System consisting of power module and arc flash protection

Abstract

The invention relates to a system comprising: a high-voltage power supply module (1) comprising a dielectric housing (2) housing electronic components of the module and comprising at least a first (101) and a second (102) connection terminal accessible from the outside of the module, the electronic components of the module being able to apply a potential difference at least equal to 1 kV between the first and second connection terminals, the first and second terminals being separated by at least one alternating groove (6) and rib (7) provided in the outer face of the dielectric housing (2); and a dielectric protection element (10) extending between the first and second connection terminals (101, 102), the protection element (10) covering the rib of the housing and comprising a rib (17) housed in the groove (6) of the housing.

Description

[0001] The present invention relates to a power supply module and in particular to the design of such a power supply module for limiting the risk of electric arcs.

[0002] The power module can have different functions, such as an electrical conversion function. The power module comprises a dielectric insulating housing that accommodates the different electrical and electronic components that implement the basic electronic functions of the module and a plurality of screw connection terminals accessible from the outside of the housing for connecting the module to other electrical components. When the power module is in use, a potential difference is applied between the connection terminals of the module.

[0003] Especially for the needs of new applications, power modules may apply an increasingly large uninterrupted potential difference between their connection terminals. There is therefore a demand for power modules for rated voltages of 3.3 kV, 6.5 kV, 10 kV or even higher. Design constraints arise from the need to standardize the dimensions of modules from different manufacturers to have relatively similar form factors in order to facilitate the design of electrical systems. Thus, power modules for rated voltages up to 10 kV must meet size restrictions.

[0004] These dimensional limitations make the design of power modules problematic in order to meet the standards for arc formation. In fact, for a given voltage level, for the outside of the housing, the profile of the dielectric housing surface between the terminals and the minimum distance in the air must be met. These conditions are particularly detailed in the IEC60664-1 standard. Such dimensioning may appear quite restrictive in a polluted environment, and the path distance must take into account the potential deposition of dust, humidity or sewage on the housing surface, which is conducive to the generation of arcs. Thus, for a 10kV module, the path distance between the terminals must exceed 100mm, which represents a large distance for a power module such as the XHP-3 form factor module with a footprint of 140x100mm proposed by Infineon. In order to be able to use compatible modules, different manufacturers adhere to the geometry of the module, especially with regard to the position of the terminals at this interval of 26mm. The distance between the terminals is therefore fixed. In order to increase the path distance, alternating grooves and ribs of the housing are inserted between the terminals. Such a solution also has limitations, because for the IEC standard applicable to pollution level 3, the groove must have a width of at least 1.5mm. The realization of XHP-3 form factor modules is a challenge for 10kV voltage.

[0005] Document US 2009 / 213553 describes a module whose housing has projections for allowing mechanical fixing of a dielectric protection insert.

[0006] The present invention aims to overcome one or more of these drawbacks.The present invention therefore relates to the claimed system.

[0007] The invention also relates to the variants of the dependent claims. A person skilled in the art will understand that each of the features of the present description or claims can be independently combined with the features of the independent claims without thereby constituting an intermediate summary.

[0008] Other characteristics and advantages of the invention will become apparent from the following description, by way of non-limiting indication, with reference to the accompanying drawings, in which:

[0009] Figure 1 shows a top view of a high voltage power module having a dielectric housing;

[0010] Figure 2 shows a top view of a high voltage power module covered by a dielectric protection element according to an exemplary embodiment of the present invention;

[0011] Figure 3 and Figure 4 Two cross-sectional views showing an assembly of a high-voltage power module covered by a dielectric protection element connected to two high-voltage contacts according to an exemplary embodiment of the invention;

[0012] Figure 5 Show Figure 3 An exploded view of a component detail;

[0013] Figure 6 is a comparison diagram of voltage withstand values ​​of a high voltage power module covered by a dielectric protection element according to an exemplary embodiment of the present invention relative to a bare module according to the prior art;

[0014] Figure 7 A cross-sectional view showing an assembly of a high-voltage power module covered by a dielectric protection element connected to two high-voltage contacts according to another exemplary embodiment of the present invention;

[0015] Figure 8 A cross-sectional view showing an assembly of a high-voltage power module covered by a dielectric protection element connected to two high-voltage contacts according to yet another exemplary embodiment of the present invention;

[0016] Fig. 9 A cross-sectional view showing an assembly of a high voltage power module covered by a dielectric protection element connected to two high voltage contacts according to yet another exemplary embodiment of the present invention.

