Trigger device and short circuit protection system

Abstract

One aspect of the invention relates to a triggering device (9) that is triggered when the current flowing into a conductor line (2) reaches a current threshold, the device comprising: - a magnetic armature (20) adapted to surround a portion of the conductor line (2) and a magnetic flap (21) movable between an open position and a closed position; - a holding mechanism (35) configured to deform when a force (Fmag) applied to the magnetic flap (21) reaches a force threshold; and - an electrical switch (12) that is turned on when the magnetic flap (21) is in the closed position.

Description

Technical Field

[0001] The technical field of this invention is short-circuit protection devices, particularly suitable for high DC voltage applications, such as protecting power supply lines in electrically propelled aircraft. Background Technology

[0002] Short circuits in an aircraft's electrical system can easily lead to serious accidents, which is why short circuit protection systems are crucial for ensuring passenger safety.

[0003] One known protection system includes a fuse sized for high-intensity short-circuit currents. More specifically, the fuse is sized to withstand high-intensity currents for a sufficiently long period. The fuse is designed such that when a current exceeding a threshold intensity that would cause the fuse to melt flows through it, the fuse disconnects the circuit by melting one or more of its elements.

[0004] However, fuses cannot control intermediate current levels. Furthermore, they cannot be tested during operation.

[0005] Patent application FR 3 129 027 discloses a protection system for achieving short-time circuit interruption (e.g., less than 5 milliseconds). The system includes, for example, a pyrotechnic actuator configured to apply a pulling force to a fuse to facilitate or accelerate its disconnection.

[0006] However, this actuator should be controlled by a triggering device. The latter may implement a probe remote from the main triggering circuit, thus introducing new failure modes. For example, a magnetic field induced by a high current flowing into the circuit may induce a current in the measured conductor line, leading to parasitic detection. Temperature and / or pressure variations within the aircraft may also affect the robustness of short-circuit detection.

[0007] Therefore, neither of the above two solutions can guarantee good protection against short circuits. Summary of the Invention

[0008] The present invention enables at least partial solutions to the above-mentioned problems.

[0009] Therefore, the present invention relates to a triggering device for triggering when the current flowing into a conductor line reaches a current threshold, the device comprising a magnetic circuit and an electrical switch.

[0010] The magnetic circuit includes:

[0011] - A magnetic armature, which extends between two ends referred to as "magnetic poles", is adapted to surround a portion of a conductor line, and has an opening between the two magnetic poles;

[0012] - A magnetic flap that is movable relative to the magnetic armature between the following positions:

[0013] - Open position, in which the magnetic flap is away from at least one of the two magnetic poles of the magnetic armature; and

[0014] - Closed position, in which the magnetic flap connects the two magnetic poles of the magnetic armature;

[0015] - A retaining mechanism for holding a magnetic flap in the open position, the retaining mechanism being configured to deform when a force is applied to the magnetic flap to close it, the retaining mechanism allowing the flap to move to the closed position when the force applied to the flap reaches a force threshold, wherein the force threshold is reached when a current threshold is reached.

[0016] The electric switch and magnetic flap are arranged to enable the switch to:

[0017] - Conductive when the magnetic flap is in the closed position; and

[0018] - Otherwise, open.

[0019] When an electric current flows into a conductor, it generates a magnetic field around the conductor. The magnetic circuit surrounding the conductor concentrates the magnetic lines of force within it. Applying magnetic force to a magnetic lever presses it against the poles of the magnetic armature and closes the magnetic circuit.

[0020] The magnetic force applied to the magnetic flap to close it is proportional to the magnetic field generated around the main conductor circuit, and therefore proportional to the current intensity flowing into the main conductor circuit.

[0021] The retaining mechanism allows setting a threshold force to be applied to close the magnetic circuit. Since the magnetic force is proportional to the current flowing into the main circuit, the retaining mechanism sets a current intensity threshold; once this threshold is exceeded, the current intensity is considered abnormal and requires triggering.

[0022] The closure of the magnetic circuit causes the electrical switch to close. This switch thus triggers, for example, an electrical disconnecting component.

[0023] The triggering device according to the invention offers several advantages in terms of detection and triggering reliability. For example, its simplicity reduces the risk of failure. In fact, the arrangement of the switch's flaps (which allows the switch to close when the magnetic flaps are closed) prevents malfunctions that electronic reading devices might experience. Furthermore, the reduced number of components also lowers the device's sensitivity to vibration.

