Power transmission device for connecting electrical devices and diagnostic method

Abstract

The invention relates to a power transmission device (3) configured to connect a connector (10) of a first electrical device (1) to a connector (20) of a second electrical device (2) in order to allow the second electrical device (2) to be powered by the first electrical device (1) with a DC supply voltage, the transmission device (3) comprising a first harness (HA) and a second harness (HB), each harness (HA, HB) comprising a first cable (La+, Lb+) and a second cable (La-, Lb-), the power transmission device (3) comprising a diagnostic device (42) configured to measure the intensity of the current (Ia+, Ib+, Ia-, Ib-) through each cable (La+, Lb+, La-, Lb-) of each harness (HA, HB) and determine a fault (DEF) in the transmission device (3) from the current intensity measurements (Ia+, Ib+, Ia-, Ib-).

Description

Power transmission device for connecting electrical equipment and diagnostic process

[0001] The present invention relates to the field of electrical connection from a first piece of equipment supplying a direct current (DC) supply to a second piece of equipment, in particular, for supplying high-voltage direct current (HVDC). This relates specifically to a DC supply voltage exceeding 270 kV. The invention is more particularly aimed at supplying power to aircraft propulsion equipment.

[0002] Climate change is a major concern for many legislative and regulatory bodies worldwide. Indeed, various restrictions on carbon emissions have been, are being, or will be adopted by different countries. In particular, an ambitious standard applies to both new types of aircraft and those already in service, requiring the implementation of technological solutions to bring them into compliance with current regulations. Civil aviation has been actively working for several years now to contribute to the fight against climate change.

[0003] Technological research efforts have already led to very significant improvements in the environmental performance of aircraft. The Applicant takes into account the factors impacting all phases of design and development in order to obtain less energy-intensive and more environmentally friendly aeronautical components and products, whose integration and use in civil aviation have moderate environmental consequences, with the aim of improving the energy efficiency of aircraft.

[0004] Consequently, the Applicant is constantly working to reduce its negative climate impact by using methods and operating virtuous development and manufacturing processes that minimize greenhouse gas emissions to the minimum possible in order to reduce the environmental footprint of its activity.

[0005] This sustained research and development work focuses on new generations of aircraft engines, the weight reduction of aircraft, particularly through the materials used and lighter on-board equipment, the development of the use of electrical technologies to provide propulsion, and, as essential complements to technological progress, aviation biofuels.

[0006] With reference to the diagram, a power supply system is represented comprising a first electrical equipment 1 providing a continuous supply voltage, in particular greater than 270 kV, to a second electrical equipment 2. In particular, the first equipment 1 includes a connector 10 and the second equipment 2 includes a connector 20 connected to the first connector by a harness 103. The harness 103 includes for this purpose a first connector 131 and a second connector 132 connected by a cable.

[0007] As is known, electrical arcs, either parallel or series, can occur in a harness. An electrical arc is a disruptive electrical discharge with a high current and self-sustaining effect at low voltage levels. A series arc corresponds to an electrical discontinuity, not short-circuiting the load, which can be exacerbated by environmental stresses such as mechanical vibrations and thermal cycles related to aircraft altitude variations.

[0008] As is well known, an aircraft power system includes a fault detection system to protect against certain types of faults, including overcurrents due to leakage currents and short circuits. This system protects the power supply and ensures flight safety and integrity. Such a detection system measures the electrical current flowing through the cables in real time. In practice, most parallel electrical arcs can be detected. Once these parallel arcs are detected, the detection system is configured to isolate one or more cables, similar to a circuit breaker.

[0009] Series arcs have only a minor impact on the electrical current flowing through a cable, making them difficult to identify. Current projects for more electric aircraft and electric hybrid systems involve an increase in onboard electrical power and necessitate a review of the overall arc fault mitigation strategy, including the mitigation of series arcs. Indeed, the increase in voltage levels and / or the requirement to use distributed DC voltage, which are being considered, lead to an increased risk of fault arcs, including series arcs.

