High-voltage electrical connector with limited risk of high-frequency ac electric arcs
Patent Information
- Application Number
- EP2023725261
- Authority / Receiving Office
- EP · EP
- Patent Type
- Applications
- Current Assignee / Owner
- Priority Date
- 2022-06-01
- Filing Date
- 2023-05-22
- Publication Date
- 2025-04-09
- Estimated Expiration
- 2043-05-22
AI Technical Summary
High voltage electrical connectors in aircraft power networks face a significant risk of electric arcs due to air ionization during high frequency alternating regimes, leading to power loss and potential damage to solid dielectrics, especially when using PWM voltage signals with high temporal variations.
The design incorporates an electrical connector with a conductive body, insulated conductor, and insulating insert featuring distinct conductive continuity zones and an elastic seal made of silicone, which eliminates ambient air as insulation, minimizing potential differences and reducing the risk of electric arcs by ensuring electrical continuity between the body and terminal.
This configuration significantly reduces the risk of electric arcs during high frequency and high voltage operations by replacing air with an elastic seal as the insulator, enhancing dielectric rigidity and preventing parasitic currents, thus protecting the connector from damage and power loss.
Smart Images
Figure 1.1
Abstract
Description
DESCRIPTION TITLE: HIGH VOLTAGE ELECTRICAL CONNECTOR WITH LIMITED ARC FIRE HAZARD IN HIGH FREQUENCY AC SYSTEMS
[0001] The present invention relates to a high-voltage electrical connector with a limited risk of electrical arcing in high-frequency alternating current. The invention finds a particularly advantageous, but not exclusive, application in connectors used on aircraft power electrical networks.
[0002] Figure 1 shows a schematic representation of a prior art assembly of a male electrical connector 10 and a female electrical connector 11 used within an aircraft power electrical network.
[0003] The male electrical connector 10 comprises a body 12 made of an electrically conductive material, an electrical conductor 13 covered with a layer of electrically insulating material 15, a male electrical terminal 16, and an insulating insert 18 for electrically insulating the male electrical terminal 16 from the body 12.
[0004] The female electrical connector 11 comprises a body 21 made of an electrically conductive material, an electrical conductor 23 covered with a layer of electrically insulating material 25, a female electrical terminal 26, and an insulating insert 28 for electrically insulating the female electrical terminal 26 from the body 21.
[0005] The increasing electrification of aircraft is leading to higher electrical voltages applied to actuation systems in order to minimize their mass and electrical losses. Voltages used in power grids are on the order of 800V, with peaks approaching 1000Vdc.
[0006] To withstand high voltage levels, it is known to increase the thickness of the solid dielectrics in electrical connectors made of thermoplastic or thermosetting materials. However, ambient air also contributes to electrical insulation between the different equipotential bonding points.
[0007] Figure 2 shows an equivalent circuit of a dielectric chain between two equipotentials, for example the electrical conductor 13, 23 and the body 12, 21 of an electrical connector 10, 11. Cs and Rs represent the capacitance and resistance of solid dielectrics, respectively. Cg and Rg represent the capacitance and resistance of gaseous dielectrics, such as ambient air, respectively.
[0008] In direct current (DC) operation, the distribution of voltage potentials is determined solely by the intrinsic resistances of the insulators (capacitors do not play a role). Furthermore, the resistivity of solid dielectrics is much higher than that of air. In practice, the voltage is distributed primarily across solid insulators designed to withstand this voltage.
[0009] In alternating current (AC) systems, the distribution of potentials is primarily determined by the intrinsic capacitors of the insulators, especially with respect to resistances at higher frequencies. These capacitors are measured in Farads, and their values are defined by the surface areas they face, the distances between equipotential lines, the permittivity of free space (E0), and the relative permittivity of the dielectric (cr).
[0010] The value of a capacitor is given by the relation C= S. £ o. £ r / L: - C being the value of the capacitor in Farads, - S being the surface area in m² 2 , - L being the distance between the opposite surfaces in meters, and - E0 being the permittivity of free space = 8.854 x 10⁻¹² F / m. The relative permittivity of air is close to 1, while that of the solid dielectrics classically used is between 3 and 5.