[0024] The implementation of the magnetic circuit allows for current measurement without contact with the conductor line. Therefore, the device is unaffected by potential differences generated in the conductor line. Consequently, the device is compatible with conductor lines operating at low voltages (e.g., "0 volts") or high DC voltages (e.g., 800 DC V). The device can be used regardless of the current direction. Furthermore, it has no maximum permissible current limit. Therefore, the device will not degrade when extremely high current peaks flow into the dominant conductor line.

[0025] The dimensions of the magnetic circuit can also be adjusted to accommodate different current levels, making it compatible with extremely high DC currents that can reach up to 10,000 A. Furthermore, when the dimensions are designed to detect high currents, the device also has the advantage of being relatively insensitive to surrounding electromagnetic interference.

[0026] The moving inertia of flap 21 also prevents it from detecting excessively fast transient current peaks, such as those less than 1 ms. In fact, rapid current peaks can occur during normal operation of the electrical system without disconnecting the circuit.

[0027] The device is also insensitive to air pressure. Therefore, it can operate in a vacuum, in a hermetically sealed enclosure that maintains a constant air pressure, or in environments where air pressure may vary significantly (such as in aircraft).

[0028] It is important to note that, unlike fuses, the closing of a magnetic latch does not involve changes in current over time. Therefore, triggering can be completed in an extremely short time, such as less than 5 ms.

[0029] Advantageously, the electrical switch includes:

[0030] - The first blade fixed to the magnetic flap; and

[0031] - Second blade,

[0032] The first and second blades are arranged to be in contact when the magnetic flap is in the closed position.

[0033] Advantageously, the magnetic flap is fixed to one of the magnetic poles and is able to rotate around the magnetic pole.

[0034] Advantageously, the device includes a component for adjusting the force threshold of the retaining mechanism, which may be, for example, a screw.

[0035] Advantageously, the mechanism remains compatible with aerospace vibration environments. "Compatible with aerospace vibration environments" means that the mechanism is, for example, sized so that the magnetic flap does not close in the presence of vibration, for example, having an amplitude equal to 12 g (where... (This assumes that the current in the conductor circuit is below the current threshold.)

[0036] Advantageously, the retaining mechanism is a spring.

[0037] Advantageously, the magnetic armature is made of ferromagnetic or paramagnetic material; and the magnetic flap is made of ferromagnetic or paramagnetic material.

[0038] The present invention also relates to a short-circuit protection system, comprising:

[0039] - Conductor circuits;

[0040] - According to the triggering device of the present invention, the magnetic armature of the device surrounds the conductor circuit;

[0041] - A first cutting device connected in series with the conductor line;

[0042] - A pyrotechnic actuator connected to an electrical switch of a triggering device and configured to actuate a first cutting-off device when the electrical switch is turned on.

[0043] Advantageously, the retaining mechanism of the magnetic flap is adapted to be positioned between the magnetic flap and the conductor line, the retaining mechanism being adapted to abut against the magnetic flap on one side and against the magnetic armature or a base integrated with the conductor line on the other side.

[0044] Advantageously, the system includes an electrically insulating joint that surrounds the conductor line and separates the magnetic armature from the conductor line.

[0045] Advantageously, the first cutting device is an electromechanical switch.

[0046] Advantageously, the system includes a second cutting device connected in parallel with the first cutting device, and the pyrotechnic actuator is also configured to actuate the second cutting device when the electrical switch of the triggering device is turned on.

[0047] Advantageously, the second cutting device includes a fuse, and when the fuse is actuated by the pyrotechnic actuator, it involves pulling the fuse.

[0048] The present invention also relates to an aircraft propulsion device comprising a power supply line and a protection system according to the invention, wherein the main body line of the protection system is connected to the power supply line. Attached Figure Description

[0049] A better understanding of the invention and its various applications will be gained after reading the following text and viewing the accompanying drawings. The drawings are illustrative by way of indication and are in no way intended to limit the invention. Unless otherwise stated, the same elements appearing in different drawings have a single reference numeral.

[0050] Figure 1 A first embodiment of the short-circuit protection system according to the present invention is illustrated schematically.

[0051] Figure 2 A second embodiment of the short-circuit protection system according to the present invention is described.

[0052] Figure 3 , Figure 4 and Figure 5 An embodiment of the triggering device according to the present invention and the operating principle of the device are described.

[0053] Figure 6 A second embodiment of the short-circuit protection system according to the present invention is described.

