FR3122802A1 - Voltage conversion system and method of manufacturing such a voltage conversion system - Google Patents

Abstract

A voltage conversion system (1000) comprising: a voltage converter (100), a housing (200) comprising a cooling device, said voltage converter (100) being positioned inside said housing ( 200) so as to be in thermal contact with said cooling device, and an electrical connector (300) comprising a first (310) and a second bus bar (330), said electrical connector (300) being adapted to electrically connect said converter voltage (100) to at least one electrical network via said first (310) and said second bus bar (330), said system being characterized in that said first bus bar (310) is in thermal contact with said cooling device through the exterior of said housing (200). Figure for abstract: Figure 1

Description

Voltage conversion system and method of manufacturing such a voltage conversion system

The subject of the invention is a voltage conversion system intended to equip a motor vehicle. The invention also relates to a method of manufacturing such a voltage conversion system.

TECHNOLOGICAL BACKGROUND

Voltage conversion systems are known comprising a voltage converter, a box comprising a cooling device, the voltage converter being positioned inside the box so as to be in thermal contact with the cooling device, and a connector electric.

In such systems, the electrical connector includes a first and a second busbar and is adapted to electrically connect the voltage converter to at least one electrical network via the first and the second busbar.

However, in such voltage conversion systems, the heat generated at the level of the electrical connector and more particularly at the level of its bus bars can become excessive when the powers implemented by the voltage converter increase.

The object of the invention is to at least partially overcome the aforementioned problem.

To this end, it is proposed, according to a first aspect of the invention, a voltage conversion system comprising:

• a voltage converter,
• a housing comprising a cooling device, the voltage converter being positioned inside the housing so as to be in thermal contact with the cooling device, and
• an electrical connector comprising a first and a second busbar, the electrical connector being adapted to electrically connect the voltage converter to at least one electrical network via the first and the second busbar.

The system is further characterized in that the first busbar is in thermal contact with the cooling device through the exterior of the case.

Within the meaning of the invention, a bus bar is a low impedance conductor, for example a metal bar, for example made of copper.

Thanks to the thermal contact of the first bus bar with the cooling device via the exterior of the case, it is possible to cool this first bus bar and thus to avoid excessive heating of the electrical connector.

A voltage conversion system according to the invention may further comprise one or more of the following optional characteristics, taken in isolation or else according to any technically possible combination.

According to a first characteristic, the electrical connector is fixed to the box.

According to another characteristic, the voltage converter is a DC-DC voltage converter also called DC/DC converter.

According to another characteristic, the voltage converter is a DC-AC voltage converter also called DC/AC converter.

According to another feature, the electrical connector further comprises a first and a second connection terminal, the first busbar and the second busbar being adapted to be mechanically and electrically connected to said at least one electrical network by means of the first connection terminal and the second connection terminal.

According to another feature, the first connection terminal is a metal stud, for example steel.

According to another characteristic, the second connection terminal is a metal stud, for example steel.

According to another feature, the second bus bar is in thermal contact with the cooling device via the exterior of the case.

According to another characteristic, the first busbar and/or the second busbar is formed in one piece, i.e. in continuity of material.

According to another feature, part of the first busbar and/or part of the second busbar is located inside the box.

According to another characteristic, the electrical connector comprises an overmolding of electrically insulating material, for example plastic, the overmolding at least partially overmolding the first and the second bus bar.

According to another characteristic, the overmoulding holding the first busbar and the second busbar together.

According to another characteristic, the box further comprises a support plate capable of delimiting a first volume of the box in which a cooling fluid is intended to circulate to cool the voltage converter with respect to a second volume of the box in which is positioned the voltage converter.

According to another characteristic, the box comprises a cooling fluid inlet, a cooling fluid outlet and the first volume comprises at least one cooling channel connecting the cooling fluid inlet to the cooling fluid outlet.

According to another characteristic, the case comprises a bottom and a peripheral side wall surrounding the bottom and the cooling channel is delimited at least in part by the support plate and/or the bottom and/or the peripheral side wall and/or by at least one wall extending between the bottom and the support plate.