[0011] In alternating current, most of the voltage variations are applied to the air, which has a much lower dielectric strength (20 to 50 times) than that of solid dielectrics (1 to 3kV / mm for air and 20kV / mm to 150kV / mm for solid dielectrics).
[0012] Under these conditions, air ionization occurs, leading to a risk of electrical arcing. This phenomenon is particularly noticeable when polyphase motors are remotely powered using PWM (Pulse Width Modulation) voltage signals. These signals exhibit significant voltage variations (dV / dt) due to short switching times and high voltages. This results in electrical power loss and heat dissipation that can damage the solid dielectrics of the electrical connector.
[0013] The invention aims to effectively remedy the aforementioned drawbacks by proposing an electrical connector comprising: - a body made of an electrically conductive material, - at least one electrical conductor covered with a layer of electrically insulating material, - at least one electrically connected terminal at one end of the electrical conductor, and - an insulating insert designed to electrically isolate the electrical terminal from the body of said electrical connector, - the insulating insert comprising a first zone of electrical continuity covered with a layer of electrically conductive material ensuring electrical continuity with the body, and - a second zone of electrical continuity covered with a layer of electrically conductive material ensuring electrical continuity with the electrical terminal, - an elastic seal being disposed in a space where an internal air volume of the electrical connector is likely to be subjected to a difference in electrical potentials between an electrical potential of the body and an electrical potential of the electrical terminal, - said elastic joint being in contact with the first zone of electrical continuity and with the second zone of electrical continuity.
[0014] The invention thus eliminates any trace of ambient air acting as an electrical insulator inside the connector by minimizing or even eliminating significant potential differences that could be applied to the air inside the electrical connector. The invention therefore minimizes the risk of generating electrical arcs during the operation of the electrical connector in a high-frequency, high-voltage regime.
[0015] According to one embodiment of the invention, the elastic seal is made of a silicone material.
[0016] According to one embodiment of the invention, the layers of electrically conductive material of the first electrical continuity zone and the second electrical continuity zone are solid layers.
[0017] According to one embodiment of the invention, the layers of electrically conductive material of the first electrical continuity zone and the second electrical continuity zone are mesh layers.
[0018] According to one embodiment of the invention, the layers of electrically conductive material of the first electrical continuity zone and the second electrical continuity zone are made of carbon.
[0019] According to one embodiment of the invention, the layers of electrically conductive material of the first electrical continuity zone and the second electrical continuity zone are made of metal.
[0020] According to one embodiment of the invention, the layers of electrically conductive material of the first electrical continuity zone and the second electrical continuity zone each have a thickness between 20nm and 100nm.
[0021] According to one embodiment of the invention, the electrical conductor and the layer of electrically insulating material are covered by a shield.
[0022] According to one embodiment of the invention, said electrical connector is of the male and / or female type.
[0023] The invention also relates to an assembly of two connectors.
[0024] The present invention will be better understood and other features and advantages will become apparent upon reading the following detailed description, which includes embodiments given by way of illustration with reference to the accompanying figures, presented by way of non-limiting examples, which may serve to complete the understanding of the present invention and the explanation of its implementation and, where appropriate, contribute to its definition, on which:
[0025] [Fig. 1] Figure 1, already described, is a schematic representation of the assembly of a male electrical connector and a female electrical connector according to the prior art;
[0026] [Fig. 2] Figure 2, already described, shows an equivalent diagram of a dielectric chain between two equipotentials of an electrical connector according to the prior art;
[0027] [Fig. 3] Figure 3 is a schematic representation of the assembly of a male electrical connector and a female electrical connector according to the invention;
[0028] [Fig. 4a] [Fig. 4b] Figures 4a and 4b show top views of a layer of electrically conductive material deposited on an insulating insert exhibiting respectively a solid configuration and a meshed configuration;
[0029] [Fig. 5] Figure 5 is a schematic representation of the distribution of a voltage gradient inside an elastic joint of an electrical connector according to the invention;
[0030] [Fig. 6a] Figure 6a is a schematic representation of a hermaphrodite-type electrical connector according to the invention;
[0031] [Fig. 6b] Figure 6b is a schematic representation of the assembly of two hermaphroditic electrical connectors according to the invention.