[0054] Figure 7 Explanation Figure 2 The operating mode of the protection system. Detailed Implementation

[0055] Figure 1 A protection system 1 according to a first embodiment is illustrated schematically. System 1 is adapted to be connected to a power supply line and to cut off the current flowing into the line when system 1 detects a short circuit.

[0056] System 1 includes conductor line 2, also referred to as the "main conductor line," which is adapted to be connected to a power supply line. System 1 also includes a first branch 3 and a second branch 5 connected in parallel with each other. The two branches 3 and 5 are inserted into the main conductor line 2.

[0057] The first branch 3 includes a first disconnecting device 4. As indicated, the first disconnecting device 4 is an electromechanical disconnecting device. The second branch 5 includes a second disconnecting device 6. As indicated, the second disconnecting device 6 is a fuse. The current flowing into the main conductor line 2 then flows through the first branch 3 and the second branch 5. Advantageously, the impedance of the second branch 5 is higher than that of the first branch 3 to facilitate the flow of current through the first disconnecting device 4 into the first branch 3. The fuse 6 is thus protected.

[0058] The first cutting-off device 4 and the second cutting-off device 6 are configured to interrupt the flow of current in the first branch 3 and the second branch 5. They are initially in the on state. For example, the first cutting-off device 4 is closed. The second cutting-off device 6 remains unchanged. For example, the first cutting-off device 4 is actuated to open. The second cutting-off device 6 may melt under the influence of the current flowing into the second branch 5. Figure 1 In one embodiment, the second device 6 can also be actuated by pulling to facilitate and / or accelerate its disconnection.

[0059] System 1 also includes an actuator 10 configured to sequentially or simultaneously actuate the first cutting-off device 4 and the second cutting-off device 6. In one implementation, actuator 10 first actuates the first device 4, opening the first branch 3 and cutting off current flow in that branch 3. Opening the first branch 3 causes all current flowing into the main conductor line 2 to be concentrated only in the second branch 5. Therefore, the current flowing through the second branch 6 increases, causing the second cutting-off device 6 to melt. Actuator 10 actuates the second cutting-off device 6 by pulling. The pulling operation facilitates the disconnection of the second cutting-off device 6.

[0060] Document FR 3 129 027 describes in more detail the operation of the first branch 3, the second branch 5, and the first cutting device 4 and the second cutting device 6.

[0061] System 1 also includes a third branch 13, referred to as the "feedback circuit," which includes a third disconnecting device 14. As illustrated, the third disconnecting device 14 is an electromechanical device actuated by actuator 10. Advantageously, it is actuated simultaneously with the first disconnecting device 4. The feedback circuit 13 is independent of the main conductor line 2. It allows the state of the protection system 1 to be known. In fact, the action of actuator 10 opens the feedback circuit 13. Therefore, the opening of the latter 13 indicates that the first device 3 and the second device 5 have been actuated to open branches 3 and 5.

[0062] The actuator 10 can be electromechanical or pyrotechnic. The system 1 includes a trip device 12 for triggering the action of the actuator 10. Figure 1 A schematic embodiment of the triggering device 9 is illustrated. In this embodiment, the triggering device 9 includes a magnetic circuit 11 and an electrical switch 12.

[0063] Switch 12 can be in two states: open (referred to as "off") or closed (referred to as "on" or "conducting"). It is initially in the open state. Its state depends on the state of magnetic circuit 11 (discussed below). Switch 12 is connected to power supply 15 on one side and actuator 10 on the other. Closing switch 12 thereby triggers actuator 10.

[0064] Magnetic circuit 11 is configured to detect short circuits flowing into the dominant conductor line 2. This is based, in particular, on the measurement and comparison of the magnetic field generated by the conductor line 2. In fact, the magnetic field generated by the conductor line depends on the intensity of the current flowing into said line 2. The higher the current intensity, the stronger the magnetic field generated. Magnetic circuit 11 (which may also be referred to as a "magnetic clamp") can have two different states, which can be referred to as "open" and "closed". Initially in the open state, magnetic circuit 11 moves to the closed state when the magnetic field generated by the dominant conductor line 2 exceeds a threshold.

[0065] Magnetic circuit 11 and switch 12 are connected such that closing magnetic circuit 11 causes switch 12 to close. In other words, detecting a magnetic field exceeding a threshold triggers actuator 10, and thus cuts off the current in main circuit 2.