According to another characteristic, the peripheral side wall comprises a first face facing the outside of the case, the peripheral side wall extending between the bottom and the support plate, a part of the support plate extending substantially perpendicular to the first face of the peripheral side wall, the part comprising a through hole arranged to receive the electrical connector, the support plate comprising a second face on which the voltage converter is positioned and a second face opposite the second face of the support plate , the electrical connector being fixed to the first face of the support plate.

According to another characteristic, the peripheral side wall, the support plate and said at least one wall extending between the bottom and the support plate are made in continuity of material, for example by a casting process.

According to another feature, the first busbar is in thermal contact with the cooling device via the exterior of the case via a thermally conductive connecting element, for example by a thermally conductive paste or by a thermal pad (of English "Gad Pad")

According to another characteristic, the cooling device comprises a sole having a first face intended to receive heat to be dissipated emitted by the voltage converter, and at least one fin extending on a second face of the sole opposite to the first face, the first face of the sole being turned towards the inside of the case, the first bus bar being in thermal contact with the second face of the sole.

According to another feature, the electrical connector further comprises a first auxiliary connection terminal, the first busbar and the second busbar being adapted to be mechanically and electrically connected to said at least one electrical network by means of the first terminal respectively auxiliary connection and the second connection terminal.

According to another feature, the electrical connector further comprises a first auxiliary connection terminal and a second auxiliary connection terminal, the first busbar and the second busbar being adapted to be mechanically and electrically connected to said at least one electrical network by the intermediary respectively of the first auxiliary connection terminal and of the second auxiliary connection terminal.

According to another feature, the first auxiliary connection terminal is a metal stud, for example steel.

According to another characteristic, the second auxiliary connection terminal is a metal stud, for example steel.

There is also proposed, according to a second aspect of the invention, a method of manufacturing a voltage conversion system according to the first aspect of the invention and:

• obtaining a voltage converter,
• obtaining a box comprising a cooling device,
• positioning the voltage converter in the case so that the voltage converter is in thermal contact with the cooling device,
• obtaining an electrical connector comprising a first and a second busbar, the electrical connector being designed to electrically connect the voltage converter to at least one electrical network via the first and the second busbar,
• placing the first busbar in thermal contact with the cooling device via the exterior of the case.

The mounting method according to the invention may further comprise the following optional characteristic, according to which the mounting method further comprises fixing the electrical connector to the box.

The invention will be better understood in the light of the following description, given solely by way of non-limiting example and referring to the following figures:

DESCRIPTION OF FIGURES

The is a top view of a voltage conversion system according to one embodiment of the invention.

The is a three-dimensional exploded view of the voltage conversion system shown in .

The is an exploded three-dimensional view of the top of the voltage conversion system case of the .

The is a view of the lower part of the case of the voltage conversion system of the .

The represents the electrical connector without overmolding of the voltage conversion system of the .

The represents, in the form of a flowchart, the different stages of a method of manufacturing the voltage conversion system of the .

DETAILED DESCRIPTION

The shows a top view of a voltage conversion system 1000 in one embodiment of the invention.

As shown on the , the voltage conversion system 1000 comprises a voltage converter 100 designed to convert a first electric voltage V1 into a second electric voltage V2, a box 200 comprising a cooling device intended to cool the voltage converter 100 and an electric connector 300 .

In the example described here, the electrical connector 300 is also attached to the box 200. In other words, the electrical connector 300 is a separate part from the box 200 before it is assembled on the box 200.

The voltage converter 100 is in the example described here a DC/DC voltage converter called DC/DC voltage converter. This voltage converter is intended to be embedded in a vehicle in order to perform a voltage conversion between a first electrical network and a second electrical network of the vehicle. Typically, the first electrical network is a low voltage network delivering a first electrical voltage V1 of less than 30V, for example approximately 24 or 12V, and the second electrical network is a high voltage network which delivers a second electrical voltage V2 greater than 30V, for example 48V.

In the example described here, the voltage converter 100 comprises an electronic card 110 comprising a plurality of voltage choppers (not represented on the ) in parallel. Each of the voltage choppers comprises an inductance and two transistors operating as electronic switches.

