ELECTRICAL DEVICES AND PROTECTION SYSTEMS

Description

TECHNICAL FIELD

[0001] The present invention relates to the technical field of electrical protection devices and systems, such as circuit breakers. STATE OF PRIOR ART

[0002] Many electromechanical electrical switching devices, such as air circuit breakers, and particularly miniature circuit breakers (MCBs), typically include an arc chute. The arc chute is configured to extinguish an electric arc that appears in the air between the device's electrical contacts when the electrical contacts are separated following a tripping of the device.

[0003] The arc chute typically consists of a stack of metal plates stacked on top of each other to extend and extinguish the electric arc. One or more holes in the casing allow the arc gases to be vented outside the device.

[0004] However, in order to improve the performance of these protection devices, it has been proposed to replace the breaking chamber with an electronic breaking device comprising power switches based on semiconductor components.

[0005] Such improved performance is, for example, advantageous in direct current (DC) electrical systems comprising electrochemical storage batteries, for which the electrical protection devices must be capable, in the event of an electrical fault occurring, of interrupting high-intensity currents with a very rapid reaction time.

[0006] These semiconductor protective devices must be able to interrupt the electric current with at least as much reliability as electromechanical protective devices.

[0007] Furthermore, for safety reasons, these protective devices must be galvanically isolated. It is therefore advantageous to maintain separable electrical contacts that ensure electrical isolation in the air ("air gap" in English) when the device is in the open state (i.e., when the electrical contacts are separated, for example following a tripping of the device, or when a user wishes to lock out the installation located downstream of the protective device).

[0008] Furthermore, for the sake of compatibility with existing installations, it is desirable that these protection devices can be contained in a housing having the same size as the housings of the electromechanical type switching devices.

[0009] There is therefore a need for electrical protection devices, such as circuit breakers, based on semiconductor components, which at least partially overcome these drawbacks.

[0010] Document EP 2 234 136 A1 discloses an electrical protection system according to the preamble of claim 1. STATEMENT OF THE INVENTION

[0011] For this purpose, one aspect of the invention relates to an electrical protection system, comprising connection terminals, separable electrical contacts connected between the connection terminals, a switching mechanism and at least one power switch connected in series with the separable electrical contacts, the separable electrical contacts being movable between an open state and a closed state, the switching mechanism comprising a movable control lever and being coupled with the separable electrical contacts to switch the separable electrical contacts to the open state, the electrical protection system further comprising an electronic control circuit coupled with said at least one power switch.

[0012] The electrical protection system further comprises a sensor coupled to the control lever configured to measure a position of the switching mechanism, and the electronic control circuit is configured to switch the at least one power switch to a blocking state when the sensor detects that the switching mechanism reaches a position preceding a position from which the electrical contacts separate.

[0013] In addition, the relative movement of the parts of the switching mechanism is configured to cause an angular offset to occur between the rotation of the control lever and the actual opening of the separable electrical contacts and in that the angular offset makes it possible to compensate for a reduction in the play when pushing in the separable electrical contacts caused by the gradual wear of the separable electrical contacts.

[0014] Thanks to the invention, during the opening phase the control circuit and the sensor make it possible to control the switching of the power switches to their blocking state before the electrical contacts are separated, which prevents the occurrence of an electric arc and thus makes it possible to interrupt the current safely. On the other hand, once the contacts are in the open position, the electrical contacts make it possible to create an electrical insulation in the air ("air gap"). This prevents an electric current, such as a leakage current from the power switches, or a current resulting from a failure of these power switches, from being able to flow again between the terminals after the device has been triggered.

[0015] According to advantageous but not mandatory aspects, such an electrical protection device may incorporate one or more of the following characteristics, taken in isolation or in any technically admissible combination: the separable electrical contacts comprise a fixed electrical contact) and a movable electrical contact movable relative to the fixed electrical contact, the switching mechanism (both coupled to the movable electrical contact; the control lever is a rotating part mounted for rotation about an axis of rotation;and the switching mechanism comprises: ∘ a transmission rod, ∘ a trigger hook, mounted in rotation and coupled to the rotating part via the transmission rod, ∘ a plate, mounted in rotation about an axis of rotation and coupled to the trigger hook, ∘ a trigger bar coupled to the plate and to the trigger hook, ∘ a contact carrier, which carries the movable electrical contact and which cooperates with the fixed electrical contact, the contact carrier being mounted in rotation about an axis of rotation, and ∘ stops which limit the rotational movement of the rotating part. the electrical protection system is configured to be housed in a housing;the rotation axes of the rotating part, the plate and the contact holder are parallel to each other and are configured to be integral with the housing. the sensor is an optical sensor, a mechanical sensor or an inductive sensor with external field compensation. the electronic control circuit is configured to switch said at least one power switch to the blocking state when an electrical fault is detected by a measuring circuit; the electrical protection system comprises an internal power supply configured to electrically power the electrical control circuit from the electrical voltage between the connection terminals; said at least one power switch is a MOSFET transistor; said at least one power switch is normally in the open state; the sensor is an optical sensor configured to measure the position of the control member of the switching mechanism;the electronic control circuit comprises a plate-shaped substrate and a conductive plate in contact with a metal sole of said at least one corresponding power switch, said at least one power switch and its respective conductive plate being mounted on one or each face of the substrate; at least one of the conductive plates comprises a portion adapted to form a fixed electrical contact which cooperates with the movable electrical contact to form together said separable electrical contacts.; the switching mechanism is a toggle mechanism;the electrical protection system is configured such that to close the separable electrical contacts, the control lever is intended to be moved to the corresponding position by a user, this movement, by means of a connecting rod of the switching mechanism, causing the rotation of a hook of the switching mechanism, the hook coming to hook onto a trigger bar of the switching mechanism, the connecting rod then rotating a plate of the switching mechanism until the closing of the separable electrical contacts; the electronic control circuit is configured to switch said at least one power switch to a blocking state when the sensor detects that the switching mechanism reaches a position immediately preceding a position from which the electrical contacts separate. ;

[0016] According to another aspect, the invention relates to an electrical protection apparatus comprising a housing and the electrical protection system as previously defined, in which the electrical protection apparatus is a miniature circuit breaker.

