IMPROVED SUPERCONDUCTING ELECTRICAL POWER SUPPLY LINE, METHOD FOR CONTROLLING A SUPERCONDUCTING ELECTRICAL POWER SUPPLY LINE AND AIRCRAFT COMPRISING SUCH A LINE.

Abstract

The invention relates to a method for controlling a superconducting electrical power supply line (100) executed in a control circuit (10), the method comprising obtaining (S1) information representative of a first electric current in said superconducting electrical power supply line, then, if (S2) said information representative of a first electric current is greater than or equal to a first predetermined threshold value, generating a current (S3), called second current, in a superconducting coil (108) arranged in proximity to said power supply line (100), the value of said second current being determined from said information representative of said first current. The invention also relates to a control circuit (10) configured for implementing the method.Thus, it is possible to reversibly operate current limiter functions by initiating a quench phenomenon in said superconducting power supply line. Fig. 1.

Description

Title of the invention: IMPROVED SUPERCONDUCTING ELECTRICAL POWER SUPPLY LINE, METHOD FOR CONTROLLING A SUPERCONDUCTING ELECTRICAL POWER SUPPLY LINE AND AIRCRAFT COMPRISING A SUCH LINE. Technical field

[0001] The present invention relates to a superconducting electrical power supply circuit provided with a current controller. The invention relates more particularly to the monitoring and control of the integrity of an aircraft superconducting power supply link, and to an aircraft comprising such a power supply link. 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 to increase the performance of electrical equipment by lowering its resistivity and consequently reducing Joule losses. It is also possible to use superconducting components. Superconducting conductors can be used for power distribution in architectures comprising various electrical components powered by superconducting power distribution networks.In such power supply architectures, the superconducting link between a source and a load must be protected against an unexpected transition from the superconducting state to the conventional state (transition usually called quench in the field of superconductivity). It is therefore important to be able to detect signs of such a transition in order to avoid excessive Joule losses that could damage the power supply circuits and their surrounding environment.

[0004] Furthermore, faults occurring in such power distribution networks must be handled quickly and reliably to avoid damage to the systems.

[0005] Current limiters (known as “Fault Current Limiters” in English) have current limiting characteristics that are calibrated at the time of manufacture and are not very adaptable to specific conditions during their use. In addition, if superconducting fuse devices can ensure a current cut-off in branches of a superconducting distribution network, their activation is irreversible and requires replacement and therefore a maintenance operation. Finally, devices of the semiconductor power circuit breaker type, often called “solid state circuit breaker”, can also be used to operate cut-offs in branches of a superconducting power distribution network, but they present a risk to the integrity of the systems in the event of a failure. In addition, semiconductor power circuit breakers have significant Joule effect losses during nominal operation.

[0006] Furthermore, the impedance of such power distribution networks is lower than the impedance standards of electrical networks conventionally integrated in an aircraft. In conventional networks, the distribution, as well as the cables, provide impedances that act as a dampener for current variations, which has a stabilizing effect in the network. With superconducting technologies, achieving zero resistivity in direct current, particularly in the cables, presents a major drawback regarding the stability of the network. In the case of a low impedance network, the stability margins of the network are reduced or even annihilated, which jeopardizes the compatibility of the source and the loads that are connected to this common network and can lead to an unstable network. Under these conditions, the systems provided cannot operate and may be damaged.

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

[0008] An object of the present invention is to provide a method for obtaining reversible current limiting functions in a superconducting power supply line reproducing the functions of a traditional fault current limiter.

[0009] For this purpose, a method for controlling a superconducting electrical power supply line is proposed, the method being executed in a control circuit of said power supply line and comprising the steps:

[0010] - i) obtaining information representative of a first electric current in said superconducting power supply line,

[0011] - ii) comparing said information representative of a first electric current in said superconducting power supply line with a first threshold value predetermined, and,

[0012] - iii) if said information representative of a first electric current is su greater than or equal to the first predetermined threshold value, generating a current, called the second current, in a superconducting coil arranged near said superconducting power supply line and configured to emit a magnetic field, said superconducting power supply line being configured to receive said magnetic field, the value of said second current being determined from said information representative of said first current.

