT), separated by insulating layers (three in the example shown, labeled 202, 204, and 206). Typically, the TOP conductive layer at the top of the stack and the BOT conductive layer at the bottom are external conductive layers, while the other conductive layers are internal conductive layers. The external conductive layers TOP and BOT are usually covered by an insulating layer, for example, solder mask 208 and 210. The TOP, INT1, INT2, and BOT conductive layers are, for example, 75 µm thick.
[0039] The primary winding 114 is thus formed in at least one of the conductive layers TOP, INT1, INT2, BOT of the multilayer printed circuit board 102. For example, as in the illustrated example, the primary winding 114 is formed in the outer layers TOP, BOT and the inner layers INT1, INT2. By For example, one turn of the primary winding 114 is formed in each of the conductive layers TOP, INT1, IN2, BOT. Thus, in the illustrated example, the primary winding 114 has four turns.
[0040] In Figure 2, the presence of conductive material is indicated by hatching, while the absence of hatching indicates the absence of conductive material.
[0041] Furthermore, the first electrical converter 100 includes at least one conductive bar 212, 214 mounted on the surface of the multilayer printed circuit board 102, for example above the upper external conductive layer TOP, preferably above the varnish layer 208, and / or below the lower internal conductive layer BOT, preferably below the varnish layer 210.
[0042] The secondary winding 116 is then formed outside the multilayer printed circuit board 102, that is to say outside the conductive layers TOP, INT1, INT2, BOT of the multilayer printed circuit board 102. More precisely, the secondary winding 116 is formed in the conductive bar(s) 212, 214. For example, one turn of the secondary winding 116 is formed in each of the conductive bars 212, 214, so as to present two turns.
[0043] Referring to [Fig. 3], the conductive bars 212, 214 are attached to and fixed on an external surface of the multilayer printed circuit board 102. This attachment is achieved by brazing or soldering, in the manner of a surface-mount component. More specifically, solder joints 302 provide the electrical connection between the bars and the conductive tracks of the board. Optionally, and to ensure robust mechanical strength, the conductive bars are secured to the multilayer printed circuit board 102 by dedicated solder joints 304, located on corresponding mounting pads.
[0044] In addition, the magnetic core 112 is for example in two parts 112A, 112B.
[0045] With reference to Figure 4, an example of the realization of the coupled inductances 118, 120 will now be described.
[0046] It will first be appreciated that the magnetic core 122 has three legs 122A, 122B, 122C passing through the multilayer printed circuit board 102.
[0047] The first inductance 118 has a winding 118A wound around the first leg 122A.
[0048] This 118A winding has at least one turn formed in at least one of the conductive layers TOP, INT 1, INT2, BOT of the multilayer printed circuit board 102. For example, as in the illustrated example, the 118A winding has one 402A turn formed in the outer layers TOP, BOT and the inner layers INT 1, INT2, these layers TOP, INT 1, INT2, BOT being connected in parallel to each other by 404A vias.
[0049] Preferably, the winding 118A further comprises at least one conductive bar 408A, 410A mounted on the surface of the multilayer printed circuit board 102 to form an additional turn of the winding 118A. A conductive bar 408A is provided, for example, above the upper outer conductive layer TOP, preferably above the varnish layer 208, and / or a conductive bar 410A is provided below the lower inner conductive layer BOT, preferably below the varnish layer 210. Thus, in the illustrated example, the conductive bar 408A forms an additional turn of the winding 118A, and the conductive bar 410A forms another additional turn of the winding 118A.
[0050] Similarly, the second inductor 120 has a winding 120B wound around the second leg 122B.
[0051] This 120B winding has at least one turn formed in at least one of the conductive layers TOP, INT 1, INT2, BOT of the multilayer printed circuit board 102. For example, as in the illustrated example, the 120B winding has one 402B turn formed in the outer layers TOP, BOT and the inner layers INT 1, INT2, these layers TOP, INT 1, INT2, BOT being connected in parallel to each other by 404B vias.
[0052] Preferably, the winding 120B further comprises at least one conductive bar 408B, 410B mounted on the surface of the multilayer printed circuit board 102 to form an additional turn of the winding 120B. A conductive bar 408B is provided, for example, above the upper outer conductive layer TOP, preferably above the varnish layer 208, and / or a conductive bar 410B is provided below the lower inner conductive layer BOT, preferably below the varnish layer 210. Thus, in the illustrated example, the conductive bar 408B forms an additional turn of the winding 120B, and the conductive bar 410B forms another additional turn of the winding 120B.
[0053] With reference to Figure 5, a second 500 electrical converter according to the invention will now be described.
[0054] The second 500 power converter is similar to the first 100 power converter, except for the following differences.
[0055] The second 500 power converter also has two output terminals OUT+, OUT'- designed to present a DC output voltage VOUT.
[0056] The second electrical converter 500 further comprises a tertiary winding 502 wound around the magnetic core 112 to be magnetically coupled to the primary winding 114.
[0057] The second electrical converter 500 further includes a third active bridge 504 comprising four 504A-D transistors mounted on the multilayer printed circuit board 102 and which the control device 108 is designed to control.
