IMPROVED METHOD FOR DETECTING A QUENCH PHENOMENON, SYSTEM EXECUTING THE METHOD, AND AIRCRAFT.

Abstract

Method of controlling a superconducting electrical power line of an aircraft comprising at least two superconducting conductors arranged in the same cryostat, said method being carried out by an electronic circuit configured to determine a first electrical voltage representative of a first potential difference measured across the terminals of a first conductor among said at least two superconducting conductors; determine a second electrical voltage representative of a second potential difference measured across the terminals of the other conductor, said second conductor, among said at least two superconducting conductors; then, provide a first information representative of the presence of a potential difference greater than a predetermined threshold value between said first electrical voltage and said second electrical voltage.It is therefore advantageously possible to optimize the resources required for integrity control of an aircraft superconducting power line. Fig. 2.

Description

Title of the invention: IMPROVED METHOD FOR DETECTING A QUENCH PHENOMENON, SYSTEM CARRYING OUT THE METHOD, AND AIRCRAFT. Technical field

[0001] The present invention relates to a superconducting electrical power supply link for an electrical load, for example a motor, in an aircraft, in particular of the type usable for the propulsion of an aircraft. The invention relates more particularly to the monitoring and control of a two-conductor superconducting power supply line in an aircraft, and to an aircraft. STATE OF THE PRIOR ART

[0002] The aeronautical industry is making profound changes in terms of aircraft design, with the aim of significantly reducing carbon dioxide and nitrogen oxide emissions, due to ecological and sustainable development constraints.

[0003] The use of liquid hydrogen as an energy source for an aircraft is a promising way to do this. Hydrogen can be used in a fuel cell, to generate electricity, or directly as fuel in a powertrain. In addition, work is specifically directed to optimize electric or hybrid propulsion systems for aircraft and hydrogen present in liquid form on board an aircraft can be used as a cold source to increase the performance of electrical equipment by lowering its resistivity and therefore reducing losses due to Joule effects. It is also possible to use superconducting components.Superconducting conductors can be used for superconducting technologies for DC (direct current) distribution components and for AC distribution in architectures comprising electric motors powered by controlled electronic power converters, such as inverters. In such motor power supply architectures, the superconducting links must be protected against an unexpected transition from the superconducting state to the conventional state (a transition usually called "quench" in the field of superconductivity). It is therefore important to be able to detect early signs of such a transition in order to avoid excessive Joule losses that could damage the power supply circuits and their surrounding environments.

[0004] The detection of the quench (i.e. the detection of transitions) of a superconducting conductor is generally carried out by monitoring the voltage at the terminals thereof and by detecting the occurrence of an increase in the voltage level at its terminals. While quench detection in continuous operation is quite simple, since it is only a matter of distinguishing between a zero and non-zero impedance (i.e. resistance) of the conductor, this is not the case in transient operation. Indeed, a load such as a motor can cause a significant variation in the current on the direct current distribution network. In this case, the inductive part of the impedance is most often predominant compared to the resistive component, which prevents quench detection with standard means. It is therefore necessary to implement a robust solution to get rid of the inductive effect on the voltage at the conductor terminals during transient phases. Quench detection can then be based on a principle of detection in a permanent direct current regime (i.e. based on the variation in resistance).Since most of the superconducting elements used are magnets, it is usually sufficient to perform quench detection in only one of the conductors of the power supply link being scanned.

[0005] In a quench detection circuit according to the prior art, a coil forming a superconducting element monitored to detect a possible quench phenomenon is divided into two half-coils and the two voltages respectively measured across the terminals of the two half-coils must be identical. To verify this, a difference value between these two measured voltages is determined. This difference should be zero in the absence of quench even if there is a current transient, because the inductance is the same in the two portions (half-coils) of the power supply line being measured. In the event of a problem on the power supply link, the impedance of one of the half-coils is no longer identical to the impedance of the other of the two half-coils and a voltage difference appears.

[0006] In a superconducting direct current distribution network (used to carry current from a source to a load), there is a conductor called a "positive conductor" and a conductor called a "negative conductor", which requires doubling the monitoring circuitry described above. In addition, it is necessary to establish connections at a midpoint of each of the two conductors called respectively "positive" and "negative".

[0007] The situation can be improved. Statement of the invention

[0008] An object of the present invention is to propose a superconducting power supply line controller for an electrical load, capable of rapidly and reliably detecting the occurrence of a quench-type phenomenon, so as to limit the current(s) delivered to the load when the superconducting power supply line between the source and the charge is about to pass from a nominal superconducting state to a state in which its resistivity increases.