[0013] It is thus advantageously possible to regulate the current in a superconducting power supply line dynamically by adjusting a limitation of the current according to the electrical distribution needs. The invention thus allows protection of the power supply line in the event of a detected fault, as well as an improvement in the stability of said power supply line.

[0014] According to one embodiment, the method further comprises a step of melting a calibrated break zone of the electrical supply line when the first electrical current has an intensity greater than a second predetermined threshold value for a predetermined time.

[0015] Another object of the invention is a control circuit for a superconducting power supply line, the control circuit comprising electronic circuitry configured to:

[0016] - i) obtaining information representative of a first electric current in said superconducting power supply line,

[0017] - ii) comparing said information representative of a first electric current in said superconducting power supply line with a first predetermined threshold value, and for,

[0018] - iii) if said information representative of a first electric current is su greater than or equal to the predetermined threshold value, generating a second current in a superconducting coil arranged in proximity to said superconducting power supply line and configured to emit a magnetic field, said superconducting power supply line being configured to receive said magnetic field, the value of said second current being determined from said information representative of said first current.

[0019] Advantageously, the control circuit of a superconducting electrical power supply line as mentioned above further comprises a calibrated rupture zone of the superconducting electrical power supply line configured to melt when the first electrical current is greater than a second predetermined threshold value for a predetermined time.

[0020] Another object of the invention is a system for controlling a superconducting electrical power supply line comprising a control circuit as previously described and a superconducting coil powered by the control circuit and arranged close to the electrical power supply line and configured to emit a magnetic field, said superconducting electrical power supply line being configured to receive said magnetic field.

[0021] The invention also relates to an aircraft comprising at least one control circuit for a superconducting power supply line as previously described or a control system as mentioned above.

[0022] The invention further relates to a computer program product comprising program code instructions for executing the steps of the method as described, when said program is executed by a processor of a control circuit of a superconducting power supply line and a storage medium comprising such a computer program product. Brief description of the drawings

[0023] 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:

[0024] [Fig-1] illustrates a superconducting power supply line provided with a current control circuit according to one embodiment;

[0025] [Fig.2] illustrates a variant of the superconducting power supply line provided with a current control circuit already shown in [Fig.l];

[0026] [Fig.3] is a flowchart illustrating a method of controlling a superconducting power supply line, executed in a control circuit, according to one embodiment;

[0027] [Fig.4] schematically illustrates an example of internal architecture of a controller device operating in a control circuit of a superconducting power supply line, according to one embodiment; and,

[0028] [Fig.5] illustrates an aircraft comprising a controlled superconducting power supply line according to one embodiment.