[0058] Thus, by magnetic coupling, the tertiary winding 502 is designed to present a tertiary alternating voltage VT~. The control device 108 is then designed to control the transistors of the third active bridge 504 so that the latter provides the DC output voltage VOUT' between the output terminals OUT+, OUT'-.
[0059] With reference to Figure 6, the multilayer printed circuit board 102 this time includes, for example, six conductive layers TOP, INT 1, INT2, INT3, INT4, BOT and five insulating layers 602, 604, 606, 608, 610 separating them.
[0060] The conductive layers TOP, INT1, INT2, INT3, INT4, BOT form turns of the primary winding 114 and the tertiary winding 502. Preferably, the turns of the two windings 114 and 502 are interlaced. For example, the turns of the primary winding 114 are formed in the layers TOP, INT2, INT4, while the turns of the tertiary winding 502 are formed in the layers INT1, INT3, BOT.
[0061] As in the first electrical converter 100, the secondary winding 116 is formed in the conductive bars 212, 214, out of the conductive layers TOP, INT1, INT2, INT3, INT4, BOT of the multilayer printed circuit board 102.
[0062] In conclusion, it is clear that a transformer such as those described above requires a reduced number of layers of the multilayer printed circuit board.
[0063] It should also be noted that the invention is not limited to the embodiments described above. Indeed, it will be apparent to those skilled in the art that various modifications can be made to the embodiments described above, in light of the information just disclosed to them.
[0064] In the detailed presentation of the invention given above, the terms used shall not be interpreted as limiting the invention to the embodiments set forth in this description, but shall be interpreted as including all equivalents which can be foreseen by a person skilled in the art by applying their general knowledge to the implementation of the teaching which has just been disclosed to them.
Claims
Demands [1] Transformer (110) comprising: a multilayer printed circuit board (102); a magnetic core (112); a primary winding (114) and a secondary winding (116) wound around the magnetic core (112) to be magnetically coupled to each other, the primary winding (114) being formed in layers (TOP, INT 1 , INT2, INT3, INT4, BOT) of the multilayer printed circuit board (102); characterized in that the secondary winding (116) is formed outside the multilayer printed circuit board (102), by at least one conductive bar (212, 214) mounted on the surface of the multilayer printed circuit board (102). [2] Transformer (110) according to claim 1, in which the primary winding (114) comprises several turns respectively formed in several conductive layers (TOP, INT 1, INT2, INT3, INT4, BOT) of the multilayer printed circuit board (102). [3] Transformer (110) according to claim 1 or 2, comprising no other winding than the primary winding (114) and the secondary winding (116). [4] Transformer (110) according to claim 1 or 2, further comprising a tertiary winding (502) formed in layers (TOP, INT 1 , INT2, INT3, INT4, BOT) of the multilayer printed circuit board (102). [5] Transformer (110) according to claim 4, wherein the primary winding (114) comprises several turns respectively formed in several conductive layers (TOP, INT1, INT2, INT3, INT4, BOT) of the multilayer printed circuit board (102), wherein the tertiary winding (502) comprises several turns respectively formed in several conductive layers (TOP, INT1, INT2, INT3, INT4, BOT) of the multilayer printed circuit board (102), and wherein the turns of the primary winding (114) and the tertiary winding (502) are interlaced. [6] Electrical converter (100; 500) comprising: a transformer (110) according to any one of claims 1 to 5; a first active bridge (104) comprising four transistors (104A-D) mounted on the multilayer printed circuit board (102), the first active bridge (104) being connected to the primary winding (114); and a second active bridge (106) comprising four transistors (106A-D) mounted on the multilayer printed circuit board (102), the second active bridge (106) being connected to the secondary winding (116). [7] Electrical converter (500) according to claim 6, wherein the transformer (110) is according to claim 4 or 5, the electrical converter (500) further comprising a third active bridge (504) comprising four transistors (504A-D) mounted on the multilayer printed circuit board (102), the third active bridge (504) being connected to the tertiary winding (502). [8] Inductance (118; 120) comprising: a multilayer printed circuit board (102); a magnetic core (122); a winding (118A; 120B) wound around the magnetic core (122), the winding (118A; 120B) comprising at least one turn (402A; 402B) formed in at least one of the layers (TOP, INT 1, INT2, BOT) of the multilayer printed circuit board (102); characterized in that the winding (118A; 120B) comprises at least one turn formed outside the multilayer printed circuit board (102), by at least one conductive bar (408A, 410A; 408B, 410B) mounted on the surface of the multilayer printed circuit board (102). [9] Inductance (118; 120) according to claim 8, wherein the winding (118A; 120B) comprises a loop formed in several conductive layers (TOP, INT1, INT2, BOT) of the multilayer printed circuit board (102), these conductive layers (TOP, INT1, INT2, BOT) being connected in parallel to each other by vias (404A; 404B). [10] Mobility device comprising a transformer according to any one of claims 1 to 6 or an electrical converter according to claim 6 or an inductor according to claim 8 or 9.