[0017] According to another aspect, the electronic control circuit and said at least one power switch are housed in a dedicated compartment inside the housing.

[0018] In another aspect, the width of the case is a multiple of 9mm.

[0019] In another aspect, the electrical protection device is an air-break circuit breaker. BRIEF DESCRIPTION OF THE FIGURES

[0020] The invention will be better understood and other advantages thereof will appear more clearly in the light of the following description of an embodiment of an electrical protection system given solely by way of example and with reference to the appended drawings, in which: there figure 1 is a schematic representation, in a sectional view, of an electrical protection device according to embodiments of the invention; figure 2 is a functional diagram of the electrical protection device of the figure 1 , in the case of a bipolar device; the figure 3 is a schematic representation of a first step of a sequence of movements of a switching mechanism of the electrical protection device of the figure 1 when the device is switched to an open state; the figure 4 is a schematic representation of a second step of a sequence of movements of a switching mechanism of the electrical protection device of the figure 1 when the device is switched to an open state; the figure 5 is a schematic representation of a third step of a sequence of movements of a switching mechanism of the electrical protection device of the figure 1 when the device is switched to an open state; the figure 6 is a graph representing the evolution over time of the angular position of a control lever associated with the switching mechanism of the figures 3 à 5 when switching the device to an open state; figure 7 is a schematic representation, according to a perspective view (insert A) and an exploded view (insert B) of a particular embodiment of a part of the protection apparatus of the figure 1 . there figure 8 is a functional diagram of the electrical protection device of the figure 1 according to a first variant in which the device is a single-phase device; the figure 9 is a functional diagram of the electrical protection device of the figure 1 according to a second variant in which the device is a three-phase device; the figure 10 is a functional diagram of the electrical protection device of the figure 1 according to a third variant in which the device is a three-phase device with a neutral line; the figure 11 is a functional diagram of the electrical protection device of the figure 1 according to a fourth variant in which the device is a four-pole device. DETAILED DESCRIPTION OF CERTAIN EMBODIMENTS

[0021] THE figures 1 And 2schematically represent an electrical protection system and apparatus 2 in accordance with embodiments of the invention.

[0022] In many embodiments, the electrical protection apparatus 2 is a circuit breaker.

[0023] Preferably, device 2 is a miniature circuit breaker.

[0024] The device 2 comprises a housing 4 inside which at least some of the components of the device 2 are housed.

[0025] For example, device 2 is an air break circuit breaker.

[0026] The housing 4 is preferably made of a rigid and electrically insulating material, such as a thermoformed polymer, for example polyamide PA 6.6, or any other suitable material.

[0027] For example, case 4 is a molded plastic case.

[0028] Preferably, the dimensions of the housing 4, and in particular the width of the housing or the form factor of the housing 4, are compatible with the dimensions of the housings of existing protection devices 4.

[0029] In a non-limiting example of implementation given for illustrative purposes, the width of the housing is preferably a multiple of 9mm, for example equal to 9mm, or to 18mm, or to 27mm.

[0030] It is understood that, in this example, the components of the electrical protection system are housed in the same housing 4. However, in certain variants, certain components could be housed in different housings. What is described here with reference to the device 2 is therefore generalizable to an electrical protection system 2 which can be dissociated from the housing 4.

[0031] The apparatus 2 also comprises connection terminals 6 and 8, separable electrical contacts 10 connected between the connection terminals 6 and 8 and a switching mechanism 12 comprising a control member 14 (also called control handle or control lever in the following, according to the invention). The control lever 14 is for example a pivoting lever accessible from outside the housing 4 and intended to be manipulated by a user.

[0032] For example, the contacts 10 may be formed by combining a fixed electrical contact and a movable electrical contact movable relative to the fixed contact, the switching mechanism 12 being coupled to the movable mechanical contact.

[0033] In practice, each electrical contact 10 may comprise a plurality of electrical contact fingers, although other implementations are possible as variants.

[0034] The separable electrical contacts are movable between an open state and a closed state. In the open state, the contacts 10 are separated from each other by a volume of ambient air acting as an electrical insulator, which prevents the flow of an electric current.

[0035] In the example of the figure 2 , the device 2 comprises two pairs of connection terminals 6,8: a first input terminal 6 connected to a first output terminal 8 via a first connection line, and a second input terminal 6 connected to a second output terminal 8 via a second connection line.

[0036] This example, given for illustrative purposes, corresponds to the case of a bipolar device (with two electrical poles, or two electrical phases). Other examples are however possible.

[0037] In many embodiments, the switching mechanism 12 is configured to move the electrical contacts 10 to an open state in response to a switching command. The switching command may be sent by a trigger or result from a user action on the control lever 14.

[0038] For example, the switching mechanism 12 is a toggle mechanism, such as a switching mechanism analogous or similar to the switching mechanism described in patents EP 2975628 B1 or EP 1542253 B1.

[0039] The device 2 also comprises an electronic cut-off module 16 which is configured to interrupt an electric current between the connection terminals 6 and 8. The electronic cut-off module 16 is here based on solid-state cut-off components, in particular semiconductor components, such as power transistors. In this, the device 2 differs from electromechanical air-break protection devices which comprise an arc extinguishing chamber (arc extinguishing chamber).

[0040] Preferably, the electronic cut-off module 16 is received in a dedicated housing of the housing 4. Even more preferably, when the housing 4 is of the same type (or even identical) as the housings of the electromechanical protection devices, said housing corresponds to the space normally occupied by the cut-off chamber as well as by means for detecting an electrical fault (of the so-called thermal and magnetic type), such as a bimetallic strip and a coil.