[0017] Figure 11 is a top view of a high voltage power supply module 1, which includes a housing dielectric housing 2 that accommodates the electronic components (not shown) of the module. The module 1 also includes connection terminals 101, 102, 103 and 104 that can be reached from the top surface 3 of the housing 2. The connection terminals 101 and 102 are aligned in the longitudinal direction and offset in the transverse direction. The connection terminals 103 and 104 are aligned in the longitudinal direction and offset in the transverse direction. The connection terminals 101 and 103 are aligned in the transverse direction and offset in the longitudinal direction.

[0018] During operation of the module 1, its electronic components (not shown) may apply or have applied a potential difference between the terminals 101 and 102, for example, at least equal to 1 kV, or even higher than 3 kV, or even higher than 6 kV, or even at least 10 kV. The module 1 can thus be regarded as a high-voltage module. The terminals 101 and 102 are spaced apart by alternating first grooves 6 and first ribs 7 in the upper outer face 3 of the housing 2. For example, the same potential difference can be observed between the terminals 101 and 103 or between 101 and 104. The terminals 101 and 103 are spaced apart by alternating second grooves 60 and third ribs 70 in the upper outer face 3 of the housing 2.

[0019] The invention proposes a solution for increasing the potential difference that can be applied between the terminals 101 to 104 of the module 1, which is able to remain unchanged in the form factor (for example in the footprint within a rectangle of 110 mm x 150 mm) and meets the current standards (in particular for pollution degree 3). The housing 2 can, for example, have a form factor designated by the company Infineon with the reference XHP-3. One embodiment of the invention consists in encapsulating the connectors of the housing 2 with a flexible dielectric protection element 10 made of a material different from that of the housing 2. While the material of the housing 2 can be chosen for its dielectric strength and mechanical rigidity, the material of the protection element 10 can be chosen for its ability to deform to conform to the top surface 3 of the housing 2 or for its ability to resist pollution conditions. The material of the element 10 can also advantageously be chosen for its dielectric properties.

[0020] Figure 2 yes Figure 1A top view of a power module of the present invention is shown, which is covered by a dielectric protection element 10 according to an example of an embodiment of the present invention. The dielectric protection element 10 forms a sealing cover by covering the entire top surface 3 of the housing 2 (except for the connection terminals 101, 102, 103 and 104). The dielectric protection element 10 also covers the sides of the housing 2 over the entire or partial height of these sides. The dielectric protection element 10 is advantageously formed in one piece to improve the sealing of the dielectric protection element 10 on the top surface 3 of the housing. The dielectric protection element 10 can be made of an elastomer, such as rubber, silicone or polyurethane, for example. The protection element 10 advantageously maintains contact with the top surface 3 by the elastic deformation applied by the housing 2 to facilitate its autonomous mechanical retention on the housing 2.

[0021] Figure 3 is a cross-sectional view of an assembly comprising a combination of a module 1 and its dielectric protection 10 with electrical connectors 31 and 32 fixed to the connection terminals 101 and 102 by means of screws 201 and 202. The section is along Figure 2 The dielectric protection element 10 advantageously comprises a second rib 17 accommodated in the first groove 6 of the housing 2. By covering the top surface 3 of the housing 2 and by having the second rib 17 accommodated in the first groove 6 of the housing 2, possible contaminants are thereby avoided from being deposited in the first groove 6, which prevents such contaminants from promoting arc formation between the connection terminals 101 and 102. As a result, even if the size of the housing 2 is reduced, in a polluted environment, the arc is transferred to a significantly higher voltage level.

