EP4342047A1

EP4342047A1 - Electrical switching device, and associated method and switching system

Info

Publication number: EP4342047A1
Application number: EP22731995.1A
Authority: EP
Inventors: Eric Domejean; Jerôme BRENGUIER
Original assignee: Schneider Electric Industries SAS
Current assignee: Schneider Electric Industries SAS
Priority date: 2021-05-20
Filing date: 2022-05-19
Publication date: 2024-03-27
Also published as: KR20240008949A; WO2022243464A1; CN117378111A; FR3123164A1; CA3219994A1

Abstract

The invention relates to a switching device (15), a switching module (20) and a control module (25) configured to command the interruption of a current by way of the switching module (20) in the event of a fault. The switching module (20) comprises a circuit carrying the current and comprising, in series, two back-to-back depletion-mode JFETs (30, 35) and a switching component (40) that switches between two configurations, the switching component (40) allowing the current to flow in one configuration and preventing the current from flowing in the other configuration, which it is in by default, the control module (25) generating a first signal for keeping the switching component (40) in the first configuration, the control module (25) being configured, in the event of a fault, to generate a second signal for commanding the interruption of the current by way of a transistor (30, 35), and configured to interrupt the first signal in the event of a fault.

Description

Electrical switching device, switching system and associated method

The present invention relates to an electrical switching device. The present invention also relates to a switching system and a method for switching an associated current.

Switching devices such as circuit breakers are frequently used to detect electrical faults related to electrical current(s) and to interrupt the current(s) upon detection of a fault. To this end, the circuit breakers are equipped with means for detecting an electrical fault, these means activating a switching device which cuts off the current when necessary.

The switching device is traditionally formed by an electrically conductive and movable contact between two positions, one in which it electrically connects two terminals between which it conducts the current, and the other in which the contact is at least one of the terminals. Such devices also have the advantage of galvanically isolating their two terminals from each other when the contact is in the second position, and thus of offering a very high level of protection, especially since their actuation mechanism maintains them, by default, in the second position.

However, the mobile switching elements of the aforementioned type remain relatively slow, since breaking generally requires one to several milliseconds. In addition, an electric arc generally appears between the moving contact and the terminal(s) from which it moves away during breaking. Such an electric arc requires a specific configuration of the switching device to be extinguished safely, via a complex arcing chamber of large dimensions, and also generates wear on the elements between which it forms, which limits the duration life of the switching device.

It has therefore been proposed to use, instead of the moving contact, one or more electronically controlled transistors, which then allow faster current breaking without the appearance of an electric arc. In order to ensure sufficient protection, the transistors used are necessarily of a "non-passing by default" type, that is to say of a type which requires a positive action (reception of a command on the gate of the transistor) to allow current to flow, and which blocks the flow of current in the absence of such action. For example, MOSFET transistors have been proposed for such use.

However, non-conducting transistors by default have a relatively high resistance to the passage of current, which is in particular troublesome, since it causes significant losses, when the intensity of the current is high. It is therefore necessary to provide a large number of transistors in parallel to limit the losses by dividing the current, so that the intensity of the current passing through each transistor is limited. Such a configuration is complex and bulky.

There is therefore a need for a device for switching an electric current which has small dimensions and a low electric resistance while allowing faster breaking of the current and having a better lifespan than the switching devices of the state of the art.

To this end, an electrical switching device is proposed comprising an input, an output, a switching module and a control module, the switching module being able to conduct an electric current between the input and the output, the module control being configured to detect an electrical fault and to control the interruption of the current by the switching module in the event of detection of a fault.

This switching module comprises an electrical circuit configured to conduct the current between the input and the output, the circuit comprising, in series, at least two first JFET transistors normally on head to tail and at least one switching member comprising a first terminal and a second terminal, the member of being configured to switch between a first configuration and a second configuration, the switching member allowing current to flow between the first terminal and the second terminal when the switching member is in the first configuration, the switching element preventing the passage of current when the switching element is in the second configuration, the switching element being in the second configuration by default, the control module being configured to generate at least a first signal electric capable of maintaining the switching member in the first configuration, the control module being configured for, in in the event of detection of a fault, generating at least one second electrical cut-off signal intended for a first transistor, each second signal being capable of controlling the interruption of the current by the corresponding first transistor, the control module being configured to interrupting the first signal in response to the detection.