[0029] DETAILED DESCRIPTION OF EMBODIMENTS

[0030] [Fig.l] is a schematic representation of a control circuit 10 of a superconducting power supply line 100. The superconducting power supply line 100 is made of at least one superconducting material and is subjected to conditions satisfactory for operation in the superconducting state of the superconducting power supply line 100. The conditions for superconducting operation of the superconducting power supply line 100 include in particular temperature conditions, magnetic environmental conditions and current density conditions. The superconducting power supply line 100 has two ends 100a and 100b respectively connected to a source of electrical energy and to a receiving device, circuit or system consuming electrical energy (not shown in the figure). According to one embodiment, the superconducting power supply line 100 has the shape of a ribbon or a cable. Advantageously, a current sensor 102 is arranged on the superconducting power supply line 100 and is configured to deliver to a controller device 104 information representative of the intensity of the current flowing in the superconducting power supply line 100.The current sensor 102 delivers the information representative of the current flowing in the superconducting electrical power supply line 100 to the controller device 104 via a link 106 also called here connection link 106. According to one embodiment, the current sensor 102 is an electronic device which comprises one or more conductive windings arranged around the superconducting electrical power supply line 100 and whose terminals are respectively connected to current measurement inputs of the current sensor 102, which then sends to the controller device 104, via the connection link 106, an analog or digital quantity whose amplitude or value is proportional to the intensity of the measured electric current. According to an alternative embodiment, the winding(s) are directly connected to inputs of the controller device 104 and the terminals of the winding(s) then jointly constitute the connection link 106.According to one embodiment, the amplitude or value addressed by the current sensor 102 is defined during a laboratory calibration phase and is extracted from a table of values ​​stored in a non-volatile memory of the current sensor 102.The control circuit 10 of the superconducting power supply line 100 further comprises a superconducting winding 108, also called here “coil” 108 physically arranged in proximity to the superconducting power supply line 100, such that, when an electric current flows in the coil 108, an induced magnetic field is applied to the superconducting power supply line 100, the induced magnetic field being such as to modify the superconducting conditions of the superconducting power supply line 100, and in particular such as to initiate a quench phenomenon capable of increasing the resistivity of the superconducting power supply line 100 and therefore increasing its electrical resistance. Alternatively, the magnetic field lines generated by the coil 108 may be guided within a magnetic circuit produced using an assembly of ferromagnetic materials.The coil 108 comprises two terminal conductors 108a and 108b also called here poles or terminals, connected to . outputs of a current generator internal to the controller device 104 and the controller device 104 is configured to deliver a current generated in the coil 108 whose intensity is a function of information representative of the current flowing in the superconducting electrical power supply line 100. Alternatively, the controller device 104 may comprise a controller having the function of acquiring the current measurement and of delivering a current supply order to the coil 108, as well as a power stage, connected to said controller, and having the function of generating the current in the coil 108 in response to the supply order received from the controller.In other words, if ISC2 (hereinafter called second current) is the current intensity in the coil 108 and ISCi (hereinafter called first current) is the current intensity in the superconducting power supply line 100, then ISC2 = / (Isci) and / is a function defined during laboratory calibration tests so as to be able to implement, by the control circuit 10, a current limiter function in the superconducting power supply line 100.Indeed, the arrangement of the control circuit 10 is such that if a fault occurs in an electrical power distribution network connected to the superconducting electrical power supply line 100, an increase in the intensity of the first current ISCi is detected by the current sensor 102 and transmitted to the controller 104 which determines the second current ISc2 according to the value of the first current ISCi, or more precisely according to information representative of the intensity of the first current ISCi, so as to generate a magnetic field B induced in the coil 108 and consequently induced in the superconducting electrical power supply line 100.The operating characteristics of the superconducting power supply line 100 are then modified by the presence of the magnetic field B to which the power supply line is subjected and results in a state called the limit state which corresponds to the controlled appearance of a quench phenomenon, which phenomenon results in an increase in the resistance of the superconducting power supply line 100 and therefore the appearance of a voltage between its ends 100a and 100b, and consequently, a reduction in the intensity of the current flowing therein. Thus, the described arrangement of the control circuit 10 of the superconducting power supply line 100 cleverly and advantageously makes it possible to control the resistance of the power supply line and therefore to control the intensity of the current in the superconducting power supply line 100, in the event of the appearance of a fault in an electrical distribution network connected to the power supply line 100.The presence of a fault being determined when the value of the intensity of the first current II which circulates in the superconducting electrical power supply line 100 becomes greater than or equal to a first predetermined threshold value.

[0031] Advantageously, the first predetermined threshold value can vary depending on predetermined operating modes of the superconducting power supply line 100. For example, the first threshold value may be equal to a value corresponding to a moderate power delivery regime, or to another value corresponding to a nominal power delivery regime or even to a value corresponding to a full power (maximum power) delivery regime.