[0010] A series arc protection system for an electric vehicle with a 42V power supply powering a grounded load is known from patent application EP1300919 A1. The system consists of a harness comprising a first cable and a second cable in parallel along a central section. Each cable contains a fuse. In the event of a fault in the first cable, all current will flow through the second cable, activating its fuse. Preferably, the fuse in the second cable activates the fuse in the first cable, thus stopping all electrical power transmission through the harness. The protection system detects and stops a series arc.

[0011] Such a protection system has several drawbacks. First, when the electrical load is not operating at full power, the fuse on the second cable cannot be activated in the event of a series arc on the first cable. This is because the activation threshold of the second cable's fuse is defined according to the maximum power of the load. Consequently, a series arc could be sustained over time without activating one of the fuses, potentially leading to a fire. This type of detection system can only detect series arcs when the load is operating at full power, risking the detection of numerous false positives. Furthermore, the detection system cannot detect precursor faults to a series arc, such as a loose connector due to vibration.

[0012] The invention aims to eliminate at least some of these drawbacks by providing a reliable (100% true positives) and robust (0% false positives) detection system for detecting series arcs independently of the load power level. Another objective is to enable the reliable detection of precursor faults to series arcs in order to perform preventive maintenance.

[0013] The invention thus aims to eliminate at least some of these drawbacks. PRESENTATION OF THE INVENTION

[0014] The invention relates to a power transport device configured to connect a connector of a first electrical equipment to a connector of a second electrical equipment in order to allow the second electrical equipment to be supplied by the first electrical equipment with a direct current supply voltage, the power transport device comprising: a first connecting element comprising a connector configured to connect to the connector of the first electrical equipment, a second connecting element comprising a connector configured to connect to the connector of the second electrical equipment, a first harness connecting the first connecting element to the second connecting element so as to transport the electrical power from the first connecting element,a second harness connecting the first connecting element to the second connecting element so as to carry the electrical power from the first connecting element independently to the first harness,

[0015] The invention is notable in that each harness comprises a first cable and a second cable, the first connecting element comprising a diagnostic device configured to: measure the current intensity on each cable of each harness and determine a fault in the transport device from the current intensity measurements.

[0016] Thanks to the invention, four current intensity measurements are available, enabling the implementation of decision logic or similarity analysis in databases to identify electrical faults corresponding to both direct disconnections that precede series arcs and indirect disconnections such as loose connectors. The power transmission system thus exhibits high reliability and a low risk of series arcs. This is particularly advantageous in an aeronautical context. Advantageously, the diagnostic device is integrated into the first connection point and measures the current intensity within that point. This allows for the use of two simple and inexpensive harnesses whose length can be freely determined.

[0017] Preferably, each first cable is configured to carry a current from a positive terminal. Preferably, each second cable is configured to carry a current from a negative terminal.

[0018] Preferably, the first connection device includes current intensity measurement components.

[0019] According to one aspect, the diagnostic device is configured to determine a fault in the first cable of the second harness if the current intensity of the first cable of the first harness in absolute value is greater than a first threshold and if the current intensity of the first cable of the second harness in absolute value is less than said first threshold.

[0020] A difference in current distribution between two cables of the same type can highlight a clear disconnection, a precursor to a series arc, which is traditionally complex to identify. Such a decision-making process is simple to implement.

[0021] In one respect, the first threshold is equal to twice the margin of error of the current measurement. Such a first threshold allows for reliable (100% true positives) and robust (0% false positives) detection.

[0022] According to one aspect, the diagnostic device is configured to determine a fault in the first cable of the first harness if the difference between the absolute value of the current intensity of the first cable of the first harness and the absolute value of the current intensity of the first cable of the second harness is greater than a second threshold.

[0023] A difference in current distribution between two cables of the same type can highlight a clear disconnection, a precursor to a series arc, which is traditionally complex to detect. Such a decision-making process is simple to implement.

[0024] According to one aspect, the second threshold is a function of the maximum difference in normal operation between the current intensity of the first cable of the first harness in absolute value and the current intensity of the first cable of the second harness in absolute value.

[0025] In one aspect, the first connection point includes a safety device configured to cut off the power supply to the harnesses when a fault is detected by the diagnostic device. Electrical safety is thus reliably ensured.