[0009] To this end, a method is proposed for controlling a direct current superconducting electrical power supply line of an aircraft, said power supply line comprising at least two superconducting conductors arranged in the same cryostat, said method being executed by electronic circuitry configured to:

[0010] - determine a first electrical voltage representative of a first difference of potential measured at the terminals of a first conductor among said at least two superconducting conductors,

[0011] - determine a second electrical voltage representative of a second potential difference measured at the terminals of the other conductor, called the second conductor, among said at least two superconducting conductors, then,

[0012] - provide first information representative of the presence of a difference of voltage greater than a predetermined threshold value between said first electrical voltage and said second electrical voltage.

[0013] It is thus advantageously possible to optimize the resources necessary for controlling the integrity of an aircraft cryogenic supply line.

[0014] According to one embodiment, the method further comprises providing a second piece of information according to which an anomaly is detected in relation to said first driver or conversely in relation to said second driver.

[0015] The invention also relates to a device for controlling a direct current electrical power supply line of an aircraft, the power supply line comprising at least two superconducting conductors arranged in the same cryostat and the control device comprising electronic circuitry configured to: - determine a first electrical voltage representative of a first potential difference measured at the terminals of a first conductor among said at least two superconducting conductors, - determine a second electrical voltage representative of a second potential difference measured at the terminals of the other conductor, called the second conductor, among said at least two superconducting conductors, and for, - provide first information representative of the presence of a voltage difference greater than a predetermined threshold value between said first electrical voltage and said second electrical voltage.

[0016] According to one embodiment, the device for controlling an electrical supply line further comprises the provision of second information according to which an anomaly is detected in relation to the first conductor or, conversely, in relation to the second conductor of the power supply line.

[0017] The invention also relates to a cryogenic electrical power supply system for an aircraft comprising a device for controlling an electrical power supply line as previously described, configured to control a superconducting electrical power supply line between a current source of the aircraft and a current consuming device (load) of the aircraft.

[0018] The invention also relates to an aircraft comprising an electrical power supply control device as described above or a cryogenic power supply system as described above.

[0019] The invention finally relates to a computer program product comprising program code instructions for executing the steps of a method for controlling a superconducting electrical power line as previously described when said instructions are executed by a processor of a device for controlling a superconducting electrical power line, as well as a storage medium comprising such a computer program product. Brief description of the drawings

[0020] The above-mentioned features of the invention, as well as others, will appear more clearly on reading the following description of an exemplary embodiment, said description being made in relation to the attached drawings:

[0021] [Fig-1] illustrates an aircraft comprising a device for controlling a line aircraft superconducting power supply configured to perform a method of controlling such a line;

[0022] [Fig.2] schematically illustrates implementation details of a device for controlling an aircraft superconducting electrical power line;

[0023] [Fig.3] is a flowchart illustrating steps of a method for controlling an aircraft superconducting power supply line; and,

[0024] [Fig.4] illustrates an example of architecture of a device for controlling an aircraft superconducting electrical power supply line configured to perform the method already illustrated in [Fig.3].

[0025] DETAILED DESCRIPTION OF EMBODIMENTS

[0026] [Fig.l] schematically and symbolically represents an aircraft 1 comprising a control device 10 for a superconducting electrical power supply line of the aircraft 1 (this device 10 is not detailed in [Fig.l], but is illustrated in [Fig.2]). Advantageously, such a device on board the aircraft 1 makes it possible to monitor the absence of a quench phenomenon in relation to the superconducting electrical power supply line, and to detect such a phenomenon as early as possible, as soon as it appears.

[0027] [Fig.2] schematically and symbolically illustrates the control device 10 of an electrical power supply line connected to the ends of a superconducting electrical power supply line EL of the aircraft 1, configured to control this superconducting electrical power supply line EL, and in particular to detect the appearance of a quench phenomenon in relation to this power supply line. The superconducting electrical power supply line EL comprises in particular two superconducting conductors LCP and LCM cooled by a cryogenic fluid. In a non-limiting manner, the two superconducting conductors LCP and LCM are for example arranged (bathed) in a cryogenic fluid within a cryostat CR enveloping the superconducting conductors LCP and LCM. The term cryostat here designates a sealed enclosure intended to minimize heat exchanges with the environment and containing a cryogenic fluid maintained at a cryogenic temperature.The superconducting conductor LCP is a first electrical superconducting conductor of the EL line, called "positive conductor" and the superconducting conductor LCM is a second superconducting conductor of the EL line, called "negative conductor". The superconducting electrical power supply line EL is connected at one of its ends between the terminals VG+ and VG- of a DC voltage source G. The other end of the power supply line EL is connected to a load LD or in other words to an energy consuming device or system LD.