[0041] This allows the architecture of existing circuit breakers to be preserved and ensures compatibility with existing installations.

[0042] The device 2 thus comprises at least one power switch 22 connected in series with the separable electrical contacts 10.

[0043] In the illustrated example, which corresponds to the illustrative case of a bipolar device, the device 2 comprises four power switches 22, identified here by the references T1, T2, T3 and T4.

[0044] For example, the first connection line comprises two power switches T1 and T2 connected in series with the separable contact between the first terminals 6 and 8. Similarly, the second connection line comprises two power switches T3 and T4 connected in series with the second separable contact 10 between the second terminals 6 and 8. For example, each of said first and second connection lines corresponds to an electrical phase.

[0045] In practice, the number of power switches can be different, depending on the topology of the device and in particular the number of poles (single-phase, polyphase, with or without neutral line) but also depending on the current rating of the device.

[0046] Each power switch can, in practice, be implemented by several components (such as transistors) connected in parallel depending on the rating of the circuit breaker that one wants to create.

[0047] For example, in apparatus 2, which for illustrative and non-limiting purposes has a rating of sixteen amperes, two pairs of transistors connected in series are used, the transistors of each pair of transistors being connected in parallel. In a variant having a higher rating, for example thirty-two amperes, it is possible to use a greater number of transistors connected in parallel.

[0048] Each power switch 22 is switchable between an electrically blocking state and an electronically conducting state.

[0049] For example, power switches 22 are power transistors.

[0050] According to a preferred embodiment, the power switches 22 are MOSFET transistors (“Metal Oxide Semiconductor Field Effect Transistor”).

[0051] This type of transistor is preferred because it has low on-resistance, but also because it remains in the off-resistance state when at rest (e.g. when no control signal is sent to the control electrode).

[0052] However, other semiconductor technologies can be considered depending on the circuit breaker rating, such as insulated gate bipolar transistors (IGBTs), or thyristors, or integrated gate switching thyristors (IGCTs), or many other technologies.

[0053] Alternatively, the power switches 22 may be JFETs (Junction Field Effect Transistors). In this case, the operation of the control circuit 24 may have to be modified, to take into account the fact that such JFETs are in the on state when they are at rest.

[0054] In practice, a diode is present in parallel with each of the power switches 22, as illustrated in the figure 2 , although other embodiments are possible as alternatives. Typically, this is a parasitic diode inherent in the construction of the power switch.

[0055] The electrical protection device further comprises an electronic control circuit 24 coupled with said at least one power switch 22 (i.e., with each power switch 22). In other words, the electronic control circuit 24 makes it possible to control each of the power switches 22.

[0056] In many embodiments, the electronic control circuit 24 includes a processor, such as a programmable microcontroller or a microprocessor.

[0057] The processor is advantageously coupled to a computer memory, or to any computer-readable data recording medium, which comprises executable instructions and / or software code intended to implement a method for detecting an electrical fault when these instructions are executed by the processor.

[0058] In particular, this process makes it possible to detect an electrical fault such as an overload current fault, a short-circuit fault, a differential current fault, a series (or differential) arc presence fault on the line to be protected, but also overvoltages or undervoltages.

[0059] According to variants not described in detail, the electronic control circuit 24 may comprise a signal processing processor (DSP), or a reprogrammable logic component (FPGA), or a specialized integrated circuit (ASIC), or any equivalent element, or any combination of these elements.

[0060] Advantageously, the device 2 may comprise one or more protection elements 26 against overvoltages, connected in parallel with the power switch(es) 22, in order to protect the power switches 22 against overvoltages, in particular in the event of the appearance of an electric arc when the contacts 10 are separated.

[0061] This makes it possible in particular to protect voltage switches during cut-off in cases where the installation includes inductive circuits.

[0062] For example, the protection elements 26 are clippers or varistors (MOV, for “Metal Oxide Varistor” in English) or Transil diodes (TVS, for “Transient Voltage Suppression” in English).

[0063] In many embodiments, the apparatus 2 comprises an internal power supply unit 28 configured to electrically power the control electrical circuit, preferably from the electrical current flowing between the connection terminals 6, 8 when the apparatus 2 is in operation.

[0064] Alternatively, the internal power supply 28 may comprise a battery, or any other means allowing an autonomous power supply.

[0065] For example, the electronic control circuit 24 is configured to switch the power switches 22 to an open state when an electrical fault is detected by a measuring circuit 30. For example, the device 2 comprises current sensors 30, here coupled to each connection line.

[0066] For example, electrical faults can be overcurrents or short circuits, but also other electrical faults such as a differential current fault, or a series (or differential) arc presence fault on the line to be protected, or even overvoltages or undervoltages.

[0067] The switching of the device 2 upon tripping (i.e., following the detection of an electrical fault requiring the immediate interruption of the electric current) can be achieved by the combined action of the switching mechanism 12 with the power switches 22.

[0068] Furthermore, according to embodiments, the device 2 also comprises a synchronization system 32 aimed at synchronizing the switching of the power switches 22 with the opening of the contacts 10, in order to avoid the appearance of electric arcs when the electrical contacts 10 open.

[0069] For this purpose, the device 2 comprises a sensor 34 configured to measure a position of the switching mechanism 12. Preferably, the sensor is configured to measure the position of the control lever 14 of the switching mechanism 12, or of a part integral with the control lever 14.

[0070] For example, the sensor 34 is connected to an input of the electronic control circuit 24 so as to send a measurement signal. The sensor 34 can be placed opposite a part of the switching mechanism 12 (for example opposite the mechanical part carrying the control lever 14). In other words, the sensor 34 can be coupled to the control lever 14.

[0071] According to a non-limiting example of implementation given by way of illustration, the sensor 34 can be configured to emit a binary signal, taking a first value when the switching mechanism 12 is in a position in which the electrical contacts 10 are closed, and taking a second value (different from the first value) when the switching mechanism is in a position preceding the position from which the electrical contacts 10 begin to separate (when the opening movement of the lever continues).

