Classifications

• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01B—CABLES; CONDUCTORS; INSULATORS; SELECTION OF MATERIALS FOR THEIR CONDUCTIVE, INSULATING OR DIELECTRIC PROPERTIES
  • H01B7/00—Insulated conductors or cables characterised by their form
  • H01B7/0045—Cable-harnesses
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01B—CABLES; CONDUCTORS; INSULATORS; SELECTION OF MATERIALS FOR THEIR CONDUCTIVE, INSULATING OR DIELECTRIC PROPERTIES
  • H01B11/00—Communication cables or conductors
  • H01B11/02—Cables with twisted pairs or quads
  • H01B11/12—Arrangements for exhibiting specific transmission characteristics
  • H01B11/14—Continuously inductively loaded cables, e.g. Krarup cables
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01B—CABLES; CONDUCTORS; INSULATORS; SELECTION OF MATERIALS FOR THEIR CONDUCTIVE, INSULATING OR DIELECTRIC PROPERTIES
  • H01B9/00—Power cables
  • H01B9/02—Power cables with screens or conductive layers, e.g. for avoiding large potential gradients

Definitions

• the present invention relates to electrical harnesses and to the limitation of electromagnetic disturbances generated in these harnesses.
• the invention relates more particularly but not exclusively to the limitation of electromagnetic disturbances in electrical harnesses used in aircraft.
• Electromagnetic Compatibility is essential for the proper functioning of a system.
• EMC Electromagnetic Compatibility
• the transmission of so-called "power" signals between the equipment of the power electronics (converter) and the loads (machine / actuators) is the source of many disturbances which are notably due to switching of the switches, these disturbances being transmitted by conduction and electrical radiation downstream and upstream of the converter.
• the increased performance of converter-cable-machine assemblies requires the use of semiconductor components operating at higher and higher frequencies with very fast switching times, which generates a very high electromagnetic environment. restrictive.
• the disturbances occur either in common mode or in differential mode.
• the power transmission function is provided by harnesses.
• An electrical harness is a set of electric wires or cables of different gauges grouped into an electrical harness and walking together to end up with connectors.
• a harness may include bulkheads. Several branches can compose a harness.
• the harness optionally comprises a protective sheath formed for example of an insulating tape or a textile or metal braid. The harness is said to be "shielded" when the protective sheath is conductive, as is the case for example with a metal braid.
• harnesses are becoming more numerous.
• the electrical harness is now considered as a separate system by the FAA and EASA regulators and must meet the requirements of EWIS (Electrical Wiring Interconnection System).
• the disturbances generated in the harnesses by the power converters and which constitute the source of the electromagnetic radiation are of two types: the disturbances in common mode and the disturbances in differential mode.
• These electromagnetic disturbances propagate in cables that support the transmission of MLI (Pulse Width Modulation) type signals or in those that support HVDC ("High Voltage Direct Curent") power.
• MLI Pulse Width Modulation
• HVDC High Voltage Direct Curent
• Armored harnesses are commonly used to address electromagnetic compatibility issues.
• the conductive protective sheath envelops all the harness and its possible branch branches to the connectors.
• This type of harness is intended to contain, beyond a few hundred Hz, conducted and radiated emissions inside the shielding sheath and to exclude conducted and radiated emissions from sources outside the shielding sheath.
• Shielding is generally considered a topological barrier characterized by its transfer impedance.
• this type of shielding is essentially used to weaken the common mode led or radiated signals generated by the converter, which does not make it possible to deal with disturbances generated in differential mode which are a priori more troublesome because they are transmitted in parallel to the differential loads and thus superimpose directly to the useful signals.
• the common-mode disturbances are very easily transformed into differential-mode disturbances as soon as an impedance imbalance appears in the equipment connected to the ends of the harnesses, this imbalance sometimes being able to come sometimes from the harness itself, in particular due to the presence of branches and connectors.
• the present invention proposes a harness for the electrical connection between several equipment, said harness comprising a beam formed of one or more electrical cables surrounded by a protective sheath, characterized in that it comprises at least one or more electromagnetic attenuation rods or ropes extending along the bundle within the protective sheath, each electromagnetic damping ring or string consisting at least partially of a magnetic material, and in that the rods or ropes separate the electrical cables from the beam or are interposed between the beam and the protective sheath.
• the harness according to the invention has a mutual inductance much higher than that of the harnesses of the prior art, which makes it possible to limit the disturbances in differential mode and in common mode and to improve the filtering capacity of the harness.