[0066] Figure 2 A second embodiment of the disconnection system 1 is illustrated. The figure shows a more detailed view of system 1, and particularly its triggering device 9. This system 1 will be integrated into the aircraft's electrical circuitry, more specifically, into a high-voltage direct current (HVDC) circuit. For example, it can be integrated into the aircraft's propulsion system. This device includes, for example, an HVDC transmission line supplying power from a turbine generator or battery to an electric motor. System 1 is connected in series with said transmission line to disconnect the current flowing to the electric motor in the event of a short circuit.

[0067] In this embodiment, system 1 includes a main line 2 extending parallel to the plane {X;Y}. It has two sections 25 and 26 forming an input terminal and an output terminal. System 1 also includes a first branch 3 inserted in series into the main line 2 and a second branch 5 inserted in series into the main line 3 and connected in parallel with the first branch 3.

[0068] The first branch 3 includes a first cutting device 4, which is an electromechanical cutting device. The second branch 5 includes a second cutting device 6, which is a pull-type actuated fuse.

[0069] More specifically, the first cutting device 4 includes a conductive member 27 and a flexible conductive clip 28. The conductive member 27 is connected to the main conductor line 2 and, in this embodiment, is located on one side of the output terminal 26. The conductive clip 28 is also connected to the main conductor line 2 and is located on one side of the input terminal 25. The conductive member 27 and the conductive clip 28 are arranged such that the conductive clip engages with the conductive member 27, thereby clamping the latter in the middle and forming electrical contact on both sides of the fixed member 27. The first cutting device 4 also includes insulating partitions 29 and 30, which are slidable parallel to the {X; Y} plane. They can be pushed to be inserted between the conductive member 27 and the conductive clip 28, thereby opening the jaws of the conductive clip 28. The insulating partitions 29 and 30 then break the electrical contact between the conductive member 27 and the conductive clip 28. The insertion of the insulating partitions 29 and 30 cuts off the current flow in the first branch 3.

[0070] The second cutting device 6 is a pull-type actuated fuse. For example, it includes a conductor line made of a fusible material, which is fixed between two anchor points. Each anchor point is connected to one of the input terminal 25 and the output terminal 26. The term "fusible material" refers to a material that can melt when it absorbs sufficient heat. A rod of fusible material extends parallel to the {X;Y} plane between the two anchor points. One of the anchor points can slide parallel to the {X;Y} plane to apply a pulling force to the fusible material rod.

[0071] The fusible material rod will break spontaneously only when an electric current flows through it and causes the fusible material to melt. Applying a tensile force to the fusible material rod promotes or even accelerates the breakage of the rod, provided that the rod has reached sufficient ductility when heated by the current passing through it. Even if the rod is not sufficiently heated, applying a tensile force to the rod forces it to break, thereby ensuring the severing of the second branch 5.

[0072] System 1 includes an actuator 10 for actuating the first cutting device and the second cutting devices 4, 6. Figure 2 In this embodiment, in particular, actuator 10 is a pyrotechnic actuator. It includes a cylinder 32, which includes a chamber and a piston 33. Detonating the gunpowder in the chamber pushes the piston 33 and actuates the first and second cutting devices 4, 6. In the illustrated example, the piston 33 transmits mechanical force to insulators 29, 30 via an arm 34 mounted on a pivot. The mechanical force generated by the piston 33 is also transmitted to the second cutting device via the rotating arm 34.

[0073] System 1 includes a device 9 for triggering the pyrotechnic actuator 10. The device 9 includes a magnetic circuit 11 and an electrical switch 12.

[0074] Magnetic circuit 11 is positioned near the input terminal 25 of protection system 1. It can also be positioned near the output terminal 26 of protection system 1. Magnetic circuit 11 includes a magnetic armature 20 and a magnetic flap 21. The magnetic armature 20 and magnetic flap 21 can be made of, for example, pure iron. It is anticipated that the magnetic lines of force generated by the main circuit 2 will be concentrated in the magnetic armature 20 and the magnetic flap 21. For this purpose, the magnetic armature 20 can be made of a ferromagnetic or paramagnetic material. The magnetic flap 21 can also be made of a ferromagnetic or paramagnetic material.

[0075] exist Figure 2 In this embodiment, the magnetic armature 20 partially surrounds the main line 2. Here, the armature 20 forms an open loop around the main line 2 (in other words, it forms a "C"). Specifically, the armature 20 extends between a first end 20a and a second end 20b, referred to as the "first magnetic pole and the second magnetic pole," and the first magnetic pole 20a and the second magnetic pole 20b are far apart from each other.

