Isolation protection for preventing inverter electric shock risk

Abstract

The invention relates to isolation protection against the risk of inverter electric shock, proposes an inverter (2) for a motor vehicle, comprising at least one cover (6) and a body delimiting a volume housing at least one printed circuit board, said volume being closed by said cover (6), said inverter (2) comprising a housing (10) projecting from said cover (6), the invention relates to an inverter (2) comprising a housing (10) defining a space housing a first connection terminal and a second connection terminal, each configured to be connected to an electrical conductor (12) intended to electrically connect an electrical energy storage device to the inverter (2), the housing (10) comprising a cover closing the housing (10), the housing (10) comprises an electrical insulation device (28) arranged between the cover and the connection terminal.

Description

Technical Field

[0001] The present invention relates to the field of power converters used in motor vehicles. More specifically, the present invention relates to a device for electrically insulating the connection terminals of an inverter. Background Art

[0002] Vehicles, in particular motor vehicles, are usually equipped with an electrical energy storage device in which electrical energy is stored. This electrical energy is used to operate various vehicle components, such as a powertrain that operates with alternating current. The vehicle is then equipped with at least one inverter to convert the electrical energy stored in the storage device into AC electrical energy.

[0003] An inverter is a power electronic device capable of generating alternating current from direct current. An inverter may be integrated into a motor vehicle, in particular a hybrid or electric vehicle, to convert the direct current supplied by the battery into alternating current to power the electric motor.

[0004] In today's electric vehicles or hybrid vehicles, the demand for electric power implies a high voltage power supply, for example in the order of 800V.

[0005] Such an inverter comprises at least one printed circuit board housed in a body, on which several electronic components are arranged, interconnected by copper tracks formed in the thickness of the board, the inverter and these electronic components being supplied with electric current by means of electrical conductors.

[0006] These electrical conductors are mechanically connected to connection terminals on the printed circuit board of the inverter. The connection terminals are accommodated in an inverter housing closed by a cover. When an operator works on the housing, the connection terminals are directly accessible and, although the electrical connection to the electrical energy storage medium has been interrupted, residual voltages may remain at the connection terminals within the housing. The residual voltages may be dangerous for the operator and prior art solutions do not provide adequate protection for the operator. Summary of the invention

[0007] The present invention is suitable for such situations and aims to overcome at least some of the disadvantages of the prior art. In particular, the present invention aims to provide an inverter in which an operator is protected from the risk of electrocution when the housing is opened.

[0008] The invention therefore relates to an inverter for a motor vehicle, the inverter comprising at least one cover and a body, the body defining a volume in which at least one printed circuit board is accommodated, the volume being closed by the cover, the inverter comprising a housing protruding from the cover, the housing defining a space in which a first connection terminal and a second connection terminal are accommodated, the first connection terminal and the second connection terminal being each configured to be connected to an electrical conductor intended to electrically connect an electrical energy storage device to the inverter, the housing comprising a cover closing the housing, the housing comprising electrical insulation means arranged between the cover and the connection terminals.

[0009] The electrical insulation device is a protective element against electric shock. Therefore, such an electrical insulation device makes it possible to protect operators working on the inverter from the risk of electric shock. The connection terminal is an inverter component that is mechanically connected to the printed circuit board. It should be understood that the current from the electrical energy storage device continuously passes through the electrical conductor and then reaches the inverter component through the connection terminal.

[0010] The housing forms a part of the inverter, within which the connection terminals are arranged, the housing being closed by a cover. When working on the housing, i.e. when reaching the connection terminals, the operator accesses the connection terminals by removing the cover. Similarly, when assembling the inverter, the cover forms an element which hermetically seals the housing. The arrangement of the electrical insulation means between the connection terminals and the cover means that the connection terminals are not directly exposed when the cover is removed. Thus, when the housing is opened, the operator is protected from the risk of electric shock if a residual voltage remains in the housing for a few seconds after disconnection of the power supply to the connection terminals.