• a current always generates a magnetic field and conversely, the Magnetic field variations induce electrical currents in neighboring conductors.
• the presence of one or more electromagnetic attenuation rods or ropes constituted at least partially by a magnetic material and placed under the protective sheath makes it possible to form in the harness an inductance (self) which opposes the fluctuations of the current.
• the electromagnetic attenuation rods or ropes separate the electric cables from the beam, they make it possible to limit the disturbances in differential mode mainly.
• each string or electromagnetic attenuation rod is made of a composite material comprising a matrix of flexible material loaded with particles of at least one magnetic material.
• the ropes or electromagnetic damping rods are capable of performing their function of limiting electromagnetic interference without reducing the initial flexibility of the harness.
• the invention also relates to an aircraft comprising at least one harness according to the invention for transferring power between an electrical source and a load.
• - Figure 1 is a perspective view of a harness according to one embodiment of the invention
• - Figure 2A is a perspective view of a harness according to another embodiment of the invention
• FIG. 2B is a perspective view showing the torsion between the beam cables and the electromagnetic attenuation elements of the harness of FIG. 2A;
• FIG. 3 is a perspective view of a harness according to another embodiment of the invention.
• FIG. 4 is a perspective view of a harness according to another embodiment of the invention.
• FIG. 5 is a perspective view of a harness according to another embodiment of the invention.
• FIG. 6 is a perspective view of a harness according to another embodiment of the invention.
• FIG. 7 is a perspective view showing the structure of the electromagnetic attenuation element of the harness of FIG. 6.
• the present invention provides a harness that can be used in particular, but not exclusively, for the transmission of energy and / or information (control signals, measurement, etc.) between electrical or electronic equipment embedded in aircraft.
• the harness according to the invention is particularly suitable for transferring power between an electrical source and a load (for example an actuator).
• a load for example an actuator.
• the structure of the harness of the invention is remarkable in that it makes it possible to increase the mutual inductance of the harness of the harness in common mode or in differential mode by the presence in the harness of a harness. or several electromagnetic attenuation elements.
• a harness 100 according to one embodiment of the invention is shown in Figure 1.
• the harness 100 comprises a central beam 110 formed here of three electric cables 111, each formed of a conductive wire 1110 surrounded by an insulating sheath 1111 and a protective sheath 120 surrounding the beam 110.
• the protective sheath 120 may consist of a flexible conductive material such as example a metal braid (armored harness) or an electrically insulating material, the protective sheath wrapping to the connectors (not shown in Figure 1) the entire harness and any branch branches.
• the harness 100 further comprises electromagnetic attenuation elements 130 constituted here by three rods or ropes 131 formed at least in part of a magnetic material and interposed between the central beam 110 and the shielding sheath 120
• the strings 131 extend axially in the harness, that is to say parallel to the cables 111 of the bundle 110.
• Ropes 131 are evenly distributed around beam 110.
• FIG. 2A illustrates the case where the electrical cables 211 of a bundle 210 are twisted inside the protective sheath 220 of a harness 200.
• the strings 231 constituting the electromagnetic attenuation elements 230 are also twisted in a pitch P231 identical to the twist pitch of the cables 211 ( Figure 2B).
• the cords 231 preferably have a section S231 which corresponds to approximately 20% of the section S211 of the cables 211 of the bundle.
• FIG. 3 represents a harness 300 comprising a beam 310 formed here of three electric cables 311, each formed of a conductive wire 3110 surrounded by an insulating sheath 3111 and a protective sheath 320 surrounding the beam 310, the protective sheath 320 which may consist of a conductive material or an electrically insulating material, the protective sheath enveloping up to the connectors (not shown in Figure 3) the entire harness and any branch branches.
• the harness 300 differs from the harnesses 100 and 200 already described in that the cables 311 are surrounded by an electromagnetic attenuation element 330 consisting of a hollow tube 331 interposed between the beam 310 and the shielding sheath 320.
• the hollow tube is formed at least in part of a magnetic material.
• the electromagnetic attenuation element or elements are arranged around the cables of the central beam constituting the phase wires and allow mainly to limit disturbances in common mode.
• the electromagnetic attenuation elements being at least partially made of magnetic material, they are able to filter all the disturbances generated in common mode in the central beam by increasing the mutual inductance of the latter.
• electromagnetic attenuation elements in the form of ropes which have a significantly smaller cross-section than the electrical cables of the beam, the filtering will most probably be carried out on differential-mode disturbances.