[0028] A first electronic circuit OA1 is configured to determine a first electrical voltage V+ representative of a first potential difference measured across the terminals of the first superconducting conductor LCP among the two superconducting conductors LCP and LCM. The electrical voltage V+ is defined between the output of the electronic circuit OA1 and a reference ground (a potential) GND1. Similarly, a second electronic circuit OA2 is configured to determine a second electrical voltage V- representative of the potential difference measured across the terminals of the other conductor, LCM, called the second conductor, among the two superconducting conductors LCP and LCM. The electrical voltage V- is defined between the output of the electronic circuit OA2 and a reference ground (a potential) GND2.Furthermore, a third electronic circuit D1 is configured to provide at least a first piece of information Q, in the form of a signal, which information is representative of the presence of a voltage difference greater than a predetermined threshold value between the first electrical voltage V+ and the second electrical voltage V-. The circuit DI is a voltage subtractor type circuit, for example based on operational amplifiers or produced digitally. The control device 10 of a superconducting electrical power supply line therefore comprises the three electronic circuits OA1, OA2 and DI.

[0029] According to one embodiment, the electronic circuitry DI further determines a signal S whose voltage is equal to V+ - V-. This second signal delivered by the electronic circuitry DI constitutes a second piece of information, according to which an anomaly is detected in relation to the first superconducting conductor LCP or in relation to the second superconducting conductor LCM. Indeed, if the sign of the difference in the voltages V+ - V- is positive, this implies that a problem has occurred in relation to the positive conductor LCP. Conversely, if the sign of the difference in the voltages V+ - V- is negative, this implies that a problem has occurred in relation to the negative conductor LCM.

[0030] According to one embodiment, the electronic circuitry OA1 is an operational amplifier type circuitry whose two inputs are respectively connected to the ends of the positive conductor LCP and the electronic circuitry OA2 is an operational amplifier type circuitry whose two inputs are respectively connected to the ends of the negative conductor LCM. According to one embodiment, the electronic circuitries OA1 and OA2 are respectively powered by electrical power supply circuits independent of each other and galvanically isolated from each other (power supply and ground).

[0031] [Fig. 3] is a flowchart illustrating steps of a method for controlling the EL superconducting power supply line shown in [Fig.2].

[0032] Step S0 is an initialization step at the end of which all the on-board systems of the aircraft 1 useful for taxiing on the ground or for the flight of the latter, including the electrical power supply line EL and the control device 10 are correctly configured and normally operational.

[0033] During a step S1, the electronic circuitry OA1 determines the first electrical voltage V+ representative of the potential difference measured across the terminals of the positive conductor of the superconducting electrical power supply line EL. At the same time, the electronic circuitry OA2 determines, during step S2, the second electrical voltage V- representative of the potential difference measured across the terminals of the negative conductor of the superconducting electrical power supply line EL. Once the voltages V+ and V- have been determined, the circuitry DI determines, during step S3, the voltage difference between the voltages V+ and V- and then provides, during step S4, the information Q representative of the presence of a voltage difference greater than a predetermined threshold value between the voltage V+ and the voltage V-.

[0034] According to one embodiment, the predetermined threshold value is less than 100 mV, preferably of the order of a few millivolts. The threshold value depends in particular on several parameters, including the length of the power supply line.

[0035] According to one embodiment, the method may comprise a step of filtering the first electrical voltage V+ and the second electrical voltage V-, or a step filtering the voltage difference between the voltages V+ and V-, so as to avoid untimely triggering and the sending of erroneous information S. According to one embodiment, the filtering is a low-pass filtering aimed at eliminating high-frequency parasitic signals.

[0036] According to one embodiment, the circuitry DI further provides the information S representative of the sign of the difference V+ - V-.

[0037] This information is for example provided to a device configured to supervise the control of the integrity of the installations and systems of the aircraft 1 or even the integrity of a subset of these installations and systems.

[0038] [Fig. 4] is a schematic representation of an example of internal architecture of the device 10 for controlling an aircraft superconducting electrical power supply line. Let us consider for illustration purposes that [Fig. 4] illustrates an internal arrangement of the control device 10 as installed in the aircraft 1. It is noted that [Fig. 4] could also schematically illustrate an example of hardware architecture of a control or supervision module comprising the control device 10 for controlling an aircraft superconducting electrical power supply line.