[0072] For example, this position may correspond to a specific angular position threshold of the control lever 14.

[0073] For illustration, the position threshold may correspond to an angle of 20° relative to the original position of the control lever 14. The angle may be chosen differently as a variant. In practice, the angle is preferably less than or equal to 20°, or 10°, or 5°.

[0074] Preferably, the sensor 34 is an optical sensor.

[0075] According to embodiments, the sensor 34 is an obstruction optical sensor, for example arranged such that the light signal received by a sensitive element of the sensor 34 is obstructed when the control lever 14 reaches a certain position, for example when the control lever 14 has started to move relative to the closed position.

[0076] For example, using an optical sensor makes it easier to put the electrical installation into safety mode in the event of a fault. If a fault occurs in the optical emitting element, the optical receiver or the electronic receiving circuit, the on-board control system automatically detects a fault (in this case, a lack of light output) and puts the product in the safety position as if the lever had been lowered. This is not necessarily the case with other technologies. For example, if a microswitch is faulty (stuck in the rest position) we will never know that there is a problem. Compared to a magnetic type sensor (Hall effect or Reed relay), an optical sensor has good immunity to the magnetic field created by the passage of current in the poles of the product or adjacent products.Compared to a mechanical sensor (such as a microswitch), an optical sensor has better robustness (number of possible operations). Compared to a proximity sensor (for example, a capacitive sensor), an optical sensor has better immunity to the electric field that can be created by the presence of transient overvoltages in the poles of the product or adjacent products.

[0077] Alternatively, the sensor 34 can be made differently and can thus be a mechanical sensor, or an inductive sensor with external field compensation.

[0078] In many embodiments, the sensor 34 is housed in the same housing as the switching mechanism 12 and the actuator 14. However, alternatively, the sensor 34 may be housed in one housing and the actuator 14, as well as at least a portion of the switching mechanism 12, are housed in another housing.

[0079] In particular, for devices with multiple poles (e.g., a three-phase circuit breaker or a two-pole DC circuit breaker), the control devices (control levers) for each pole are mechanically interconnected. In this system, it may be advantageous to use a single sensor for the entire protection device, rather than using a sensor for each pole. This single sensor can then be moved to another housing.

[0080] As will be explained in more detail with reference to the figures 2 à 6 , the electronic control circuit 24 is configured to switch the power switch(es) 22 to the blocking state when the sensor 34 detects that the switching mechanism moves to the open position, and more particularly before the electrical contacts 10 separate.

[0081] In optional but nevertheless advantageous embodiments, the apparatus 2 may comprise an auxiliary sensor (not shown), configured to measure a position of the switching mechanism, the auxiliary sensor being configured to operate in conjunction with the optical sensor 34. This arrangement is particularly applicable to large circuit breakers, in order to improve the reliability of the detection of the position of the switching mechanism 12. This auxiliary sensor may however be omitted.

[0082] Optionally, the synchronization device 32 may comprise an actuator 36 configured to set the switching mechanism 12 in motion. The actuator 36 comprises, for example, an electric motor, or an electromagnetic actuator comprising a movable mechanical part that can be moved under the action of an electromagnetic actuator. For example, the actuator 36 is controlled by the electronic control circuit 24 and can thus control the opening of the electrical contacts 10 via the mechanism 12.

[0083] In optional embodiments, an external trigger outside the electronic control circuit 24 can be connected to an input of the electronic control circuit 24 in order to transmit a triggering order and thus cause triggering of the device 2 via the electronic control circuit 24.

[0084] The trigger order issued by the external trigger can be transmitted electronically, by a wired connection or by a radio frequency signal.

[0085] In other embodiments, the external trigger may be mechanically coupled to the switching mechanism 12 or to the control electronics 12 (e.g., via an electromechanical sensor).

[0086] In some implementations, an auxiliary power supply 38 may be used to provide power to the control electronics 24.

[0087] For example, an auxiliary power supply 38 external to the apparatus 2 is connected to terminals A1, A2 of the apparatus 2, said terminals being connected to an electrical distribution circuit (such as a power rail).

[0088] An example of operation of the switching mechanism 12 and the synchronization system 32 is now described with reference to figures 3 à 5 .

[0089] THE figures 3 , 4 And 5 schematically represent a simplified version 50 of the switching mechanism 12 in different successive configurations over time. More precisely, the figure 3 corresponds to the closed state of the switching mechanism 12, in which the electrical contacts 10 are in contact (in the closed state) and allow the flow of a current. figure 5 corresponds to an open state of the switching mechanism 12, in which the electrical contacts 10 are separated from each other. The figure 4 corresponds to an intermediate state during a transition from the closed state to the open state.

[0090] As illustrated on the figure 3 , the switching mechanism 12 comprises: the control lever 14, which has the form of a rotating part 52 mounted in rotation around an axis of rotation integral with the housing 4 (the hatched areas visible on the figure 3 , one of which bears the reference 51, represent anchoring points which are stationary relative to the housing 4); a transmission rod 54, or connecting rod; a trigger hook 56, mounted in rotation and coupled to the part 52 via the transmission rod 54; a plate 53, mounted in rotation about an axis of rotation integral with the housing 4 and coupled to the hook 56; a trigger bar 58, coupled to the plate 53 and to the hook 56; a contact holder 60, which carries the movable electrical contact 10 and which cooperates with the fixed electrical contact 61, the contact holder being mounted in rotation about an axis of rotation integral with the housing 4; stops 62 which limit the rotational movement of the control lever 52, for example respectively in the open and closed positions.

[0091] The axes of rotation are here arranged parallel, for example by all being arranged perpendicular to a side wall of the housing 4.

[0092] During the triggering phase, the trigger bar 58 is rotated, which releases the hook 56 and rotates the plate 53 and the contact holder 60 towards the open position. In parallel, the movement of the plate triggers a rotational movement of the part 52 via the transmission rod 54.