[0032] [Fig.2] illustrates a variant of the control circuit 100 of the power supply line superconducting electrical power supply line 100 according to which the superconducting electrical power supply line 100 further has a rupture initiation zone (by melting) 100f calibrated to melt when the current intensity in the superconducting electrical power supply line 100 is greater than or equal to a second threshold value for a predetermined time (a duration). Such a configuration advantageously makes it possible to interrupt the flow of current in the superconducting electrical power supply line 100 (by breaking and opening it) in the event of a malfunction of the control circuit 10, for example due to a malfunction of the controller device 104. This consequently makes it possible to prevent or limit the effects induced by the installation of a quench phenomenon and excessive dissipation of energy by Joule effect in the power distribution systems described or in neighboring systems.

[0033] [Fig.3] is a flowchart type diagram which illustrates steps of a control method executed by the control circuit 10 of the superconducting power supply line 100.

[0034] A step S0 comprises operations of initialization and configuration of the set of systems present aiming to obtain a nominal state defined as a normally operational configuration for use of the superconducting electrical power supply line 100, of the set of systems that this power supply line supplies and of the control circuit 10.

[0035] A step SI comprises a measurement of the intensity of the first current ISCi flowing in the superconducting electrical power supply line 100 by the current sensor 102 and the provision of information representative of this intensity of the current ISCi to the control device 104 via the connection link 106.

[0036] During a step S2, the control device 104 reads the information representative of the intensity of the current ISCi which flows in the superconducting electrical power supply line 100 and determines whether the current ISCi is or is not greater than or equal to a first predetermined threshold value. If the current ISci is not greater than or equal to the first predetermined threshold value, then the method returns to step S1 to carry out a new iteration of measurement and test of magnitude in relation to steps S1 and S2 described above.

[0037] But if at step S2 the current ISCi is greater than or equal to the first predetermined threshold value without however reaching the second predetermined threshold value from which the rupture zone 100f could begin to melt, then the control device 104 generates a current between the terminals 108a and 108b, in the coil 108, so as to increase the magnetic field B to which the superconducting electrical power supply line 100 is subjected, so as to increase its resistance and then reduce the value of the current ISC1.

[0038] According to one embodiment, the controller device 104 reads a value of the second current ISC2 to be generated as a function of a table stored in a non-volatile memory that it integrates, from the value of the first current ISCi or from information representative of the value of the first current ISCL. It should be noted that here we call indifferently "value of the current", "intensity of the current" or "value of the intensity of the current", an intensity of electric current circulating in a conductive or superconductive element.

[0039] According to one embodiment, when the first current ISci reaches the second predetermined threshold value for a predetermined duration Tl, the fusion rupture zone 100f melts and opens the superconducting electrical power supply line 100 during a step S4 subsequent to step S3 which only occurs in the event of failure or malfunction of the control circuit 10, in particular in the presence of a fault current in the superconducting electrical power supply line 100.

[0040] According to one embodiment, the control circuit 10 is configured so that the magnetic field B is zero when the first current ISCi is less than the first current threshold value and so that the magnetic field B is progressively increased with an increase in the current ISCi when the first current ISCi is greater than the first current threshold value.

[0041] [Fig.4] is a diagram illustrating an example of internal architecture of the controller device 104 of the control circuit 10 of a superconducting electrical power supply line, according to one embodiment.

[0042] According to the example of hardware architecture shown in [Fig. 4], the superconducting power supply line controller device 104 100 then comprises, connected by a communication bus 1040: a processor or CPU (“Central Processing Unit” in English) 1041; a RAM (“Random Access Memory” in English) 1042; a ROM (“Read Only Memory” in English) 1043; a storage unit such as a hard disk (or a storage media reader, such as an SD (“Secure Digital” in English) card reader) 1044; at least one interface module 1045 allowing the controller device 104 to interact with devices present in the control circuit 10, such as for example, the current sensor 102 and the coil 108. Advantageously, the interface module INTER 1065 includes in particular input-output ports, inputs of digital / analog converters and analog / digital converters, outputs controlled by pulse width modulation, and more generally all types of interfaces, including power, particularly useful for measuring a current in a superconducting electrical power supply line and for generating a current in a superconducting electrical coil. In particular, the INTER 1065 interface module of the controller device 104 is configured to operate in particular electric current monitoring and electric current generation functions.