[0032] It should be noted that the structural and / or functional elements common to the different embodiments have the same references. Thus, unless otherwise stated, such elements have identical structural, dimensional, and material properties.
[0033] Figure 3 shows a male electrical connector 10 making electrical contact with a female electrical connector 11. The electrical connectors 10 and 11 can, for example, be used on a high-voltage electrical network of an aircraft.
[0034] The male electrical connector 10 comprises a body 12 made of an electrically conductive material and having at least one conductor passage opening 14. The body 12 of the male electrical connector 10 has a shape complementary to a body 21 of the female electrical connector 11. At least one electrical conductor 13 is inserted inside the conductor passage opening 14. The electrical conductor 13 may be made of an electrically conductive material, such as copper, aluminum, or any other electrically conductive material suitable for the application. The electrical conductor 13 may optionally be coated with a thin finishing layer to improve its electrical conductivity, such as a layer of palladium, gold, silver, tin, nickel, or any other electrically conductive material suitable for the application.
[0035] The electrical conductor 13 may be a single wire with a round cross-section, a flat cross-section, or any other shape suitable for the application. Alternatively, the electrical conductor 13 may be stranded, meaning it may consist of a plurality of wires arranged side by side. The electrical conductor 13 is covered by a layer of electrically insulating material 15. The electrically insulating material of the layer 15 may be a dielectric sheath covering the electrical conductor 13 or possibly an enamel coating.
[0036] The electrical conductor 13 and the layer of electrically insulating material 15 are covered by a shield 19. The shield 19 is made in a electrically conductive material. The shield 19 is electrically connected to the body 12 of the male electrical connector 10.
[0037] At least one male electrical terminal 16 is electrically connected to one end of the electrical conductor 13. The connection between the male electrical terminal 16 and the electrical conductor 13 may be made by crimping, welding (with or without filler material), or any other electrical connection technique suitable for the application. The male electrical terminal 16 has a shape complementary to the female electrical terminal 26.
[0038] An insulating insert 18 is intended to electrically insulate the male electrical terminal 16 from the body 12 of the electrical connector 10. The insulating insert 18 also has a function of electrically retaining the male electrical terminal 16. The insulating insert 18 is disposed inside a housing 20 provided in the body 12. The insulating insert 18 extends at least partially around the male electrical terminal 16. The insulating insert 18 has a shape intended to cooperate with a complementary shape of the insulating insert 28 of the female electrical connector 11. The insulating insert 18 may be made of any rigid dielectric material, such as a thermoplastic or a thermosetting material.
[0039] The insulating insert 18 has a first electrical continuity zone 31.1 covered with a layer of electrically conductive material 32 ensuring electrical continuity with the body 12 of the electrical connector, and a second electrical continuity zone 31.2 covered with a layer of electrically conductive material 33 ensuring electrical continuity with the male electrical terminal 16.
[0040] The first electrical continuity zone 31.1 and the second electrical continuity zone 31.2 are distinct from each other, i.e. there is no continuity of material between the layer 32 of electrically conductive material of the first electrical continuity zone 31.1 and the layer of electrically conductive material 33 of the second electrical continuity zone 31.2.
[0041] Furthermore, the female electrical connector 11 comprises a body 21 made of an electrically conductive material and having at least one conductor passage opening 24. The body 21 of the female electrical connector 11 has a shape complementary to the body 12 of the male electrical connector 10. At least one electrical conductor 23 is inserted inside the conductor passage opening 24. The electrical conductor 23 may be made of an electrically conductive material, such as copper, aluminum, or any other electrically conductive material suitable for the application. The electrical conductor 23 may optionally be coated with a thin finishing layer to improve its electrical conductivity, such as a layer of palladium, gold, silver, tin, nickel, or any other electrically conductive material suitable for the application.