[0011] According to one feature of the invention, the electrical insulating device is fixed to the cover by a fixing member passing through the cover. The fixing member helps to seal the housing by closing the hole in the cover. The fact that the electrical insulating device is held in place by the fixing member limits the displacement of the electrical insulating device in the housing and also reduces the risk of the electrical insulating device being overlooked when assembling the housing and the components housed inside.

[0012] According to a feature of the invention, the electrical insulating device comprises a hole for receiving the fixing member. The hole comprises a thread complementary to the fixing member. Thus, the fixing member can only be installed to hermetically seal the housing if the electrical insulating device is present in the housing and is correctly positioned.

[0013] According to a feature of the invention, the cover comprises a safety device configured to prevent power supply to the inverter when the cover is detached from the housing. The safety device can stop power supply to the connection terminals when the housing is without a cover. Due to the presence of the electrical isolation device, the residual voltage (i.e. the current that persists in the housing for a few seconds after the power supply is turned off) does not lead to a risk of electric shock to the operator.

[0014] The invention also relates to a power converter intended to equip a motor vehicle comprising at least one inverter, the power converter comprising at least one electrical conductor electrically connected to one of the connection terminals, wherein the electrical insulating device is fixed to at least one of the electrical conductors by at least one fastening element. By integrating the electrical insulating device into the various elements used to fasten the various power converter components together, it is possible to ensure that the electrical insulating device is present and correctly positioned.

[0015] According to a feature of the invention, each electrical conductor comprises a connection element mechanically connected to one of said connection terminals, electrical insulation means being arranged between said connection element and the cover.

[0016] According to a feature of the invention, the fastening element prevents at least one movement of the electrical conductor relative to the housing.

[0017] According to one feature of the present invention, the housing comprises at least a first barrel and a second barrel, the first barrel and the second barrel are configured to receive a portion of the electrical conductor, and the fastening element passes through at least one of the barrels.

[0018] According to one feature of the invention, the electrical insulation device is supported by at least one of the cylinders. Such positioning of the electrical insulation device limits the stresses on the electrical insulation device. Furthermore, such positioning of the electrical insulation device ensures that the electrical insulation device covers both the connection terminal and the connection element.

[0019] According to one feature of the invention, the fastening element comprises a head in contact with the electrical insulating means and a body comprising a thread, the body being received in a compartment formed in one of the electrical conductors, the compartment comprising a thread cooperating with a thread of the body of the fastening element.

[0020] According to a feature of the invention, the fastening element is spaced apart from the bottom of the compartment by a distance strictly smaller than the thickness of the electrical insulation means.

[0021] This distance between the fastening element and the bottom of the compartment ensures that the electrical insulation is correctly positioned when the electrical conductor is attached to the housing. If the electrical insulation is missing, the fastening element will abut the bottom of the compartment and the electrical conductor will not be optimally fixed to the housing, allowing the operator to see that the electrical insulation is missing.

[0022] The present invention also relates to a method for disassembling a power converter, the method comprising at least:

[0023] - a first step in which the cover is disengaged from the housing by removing at least the fixing member,

[0024] - a second step, in which the electrical insulation device is detached from the housing by removing at least one fastening element,

[0025] - a third step, in which the electrical conductor is separated from the connection terminal,

[0026] - A fourth step, in which the electrical conductor is extracted from the housing by sliding the electrical conductor.

[0027] It should be noted that the second step of the method for disassembling a power converter is performed by means of the element for fixing the electrical insulation means to the housing over a time interval greater than the time interval during which a residual voltage remains in the housing. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Other characteristics, details and advantages of the invention will become more apparent on the one hand by reading the following description and on the other hand by reference to the examples of implementation given by way of indication and non-limitation in the attached schematic drawings, in which:

[0029] Figure 1 shows an overall view of a power converter consisting of an inverter connected to electrical conductors in a housing;

[0030] Figure 2 Shows Figure 1 An overall view of a power converter is shown, wherein a housing cover for enclosing a space in which inverter connection terminals are arranged has been removed;

[0031] Figure 3 A detailed view of an electrical insulation device is shown, which is designed to be mounted on Figure 2 In the space between the cover and the connection terminals visible on the top;

[0032] Figure 4 shows a view of a power converter with the housing cover removed and the electrical insulation received in and secured to the inverter housing;

[0033] Figure 5 A cross-sectional view of a power converter is shown at a fastening element which is involved in fixing the electrical insulation, the housing and the electrical conductor to each other. DETAILED DESCRIPTION

[0034] The features, variants and different embodiments of the present invention may be associated with each other in various combinations, as long as they are not incompatible or mutually exclusive. In particular, it is conceivable that a variant of the present invention includes only the selection of the features described below separated from the other features described, if the selection of the features is sufficient to confer a technical advantage or to distinguish the present invention from the prior art.