[0022] At the connection terminal 101, a screw 201 is screwed into a threaded hole 8 of the housing 2 (the threaded hole 8 can also be replaced by a cage nut, for example). The screw 201 provides an electrical connection between the connection terminal 101 and the electrical connector 31 (sometimes referred to as a busbar in the literature). The screw 201 also provides a mechanical connection between the electrical connector 31 and the housing 2. According to one embodiment of the present invention, the screw head 201 is made of a dielectric material. The periphery of the threaded hole 8 is advantageously covered by an extension 21 of the protective element 10 to limit the ability to deposit contaminants as close to the connector 101 as possible.

[0023] The extension 21 covers the periphery of the threaded hole 8. The extension 21 has a hole 23 arranged vertically relative to the threaded hole 8. The screw 201 passes through the hole 23 of the extension 21. The hole 23 of the extension 21 is defined by a vertical cylindrical wall 27. Such a cylindrical wall can be deformed by compression between the screw head 201 (through the connector 31) and the housing 2 to improve the sealing under the screw head and make it more difficult to form an arc. This ensures that no metal parts are exposed to the air and forms an airtight barrier at the connection terminal 101. This ensures that there is no possible arc path, whether in the bypass or in the path. The dielectric protection element 10 can, for example, have a Shore A hardness of 30 to 50 to promote the elastic deformation of the vertical cylindrical wall 27 during this compression process. The vertical cylindrical wall 27 is advantageously surrounded by a vertical sleeve 25 here. Such a vertical sleeve 25 further improves the sealing at the connector 101. The dielectric protection element 10 having a Shore A hardness of 30 to 50 also facilitates elastic deformation of the vertical sleeve 25 during such compression.

[0024] At the connection terminal 102, a screw 202 is screwed into the threaded hole 9 of the housing 2. The screw 202 provides an electrical connection between the connection terminal 102 and the electrical connector 32 (sometimes referred to as a busbar in the literature). The screw 202 also provides a mechanical connection between the electrical connector 32 and the housing 2. According to one embodiment of the present invention, the screw head 202 is made of a dielectric material. The periphery of the threaded hole 9 is advantageously covered by an extension 22 of the protective element 10 to limit the ability to deposit contaminants as close to the connector 102 as possible.

[0025] The extension 22 covers the periphery of the threaded hole 9. The extension 22 has a hole 24 arranged vertically relative to the threaded hole 9. The screw 202 passes through the hole 24 of the extension 22. The hole 24 of the extension 22 is defined by a vertical cylindrical wall 28. Such a cylindrical wall can be deformed by compression between the screw head 202 (via the connector 32) and the housing 2 to improve the sealing under the screw head and make it more difficult to form an arc. The dielectric protection element 10 can, for example, have a Shore A hardness of 30 to 50 to facilitate the elastic deformation of the vertical cylindrical wall 28 during such compression. The vertical cylindrical wall 28 is advantageously surrounded by a vertical sleeve 26 here. Such a vertical sleeve 26 further improves the sealing at the connector 102. The dielectric protection element 10 with a Shore A hardness of 30 to 50 also helps to promote the elastic deformation of the vertical sleeve 26 during such compression.

[0026] The remaining space between the vertical wall 27 and the screw 201 is advantageously filled with a dielectric resin 50 here, in order to further limit the risk of contamination and the corresponding electric arcs. Similarly, the remaining space between the vertical wall 28 and the screw 202 is advantageously filled with a dielectric resin 50 here.

[0027] Figure 4 is a cross-sectional view of an assembly comprising a combination of a module 1 and its dielectric protection element 10 with electrical connectors 31 and 33 fixed at connection terminals 101 and 103 by means of screws 201 and 203. Figure 2 The dielectric protection element 10 comprises a fourth rib 18 received in the second groove 60 of the housing 2 .