These two transistors are, in the example described here, MOSFET transistors (from the English “Metal Oxide Semiconductor Field Effect Transistor”). As a variant, these transistors can also be IGBT transistors (standing for “Insulated Gate Bipolar Transistor”) or even FET power transistors (standing for “Field Effect Transistor”) made of gallium nitride (GaN).

It is known that such a voltage converter 100 can address different operating powers depending on the number of voltage choppers arranged in parallel.

With reference to the and at the , the case 200 comprises a bottom 210, a peripheral side wall 220 surrounding the bottom 210, a support plate 230 and a cooling device intended to cool the voltage converter 100.

The peripheral side wall 220 extends between the bottom 210 and said support plate 230 and comprises a first face facing the outside of the box 200.

The bottom 210 is in the form of a cover positioned on a bearing surface of the peripheral side wall 220 and fixed, for example by friction-mixing, to the peripheral side surface 220.

As a variant, the lid can be screwed onto a bearing surface of the peripheral side wall 220 by inserting a seal between the lid and the peripheral side wall 220.

The support plate 230 delimits a first volume PV1 of the box 200 in which a cooling fluid, for example water, is intended to circulate to cool the voltage converter 100 and a second volume PV2 of the box 200 in which is mounted the voltage converter 100.

The support plate 230 thus comprises a first face facing the first volume PV1 and a second face facing the second volume PV2, the second face being opposite the first face.

Furthermore, the voltage converter 100 is positioned and fixed on the second face, for example by screws. As a variant, the voltage converter 100 is fixed on the second face by riveting or else by gluing.

The box 200 further comprises a cooling fluid inlet 240 and a cooling fluid outlet 250 while the first volume consists of a cooling channel connecting the cooling fluid inlet 240 to the cooling fluid outlet. 250.

In the embodiment described here, the cooling channel is delimited by the first face of the support plate 230, by the bottom 210, by the peripheral side wall 220 and by walls 260 extending between the bottom 210 and the plate. -bracket 230.

In this way, the circulation of the cooling fluid in the cooling channel and, consequently, under the support plate 230 supporting the voltage converter 100 makes it possible to cool this voltage converter 100.

Thus, the cooling channel, the cooling fluid inlet, the cooling fluid outlet and the support plate constitute a cooling device for the voltage converter 100.

In addition, a part 235 of the support plate 230 extends substantially perpendicular to the first face of the peripheral side wall 220, this part 235 comprising a through hole 236 arranged to receive the electrical connector 300 so that this electrical connector 300 is fixed to the first face of the support plate 230.

In the example described here, the peripheral side wall 220, the support plate 230 and the walls 260 are made in continuity of material, for example of metal such as aluminum, for example by a casting process. In other words, the peripheral side wall 220, the support plate 230 and the walls 260 constitute a single piece of metal, for example aluminum, made for example by a casting process. Alternatively, the peripheral side wall 220, the support plate 230 and the walls 260 can be parts made separately before being assembled.

With reference to the , the electrical connector 300 comprises a first positive bus bar 310, a second positive bus bar 320 and a negative bus bar 330, the negative bus bar 330 being intended to be connected to an electrical ground.

In the example described here, the first positive bus bar 310 is metallic, for example copper. Likewise, the second positive bus bar 320 is metallic, for example copper. Finally, the negative bus bar 330 is also metallic, for example copper.

In the example described here, the first positive busbar 310, the second positive busbar 320 and the negative busbar 330 are further formed in one piece, i.e. in continuity of material.

The electrical connector 300 is designed to electrically connect the voltage converter 100 to the first electrical network via the first positive busbar 310 and the negative busbar 330 and to the second electrical network via the second busbar positive 320 and negative bus bar 330.

It will be appreciated that in the example described, the first positive busbar 310, the second positive busbar 320 and the negative busbar 330 are rigid electrical conductors designed to withstand electrical current densities of at least 10A/mm².

Thus the first positive bus bar 310 and the negative bus bar 330 present between them the first electric voltage V1 and the second positive bus bar 320 and the negative bus bar 330 present between them the second electric voltage V2 when the voltage converter 100 converts the first electric voltage V1 into the second electric voltage V2.