[0035] In the drawings, elements common to several figures retain the same reference numerals.

[0036] In the following detailed description, the terms "longitudinal", "transverse" and "vertical" refer to the orientation of the inverter according to the invention arbitrarily designated by the trihedrons L, V, T.

[0037] Figure 1 An inverter 2 according to the invention and intended to equip a motor vehicle is shown. The inverter 2 consists of a body 4 and a cover 6 which delimit a volume housing at least one printed circuit board. The printed circuit board comprises a plurality of electronic components involved in the operation of the inverter 2.

[0038] The body 4 and the cover 6 form two separate parts of the inverter 2. When the printed circuit board and various components involved in the operation of the inverter 2 are mounted in the volume defined by the body 4, the cover 6 is attached to the body 4 in a manner to seal the volume.

[0039] In the embodiment shown, the cover 6 is fastened to the body 4 by compressing the seal between the body 4 and the cover 6 using screws. Figure 1 In the embodiment, only the fastening area 8 using screws is visible.

[0040] The inverter 2 comprises a housing 10 arranged against the cover 6. The housing provides power to the inverter 2. In the housing 10, electrical conductors 12 are electrically connected to connection terminals, which are connected to a printed circuit board housed in the body 4. These electrical conductors 12 enable current to be routed from the electrical energy storage device to the inverter 2. The resulting assembly of the inverter 2 connected to the electrical conductors 12 forms the power converter 1.

[0041] As will be described in more detail in the following description, the connection terminals are housed in a space defined by the housing 10. More specifically, the space is defined by the cover 6, walls 14 extending perpendicularly to the main longitudinal and transverse planes of extension of the cover 6, and a cover 16 fixed to the walls 14. The walls 14 are arranged side by side so as to form a housing defining said space.

[0042] It is worth noting that in Figure 1 In the embodiment shown, the housing 10 forms a separate part from the cover 6. To this end, the housing 10 comprises, at one end of the wall 14, a fixing point 15 formed by cooperation between an eyelet 17 integral with the wall 14 and a screw received in the cover 6 through said eyelet 17. It should be noted that in an alternative embodiment of the invention, the wall 14 can be made of the same material as the cover 6. It should be understood that in this alternative embodiment of the invention, there is continuity of material between the wall 14 and the cover 6, in which case the fixing point 15 is not used.

[0043] Furthermore, the housing 10 comprises a first cylinder 19 and a second cylinder 21, each protruding from the same wall 14 of the housing 10 about a rotation axis, which are parallel to each other. The first cylinder 19 and the second cylinder 21 each accommodate an electrical conductor 12, so that a connection element for the electrical conductor 12 (which will be described in more detail in the following description) can be mechanically connected to the connection terminal.

[0044] Figure 2 A view of the cover 6 and housing 10 of the power converter 1, and more specifically of the inverter 2, is shown, wherein the cover 16 is not visible. This view of the housing 10 shows the first connection terminal 18 and the second connection terminal 20, both of which are accommodated in the aforementioned space of the housing 10. It should be noted that in the following description, when referring to the first connection terminal 18 and the second connection terminal 20, reference will be made to the "connection terminals".

[0045] Figure 2 In particular, the connection of a first connection element 23 of an electrical conductor 12 to the first connection terminal 18 and the connection of a second connection element 25 of another electrical conductor 12 to the second connection terminal 20 are shown. The first connection element 23 and the second connection element 25 respectively form the free ends of two separate electrical conductors 12 intended to be mechanically connected to the inverter 2.