[0093] In the illustrated example, the sensor 34 is arranged such that, in the open state, at least a portion of the part 52 is placed in front of the sensor 34, so as, for example, to mask at least one sensitive portion of the sensor 34. On the contrary, in the closed state, the part 52 remains distant from the sensor 34 and does not mask the sensitive portion of the sensor 34. The position from which the sensitive portion of the sensor 34 is masked by the part 52 may correspond to an angular position threshold. When the part 52 passes in front of the sensor, the sensor 34 changes state and then sends a different measurement signal.

[0094] With the configuration retained in the illustrated example, the angular position threshold is reached at the latest just before the electrical contacts 10 begin to separate, as illustrated in the figure 4 and on the figure 6 .

[0095] On the figure 6 , the chronogram 70 represents the evolution, as a function of time (noted “t”, on the abscissa axis): of the position of the switching mechanism 12, represented here by the angular position of the control lever 14 (curve 72), of the state of the optical sensor 34 (curve 74, which can here take either a low value or a high value, depending on whether the measurement signal takes the first value or the second value, respectively); of the closed or open state of the separable electrical contacts 10 (curve 76, which can here take either a low value or a high value, corresponding respectively to the open state and the closed state).

[0096] Thus, following a trigger, the angle of the control lever 14 until reaching a threshold (materialized here by the first dotted vertical line on the curve 74) for which the sensor changes state. In response, the electrical control circuit 24 triggers the switching of the power switches 22 to their blocking state, in order to interrupt the flow of current. After a certain delay, here immediately after the position visible on the figure 4 , the electrical contacts 10 are finally separated by the switching mechanism 12, which then reaches the end of the opening movement.

[0097] Such operation can be advantageously achieved with specific switching mechanisms, such as toggle switching mechanisms, such as those described above, in which the relative movement of the parts of the mechanism is configured to cause the occurrence of an angular offset between the rotation of the control lever 14 and the actual opening of the contacts 10, according to the invention, for example to briefly delay the separation of the contacts 10 upon triggering to open.

[0098] This angular offset, according to the invention, makes it possible to compensate for a reduction in the play when pushing in the electrical contacts caused by the gradual wear of the electrical contacts throughout the lifetime of the device 2.

[0099] In practice, in these embodiments, the control circuit 24 takes advantage of this offset so that the switching of the power switches (caused by the start of rotation of the control lever 14, as detected by the sensor 34) anticipates the separation of the electrical contacts 10.

[0100] Thanks to the invention, during the opening phase the electronic control circuit 32 and the sensor 34 make it possible to synchronize the action of the power switches 22 and the switching mechanism 12, in particular to order the switching of the power switches 22 to their blocking state before the electrical contacts 10 are separated. This prevents the occurrence of an electric arc between the electrical contacts 10 and thus makes it possible to interrupt the current safely.

[0101] In other words, the time delay between the switching of the power switches and the separation of the electrical contacts which results from the design of the switching mechanism 12 is used here.

[0102] This is particularly useful when the device is used in a direct current installation, since the separable electrical contacts 10 are generally not sufficient on their own to interrupt the current.

[0103] On the other hand, once in the open position, the separable electrical contacts 10 make it possible to create electrical insulation in the air and prevent an electric current from flowing again between the terminals 6 and 8 after the device 2 has been triggered.

[0104] To close the contacts 10 (i.e. to switch the device 2 back to the closed state), the control lever 14 is moved to the corresponding position by a user. This movement, via the connecting rod 54, causes the hook 56 to rotate, which hooks onto the trigger bar 58. The connecting rod 54 then causes the plate 53 to rotate until the contacts 10 close.

[0105] Furthermore, the use of a housing 4 that is analogous or similar, or even identical, to the housings of electromechanical protection devices ensures compatibility with previous ranges. For example, device 2 can be mounted in an electrical panel to replace a previous generation protection device without having to modify the rest of the installation. This also allows the use of already existing auxiliary devices.

[0106] The use of an optical sensor 34 is advantageous, because such a sensor has a small size and can be easily integrated into the device 2, which makes it possible to produce a compact device 2. An optical sensor also has the advantage of being precise and of not being sensitive to surrounding electromagnetic disturbances (and of not being the source of electromagnetic disturbances which could harm the operation of the installation or of the device 2 itself).

[0107] Finally, using a toggle mechanism as the switching mechanism 12 allows for play compensation when the contacts are pressed in before reaching the contact open position, as explained above.

[0108] There figure 7 represents an advantageous but not obligatory example of construction of the electronic cut-off module 16.

[0109] In this example, at least part of the electronic cut-off module 16 is constructed in the form of an integrated block 80, or even several such integrated blocks 80.

[0110] Preferably, the or each integrated block 80 comprises the power switches 22 associated with a pole of the device (i.e. with one of said electrical conduction lines, itself associated with an electrical phase of the device 2).

[0111] The integrated module 80 comprises a plate-shaped substrate 82, for example made of an electrically insulating material.

[0112] In practice, it may be a composite material, such as glass fiber reinforced epoxy resin, commonly referred to as "FR4".

[0113] At least some of the power switches 22 are mounted on the substrate 82, in particular on main faces of the substrate 82.

[0114] For example, the transistors T1 and T2, associated with the first connection line, are mounted on opposite faces of the substrate 82 as visible on the insert B) of the figure 7 , these switches bearing here the numerical reference 84.

[0115] Indeed, as explained previously, each transistor T1, T2 illustrated on the figure 2 can be implemented in practice by a group of two transistors connected in parallel, depending in particular on the rating of the device 2 and the properties of the transistors used.

[0116] In the illustrated example, given for illustration purposes, the group of two transistors connected in parallel are used to implement “transistor T1”, these two transistors being mounted on a first face of the substrate 82. A group of two other transistors connected in parallel are used to implement “transistor T2”, these two other transistors being mounted on a second face of the substrate 82, the second face of the substrate 82 being opposite the first face of the substrate 82.