[0039] According to the example of hardware architecture shown in [Fig. 4], the control device 10 then comprises, connected by a communication bus 10-9: a processor or CPU (“Central Processing Unit” in English) 10-1; a RAM (“Random Access Memory” in English) 10-2; a ROM (“Read Only Memory” in English) 10-3; a storage unit such as a hard disk (or a storage media reader, such as an SD (“Secure Digital” in English) card reader) 10-4; a communication interface module 10-5 allowing the control device 10 to communicate with remote devices, such as other on-board systems of the aircraft 1, for example one or more systems for supervising the integrity of the systems of the aircraft 1.

[0040] The processor 10-1 of the control device 10 is capable of executing instructions loaded into the RAM 10-2 from the ROM 10-3, from an external memory (not shown), from a storage medium (such as an SD card), or from a communication network. When the control device 10 of a superconducting power line is powered up, the processor 10-1 is capable of reading instructions from the RAM 10-2 and executing them. These instructions form a computer program causing the implementation, by the processor 10-1, of all or part of a method for controlling a superconducting power line described in relation to [Fig. 3] or of described variants of this method.

[0041] All or part of the method described in relation to [Fig. 3] or its described variants can be implemented in software form by executing a set of instructions by a programmable machine, for example a DSP (“Digital Signal Processor” in English) or a microcontroller, or be implemented in hardware form by a machine or a dedicated component, for example an FPGA (Field-Programmable Gate Array) or an ASIC (Application-Specific Integrated Circuit). In general, the control device 10 of an aircraft superconducting power supply line comprises electronic circuitry configured to implement the method described in relation to itself. Obviously, the control device 10 further comprises all the elements usually present in a system comprising a control unit and its peripherals, such as a power supply circuit, a power supply supervision circuit, one or more clock circuits, a reset circuit, input-output ports, interrupt inputs, bus drivers, this list being non-exhaustive.

Claims

Claims

1. Method for controlling a direct current electrical power supply line (EL) of an aircraft (1), said power supply line (EL) comprising at least two superconducting conductors (LCP, LCM) arranged in the same cryostat (CR), said method being executed by electronic circuitry configured to: - determine (SI) a first electrical voltage V+ representative of a first potential difference measured at the terminals of a first conductor (LCP) among said at least two superconducting conductors (LCP, LCM), - determine (S2) a second electrical voltage (V-) representative of a second potential difference measured at the terminals of the other conductor (LCM), called the second conductor (LCM), among said at least two superconducting conductors (LCP, LCM), then,- providing (S4) first information (Q) representative of the presence of a voltage difference greater than a predetermined threshold value between said first electrical voltage (V+) and said second electrical voltage (V-).,

2. A method of monitoring a power supply line according to claim 1, further comprising providing second information (S) that an anomaly is detected in relation to said first conductor (LCP) or in relation to said second conductor (LCM).

3. Control device (10) for a direct current electrical power supply line (EL) of an aircraft (1), said power supply line (EL) comprising at least two superconducting conductors (LCP, LCM) arranged in the same cryostat (CR), said control device (10) comprising electronic circuitry configured to: - determine (SI) a first electrical voltage (V+) representative of a first potential difference measured at the terminals of a first conductor (LCP) among said at least two superconducting conductors (LCP, LCM), - determine (S2) a second electrical voltage (V-) representative of a second potential difference measured at the terminals of a first conductor (LCP) among said at least two superconducting conductors (LCP, LCM), terminals of the other conductor (LCM), called the second conductor (LCM), among said at least two superconducting conductors (LCP, LCM), then, - provide (S4) a first piece of information (Q) representative of the presence of a voltage difference greater than a predetermined threshold value between said first electrical voltage and said second electrical voltage.

4. A device for monitoring an electrical power line (EL) according to claim 3, further comprising providing second information (S) that an anomaly is detected in relation to said first conductor (LCP) or in relation to said second conductor (LCM).

5. Cryogenic electrical power supply system of an aircraft (1) comprising a control device (10) of an electrical power supply line (EL) according to one of claims 3 and 4 configured to control a cryogenic electrical power supply line between a current source (G) of said aircraft (1) and a current consuming device (LD) of said aircraft (1).

6. Aircraft (1) comprising an electrical power line control device (10) according to one of claims 3 and 4 or a cryogenic power supply system according to claim 5.

7. Computer program product comprising program code instructions for executing the steps (S1, S2, S4) of a method according to one of claims 1 to 2 when said instructions are executed by a processor of a control device (10) of an electrical power line.

8. A storage medium comprising a computer program product according to claim 7.

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