[0046] The first connection terminal 18 and the second connection terminal 20 each include a first aperture 26 facing a second aperture 27 in each of the first connection element 23 and the second connection element 25. This arrangement of the first aperture 26 of the connection terminals 18, 20 facing the second aperture 27 of the connection elements 23, 25 enables the connection elements 23, 25 to be joined to the connection terminals 18, 20 by means of, for example, screws, so as to enable current to flow from the electrical energy storage device to the inverter 2. It should be noted that Figure 2 The screws which enable the connection elements 23 , 25 to be joined to the connection terminals 18 , 20 are not shown.

[0047] Figure 2 It is also shown that each electrical conductor 12 is fastened to the housing 10 by means of a fastening leg 30. Each fastening leg 30 is associated with a cylinder 19, 21 and extends the cylinder 19, 21 into the space defined in the housing 10. In other words, the cylinders 19, 21 protrude from the wall 14 in a direction opposite to the direction in which they extend. Each fastening leg 30 comprises a first opening 32 through which the fastening element is adapted to fasten at least the housing 10 to the electrical conductor 12 extending in one of said cylinders 19, 21.

[0048] The connection terminals 18, 20 are covered with an insulating coating 22 which electrically insulates the connection terminals 18, 20 from each other. The insulating coating 22 is made of an insulating polymer material which limits the risk of a short circuit between the first connection terminal 18 and the second connection terminal 20.

[0049] Furthermore, the housing 10 includes a safety device 24 consisting of a first portion connected to the printed circuit board and a second portion formed on the cover 16. The first portion of the safety device 24 includes two connection points configured to contact the second portion of the cover 16 when the second portion of the cover 16 is attached to the wall 14. In fact, the cover 16 is fixed to the wall 14 by a plurality of screws, and of course, if necessary, a seal is inserted between the cover 16 and the wall 14 to ensure the tightness of the housing 10.

[0050] The safety device 24 is advantageously configured to allow power to be supplied to the inverter 2 when the cover 16 is attached to the wall 14, and to prevent power to the inverter 2 when the cover 16 is removed from the wall 14. It should be noted that when the power supply to the inverter 2 is cut off by removing the cover 16, a residual voltage of the order of several seconds may remain. For this reason, the inverter 2 includes Figure 3 and Figure 4 An electrical isolation device 28 is visible in the figure to protect operators working on the inverter 2.

[0051] Figure 3 and Figure 4 Detailed views of the electrical insulation device 28 and views of the power converter 1 when the electrical insulation device 28 is attached to the housing 10 are shown, respectively. Figure 4 In the embodiment shown in FIG. 1 , the cover 16 of the housing 10 is not visible, so that the electrical insulation device 28 is visible. The electrical insulation device 28 is designed to face the connection terminals 18, 20 and the connection elements 23, 25. To this end, the electrical insulation device 28 comprises two second openings 34, each of which is designed to face the first opening 32 of a separate fastening leg 30.

[0052] More specifically, when assembling the power converter 1, the second opening 34 of the electrical insulation device 28 is on the fastening leg 30, facing the associated first opening 32, and the connecting elements 23, 25 themselves are arranged facing said first opening 32. In this way, the fastening leg 30 is arranged between the electrical insulation device 28 and the cover 16. This arrangement enables the electrical insulation device 28 to rest on the fastening leg 30.

[0053] This alignment of the first opening 32 in the fastening leg 30 and the second opening 34 in the electrical insulation 28 enables the fastening leg 30 to be fastened to the electrical insulation 28 by means of the fastening element 40 .

[0054] It should be noted that the combination Figure 5This connection of the electrical insulation 28 to the housing 10 via the fastening element 40 is described in more detail.

[0055] Furthermore, it is worth noting that the electrical insulating device 28 includes a hole 36 at a substantially central position. The hole 36 is used to receive Figure 1 Visible therein are fixing members 38 for fixing the electrical insulation 28 to the cover 16 .