[0076] The magnetic flap 21 is a separate part from the armature 20. It is movably fixed to the second magnetic pole 20b so that it can rotate around the second magnetic pole 20b. The length of the flap allows it to be in a so-called "closed" position to reach the first magnetic pole 20a. Therefore, when the flap 21 is in its closed position, the magnetic circuit 11 is closed. The magnetic circuit 11 thus completely surrounds the main circuit 2.

[0077] When the flap is in the so-called "open" position, it is away from the first magnetic pole 20a. Therefore, when the flap 21 is in its open position, the magnetic circuit 11 is open. The magnetic circuit 11 no longer completely surrounds the main circuit 2.

[0078] The flap 21 is positioned in the {X; Y} plane relative to the rotation axis of the armature 20, specifically along the X direction, which is the direction along which a portion of the main line 2 around which the magnetic circuit 11 extends. In other words, the flap 21 moves in the transverse plane, i.e., Figure 2 {Y; Z} in the context of the universe.

[0079] For example, the second magnetic pole 20b of the armature 20 may have a hinge, and one end of the flap 21 is fitted into the hinge.

[0080] The armature 20 is preferably fixed relative to the conductor line 2. However, it can also be movable relative to the main line 2. Even more preferably, it can be movable in the transverse plane (i.e., Figure 2 The {X; Y}) in the circuit can be rotated or translated. Taking into account the rotation of the armature 20 and the flap 21, the magnetic circuit 11 can then have a movement similar to that of a clamp capable of clamping onto the conductor line 2.

[0081] Alternatively, the flap 21 can be mounted translationally relative to the armature 20. For example, it can move along the Z-axis. In the open position, the flap 21 will be away from the two magnetic poles 20a and 20b. In the closed position, the flap 21 will be pressed against the two magnetic poles 20a and 20b. The armature 20 can be fixed relative to the main line 2, or movable relative to the main line 2, and can also be translationally movable relative to the main line 2.

[0082] Magnetic circuit 11 also has a holding mechanism 35, which is not in Figure 2 The middle is indicated, but reference is made. Figure 3 , Figure 4 and Figure 5 The retaining mechanism 35 is used to resist the force applied to the flap 21 and intended to close the flap 21. The retaining mechanism 35 is configured to allow the flap 21 to close when the force applied to the flap 21 exceeds a threshold.

[0083] In this embodiment, system 1 includes a base 31, also referred to as a "support". Different components can be fixed to the base 31, thus becoming integral with the base 31. For example, conductor line 2 can be fixed to the base 31 while being electrically insulated from it. Magnetic armature 21 can also be fixed to the base 31.

[0084] The electrical switch 12 is arranged as follows:

[0085] - Closes when flap 21 is in the closed position; and

[0086] - Open when flap 21 is in the open position.

[0087] In this implementation, switch 12 specifically includes a first conductive blade 22 fixed to and moving with the flap 21. Switch 12 also includes a second conductive blade 23 fixed relative to the armature 20. Figure 2 In this example, since the armature 20 is fixed relative to the main line 2, the second blade 23 is also fixed relative to the main line 2. It can rest against the base 31. The first blade 22 can be connected to a power source (not shown) by means of a conductive blanket. The second blade 23 is connected to the actuator 10 so that the actuator 10 is triggered when current passes through it. When the flap 21 is in the closed position, the first and second blades contact each other 24, thereby triggering the actuator 10.

[0088] According to an alternative embodiment, the armature 20 and the flap 21 form a switch 12. For this purpose, when the flap 21 is in the open position, it is electrically insulated from the armature 20; when the flap 21 is in the closed position, it is electrically connected to the armature 20. According to one embodiment, the hinge formed in the second magnetic pole 20b about which the flap 21 rotates includes an electrically insulating layer. According to another embodiment, the flap 21 translates relative to the armature 20, moving away from the armature 20 in the open position, and is pressed against the magnetic poles 20a and 20b of the armature 20 in the closed position.

[0089] Therefore, the flap 21 can be connected to a power source by means of a conductive blanket, and the armature 20 can be connected to the actuator 10 so as to trigger the actuator 10 when current flows through the actuator 10 (when the flap 21 contacts the armature 20).

[0090] Figure 3 , Figure 4 and Figure 5 The magnetic circuit 11 and the main circuit 2 are schematically shown in cross-section, with the flap 21 in the open position. Figure 3 and Figure 4 ) and closed position ( Figure 5In these examples, the armature 20 partially surrounds the main line 2. A flap 21 is movably mounted to the armature 20. Specifically, it is rotatably movable about the second magnetic pole 20b of the armature 20.