In the example described here, a first positive connection terminal is fixed on a planar portion of the first positive bus bar 310, a second positive connection terminal is fixed on a planar portion of the second positive bus bar 320 and a negative connection is attached to a flat portion of the negative bus bar 330.

The first positive connection terminal, the second positive connection terminal and the negative connection terminal are respectively, in the example described here, studs 312, 322, 332. The studs 312, 322, 332 are threaded and made of metal, for example steel.

The first positive connection terminal and the negative connection terminal make it possible to mechanically attach the busbars 310, 330 to electrical power cables in order to electrically connect these busbars 310, 330 to the first electrical network. Similarly, the second positive connection terminal and the negative connection terminal make it possible to mechanically attach the busbars 320, 330 to electrical power cables in order to electrically connect these busbars 320, 330 to the second electrical network.

The attachment of an electric cable to one of these busbars is carried out for example by inserting the threaded stud of the busbar into the eye of a terminal of the electric cable then by screwing a nut on the threaded stud so pressing the terminal against the bus bar in order to make the electrical connection between the bus bar and the terminal.

Optionally, a first auxiliary positive connection terminal is attached to a planar portion of the first positive bus bar 310 and an auxiliary negative connection terminal 334 is attached to a planar portion of the negative bus bar 330.

The first auxiliary positive connection terminal and the auxiliary negative connection terminal are respectively, in the example described here, studs 314, 334. The studs 314, 334 are made of metal, for example steel.

The first auxiliary positive connection terminal and the auxiliary negative connection terminal make it possible to mechanically attach the busbars 310, 330 to electrical power cables in order to electrically connect these busbars 310, 330 to the first electrical network.

The use of two different connection terminals makes it possible to mechanically and electrically fix the positive bus bar to the first electrical network by means of two different electrical supply cables.

Thus, the electric current passing through each of these two electric cables is reduced so that the electric cables heat up less.

Similarly, the second positive connection terminal and the auxiliary negative connection terminal make it possible to mechanically attach the busbars 320, 330 to electrical power cables in order to electrically connect these busbars 320, 330 to the second electrical network.

The electrical connector 300 further includes a magnetic core 340 surrounding the first positive bus bar 310, the second positive bus bar 320 and the negative bus bar 330.

The first positive bus bar 310, the second positive bus bar 320 and the negative bus bar 330 are at least partly overmoulded with an insulating material 350 (not visible on the but visible on the ), for example by an insulating plastic material.

In the example described here, the magnetic core 340 is mounted around the first positive busbar 310, the second positive busbar 320 and the negative busbar 330 after molding these three busbars 310, 320, 330.

In the example described here, the first end of the first positive busbar 310 has a general T shape. The first positive connection terminal and the first auxiliary positive connection terminal are each fixed to a different end of the crossbar of this T. Similarly, in the example described, the first end of the negative bus bar 330 has the general shape of a T. The negative connection terminal and the auxiliary negative connection terminal are each located at a different end of the bar transverse of this T.

Alternatively, the first end of the first positive bus bar 310 could have a general Y shape. The first positive connection terminal and the first auxiliary positive connection terminal would each be attached to one end of a different leg of this Y. Similarly, the first end of the negative bus bar 330 could have a general Y shape. The negative connection terminal and the auxiliary negative connection terminal would each be located at one end of a different leg of this Y.

In the example described here, the electrical connector 300 is fixed, for example by screws, to the outside of the box 200 on the first face of the support plate 230. In the example described here, the electrical connector 300 is fixed on the first face of the support plate 230 at the level of a stud 270 located at the level of its part 235 and at the level of at least one fixing stud 271 located on the first face of the support plate 230.

To secure the electrical connector 300 to the exterior of the housing 200, a second end of the first positive busbar 310, a second end of the second positive busbar 320 and a second end of the negative busbar 330 are inserted into the hole. opening 236 so that these ends are located inside the box 200 and more precisely in the second volume PV2 of the box 200 and so that these ends can be physically connected to the voltage converter 100. To ensure the seal between the electrical connector 300 and housing 200, a gasket surrounding through hole 236 may be inserted between electrical connector 300 and housing 200 when attaching electrical connector 300 to housing 200.