[0056] This fixing member 38 can be associated with a sealing member to ensure the tightness of the cover 16. In the embodiment shown, the hole 36 includes a thread designed to fix the fixing member 38 to the electrical insulating device 28. More specifically, the combination of the fixing member 38 and the hole 36 forms a control device for ensuring that the electrical insulating device 28 is correctly positioned in the housing 10 when the housing 10 is closed. In fact, by positioning the fixing member 38 to hermetically close the housing 10, the operator can see whether the electrical insulating device 28 is present. In the event that the electrical insulating device 28 is not present in the housing 10 when the operator seals the cover 16 to the wall 14, the operator will not be able to seal the housing 10 by the fixing member 38.

[0057] Figure 5 A cross-sectional view of the power converter 1 through a vertically and longitudinally extending section plane is shown. This view of the power converter 1 highlights the attachment of the electrical insulation 28 to the housing 10 and the electrical conductors 12.

[0058] like Figure 5 As shown, the electrical conductor 12 includes a compartment 42 in which the fastening element 40 is threadedly engaged. Figure 5 It is particularly noteworthy that the fastening element 40 includes a main body 44 passing through the first opening 32 and the second opening 34 disposed opposite to the first opening 32 .

[0059] The body 44 of the fastening element 40 is housed in a compartment 42 made of the electrical conductor 12. Figure 5 The description of the fastening element 40 shown in FIG. 1 applies mutatis mutandis to another fastening element 40 cooperating with the other first opening 32 and second opening 34 described above.

[0060] Compartment 42 has threads complementary to threads on body 44 so that fastening element 40 can be used to connect electrical insulation 28, housing 10 and electrical conductor 12 to one another via fastening legs 30. It will be appreciated that fastening element 40 prevents movement of electrical conductor 12 relative to housing 10.

[0061] When the fastening element 40 is received in the compartment 42, the head 46 of the fastening element 40 is in contact with the electrical insulation 28. This bearing of the head 46 against the electrical insulation 28 presses the electrical insulation 28 against the fastening leg 30.

[0062] like Figure 5 As shown, the distance between the end of the fastening element 40 located in the compartment 42 and the bottom of the compartment 42 is less than the thickness of the electrical insulating device 28. Such a feature enables the operator to ensure that the electrical insulating device 28 is in place when assembling the housing 10 and the components inside the housing 10. In fact, in the case where the operator forgets to position the electrical insulating device 28 before inserting the fastening element 40 to fix the electrical conductor 12 to the housing 10, the fastening element 40 abuts against the bottom of the compartment 42 and does not ensure optimal retention of the electrical conductor 12 to the housing 10.

[0063] As can be understood from the above, the assembly of the power converter 1 follows a method of assembly and disassembly. When the power converter 1 is assembled, an operator who wishes to disassemble the power converter 1 must then follow a method for disassembling the power converter 1, which involves a first step in which the cover 16 is removed, in particular by removing the fastening elements 38. Then, in a second step, the electrical insulation device 28 is removed from the housing 10 by removing at least one fastening element 40, in this case, in the embodiment shown, two fastening elements 40. In a third step of the method for disassembling the power converter 1, the electrical conductor 12 is separated from the connection terminals 18, 20, and in a fourth step, said electrical conductor 12 is removed from the housing 10 by means of a sliding movement. It should be noted that this sliding movement is performed along the axis of rotation of each cylinder 19, 21.

[0064] It should be noted that the second step of the method for disassembling the power converter 1 is performed within a time interval greater than the time interval during which the residual voltage persists in the housing 10. In particular, this second step of the method for disassembling the power converter 1 is performed at a time interval of at least 5 seconds. Therefore, during the dissipation of the residual voltage in the housing 10, the connection terminals 18, 20 are separated from the operator by the electrical insulation device 28.

[0065] The assembly of the power converter 1 also follows a method for assembling the power converter 1, which implements steps substantially similar to those of the method for disassembling the power converter, starting from the fourth step. Thus, the method for assembling the power converter 1 implements a first step during which the electrical conductor 12 is inserted into the housing 10 by means of a sliding movement through the cylinders 19, 21. Then, in a second step of the method for assembling, the electrical conductor 12 is placed opposite the connection terminals 18, 20. More specifically, in this second step, the second orifices 27 of the connection elements 23, 25 are each opposite to the first orifices 26 of the connection terminals 18, 20. In a third step of the process for assembling the power converter 1, the electrical insulation device 28 is positioned on the housing 10. Then, in a fourth step, at least one fastening element 40 is positioned. This positioning of the fastening element 40 is performed so that, according to what has been previously described, the housing 10, the electrical insulation device 28 and the electrical conductor 12 are fixed to each other.