[0117] Still in this example, the transistors T3, T4 associated with the second connection line are mounted on opposite faces of the substrate 82 of a second integrated block 80, this second integrated block 80 being connected in parallel with the present integrated block 80 and being identical or at least similar to the present integrated block 80.

[0118] This second block 80 is for example mounted alongside the first block 80.

[0119] Preferably, the or each integrated block 80 is received in said dedicated housing of the previously mentioned housing 4.

[0120] In practice, each power switch 22 may comprise a heat dissipation plate 86, also called a base, which surmounts the body of the power switch 22. In other words, the heat dissipation plate 86 is thermally connected to the body of said power switch.

[0121] For example, the heat sink plate 86 is a metal plate natively attached to the ceramic body of the power switch 22 by the manufacturer of the power switch 22.

[0122] Optionally, components of the electronic control circuit 24 may also be mounted on one or both main faces of the substrate 82.

[0123] For example, one or more of the current sensors 30 associated with a connection line may be integrated into the corresponding module 80 and mounted on the substrate 82.

[0124] The block 80 also comprises two electrically conductive plates 90 and 92, each plate 90, 92 being mounted on each face of the substrate 82 so as to cover this substrate 82. It is understood that in the assembled position, the plates 90 and 92 also cover the components mounted on the faces of the substrate 82.

[0125] In this description, the plates 90 and 92 are made of a metallic material, and are referred to hereinafter as "metal plates". However, alternatively, other materials or compositions of materials may be used as long as the plates 90 and 92 are electrically conductive.

[0126] Advantageously, each metal plate 90, 92 is in contact (preferably in direct contact) with the metal sole 86 of the corresponding power switches (i.e., power switches 84 placed under this metal plate 90, 92). In other words, each metal plate 90, 92 is electrically and thermally connected to the corresponding power switches 84.

[0127] This arrangement allows the plates 90 and 92 to be used both as heat sinks and as electrically conductive elements allowing the power switches 22 to be connected.

[0128] Indeed, when the power switch 22 is a MOSFET transistor, the metal sole 86 is connected to the drain. Thus, the sole 86 can be crossed by the power current flowing in the connection line of the device 2. The metal plates 90 and 92 are then connected respectively to the terminals 8 and 6 of the corresponding connection line.

[0129] Using the sole 86 to conduct the power current does not cause a safety risk to users, since the sole 86 is electrically insulated from the outside by the housing 4 of the device, which is made of electrically insulating material and which prevents a user from touching the sole 86.

[0130] The thermal energy released by the switches 22 is here dissipated towards the outside of the device 2 by conduction along the electrical conductors.

[0131] For example, thermal energy is mainly dissipated by conduction and radiation through the conductive parts to the outside of the device 2.

[0132] Advantageously, heat dissipation phenomena by air convection can also be used, provided that ventilation orifices compatible with the electrical insulation criteria are provided, such as ventilation slots or vents.

[0133] For the dissipation of thermal energy by conduction, the entire current flow chain inside the circuit breaker is concerned, i.e. all the electrical conductors, electrical power cables and electrical conduction lines which allow the circulation of current from upstream to downstream of the device 2.

[0134] For example, by construction, the circuit breaker connection pads are compatible with the maximum temperature of the cable insulation, this temperature being able for example to reach a maximum of 90°C at the connection pads connected with copper cables fitted with PVC sheaths.

[0135] In practice, the hottest point being generally at the center of the device 2, we observe a decreasing temperature profile from the center of the device 2 towards the cable connection pads.

[0136] Advantageously, the metal plates 90 and 92 are made mainly of copper, which has good electrical and thermal conduction properties.

[0137] Alternatively, however, other materials with good electrically and thermally conductive properties may be used, such as aluminum.

[0138] It is also possible to use, to construct the metal plates 90 and 92, materials that have undergone a surface treatment, such as a tin-plated plate, or a plate partially or completely covered with a thin layer of silver, to improve certain properties such as the contact resistances between the power switches and the metal plates. The surface treatment can also improve radiation dissipation, such as the application of paint or the implementation of anodization.

[0139] Preferably, the metal plates 90 and 92 are oversized in order to increase the dissipation of thermal energy mainly by conduction but also by radiation and convection. This oversizing also contributes to reducing losses by Joule effect.

[0140] More preferably, in the assembled configuration, the (or each) metal plates 90 and 92 extend parallel to the widest walls of the housing 4. In the illustrated example, these are the side walls of the housing 4 of the device 2, these walls being oriented vertically when the device 2 is mounted in an electrical cabinet or an electrical panel. Preferably, each metal plate 90, 92 covers at least 40% of the surface area of ​​the corresponding face of the side wall of the housing 4.

[0141] The thickness of each of the plates 90 and 92 is preferably less than or equal to 5 mm and, even more preferably, between 1 mm and 3 mm.

[0142] In particular, the greater the thickness of the 90 and 92 plates, the higher the thermal conduction, which makes heat dissipation more efficient.

[0143] As an illustrative example, in the case of a module 80 comprising four transistors (two transistors connected in parallel on each face of the substrate 82), each transistor dissipating a thermal power of 1 watt, for the case of a monopolar device with a current rating of 16 amperes, it has been observed that a thickness of 1.0 mm of copper for the plates 90 and 92 makes it possible to obtain an internal temperature of 114.6°C, while a thickness of 3 mm of copper for the plates 90 and 92 makes it possible to reduce the internal temperature to 105°C.

[0144] In practice, the substrate 82 may include fixing holes 88 which, in the assembled configuration, are aligned with corresponding holes drilled in the metal plates 90 and 92.

[0145] In the illustrated example, one of the metal plates (in this case the metal plate 92) comprises a folded portion 94 folded relative to the rest of the metal plate 92, for example by extending perpendicular to the plane of said metal plate from an edge of said metal plate. In particular, the portion 94 is folded at 90 degrees relative to the metal plate to be oriented towards the pivoting of the movable electrical contact and thus form a fixed contact portion.