Further, when attaching electrical connector 300 to housing 200, first positive busbar 310 and negative busbar 330 are brought into thermal contact with housing cooler 200 via the exterior of this box 200.

Thanks to this thermal contact with the cooling device of the box 200 from the outside of this box 200, the first positive bus bar 310 and the negative bus bar 330 can be cooled which limits their heating as well as the heating of the electrical connector 300 and cables connected to the terminals of this electrical connector 300.

In the example described here, the first positive bus bar 310 is in thermal contact with the exterior of the case 200 via at least one thermal pad placed between an exterior surface of the case 200 and a surface of the first bar. positive omnibus 310.

In the example described, three thermal pads 410, 420 and 430 (on the , only the thermal pads 410 and 430 are visible) are placed between the box 200 and the first positive bus bar 310

Similarly, negative bus bar 330 is in thermal contact with the exterior of housing 200 through at least one thermal pad placed between an exterior surface of housing 200 and a surface of negative bus bar 330.

Alternatively, the first positive bus bar 310 and/or the negative bus bar 330 are in thermal contact with the exterior of the housing 200 via a thermally conductive paste placed between them and an exterior surface of the housing 200.

In the example described here, the first positive bus bar 310 is in thermal contact with the bottom 210 and with the peripheral side wall 220 of the casing 200. In this way, the circulation of the cooling fluid in the cooling channel and, by Consequently, in contact with the bottom 210 and with the peripheral side wall 220 makes it possible to cool the first positive bus bar 310.

In the example described here, the negative bus bar 330 is in thermal contact with the first surface of the support plate 230. In this way, the circulation of the cooling fluid in the cooling channel and, therefore, in contact with the support plate 230 makes it possible to cool the negative bus bar 330.

Optionally, the cooling device may comprise a radiator comprising a soleplate and at least one fin (not shown in the figures). The sole of the radiator comprises a first face intended to receive the heat to be dissipated emitted by the voltage converter 100, and a second face opposite the first face. On the second face, said at least one fin extends. In other words, the first side of the sole faces the inside of the case and the second side of the sole faces the outside of the case. For example, the bottom 210 of the case 220 can constitute such a sole. In the example described here, the first positive bus bar 310 is in thermal contact with the second face of the sole, i.e. with the outer part of the bottom 210, via said at least one thermal pad and by the side walls 220 of the box 200.

With reference to the , an exemplary method 2000 of manufacturing the voltage conversion system 1000 will now be described.

During a step E2100, a voltage converter 100 is obtained.

During a step E2200, a box 200 comprising a cooling device is obtained.

During a step E2300, the voltage converter 100 is positioned in the case 200 so that the voltage converter 100 is in thermal contact with the cooling device,

During a step E2400, an electrical connector 300 comprising a first 310 and a second 330 bus bar, said electrical connector being designed to electrically connect said voltage converter 100 to at least one electrical network via said first and of said second bus bar is obtained,

During a step E2500, the electrical connector 300 is attached to the box 200,

During a step E2600, the first busbar 310 is placed in thermal contact with the cooling device via the outside of the box 200.

During a step E2700, the second bus bar 330 is placed in thermal contact with the cooling device via the outside of the box 200.

It will also be noted that the invention is not limited to the embodiments described above. It will indeed appear to those skilled in the art that various modifications can be made to the embodiments described above, in the light of the teaching which has just been disclosed to them.

For example, the voltage converter could be a DC/AC voltage converter and the electrical connector could only be able to electrically connect the voltage converter 100 to the second electrical network. In other words, in this exemplary embodiment, the electrical connector would comprise only the second positive bus bar and the negative bus bar, said second positive bus bar being in thermal contact for its cooling with the exterior of the case of the conversion system electric.

As another example, voltage conversion system 100 could have no cooling channel and only include a heatsink. In this embodiment, the bottom 210 and the support wall 230 constitute one and the same piece.

Furthermore, the terms used in the claims should not be interpreted as being limited to the elements of the embodiments previously described, but should on the contrary be interpreted as including all equivalent elements the provision of which is within the reach of those skilled in the art. applying general knowledge.