[0042] The electrical conductor 23 may be a single wire with a round cross-section, a flat cross-section, or any other shape suitable for the application. Alternatively, the conductor may be stranded, meaning it may consist of a plurality of wires arranged side by side. The electrical conductor 23 is covered by a layer of electrically insulating material 25. The electrically insulating material of the layer 25 may be a dielectric sheath covering the electrical conductor 23 or, optionally, a layer of enamel.
[0043] The electrical conductor 23 and the layer of electrically insulating material 25 are covered by a shield 29. The shield 29 is made of an electrically conductive material. The shield 29 is electrically connected to the body 21 of the female electrical connector 11.
[0044] At least one female electrical terminal 26 is electrically connected to one end of the electrical conductor 23. The connection between the female electrical terminal 26 and the electrical conductor 23 may be made by crimping, welding (with or without filler material), or any other electrical connection technique suitable for the application. The female electrical terminal 26 has a shape complementary to the male electrical terminal 16.
[0045] An insulating insert 28 is intended to electrically insulate the female terminal 26 from the body 21 of the electrical connector 11. The insulating insert 28 also serves to electrically retain the female terminal 26 of the electrical connector 11. The insulating insert 28 is disposed within a recess 30 provided in the body 21. The insulating insert 28 extends at least partially around the female terminal 26. The insulating insert 28 has a shape designed to cooperate with a complementary shape of the insulating insert 18 of the male electrical connector 10. The insulating insert 28 may be made of any rigid dielectric material, such as a thermoplastic or a thermosetting material.
[0046] The insulating insert 28 has a first zone of electrical continuity 36.1 covered with a layer of electrically conductive material 34 ensuring electrical continuity with the body 21 of the electrical connector 11, and a second electrical continuity zone 36.2 covered with a layer of electrically conductive material 35 ensuring electrical continuity with the female electrical terminal 26.
[0047] The first electrical continuity zone 36.1 and the second electrical continuity zone 36.2 are distinct from each other, that is to say there is no continuity of material between the layer of electrically conductive material 34 of the first electrical continuity zone 36.1 and the layer of electrically conductive material 35 of the second electrical continuity zone 36.2.
[0048] When the male electrical connectors 10 and 11 are assembled together, there is electrical continuity between the first electrical continuity zone 31.1 of the male electrical connector 10 and the first electrical continuity zone 36.1 of the female electrical connector 11. There may also be electrical continuity between the second electrical continuity zone 31.2 of the male electrical connector 10 and the second electrical continuity zone 36.2 of the female electrical connector 11.
[0049] Thus, the volume of air V1 extending radially between an external face of the insulating insert 18 and an internal face of the body 12 is subjected on both sides to The electrical potential of the bodies 12, 21 of the electrical connectors 10, 11 is maintained, thus preventing the occurrence of parasitic currents in high-voltage alternating current in this area. Similarly, the air volume V2 is subjected on both sides to the electrical potential of the electrical terminals 16, 26 of the electrical connectors 10, 11, which prevents the occurrence of parasitic currents in high-voltage alternating current in this area.
[0050] As illustrated by Figure 4a, the layers of electrically conductive material 32, 33, 34, 35 of the first electrical continuity zone 31.1, 36.1 and of the second electrical continuity zone 31.2, 36.2 may be solid layers.
[0051] Alternatively, as illustrated in Figure 4b, the layers of electrically conductive material 32, 33, 34, 35 of the first electrical continuity zone 31.1, 36.1 and of the second electrical continuity zone 31.2, 36.2 may be mesh layers. The mesh layers comprise an alternation of empty zones 38, i.e., zones devoid of electrically conductive material, and arms 39 delimiting the mesh of the layer.
[0052] The electrically conductive material layers 32, 33, 34, 35 of the first electrical continuity zone 31.1, 36.1 and of the second electrical continuity zone 31.2, 36.2 are preferably made of carbon. Alternatively, the layers 32, 33, 34, 35 are made of metal.
[0053] The layers of electrically conductive material 32, 33, 34, 35 can be deposited by ultrasonic welding, plasma deposition, or any other thin-film deposition technique of electrically conductive material onto a component made of a dielectric material. The type of electrically conductive material is chosen based on its compatibility with the material of the insulating insert 18, 28 onto which the layer 32, 33, 34, 35 is deposited.