[0066] The invention achieves its intended purpose by providing an inverter in which the risk of electric shock to an operator working on the inverter housing in which the connection terminals are accommodated is limited. This risk of electric shock is limited by electrical insulation means arranged between the connection terminals and the cover of the housing.

[0067] However, the present invention is not limited to the devices and configurations described and illustrated herein, and extends equally to any equivalent devices and configurations, and to any technically operable combination of these devices.

Claims

1. An inverter (2) for a motor vehicle, comprising at least one cover (6) and a body (4), the body (4) defining a volume for accommodating at least one printed circuit board, the volume being closed by the cover (6), the inverter (2) comprising a housing (10) protruding from the cover (6), the housing (10) defining a space for accommodating a first connection terminal (18) and a second connection terminal (20), the first connection terminal (18) and the second connection terminal (20) each being configured to be connected to an electrical conductor (12), the electrical conductor (12) being used to electrically connect an electrical energy storage device to the inverter (2), the housing (10) comprising a cover (16) closing the housing (10), the housing (10) comprising an electrical insulation device (28) arranged between the cover (16) and the connection terminals (18, 20).

2. The inverter (2) according to claim 1, wherein: The electrical insulation device (28) is fixed to the cover (16) by a fixing member (38) passing through the cover (16).

3. The inverter (2) according to claim 2, wherein: The electrical insulation device (28) includes a hole (36) for receiving the fixing member (38).

4. The inverter (2) according to any one of claims 1 to 3, wherein: The cover (16) includes a safety device (24) configured to prevent power from being supplied to the inverter (2) when the cover (16) is detached from the housing (10).

5. A power converter (1) for equipping a motor vehicle, comprising at least one inverter (2) according to any one of claims 1 to 4, the power converter (1) comprising at least one electrical conductor (12) electrically connected to one of the connection terminals (18, 20), wherein the electrical insulation device (28) is fixed to at least one of the electrical conductors (12) by at least one fastening element (40).

6. A power converter (1) according to claim 5, wherein each electrical conductor (12) comprises a connecting element (23, 25) mechanically connected to one of the connecting terminals (18, 20), the electrical insulation means (28) being arranged between the connecting element (23, 25) and the cover (16).

7. A power converter (1) according to any one of claims 5 and 6, wherein: The fastening element (40) prevents at least one movement of the electrical conductor (12) relative to the housing (10).

8. A power converter (1) according to any one of claims 5 to 7, wherein: The housing (10) comprises at least a first cylinder (19) and a second cylinder (21), wherein the first cylinder (19) and the second cylinder (21) are configured to receive a portion of the electrical conductor (12), and the fastening element (40) passes through at least one of the cylinders (19, 21).

9. The power converter (1) according to claim 8, wherein: The electrical insulation (28) is supported by at least one of the cylinders (19, 21).

10. The power converter (1) according to any one of claims 5 to 9, wherein: The fastening element (40) includes a head (46) that contacts the electrical insulation (28) and a body (44) including threads, the body (44) being received in a compartment (42) formed in one of the electrical conductors (12), the compartment (42) including threads that cooperate with threads of the body (44) of the fastening element (40).

11. The power converter (1) according to claim 10, wherein: One end of the fastening element (40) is spaced from the bottom of the compartment (42) by a distance which is strictly less than the thickness of the electrical insulation (28).

12. A method for disassembling a power converter (1) according to any one of claims 5 to 12 in combination with claim 2, comprising at least: - a first step in which the cover (16) is disengaged from the housing (10) by removing at least the fixing member (38), - a second step, in which the electrical insulation device (28) is detached from the housing (10) by removing at least one fastening element (40), - a third step, in which the electrical conductor (12) is separated from the connection terminal (18, 20), - A fourth step, in which the electrical conductor (12) is extracted from the housing (10) by sliding the electrical conductor (12).

Images