[0146] The folded portion 94 is here used as a fixed electrical contact which cooperates with the movable contact 10 to together form said separable electrical contacts, as illustrated in the figure 1 , and thus achieve the galvanic isolation function when the contacts are open.

[0147] Alternatively, portion 94 could be replaced by a contact portion having a different shape. For example, the contact portion could be formed directly on an edge or slice of the metal plate, without having a folded protrusion.

[0148] Alternatively, the folded portion 94 may be omitted. The contact portion may also be omitted, in particular when the plates 90 and 92 and more generally the block 80 are placed in a housing separate from the housing comprising the movable electrical contact, as for example in the case mentioned above where the power switches are housed in a housing separate from the housing comprising the switching mechanism. This makes it possible, for example, to place a card and metal plates with larger surfaces.

[0149] The metal plates 90 and 92 are here brought into contact by means of a surge limiter element 96, which corresponds to a surge protection element 26 described with reference to the figure 2 .

[0150] The surge limiter element 96 is electrically connected to the metal plates 90 and 92, for example by means of tin soldering. However, alternatively, other soldering or assembly principles can be implemented. For example, the element 96 is plated in direct contact with the metal plates 90 and 92 by screwing.

[0151] In some variations, when the protective element 26 is omitted, the element 96 may be replaced by an electrical conductor.

[0152] But, alternatively, block 80 can be constructed differently.

[0153] For example, in the case of a direct current (DC) device with unidirectional current flow, only one power switch may be used. In this case, only one face of the substrate 82 may be used and only one metal plate 90 or 92 may be used covering this face of the substrate, this plate being connected between the terminals 6 and 8. Preferably, this single plate is mounted on the side of the substrate 82 which is opposite the movable electrical contact 10.

[0154] The embodiments relating to block 80 and in particular to plates 90 and 92 can be implemented independently of the previous embodiments, and in particular of the embodiments relating to the control methods of the switches 22 and to the operation of the sensor 34.

[0155] Block 80 may be constructed with other types of power switches, for example, IGBT transistors, SiC MOSFETs, GaN MOSFETs, and SiC JFET transistors, these examples not being limiting.

[0156] Generally, embodiments relating to block 80 may relate to an electrical protection apparatus 2 comprising a housing 4, connection terminals 6, 8, separable electrical contacts 10 connected between the connection terminals 6, 8, a switching mechanism 12 and at least one power switch 22 connected in series with the separable electrical contacts.

[0157] The separable electrical contacts 10 being movable between an open state and a closed state, the switching mechanism 12 comprising a control lever 14 and being coupled with the separable electrical contacts 10 to switch the separable electrical contacts to the open state, the electrical protection apparatus further comprising an electronic control circuit 24 coupled with said at least one power switch 22.

[0158] The electrical protection device 2 further comprises at least one power switch, or even a pair of power switches, such as field effect transistors T1, T2, and preferably MOSFETS transistors, each power switch comprising a metal sole 86 connected to the drain (or more generally to an electrode) of said power switch.

[0159] Said metal sole 86 being thermally connected to the body of said power switch, and the power switches are connected in series with separable electrical contacts (capable of forming an insulation in air, or "air gap") between the connection terminals 6, 8 by means of metal plates 90, 92 connected (electrically and thermally) to the metal soles 86 of the respective power switches.

[0160] Other embodiments of the device 2 are nevertheless possible.

[0161] In particular, the device 2 can be modified for use in a single-phase installation, or in a polyphase installation, as explained previously.

[0162] There figure 8 represents an embodiment of a single-phase device 200.

[0163] The apparatus 200 is similar to the apparatus 2 described with reference to the figure 2 , except that one of the connection lines is replaced by a neutral conductor line without power switches T3 and T4 (and protection component 26).

[0164] Apart from these differences, the elements of the apparatus 200 which are analogous to the corresponding elements of the apparatus 2 bear the same references and are not described in detail, insofar as the above description can be transposed to them.

[0165] For the sake of readability, certain optional elements of the device 2, such as the auxiliary power supply 38, are not shown on the figure 8 , although they could optionally be included in this embodiment.

[0166] There figure 9 represents an embodiment of a three-phase 300 device.

[0167] The apparatus 300 is similar to the apparatus 2 described with reference to the figure 2 , except that the apparatus 300 comprises a third connection line connected in parallel with the first connection line and the second connection line between the terminals 6 and 8.

[0168] The third electrical connection line is similar or identical to the first connection line and the second connection line and comprises at least one of said power switches 22 (here two in number and denoted T5 and T6) and an electrical contact 10 as described previously, connected in series with the power switch(es) 22 by one or more electrical conductors.

[0169] Advantageously, the third connection line comprises an overvoltage protection element 26, connected in parallel with the power switches 22, as previously described.

[0170] Here again, for the sake of readability, certain optional elements of the device 2, such as the auxiliary power supply 38, are not shown on the figure 9 , although they could optionally be included in this embodiment.

[0171] There figure 10 depicts an embodiment of a three-phase (three-pole) neutral device 400 having three electrical connection lines and a neutral line similar to the neutral line of device 200.

[0172] The apparatus 400 is similar to the apparatus 300 described with reference to the figure 9 , except that the device 400 additionally comprises a neutral line connected in parallel with the first connection line and the second connection line between terminals 6 and 8.

[0173] Apart from these differences, the elements of the apparatus 400 which are analogous to the corresponding elements of the apparatus 300 bear the same references and are not described in detail, insofar as the above description can be transposed to them.

[0174] There figure 11 represents an embodiment of a four-phase (four-pole) apparatus 500 having four electrical connection lines similar to the connection lines previously described.

[0175] The apparatus 500 is similar to the apparatus 4 described with reference to the figure 10 , except that the device 500 comprises, in place of the neutral line, a fourth connection line connected in parallel with the first connection line and the second connection line between terminals 6 and 8.