[0054] The layers of electrically conductive material 32, 33, 34, 35 of the first electrical continuity zone 31.1 and of the second electrical continuity zone 31.2 each have a thickness between 20nm and 10Onm.
[0055] An elastic seal 40, visible in Figure 3, is disposed in a space 41 where an internal air volume of the electrical connector is likely to be subjected to a potential difference between the electrical potential of the body 12, 21 and the electrical potential of the electrical terminal 16, 26. The elastic seal 40 is disposed between the male electrical connector 10 and the female electrical connector 11. The space 41 extends axially between the insulating insert 18 of the connector 10 and the insulating insert 28 of the connector 11. The space 41 extends radially between one of the electrical terminals 16 or 26 and one of the insulators 18 or 28.
[0056] The elastic seal 40 is made of a material capable of withstanding the maximum internal stress to which the electrical connector is subjected. The elastic seal 40 is preferably made of silicone, but any other material suitable for the application is acceptable. When the connectors 10 and 11 are assembled, the elastic seal 40 is compressed to expel the air from the space 41. The air is thus replaced by the elastic seal 40 as an electrical insulator. The elastic seal 40 therefore significantly increases the dielectric strength compared to air by a factor of at least 10.
[0057] As can be seen more precisely in Figure 5, the joint 40 is in contact with the first electrical continuity zone 31.1 and the second electrical continuity zone 31.2 of the electrical connector 10, in particular one end of the first electrical continuity zone 31.1 and one end of the second electrical continuity zone 31.2 of the electrical connector 10. The joint 40 is also in contact with the first electrical continuity zone 36.1 and the second electrical continuity zone 36.2 of the electrical connector 11, in particular one end of the first electrical continuity zone 36.1 and one end of the second electrical continuity zone 36.2 of the electrical connector 11.
[0058] On a first face 42 of the space 41 delimiting the air volume, the end of the first electrical continuity zone 31.1 is separated by a distance, for example on the order of a millimeter, from the end of the second electrical continuity zone 31.2 of the electrical connector 10.
[0059] On a second face 43 of the space 41 delimiting the air volume, the end of the first electrical continuity zone 36.1 is separated by a distance, for example on the order of a millimeter, from the end of the second electrical continuity zone 36.2 of the electrical connector 11.
[0060] In the example shown, the first face 42 and the second face 43 of the space 41, on which the electrical continuity zones terminate, are adjacent to each other. Alternatively, the first face 42 and the second face 43 may be opposite each other.
[0061] Thus, the voltage gradient gradV between the electrical potential of the terminals and the electrical potential of the body 12, 21 is distributed inside the elastic joint 40.
[0062] Figure 6a shows an example of an implementation of the invention with a hermaphrodite-type electrical connector 50, that is, a connector that is a combination of a male and a female connector. This type of connector is used for economies of scale or when the mounting operation on equipment (harness or housing) is irreversible, in order to avoid assembly errors.
[0063] More specifically, the electrical connector 50 comprises a body 51 made of an electrically conductive material, an electrical conductor 52 covered with a layer of electrically insulating material 53 and a shield 54 electrically connected to the body 51. The connector 50 also comprises an electrical terminal 55 having a male portion and a female portion, as well as an insulating insert 56 for electrically isolating the electrical terminal 55 from the body 51.
[0064] In a manner analogous to the previous embodiments, the insulating insert 56 comprises a first electrical continuity zone 57.1 covered with a layer of electrically conductive material ensuring electrical continuity with the body 51, and a second electrical continuity zone 57.2 covered with a layer of electrically conductive material ensuring electrical continuity with the electrical terminal 55.
[0065] The first electrical continuity zone 57.1 and the second electrical continuity zone 57.2 are distinct from each other, that is to say there is no continuity of material between the layer of electrically conductive material of the first electrical continuity zone 57.1 and the layer of electrically conductive material of the second electrical continuity zone 57.2.