[0026] In one aspect, the first connection element comprises a first socket and a second socket that are electrically connected via a circuit to the connector of the first connection element, and the second connection element comprises a first socket and a second socket that are electrically connected via a circuit to the connector of the second connection element. Each connection element allows for optimal current distribution.

[0027] In one configuration, the first harness is connected, on one side, to the first socket of the first connecting device and, on the other side, to the first socket of the second connecting device, and the second harness is connected, on one side, to the second socket of the first connecting device and, on the other side, to the second socket of the second connecting device. The sockets advantageously allow for the distribution of current, preferably in a balanced manner.

[0028] The invention relates to an assembly comprising a first electrical equipment including a connector, a second electrical equipment including a connector and a power transport device as previously described to allow the second electrical equipment to be supplied by the first electrical equipment with a DC supply voltage.

[0029] The invention also relates to an aircraft comprising an assembly as previously described.

[0030] In one respect, the second electrical equipment is an electric propulsion motor.

[0031] The invention also relates to a method for diagnosing a power transport device as previously described, connecting a connector of a first electrical equipment to a connector of a second electrical equipment in order to allow the second electrical equipment to be supplied by the first electrical equipment with a DC supply voltage, the method comprising steps, implemented by the diagnostic device, of: measuring the current intensity on each cable of each harness and determining a fault in the transport device from the current intensity measurements.

[0032] The invention also relates to a computer program type product, comprising at least one sequence of instructions stored and readable by a processor and which, once read by this processor, causes the execution of the steps of the process as previously presented.

[0033] The invention further relates to a computer-readable medium containing the computer program-type product as previously described. PRESENTATION OF THE FIGURES

[0034] The invention will be better understood upon reading the following description, given by way of example, and referring to the following figures, given by way of non-limiting examples, in which identical references are given to similar objects.

[0035] This is a schematic representation of a power transport device according to the prior art.

[0036] This is a schematic representation of a power transport device according to one embodiment of the invention.

[0037] This is a schematic representation of the appearance of an energetic series arc on the first cable of the second harness (curve 3a) and its impact on the currents of the first cables of the harnesses (curve 3b).

[0038] This is a more detailed representation of the currents in the first cables of the harnesses of curve 3b of the.

[0039] This is a schematic representation of the variations in differential resistance in the power transmission device.

[0040] It should be noted that the figures explain the invention in detail for implementing the invention, said figures being of course able to serve to better define the invention where appropriate. DETAILED DESCRIPTION OF THE INVENTION

[0041] With reference to the diagram, an assembly is shown comprising a first electrical device 1 including a connector 10, a second electrical device 2 including a connector 20, and a power supply device 3, in an embodiment that allows the second electrical device 2 to be supplied with a DC voltage by the first electrical device 1. The power supply device 3 connects the connectors 10 and 20 of the electrical devices 1 and 2 in the manner of a traditional harness.

[0042] Electrical equipment 1 and 2 can take various forms, including generators, voltage buses, electric propulsion motors, and others. Transmission device 3 is particularly suitable for transmitting high power, especially high-voltage direct current (HVDC). This applies specifically to DC supply voltages exceeding 270 kV.

[0043] Transport device 3 is particularly suitable for electrically connecting electrical equipment that is far apart from each other in an aircraft.

[0044] As illustrated in the figure, the power transport device 3 includes a first connecting member 4 comprising a connector 41 configured to connect to the connector 10 of the first electrical equipment 1. The connectors 10, 41 are configured to cooperate together, in particular by push-fitting or clamping, and may be liable to disconnect due to vibrations of the aircraft.

[0045] The first connection element 4 further comprises a first socket 40A and a second socket 40B which are electrically connected to the connector 41 by an electrical circuit such that the electrical power received at the connector 41 is distributed between the sockets 40A and 40B. Preferably, the electrical power is distributed equally between the two sockets 40A and 40B.

[0046] The power transport device 3 further includes a second connection element 5 comprising a connector 51 configured to connect to the connector 20 of the second electrical equipment 2. The connectors 20, 51 are configured to cooperate together, in particular by push-fitting or clamping, and may be liable to disconnect due to aircraft vibrations.