[0028] Figure 5 yes Figure 3 Exploded view of a detail of the assembly shown. The module 1, of which only one longitudinal end 4 of the housing 2 is shown here, is covered by a dielectric protection element 10 according to an exemplary embodiment of the invention, of which only the end 11 is shown here. The assembly is assembled to the electrical connectors 31 and 32 and fixed at the connection terminals 101 and 102 by means of screws 201 and 202.

[0029] Figure 6 : is a comparison diagram of the voltage before the arc is formed according to different configurations of high-voltage power modules. Measurements A, B, C, D, E and F are obtained on a module with an exposed top surface according to the prior art. Measurements A', B', C', D', E' and F' are obtained on a module covered with a dielectric protection element according to an exemplary embodiment of the present invention. Measurements A, A', B, B', C and C' are obtained on a dry module. Measurements D, D', E, E', F and F' are obtained on a module on which deionized water is sprayed manually. Measurements A, A', D and D' are obtained on a clean module. Measurements B, B', E and E' are obtained on a module treated with kaolin, which corresponds to a contamination level of 2. Measurements C, C', F and F' are obtained on a module treated with salt, which corresponds to a contamination level of 3.

[0030] exist Figure 6 As can be seen in the figures, the use of the dielectric protection element according to the invention makes it possible to achieve arc formation voltages above 20 kV in all cases, wherein an unprotected module according to the prior art would be able to produce an arc at voltages below 10 kV.

[0031] The invention has been described with reference to a high voltage power supply module 1. The invention can also be applied to other types of power supply modules.

[0032] An independent aspect of the present invention relates to a system comprising:

[0033] a high-voltage power supply module comprising a dielectric housing housing the electronic components of said module and comprising at least a first and a second connection terminal accessible from the outside of the module, between which the electronic components of the module are capable of applying a potential difference at least equal to 1 kV, said first and second connection terminals being separated by at least one alternating first groove and first rib in the external face of the dielectric housing;

[0034] - a dielectric protection element extending between said first connection terminal and said second connection terminal, said protection element covering said first rib of said housing and comprising a second rib received in said first groove of said housing.

[0035] This independent aspect of the invention can be combined with each of the technical features described in this description and in the appended claims.

[0036] Figure 7 2 is a cross-sectional view of another embodiment of a component comprising a combination of a module 1 and a dielectric protection 10, with electrical connectors 31 and 32 fixed at the connection terminals 101 and 102 by means of screws 201 and 202. The module 1 and the dielectric protection 10 have the same structure as the previous embodiment. The electrical connectors 31 and 32 are encapsulated in the dielectric protection element 30. The screws 201 and 202 keep the ends of the connectors 31 and 32 in electrical contact with the connection terminals 101 and 102, respectively. The screws 201 and 202 are made of a dielectric material. The screws 201 and 202 pass through the corresponding holes of the connectors 31 and 32. The dielectric protection element 10 advantageously comprises a second rib 17 accommodated in the first groove 6 of the housing 2.

[0037] Figure 8 yes Figure 7 A cross-sectional view of a variation of the embodiment of Figure 7 The embodiment of differs only in the presence of a projection 35, which projects vertically from the dielectric protection element 30. The projection 35 is here positioned between the screws 201 and 202. The projection 35 is in the form of a fin, the function of which is to extend the arc path above the electrical connectors 31 and 32.

[0038] Fig. 9 yes Figure 7 A cross-sectional view of a variation of the embodiment of Figure 7 The embodiment of the invention differs only in the presence of a protrusion 36, which protrudes vertically from the dielectric protection element 30. The protrusion 36 is here positioned between the screws 201 and 202, the other protrusions being positioned at the periphery of the dielectric protection element 30. The protrusion 36 is in the form of a fin, the function of which is to extend the arc path above the electrical connectors 31 and 32.