[0091] Circuit 11 includes a retaining mechanism 35. This mechanism 35, for example, has elastic mechanical behavior and is characterized by a predetermined compressive force. For example, it can be a spring or a deformable body exhibiting said compressive force. The retaining mechanism 35 is configured to resist forces acting on the flap 21 and intended to close the flap 21 (in the context of "closed," it means moving the flap 21 to its closed position). For example, the force applied to the flap 21 is a magnetic force Fmag, which is intended to close the magnetic circuit 11 and originates from a magnetic field B flowing into the magnetic circuit 11.

[0092] In fact, the flow of current I in main circuit 2 induces a magnetic field B near main circuit 2. Magnetic field B is concentrated in the magnetic material of armature 20 and flap 21. When flap 21 is in the open position, a force Fmag is applied to flap 21 to close it. This force Fmag from the magnetic source aims to minimize the path of magnetic field lines B outside the magnetic material. Therefore, retaining mechanism 35 resists this magnetic force Fmag.

[0093] However, the retaining mechanism 35 is configured to allow the flap 21 to close when the magnetic force Fmag reaches a threshold. In the case of a spring, such as a prestressed spring, which resists the closing of the flap in a compressed state, the preload (e.g., from the placement of the spring) is sized such that when the magnetic force Fmag reaches the threshold, the spring allows the flap 21 to close.

[0094] Alternatively, the retaining mechanism 35 is a body capable of exhibiting plastic rather than elastic behavior. When the magnetic force reaches a threshold Fmag, it undergoes irreversible compression (or stretching) until it allows the flap 21 to close. Alternatively, the retaining mechanism 35 is a body that breaks when the magnetic force reaches the threshold, such as a capsule. Therefore, once the retaining mechanism 35 breaks, the closing of the flap 21 is no longer hindered. The advantage of irreversible deformation is that it keeps the magnetic circuit 11 in its closed state even if the current intensity in the main circuit 2 decreases. In contrast, a retaining mechanism exhibiting reversible deformation can return to its initial open position after the cutting devices 4 and 6 are opened.

[0095] The magnitude of the magnetic force Fmag applied to the flap 21 depends on the magnitude of the magnetic field flowing in the magnetic circuit 11. The higher this magnitude, the greater the force applied to the flap 21. The magnitude of the magnetic field in the magnetic circuit 11 is proportional to the magnitude of the current I flowing into the main circuit 2. Therefore, the threshold force Fmag applied to the flap 21 to close it defines the threshold of the current flowing into the main circuit 2. Thus, the retaining mechanism 35 allows for the definition of a maximum current that can flow through the main circuit 2, exceeding which the magnetic circuit 11 closes.

[0096] Figure 4 and Figure 5 The diagrams illustrate two scenarios: the current I flowing into the main circuit 2 is below and above the current threshold. The force threshold of spring 35 (e.g., corresponding to the preload) defines the threshold magnetic force applied to the flap, and thus directly defines the current threshold. When the current I flowing into the main circuit 2 is below the current threshold, the magnetic force Fmag applied to flap 21 is insufficient to close the flap ( Figure 4 However, as long as the amplitude of the current I exceeds the current threshold, the magnetic force will exceed the applied threshold force, thereby allowing the flap 21 to close. Figure 5 ).

[0097] Therefore, the magnetic circuit 11 and its holding mechanism 35 allow for the definition of a current threshold, exceeding which triggers the circuit. This enables the detection of short circuits in the main circuit 2.

[0098] Figure 4 and Figure 5 The diagram also shows a switch 12, particularly a switch 12 comprised of blades 22 and 23. These figures also show a conductive blanket 40 connected to the first blade 22 fixed to the flap 21 and capable of transmitting current to the switch 12. Figure 4 In the example, when the current I is too low to cause flap 21 to close, blades 22 and 23 remain separated. Conversely, in Figure 5 In the example, when the current I is high enough (e.g., short circuit), flap 21 closes and the two blades 22 and 23 of switch 12 contact, thereby triggering actuator 10 and thus cutting off the current in the two branches 3 and 5.

[0099] The magnetic force Fmag applied to the flap 21 depends on several parameters. In particular, it depends on the proximity of the magnetic circuit 11 to the main circuit 2. In fact, the magnetic field decreases by 1 / r, where r is the distance from the main circuit 2. The farther the armature 20 and the flap 21 are from the main circuit 2, the smaller the magnetic force applied to the flap 21. The magnetic force Fmag also depends on the materials of the armature 20 and the flap 21.