[0047] The second connection element 5 further comprises a first 50A socket and a second 50B socket which are electrically connected to the connector 51 by an electrical circuit so that the electrical power received on the 50A, 50B sockets is transmitted to the connector 51. Preferably, the electrical power is distributed equally between the two 50A, 50B sockets.

[0048] With further reference to the, the power transport device 3 further comprises: a first harness HA connecting the first connecting element 4 to the second connecting element 5 so as to transport the electrical power from the first connecting element 4 and a second harness HB connecting the first connecting element 4 to the second connecting element 5 so as to transport the electrical power from the first connecting element 4 independently of the first harness HA.

[0049] According to the invention, each harness HA, HB comprises a first cable La+, Lb+, designated "positive cable", and a second cable La-, Lb- designated "negative cable".

[0050] The first HA harness is connected, on the one hand, to the first 40A socket of the first connecting element 4 and, on the other hand, to the first 50A socket of the second connecting element 5. Each cable La+, La- carries a current respectively noted Ia+, Ia-.

[0051] Similarly, the second HB harness is connected, on the one hand, to the second 40B socket of the first connecting element 4 and, on the other hand, to the second 50B socket of the second connecting element 5. Each cable Lb+, Lb- carries a current denoted respectively Ib+, Ib-.

[0052] The power transport device 3 thus has a double harness HA, HB which advantageously allows the detection of various electrical faults which may affect the operation of the power transport device 3. The double harness HA, HB extends over most of the length of the power transport device 3 in order to allow optimal detection when the electrical equipment 1, 2 are far apart.

[0053] According to the invention, with reference to the, the first connecting member 4 comprises a diagnostic device 42 configured to measure the current intensity Ia+, Ib+, Ia-, Ib- on each cable La+, Lb+, La-, Lb- of each harness HA, HB.

[0054] For this purpose, the diagnostic device 42 is connected to current measuring devices to determine the current on each cable La+, Lb+, La-, Lb- of each harness HA, HB. The measuring devices can be of various forms (current sensor, etc.) and are preferably mounted on the circuit of the first connecting device 4. This advantageously allows the harnesses HA, HB to have a simple structure without a switch or measuring device, thus reducing their cost. The measuring devices are integrated into the first connecting device 4.

[0055] The length and conductivity of each HA, HB harness are such that the potential difference between the split points is lower than the arc-sustaining voltage (~15V). The minimum arc voltage is defined in the literature as the sum of the anodic and cathodic drops and the arc column voltage. By having a potential difference (between the cables) lower than the minimum arc voltage, the arc will not occur, and all the current will flow in the undamaged cable.

[0056] The diagnostic device 42 is configured to determine a DEF fault of the transport device 3 from the current intensity measurements Ia+, Ib+, Ia-, Ib-. The diagnostic device 42 is preferably in the form of a calculator to determine a DEF fault by applying decision logics or by comparison to a fault database 44 which associates electrical faults DEFi with current intensity measurements Iai+, Ibi+, Iai-, Ibi- as illustrated in the figure.

[0057] With further reference to the first connection point 4, the first connection element includes a safety device 43, for example a switch or other device, configured to interrupt the power supply to the harnesses HA, HB when a fault DEF is detected by the diagnostic device 42. This ensures electrical safety in the power transmission system 3 and, more generally, in the aircraft. Preferably, in the event of a fault DEF, the safety device 43 is configured to isolate one or more cables La+, Lb+, La-, Lb- in the manner of a circuit breaker.

[0058] According to one aspect of the invention, the first connecting member 4 and the second connecting member 5 have the same structure so as to allow the power transport device 3 to be used in reverse. Thus, it is not necessary to take into account the orientation of the power transport device 3 during connection, which limits the risk of error and speeds up assembly and maintenance.

[0059] The invention also relates to a method for diagnosing a power transport device 3 connecting a connector 10 of a first electrical equipment 1 to a connector 20 of a second electrical equipment 2 in order to allow the supply of the second electrical equipment 2 by the first electrical equipment 1 with a direct supply voltage, the method comprising steps, implemented by the diagnostic device 42, consisting of: measuring the current intensity Ia+, Ib+, Ia-, Ib- on each cable La+, Lb+, La-, Lb- of each harness HA, HB and determining a fault DEF of the transport device 3 from the current intensity measurements Ia+, Ib+, Ia-, Ib-.