Claims

1. A system including a high voltage power supply module, comprising: - A high-voltage power supply module (1) comprising a dielectric housing (2) accommodating electronic components of the module and comprising at least a first connection terminal (101) and a second connection terminal (102) accessible from the outside of the module, the electronic components of the module being able to apply a potential difference at least equal to 1 kV between the first connection terminal (101) and the second connection terminal (102), the first connection terminal (101) and the second connection terminal (102) having respective fixing elements (8, 9), characterised in that the first connection terminal (101) and the second connection terminal (102) are separated by at least one alternating first groove (6) and first rib (7) provided in the outer face of the dielectric housing (2); - a dielectric protection element (10) extending between the first connection terminal (101) and the second connection terminal (102), the protection element (10) covering the first rib (7) of the housing, the protection element comprising first and second extensions (21, 22) covering the periphery of the fixing elements of the first connection terminal (101) and the second connection terminal (102), respectively, each of the first and second extensions comprising a through hole (23, 24) vertically positioned through the fixing elements of the first connection terminal (101) and the second connection terminal (102).

2. The system according to claim 1, wherein: The dielectric protection element (10) has a second rib (17) received in a first groove (6) of the housing.

3. The system according to claim 1 or 2, wherein: The fixing element is a threaded hole.

4. The system according to claim 3 comprises a first and a second screw (201, 202), which are respectively screwed into the threaded holes (8, 9) of the first connecting terminal (101) and the second connecting terminal (102) and pass through the through holes (23, 24) of the first and second extension parts.

5. The system according to claim 4, wherein: The first and second screws (201, 202) are made of dielectric material.

6. The system according to claim 1, wherein: The through holes (23, 24) are delimited by vertical walls (27, 28) of the first and second extensions of the protection element (10).

7. System according to claim 6, comprising a dielectric resin (50) interposed between the fixing element and the vertical walls (27, 28) of the first and second extensions of the protection element.

8. The system according to claim 6 or 7, wherein: The extension comprises first and second vertical sleeves (25, 26) surrounding respectively the vertical walls (27, 28) of the first and second extensions of the protection element (10).

9. The system according to claim 1 or 2, comprising a first and a second electrical connector (31, 32), the first extension portion being compressed between the first electrical connector and a first connecting terminal (101), and the second extension portion being compressed between the second electrical connector and a second connecting terminal (102).

10. The system according to claim 1 or 2, wherein: The protective element (10) forms a sealing cover covering the top surface (3) of the dielectric housing (2) except for the fixing elements (8, 9).

11. The system according to claim 9, wherein: The protection element (10) is maintained in contact with the top surface of the dielectric housing (2) by elastic deformation applied by the housing.

12. The system according to claim 1 or 2, wherein: The protection element (10) is formed integrally.

13. The system according to claim 1 or 2, wherein: The material of the protective element (10) is different from the material of the dielectric housing (2).

14. The system according to claim 1 or 2, wherein: The protection element (10) is made of a material with a Shore A hardness of 30 to 50.

15. The system according to claim 1 or 2, wherein: - the power module (1) comprises a third connection terminal (103) accessible from the outside of the module, the electronic components of the module being capable of applying a potential difference at least equal to 1 kV between the first connection terminal (101) and the third connection terminal (103), the first connection terminal (101) and the third connection terminal (103) being separated by at least one alternating second groove (60) and third rib (70) provided in the outer face of the dielectric housing (2); - The dielectric protection element (10) extends between the first connection terminal (101) and the third connection terminal (103), the protection element covers a third rib of the shell arranged between the first connection terminal (101) and the third connection terminal (103), and has a fourth rib (18) accommodated in a second groove (60) of the shell (2) arranged between the first connection terminal (101) and the third connection terminal (103).

16. The system according to claim 1 or 2, wherein: The housing (2) has a footprint within a rectangle of 110 mm x 150 mm.

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