[0176] The fourth electrical connection line is similar or identical to the first connection line and the second connection line and comprises at least one of said power switches 22 (here two in number and denoted T7 and T8) and an electrical contact 10 as described previously, connected in series with the power switch(es) 22 by one or more electrical conductors.

[0177] Advantageously, the fourth connection line comprises an overvoltage protection element 26, connected in parallel with the power switches 22, as previously described.

[0178] Apart from these differences, the elements of the apparatus 500 which are analogous to the corresponding elements of the apparatus 400 bear the same references and are not described in detail, insofar as the above description can be transposed to them.

[0179] Again, in these two cases, for the sake of readability, certain optional elements, such as the auxiliary power supply 38, are not shown on the figures 10 And 11 , although they could optionally be included in these embodiments.

Claims

1. An electrical protection system (2), comprising connection terminals (6, 8), separable electrical contacts (10) connected between the connection terminals (6, 8), a switching mechanism (12) and at least one power switch (22) connected in series with the separable electrical contacts, the separable electrical contacts (10) being movable between an open state and a closed state, the switching mechanism (12) comprising a movable operating lever (14) and being coupled with the separable electrical contacts (10) to switch the separable electrical contacts to the open state, the electrical protection system further comprising an electronic control circuit (24) coupled to said at least one power switch (22), wherein the electrical protection system further comprises a sensor (34) coupled to the operating lever (14) to measure a position of the switching mechanism, and wherein the electronic control circuit (24) is configured to switch said at least one power switch (22) to a off state when the sensor (34) detects that the switching mechanism (12) has reached a position preceding a position from which the electrical contacts (10) separate, characterised in that the relative movement of the parts of the switching mechanism (12) is configured to cause the occurrence of an angular offset between the rotation of the control lever (14) and the actual opening of the separable electrical contacts (10) and in that the angular offset makes it possible to compensate for a reduction in the clearance, upon being pressed, of the separable electrical contacts (10) caused by the gradual wear of the separable electrical contacts (10).

2. The electrical protection system according to claim 1, wherein the separable electrical contacts (10) comprise a fixed electrical contact (61) and a mobile electrical contact (10) movable relative to the fixed electrical contact, the switching mechanism (12) being coupled to the mobile electrical contact, wherein the operating lever (14) is a rotatable part mounted to rotate about an axis of rotation, and wherein the switching mechanism (12) comprises: - a transmission rod (54), - a release hook (56), rotatably mounted and coupled to the rotating part (52) via the transmission rod (54), - a plate (53), mounted so as to rotate about an axis of rotation and coupled to the release hook (56), - a release bar (56), coupled to the plate (53) and to the release hook (56), - a contact carrier (60), which carries the mobile electrical contact (10) and which cooperates with the fixed electrical contact (61), the contact carrier being mounted so as to rotate about an axis of rotation, and - stops (62) which limit the rotational movement of the rotating part (52).

3. The electrical protection system according to claim 2, the electrical protection system being configured to be housed in a casing (4), wherein the axes of rotation of the rotating part (52), the plate (53) and the contact holder (60) are parallel to each other and are configured to be integral with the casing (4).

4. The electrical protection system according to any one of the preceding claims, wherein the sensor (34) is an optical sensor, a mechanical sensor, or an inductive sensor with external field compensation.

5. The electrical protection system according to any one of the preceding claims, wherein the electronic control circuit (24) is configured to switch said at least one power switch (22) to the off state when an electrical fault is detected by a measurement circuit.

6. The electrical protection system according to any one of the preceding claims, wherein the electrical protection system (2) comprises an internal power supply (28) configured to supply electrical power to the electrical control circuit from the electrical voltage between the connection terminals.

7. The electrical protection system according to any one of the preceding claims, wherein said at least one power switch (22) is a MOSFET transistor.

8. The electrical protection system according to any one of the preceding claims, wherein said at least one power switch (22) is normally in the open state.

9. The electrical protection system according to any one of the preceding claims, wherein the electronic control circuitry comprises a plate-like substrate (82) and a conductive plate (90, 92) in contact with a metallic pad (86) of said at least one corresponding power switch, said at least one power switch (22, 84) and its respective conductive plate (90, 92) being mounted on one or each face of the substrate (82).

10. The electrical protection system according to claim 9, wherein at least one of the conductive plates (92) has a portion adapted to form a fixed electrical contact which co-operates with the mobile electrical contact (10) to jointly form said separable electrical contacts.

11. The electrical protection system according to any one of the preceding claims, wherein the switching mechanism (12) is a toggle mechanism.

12. The electrical protection system according to any one of the preceding claims, wherein the electrical protection system (2) is configured so that to close the separable electrical contacts (10), the control lever (14) is intended to be moved to the corresponding position by a user, this movement, by means of a connecting rod (54) of the switching mechanism, causing the rotation of a hook of the switching mechanism, the hook catching onto a release bar (58) of the switching mechanism, the connecting rod (54) then rotating a plate (53) of the switching mechanism until the separable electrical contacts close.

13. The electrical protection system according to any one of the preceding claims, wherein the electronic control circuit (24) is configured to switch said at least one power switch (22) to an off state when the sensor (34) detects that the switching mechanism (12) has reached a position immediately preceding a position from which the electrical contacts (10) separate.

14. An electrical protection device comprising a casing (4) and the electrical protection system (2) according to any one of the preceding claims, wherein the electrical protection device (2) is a miniature circuit breaker.

15. The electrical protection device according to claim 14, wherein the electronic control circuit (24) and said at least one power switch (22) are housed in a dedicated compartment inside the casing (4).

16. The electrical protection device according to one of claims 14 or 15, wherein the width of the casing (4) is a multiple of 9mm.

17. The electrical protection device comprising a casing and the electrical protection system (2) according to any one of claims 1 to 13, wherein the electrical protection device (2) is an air circuit breaker.