• FIG 4 illustrates a harness 400 according to another embodiment of the invention.
• the harness 400 comprises a central bundle 410 formed here of three electrical cables 411, each formed of a conductive wire 4110 surrounded by an insulating sheath 4111 and a protective sheath 420 surrounding the bundle 410, the protective sheath 420 which may be constituted a conductive or electrically insulating material, the protective sheath enveloping up to the connectors (not shown in Figure 1) the entire harness and any branch branches.
• the harness further comprises electromagnetic attenuation elements 430 constituted here by four rods or ropes 431 formed at least in part of a magnetic material and separating the electrical cable 411 from the central beam 410.
• the electrical cables of the beam are twisted, as is the case in Figure 4, the strings 431 are also twisted in the same pitch as that of the cables 411.
• the ropes 431 preferably have a section S431 identical to the section S411 of the cables 411 beam.
• the cords 531 constituting the electromagnetic attenuation elements 530, extend axially in the protective sheath 520 of the harness 500; that is to say parallel to the cables 511 of the beam 510.
• the separation of the cables of the central beam can also be performed with a single piece as shown in FIG. 6.
• a harness 600 comprising a bundle 610 formed here of three electric cables 611 and a protective sheath 620 surrounding the bundle 610 (conductive or insulating sheath), furthermore comprises an element of electromagnetic attenuation 630 consists of a one-piece part 631. More specifically, the part 631 comprises housings 632 each for receiving a cable 611 of the beam 610. Once arranged in the housing 632 the cables 611 are separated from each other by walls 633 present between the housings 632.
• the housings 632 of the one-piece piece 630 have a helical shape varying according to a pitch P632 corresponding to the pitch defined to twist the cables as illustrated in Figure 7.
• the housing of the room monobloc extend axially in the harness, that is to say parallel to the cables of the beam in the same cable separation position as that shown in harness section in Figure 6.
• the electromagnetic attenuation element or elements are arranged around the cables of the central beam constituting the phase wires and mainly allow to limit the disturbances in differential mode.
• the electromagnetic attenuation elements being at least partially magnetic material, they are able to filter all the disturbances generated in differential mode in the central beam by increasing the mutual inductance of the latter.
• the electromagnetic attenuation element or elements described above namely the strings 131, 231, 431 and 531, the tube 331 and the one-piece part 631 are made from a magnetic or partially magnetic material .
• the possible magnetic materials include iron, cobalt, nickel, manganese and ferrites.
• the electromagnetic attenuation elements are preferably made of a composite material comprising a matrix of flexible and / or flexible material loaded with particles of one or more magnetic materials.
• the electromagnetic attenuation elements described above can be made from a polymer matrix of PTFE (Teflon TM or PolyTetrafluoroethylene), ETFE (Tefzel TM or Ethylene-TetraFluoroethylene), PFA (tetrafluoroethylene or PerFluoroalkoxy) type, FEP (tetrafluoroethylene or perfluoropropylene), charged with a powder of particles of one or more magnetic materials selected from among others iron, cobalt, nickel, manganese and ferrites.
• PTFE Teflon TM or PolyTetrafluoroethylene
• ETFE Tefzel TM or Ethylene-TetraFluoroethylene
• PFA tetrafluoroethylene or PerFluoroalkoxy
• FEP tetrafluoroethylene or perfluoropropylene
• the composite material constituting the electromagnetic attenuation elements that can also be made from a foam, such as a polyurethane foam or Styrofoam TM, loaded with particles of magnetic material (s).
• a foam such as a polyurethane foam or Styrofoam TM
• particles of magnetic material s.
• Different technologies can be used for shaping the electromagnetic attenuation elements. In the case of ropes or rods and tubes, one can for example form these elements by wire extrusion.
• the tubes may also be formed by winding a charged polymer tape or from a sheath. In the case of a single piece, such as the piece 430 previously described, it can be formed by molding.
• FIGS. 1 to 3 can be combined with one of the embodiments shown in FIGS. 4 to 7 in order to form a harness capable of limiting disturbances both in common mode and in differential mode, this mutualization however, the filtering has an impact on the flexibility and overall mass of the harness.

Landscapes

• Insulated Conductors (AREA)
• Shielding Devices Or Components To Electric Or Magnetic Fields (AREA)
• Communication Cables (AREA)

Applications Claiming Priority (2)

Publications (1)

Family

ID=50976815

Family Applications (1)

Country Status (5)

Families Citing this family (1)

Citations (3)

Family Cites Families (12)

• 2014
  • 2014-02-21 FR FR1451402A patent/FR3017984B1/fr active Active
• 2015
  • 2015-02-19 US US15/120,159 patent/US20170229210A1/en not_active Abandoned
  • 2015-02-19 WO PCT/FR2015/050401 patent/WO2015124871A1/fr not_active Ceased
  • 2015-02-19 EP EP15709278.4A patent/EP3108480A1/de not_active Withdrawn
  • 2015-02-19 CN CN201580009850.0A patent/CN106463204A/zh active Pending

Patent Citations (3)

Non-Patent Citations (1)

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