[0060] A first example of implementation of the invention is shown in figures 3 and 4 to highlight an electrical fault DEF.

[0061] In this example, with reference to the [reference to the previous example], an electrical fault DEF occurs on the first cable Lb+ of the second harness HB at a time Tdef. The fault DEF here is a complete disconnection.

[0062] Thanks to the diagnostic device 42, it is advantageously observed on curve 3a that the voltage V H B In the second harness, HB increases significantly at time Tdef due to the electrical fault DEF, which leads to a decrease in electrical conductivity and an increase in electrical resistance. Advantageously, the fault DEF does not immediately generate a series arc since the potential difference cannot be reached. Indeed, the potential difference induced by an electrical arc on the Lb+ cable would be greater than the potential difference induced by undamaged cables (La+ - Lb+).

[0063] Determining an electrical fault (DEF) is straightforward, as current flows primarily through the first cable (La+) of the first harness (HA), which is unaffected. As illustrated in curve 3b, the current intensity (Ia+) increases sharply while the current intensity (Ib+) drops sharply following the occurrence of the fault (DEF).

[0064] As an example, diagnostic device 42 implements the following decision logic: If abs(Ia+)<ε & abs(Ib+)> ε then DEF fault on cable La+ If abs(Ia-)<ε & abs(Ib-)> ε then DEF fault on cable La- If abs(Ib+)<ε & abs(Ia+)> ε then DEF fault on cable Lb+ If abs(Ib-)<ε & abs(Ia-)> ε then DEF fault on cable Lb-

[0065] In this context, ε is a first threshold which is preferably equal to twice the accuracy margin of the current measurement, in particular, of a current sensor. For example, the first threshold ε is between 10mA and 1A.

[0066] In the present case, the diagnostic device 42 determines a series arc fault DEF of the first cable Lb+ of the first harness HA because the current intensity Ia+ of the first cable La+ of the first harness HA in absolute value is greater than the first threshold ε () and the current intensity Ib+ of the first cable Lb+ of the second harness HB in absolute value is less than said first threshold ε ().

[0067] As an example, the diagnostic device 42 can also implement the following decision logic: If abs(Ia+)-abs(Ib+)> δ then DEF fault on cable Lb+ If abs(Ib+)-abs(Ia+)> δ then DEF fault on cable La+ If abs(Ia-)-abs(Ib-)> δ then DEF fault on cable Lb- If abs(Ib-)-abs(Ia-)> δ then DEF fault on cable La-

[0068] In this context, δ is a second threshold that is a function of the maximum difference, under normal operating conditions, between two current intensity measurements on the same type of cable. For example, the second threshold δ is between 1% and 5% of the average current flowing through the cables.

[0069] Based on decision logic, it is advantageously possible to detect a DEF fault, which corresponds to a complete disconnection, and to locate it precisely. Thanks to the invention, DEF fault detection is performed before the occurrence of a series arc, which is highly beneficial. Optionally, the current intensity measurements can be filtered to limit the effect of noise.

[0070] Advantageously, the diagnostic device 42 also allows the detection of DEF faults other than clear disconnections, for example, a connector having a connection fault due to aircraft vibrations which can lead to loosening, unplugging or dislodging, i.e., an untimely disconnection.

[0071] The diagnostic device 42 allows the measurement of a differential impedance variation IMPd (representing the variation of the differential resistance) from the current intensity measurements Ia+, Ib+, Ia-, Ib-. Such a measurement is made possible by the presence of the two harnesses HA, HB.

[0072] Advantageously, the duplication of the harnesses makes it possible to detect faults other than outright disconnections:

[0073] Advantageously, with reference to the diagnostic device 42, the diagnostic device compares the differential impedance variation IMPd to a fault database that associates electrical faults DEFi with differential impedance variations IMPdi. According to a preferred aspect, the fault database is obtained through machine learning. It is understood that the diagnostic device 42 could also apply decision logic to the differential impedance variation IMPd to determine whether a connector is loose.