[0100] To correctly define the force threshold, and therefore the current threshold in the main circuit 2, the retaining mechanism 35 is preferably adjustable. "Adjustable" means that at least one parameter of the retaining mechanism can be adjusted to resist the magnetic force applied to the flap 21. For this purpose, the triggering device 9 includes an adjusting member 52. In the case where the retaining mechanism 35 is a spring, for example, the adjusting member 52 adjusts the initial opening of the flap (that is, the angle at which the flap is in its open position). The greater the opening of the flap 21, the greater the force applied to the flap 21 to close it. Therefore, increasing the initial opening of the flap 21 increases the threshold force applied to the flap 21 to close it, thereby increasing the current threshold to be reached for triggering the device 9 by the same amount. Alternatively, the adjusting member 52 can change the preload of the spring (thus changing the compressive force applied to resist the closing of the flap). For example, the adjusting member 52 can be a screw that preloads the spring, thereby increasing or decreasing the preload.

[0101] Figure 6 An embodiment of system 1, and particularly of triggering device 9 inserted into protection system 1, is shown. In this embodiment, system 1 includes a connector 50 surrounding the main line 2. The connector 50 isolates the main line 2 from the magnetic circuit. Here it is an electrically insulating connector 50 for protecting the magnetic circuit 11 and / or switch 12 from direct electrical contact with the main line 2. Such electrical contact could trigger parasitic triggering of actuator 10.

[0102] In this embodiment, the retaining mechanism 35 of the magnetic circuit is a spring. It is positioned between the magnetic flap 21 and the main circuit 2 to act in compression to resist the closing of the flap 21. On the one hand, it abuts against the main circuit 2, and especially against the insulating joint 50 surrounding it; on the other hand, it abuts against the flap 21.

[0103] Furthermore, in this embodiment, the retaining mechanism 35 includes a ring 51 for holding the spring 35 in a fixed position and preventing it from shifting or falling off. Therefore, the spring 35 can operate freely until the flap 21 is closed. The ring 51 can abut against the magnetic armature 20 or the base 31. It can also abut against the connector 50.

[0104] In another embodiment, the retaining mechanism 35 may be an insulating elastomer, such as an elastomer. In this case, the retaining mechanism 35 no longer requires the use of an insulating joint 50 to ensure good insulation between the flap 21 and the line 2.

[0105] exist Figure 6 In this device 9, a component 52 is included for adjusting the retaining mechanism 30. Component 52 is a screw against which the flap 21 stops when it is in the open position. The screw 52 allows adjustment of the initial opening degree of the flap 21.

[0106] Figure 7 Explained as follows Figure 2 The operating mode of protection system 1 is described herein. System 1 operates at a voltage of 800 V. The current threshold is 4000 A; exceeding this current threshold, system 1 is expected to interrupt the current. System 1 can preferably be operated at an atmospheric pressure of 572 mbar. Assuming an air temperature of 0°C, this pressure is equivalent to an altitude of 15,000 feet, or 4,572 meters.

[0107] Figure 7 Several curves 80, 81, 82, 83, and 84 are illustrated as functions of the common time axis 70. More specifically, these curves represent:

[0108] - The supply voltage applied to system 1 is 80;

[0109] - Current 81 flowing in main line 2;

[0110] - The voltage 82 through the first branch 3, and in particular the voltage 82 through the first disconnecting device 4;

[0111] - The current 83 flowing into the second branch 5, especially the current 83 flowing through the fuse 6;

[0112] - Current 84 flows into the pyrotechnic actuator 10.

[0113] The duration under consideration is approximately 13 ms.

[0114] At the first moment 71, the current 81 flowing into the main line 2 reaches the current threshold of 4000 A. The current 81 induces a magnetic field around the main line 2.

[0115] At the second time 72, the electrical switch 12 closes, allowing current 84 to flow through the actuator 10. The time interval between the first time 71 and the second time 72 corresponds to the time required to detect the short circuit 81 in the main line 2. This time interval takes into account the duration for the flap 21 to move from its open position to its closed position. This time interval 72–71 may last approximately 1.5 ms.

[0116] At the third moment 73, the electromechanical disconnect device 4 begins to move to cut off the flow of current 81 in the first branch 3. The time interval between the second moment 72 and the third moment 73 takes into account the triggering of the pyrotechnic actuator 10. This time interval 73–72 may last for approximately 0.5 ms. After the electromechanical disconnect device 4 is fully open, the current 81 flowing into the main line 2 flows entirely into the second branch 5, and more specifically into the fuse 6.