[0066] As illustrated by Figure 6b, when two hermaphroditic electrical connectors 50 and 50' are assembled together, the male portion of the electrical terminal 55 of connector 50 cooperates with the female portion of the electrical terminal 55 of connector 50' while the female portion of the electrical terminal 55 of connector 50 cooperates with the male portion of the electrical terminal 55 of connector 50'.
[0067] There is electrical continuity between the first electrical continuity zone 57.1 of electrical connector 50 and the first electrical continuity zone 57.1 of electrical connector 50'. There is also electrical continuity between the second electrical continuity zone 57.2 of electrical connector 50 and the second electrical continuity zone 57.2 of electrical connector 50'.
[0068] Alternatively, the electrical connector 10, 11, 50 is a multi-pin connector having two or more of two electrical terminals 16, 26, 55. In this case, an electrical continuity zone is provided for each electrical terminal 16, 26, 55 of the electrical connector 10, 11. Of course, the various features, variations, and / or embodiments of the present invention can be combined in various ways, provided they are not incompatible or mutually exclusive. Furthermore, the invention is not limited to the embodiments described above, which are provided solely by way of example. It encompasses various modifications, alternative forms, and other variations that a person skilled in the art might consider within the scope of the present invention, and in particular, all combinations of the different modes of operation described above, whether considered separately or in combination.
Claims
CLAIMS Electrical connector (10, 11, 50) comprising: - a body (12, 21) made of an electrically conductive material, - at least one electrical conductor (13, 23) covered with a layer of electrically insulating material (15, 25), - at least one electrical terminal (16, 26) electrically connected to one end of the electrical conductor (13, 23), and - an insulating insert (18, 28) intended to electrically insulate the electrical terminal (16, 26) from the body (12, 21) of said electrical connector (10, 11), characterized in that the insulating insert (18, 28) comprises a first zone of electrical continuity (31.1) covered with a layer of electrically conductive material (32, 34) ensuring electrical continuity with the body (12, 21), and - a second zone of electrical continuity (31.2) covered with a layer of electrically conductive material (33, 35) ensuring electrical continuity with the electrical terminal (16, 26, - an elastic seal (40) being disposed in a space (41) where an internal air volume of the electrical connector (10, 11) is likely to be subjected to a difference in electrical potentials between an electrical potential of the body (12, 21) and an electrical potential of the electrical terminal (16, 26), - said elastic seal (40) being in contact with the first electrical continuity zone (31.1) and with the second electrical continuity zone (31.2). Electrical connector according to claim 1, characterized in that the elastic seal (40) is made of a silicone material. Electrical connector according to claim 1 or 2, characterized in that the layers of electrically conductive material (32, 33, 34, 35) of the first electrical continuity zone (31.1, 36.1) and of the second electrical continuity zone (31.2, 36.2) are solid layers. Electrical connector according to claim 1 or 2, characterized in that the layers of electrically conductive material (32, 33, 34, 35) of the The first electrical continuity zone (31.1, 36.1) and the second electrical continuity zone (31.2, 36.2) are mesh layers.
5. Electrical connector according to any one of claims 1 to 4, characterized in that the layers of electrically conductive material (32, 33, 34, 35) of the first electrical continuity zone (31.1, 36.1) and of the second electrical continuity zone (31.2, 36.2) are made of carbon.
6. Electrical connector according to any one of claims 1 to 4, characterized in that the layers of electrically conductive material (32, 33, 34, 35) of the first electrical continuity zone (31.1, 36.1) and of the second electrical continuity zone (31.2, 36.2) are made of metal.
7. Electrical connector according to any one of claims 1 to 6, characterized in that the layers of electrically conductive material (32, 33, 34, 35) of the first electrical continuity zone (31.1, 36.1) and of the second electrical continuity zone (31.2, 36.2) each have a thickness between 20nm and 100nm.
8. Electrical connector according to any one of claims 1 to 7, characterized in that the electrical conductor (13, 23) and the layer of electrically insulating material (15, 25) are covered by a shield (19, 29).
9. Electrical connector according to any one of claims 1 to 8, characterized in that it is of male and / or female type.