Claims (14)

Voltage conversion system (1000) comprising:

1. a voltage converter (100),
2. a housing (200) comprising a cooling device, said voltage converter (100) being positioned inside said housing (200) so as to be in thermal contact with said cooling device, and
3. an electrical connector (300) comprising a first (310) and a second busbar (330), said electrical connector (300) being designed to electrically connect said voltage converter (100) to at least one electrical network via said first (310) and said second busbar (330),

said system being characterized in that said first busbar (310) is in thermal contact with said cooling device through the exterior of said housing (200). A voltage conversion system (1000) according to the preceding claim wherein the electrical connector (300) further comprises a first (312) and a second (332) connection terminal, said first busbar (310) and said second busbar (330) being capable of being mechanically and electrically connected to said at least one electrical network via said first connection terminal (312) and said second connection terminal (332), respectively. A voltage conversion system (1000) according to one of the preceding claims wherein said second bus bar (330) is in thermal contact with said cooling device through the exterior of said housing (200). Voltage conversion system (1000) according to one of the preceding claims, in which said first busbar (310) and/or said second busbar (330) is formed in one piece, i.e. in continuity of material. A voltage conversion system (1000) according to one of the preceding claims wherein a portion of said first busbar (310) and/or said second busbar (330) is located inside said housing. Voltage conversion system (1000) according to one of the preceding claims, in which the electrical connector (300) comprises an overmolding (350) of electrically insulating material, for example plastic, said overmolding (350) at least partially overmolding the first (310) and the second (330) bus bar. Voltage conversion system (1000) according to one of the preceding claims, in which the box (200) further comprises a support plate (230) capable of delimiting a first volume (PV1) of the box (200) in which a fluid cooling is intended to circulate to cool said voltage converter (100) relative to a second volume (PV2) of the box (200) in which said voltage converter (100) is positioned. Voltage conversion system (1000) according to the preceding claim wherein said box (200) comprises a cooling fluid inlet (240), a cooling fluid outlet (250) and said first volume (PV1) comprises at least one cooling channel connecting said cooling fluid inlet (240) to said cooling fluid outlet (250). Voltage conversion system according to the preceding claim, in which the case comprises a bottom (210) and a peripheral side wall (220) surrounding said bottom (210) and in which the cooling channel is delimited at least in part by said plate- support (230) and/or said bottom (210) and/or said peripheral side wall (220) and/or by at least one wall (260) extending between said bottom (210) and said support plate (230) . System (1000) according to the preceding claim wherein said peripheral side wall (220), said support plate and said walls (240, 250) extending between said bottom (210) and said support plate (230) are made in continuity of material, for example by a foundry process. A voltage conversion system (1000) according to one of the preceding claims wherein said first bus bar (310) is in thermal contact with said cooling device through the exterior of said housing (200) via a thermally conductive connection, for example by a thermally conductive paste or by a thermal pad (410, 430). Voltage conversion system (1000) according to one of the preceding claims, in which the said cooling device comprises a sole having a first face intended to receive the heat to be dissipated emitted by the said voltage converter, and at least one fin extending over a second face of the sole opposite the first face, said first face of the sole facing the interior of the case, said first bus bar being in thermal contact with said second face of the sole. A voltage conversion system (1000) according to one of the preceding claims wherein the electrical connector (300) further comprises a first auxiliary connection terminal (314), said first bus bar (310) and said second bus bar (330 ) being capable of being mechanically and electrically connected to said at least one electrical network via said first auxiliary connection terminal (314) and said second connection terminal (332), respectively. Method of manufacturing (2000) a voltage conversion system (1000) according to one of the preceding claims comprising:

1. obtaining (E2100) a voltage converter (100),
2. obtaining (E2200) a box (200) comprising a cooling device,
3. positioning (E2300) the voltage converter in said case so that said voltage converter is in thermal contact with said cooling device,
4. obtaining (E2400) an electrical connector (300) comprising a first (310) and a second 330) bus bar, said electrical connector (300) being adapted to electrically connect said voltage converter (100) to at least one electrical network via said first (310) and said second (330) bus bar,
5. thermally contacting (E2600) said first busbar (310) with said cooling device through the exterior of said housing (200).