[0117] At the fourth time 74, the current 83 flowing through the fuse is interrupted due to the fuse 6 blowing and / or by pulling the electric cutting device 4. The time interval between the third time 73 and the fourth time 74 may last less than 1 ms.

[0118] At the fifth moment 75, the flow of current 81 in the first branch 3 and / or the second branch 5 ceases. The system has been switched to a closed state to prevent short-circuit current from flowing through the power supply lines.

[0119] The time interval (referred to as the "cut-off time") between the occurrence of a short circuit on the main line (first moment 71) and the final disconnection of System 1 (fifth moment 75) may last less than 3 ms.

[0120] to and Figure 2 Two tests performed on a system similar to System 1 showed that the first cutoff time was 3.327 ms and the second cutoff time was 2.979 ms. Therefore, System 1 according to the invention enables a cutoff to be performed in less than 5 ms.

Claims

1. A triggering device (9) for triggering when the current flowing into a conductor line (2) reaches a current threshold, the device comprising a magnetic circuit (11) and an electrical switch (12), the magnetic circuit (11) comprising: - A magnetic armature (20) extending between two ends (20a, 20b) referred to as "magnetic poles", the magnetic armature (20) being adapted to surround a portion of a conductor line (2), and the magnetic armature (20) having an opening between the two magnetic poles (20a, 20b); - Magnetic flap (21), which is movable relative to the magnetic armature (20) between the following positions: - In the open position, the magnetic flap (21) is away from at least one of the two magnetic poles (20a, 20b) of the magnetic armature (20); as well as - In the closed position, the magnetic flap (21) connects the two magnetic poles (20a, 20b) of the magnetic armature (20). - A mechanism (35) for holding the magnetic flap (21) in the open position, the holding mechanism (35) being configured to deform when a force (Fmag) is applied to the magnetic flap (21) to close the magnetic flap (21), the holding mechanism (35) allowing the flap to move to the closed position when the force applied to the flap reaches a force threshold, wherein the force threshold is reached when a current threshold is reached. An electric switch (12) and a magnetic flap (21) are arranged such that the switch (12): - Conductive when the magnetic flap (21) is in the closed position; and - Otherwise, open.

2. The device (9) according to the preceding claim, wherein the electric switch (12) comprises: - The first blade (22) is fixed to the magnetic flap (21); as well as - Second leaflet (23). The first and second blades (22, 23) are arranged to be in contact when the magnetic flap (21) is in the closed position.

3. The device (9) according to any one of the preceding claims, wherein the magnetic plate (21) is fixed to one of the magnetic poles (20a, 20b) and can rotate around the magnetic pole (20a, 20b).

4. The device (9) according to any one of the preceding claims includes a member (52) for adjusting the force threshold of the holding mechanism (35).

5. The device (9) according to any one of the preceding claims, wherein the holding mechanism (35) is a spring.

6. The device (9) according to any one of the preceding claims, wherein the magnetic armature (20) is made of ferromagnetic or paramagnetic material; and wherein the magnetic flap (21) is made of ferromagnetic or paramagnetic material.

7. A short-circuit protection system (1), comprising: - Conductor circuit (2); - According to any one of the preceding claims, the triggering device (9) has a magnetic armature (20) surrounding the conductor line (2). - A first cutting device (4) connected in series with the conductor line (2); - A pyrotechnic actuator (10) is connected to an electrical switch (12) of a triggering device (9) and is configured to actuate a first cutting device (4) when the electrical switch (12) is turned on.

8. The system (1) according to the preceding claim, wherein the holding mechanism (35) of the magnetic flap (21) is adapted to be disposed between the magnetic flap (21) and the conductor line (2), the holding mechanism (35) being adapted to abut against the magnetic flap (21) on one side and against the magnetic armature (20) or the base (31) integral with the conductor line (2) on the other side.

9. The system (1) according to any one of the preceding two claims, wherein the first cutting device (4) is an electromechanical switch.

10. The system (1) according to any one of the preceding three claims includes a second cutting device (6) connected in parallel with the first cutting device (4), and the pyrotechnic actuator (10) is further configured to actuate the second cutting device (6) when the electrical switch (12) of the triggering device (9) is turned on.

11. The system according to the preceding claims, wherein the second cutting device (6) includes a fuse, and wherein actuation by the pyrotechnic actuator (10) is pulling the fuse.

12. A propulsion device for an aircraft, comprising a power supply line and a protection system according to any one of the preceding five claims, wherein a main body line of the protection system is connected to the power supply line.

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