[0043] The processor 1041 is capable of executing instructions loaded into the RAM 1042 from the ROM 1043, an external memory (not shown), a storage medium (such as an SD card), or a communications network. When the device 104 is powered on, the processor 1041 is capable of reading program code instructions from the RAM 1042 and executing them. These instructions form a computer program causing the processor 1041 to implement all or part of a method described in relation to [Fig. 3], or all or part of the described variants of this method.

[0044] All or part of the method described in relation to [Fig. 3], or its described variants may be implemented in software form by executing a set of instructions by a programmable machine, for example a DSP (Digital Signal Processor) 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 superconducting power line controller device 104 comprises electronic circuitry configured to implement the methods described in relation to the control circuit 10 or the controller device 104.Obviously, the superconducting power supply line 100 controller device 104 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, related input-output ports, interrupt inputs, bus drivers, this list being non-exhaustive.

[0045] [Fig. 5] illustrates an aircraft 1 advantageously comprising the control circuit 10 of a superconducting electrical power supply line as previously described, which circuit comprises the controller device 104. The use of such a system on board an aircraft comprising superconducting components makes it possible to offer an increased level of safety in the event of the occurrence of a fault in an on-board electrical distribution network. In addition, it is advantageously possible to adapt the first threshold value of the first ISCi current as a function of different flight phases of aircraft 1. For example, the first threshold value during takeoff of aircraft 1 may be higher than the first threshold value during a cruise or descent phase of aircraft 1.

Claims

Claims

1. Method for controlling a superconducting electrical power supply line (100), the method being executed in a control circuit (10) of said power supply line and comprising the steps: - i) obtaining (S1) information representative of a first electric current in said superconducting electrical power supply line, - ii) comparing said information representative of a first electric current in said superconducting electrical power supply line with a first predetermined threshold value, and, - iii) if (S2) said information representative of a first electric current is greater than or equal to the first predetermined threshold value, generating (S3) a current, called second current, in a superconducting coil arranged in the vicinity of said superconducting electrical power supply line and configured to emit a magnetic field,said superconducting power supply line being configured to receive said magnetic field, the value of said second current being determined from said information representative of said first current.,

2. A control method according to claim 1, further comprising a step of melting (S4) a calibrated rupture zone (100f) of said superconducting electrical power supply line (100) when said first electrical current has an intensity greater than a second predetermined threshold value for a predetermined time.

3. Control circuit (10) of a superconducting power supply line (100), the control circuit comprising electronic circuitry configured to: - i) obtain information representative of a first electric current in said superconducting power supply line, - ii) compare said information representative of a first electric current in said superconducting power supply line with a first predetermined threshold value completed, and for, - iii) if said information representative of a first electric current is greater than or equal to a predetermined threshold value, generating a second current in a superconducting coil arranged near said superconducting electrical power supply line and configured to emit a magnetic field, said superconducting electrical power supply line being configured to receive said magnetic field, the value of said second current being determined from said information representative of said first current.

4. A circuit for controlling a superconducting power supply line (100) according to claim 3 further comprising a calibrated rupture zone (100f) of said superconducting power supply line configured to melt when said first electric current is greater than a second predetermined threshold value for a predetermined time.

5. A system for controlling a superconducting power supply line comprising a control circuit (10) according to one of claims 3 and 4 and a superconducting coil (108) powered by said control circuit (10) and arranged in proximity to said superconducting power supply line (100).

6. Aircraft (1) comprising at least one control circuit (10) of a superconducting power supply line (100) according to one of claims 3 and 4 or a control system according to claim 5.

7. Computer program product comprising program code instructions for executing the steps of the method according to one of claims 1 to 2, when said program is executed by a processor (104) of a control circuit (10) of a superconducting electrical power supply line (100).

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

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