[0074] Thanks to the power transmission device 3 according to the invention, various types of faults can be determined and located practically, rigorously, and precisely. This improves electrical safety during power supply, particularly in aircraft. Furthermore, these faults can be detected at any power level of the electrical equipment 1, 2, unlike the use of fuses as in the prior art.

Claims

Power transport device (3) configured to connect a connector (10) of a first electrical equipment (1) to a connector (20) of a second electrical equipment (2) in order to allow the second electrical equipment (2) to be supplied by the first electrical equipment (1) with a direct current supply voltage, the power transport device (3) comprising: A first connecting element (4) comprising a connector (41) configured to connect to the connector (10) of the first electrical equipment (1), A second connecting element (5) comprising a connector (51) configured to connect to the connector (20) of the second electrical equipment (2), a first harness (HA) connecting the first connecting element (4) to the second connecting element (5) so as to carry the electrical power from the first connecting element (4),a second harness (HB) connecting the first connecting element (4) to the second connecting element (5) so as to independently carry the electrical power from the first connecting element (4) to the first harness (HA), a transport device characterized in that each harness (HA, HB) comprises a first cable (La+, Lb+) and a second cable (La-, Lb-), the first connecting element (4) comprising a diagnostic device (42) configured to: measure the current intensity (Ia+, Ib+, Ia-, Ib-) on each cable (La+, Lb+, La-, Lb-) of each harness (HA, HB) and determine a fault (DEF) of the first cable (Lb+) of the second harness (HB) if the absolute value of the current intensity (Ia+) of the first cable (La+) of the first harness (HA) is greater than a first threshold (ε) and if the current intensity (Ib+) of the first cable (Lb+) of the second harness (HB) in absolute value is lower than said first threshold (ε),the first threshold (ε) being equal to twice the accuracy margin of the current measurement. Power transport device (3) according to claim 1, wherein the diagnostic device (42) is configured to: determine a fault (DEF) of the first cable (La+) of the first harness (HA) if the difference between the current intensity (Ia+) of the first cable (La+) of the first harness (HA) in absolute value and the current intensity (Ib+) of the first cable (Lb+) of the second harness (HB) in absolute value is greater than a second threshold (δ). Power transport device (3) according to any one of claims 1 to 2, wherein the first connecting member (4) includes a safety device (43) configured to stop the power supply to the harnesses (HA, HB) when a fault (DEF) is determined by the diagnostic device (42). Power transport device (3) according to any one of claims 1 to 3, wherein: the first connecting member (4) comprises a first socket (40A) and a second socket (40B) which are electrically connected by an electrical circuit to the connector (41) of the first connecting member (41) and the second connecting member (5) comprises a first socket (50A) and a second socket (50B) which are electrically connected by an electrical circuit to the connector (51) of the second connecting member (5). Power transport device (3) according to claim 4, in which: the first harness (HA) is connected, on the one hand, to the first socket (40A) of the first connecting member (4) and, on the other hand, to the first socket (50A) of the second connecting member (5) and the second harness (HB) is connected, on the one hand, to the second socket (40B) of the first connecting member (4) and, on the other hand, to the second socket (50B) of the second connecting member (5). Assembly comprising: a first electrical equipment (1) including a connector (10), a second electrical equipment (2) including a connector (20) and a power transport device (3) according to any one of claims 1 to 5 to allow the supply of the second electrical equipment (2) by the first electrical equipment (1) with a direct supply voltage. Aircraft comprising an assembly according to claim 6. A method for diagnosing a power transport device (3) according to any one of claims 1 to 5 connecting a connector (10) of a first electrical equipment (1) to a connector (20) of a second electrical equipment (2) in order to allow the second electrical equipment (2) to be supplied by the first electrical equipment (1) with a DC supply voltage, the method comprising steps, implemented by the diagnostic device (42), of: measuring the current intensity (Ia+, Ib+, Ia-, Ib-) on each cable (La+, Lb+, La-, Lb-) of each harness (HA, HB) and determining a fault (DEF) of the transport device (3) from the current intensity measurements (Ia+, Ib+, Ia-, Ib-).

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