Thanks to the invention, the current is cut off quickly by the JFETs in the event of detection of an electrical fault. In addition, the switching device, being in the second configuration and therefore non-conducting by default, maintains this protection even when the control module is not electrically powered and therefore cannot maintain the JFETs in their non-passing state.

Moreover, since the JFETs cut the current very quickly, the switching device does not have to be sized in such a way as to allow this cut, but only the maintenance of the insulation. In particular, no electric arc appears even if the switching member is of the moving contact type, which limits its wear and therefore avoids the need for an interrupting chamber, while allowing the device 15 to be used in an explosive atmosphere.

In general, the switching device can have a high electrical conductivity since it does not have to break high currents and therefore have to withstand a high overvoltage during breaking, this role being played by the JFETs, which have them naturally a very high conductivity. The electrical resistance of the switching device is therefore low.

Thus, the main defect of JFETs - the fact that they are conductive by default, which is generally considered to disqualify them for use in an electrical switching device - is compensated for by the presence of the switching device without their advantages (their high conductivity) are offset by the electrical resistance of the switching device since the latter remains limited.

According to advantageous but not mandatory aspects of the invention, the switching device has one or more of the following characteristics, taken in isolation or in all technically possible combinations:

- the switching member comprises a first actuator and a first electrically conductive contact, the first contact being movable between a first position and a second position, the first contact being in the first position when the switching member is in the first configuration and being in the second position when the switching member is in the second configuration, the first contact conducting current between the first terminal and the second terminal when the first contact is in the first position, the first contact being at least at least one of the first and second terminals when the first contact is in the second position, the first actuator being configured to maintain the first contact in the first position when the actuator is supplied with the first electrical signal.

- the switching device comprises two second MOSFET transistors, of the non-conducting by default type, in head-to-tail series between the first terminal and the second terminal, each second transistor conducting the current when the second transistor is supplied by a respective first signal and preventing the flow of current in the absence of the first signal.

- the circuit further comprises a disconnector connected in series with the first transistors and with the switching device, the disconnector comprising a third terminal, a fourth terminal, a second contact, a second actuator and a control device, the second contact being movable between a third position and a fourth position, the second contact conducting current between the third terminal (80) and the fourth terminal when the second contact is in the third position, the second contact being remote from at least one of the third and fourth terminals when the second contact is in the fourth position, the second actuator being configured to move the second contact between the third position and the fourth position when the control member is actuated by an operator.

- the control device is a rotary handle.

- The device comprises a control member operable by an operator to control the cut-off, by the control module, of the first signal.

- each first transistor comprises a source, a drain and a gate, the sources of two of the first transistors being interposed, along the current path, between the drains of said two first transistors.

- the number of first transistors is greater than or equal to four, the first transistors being divided into pairs of groups of first transistors, each group containing at least one first transistor, the first transistors of each group being connected successively to each other in series in the same direction if the group comprises more than one first transistor, each first transistor of a group being in the different direction from the first transistor or transistors of the other group of the same pair, each group of a pair being connected in series to the other group of the pair, the pairs being connected in series to each other.

- the first transistors are made of SiC or GaN.

- the device comprises a single input and a plurality of outputs, each output being connected to a single point, the first transistors being interposed between the input and said single point, the switching module comprising, for each output, a switching member respective interposed between the output and said single point.

- the device comprises a switching device and a control device, the switching device comprising the switching module, the control device comprising the control module, the switching device and the control device being remote each other and being configured to communicate with each other.

There is also proposed a switching system configured to transmit a plurality of currents between respective inputs and outputs, to detect an electrical fault according to measurements of parameters of at least one current, and to interrupt at least the corresponding current in case of detection of an electrical fault, comprising a plurality of switching devices as previously described.

A method for switching a current is also proposed, implemented by an electrical switching device comprising an input, an output, a switch and a control module, the switch module being adapted to conduct an electric current between the input and the output, the switch module comprising an electric circuit configured to conduct the current between the input and the output, the circuit comprising , in series, at least two first JFET transistors normally on head to tail and at least one switching element comprising a first terminal and a second terminal, the switching element being configured to switch between a first configuration and a second configuration, the switching member allowing the passage of current between the first terminal and the second terminal when the switching member is in the first configuration, the switching member preventing the flow of current when the switching member is in the second configuration , the switching member being in the second default configuration, the method comprising steps of:

- generation, by the control module, of at least a first electrical signal capable of maintaining the switching device in the first configuration,

- detection of an electrical fault by the control module,

- following the detection of a fault, interruption of the first signal by the control module and generation by the control module of a second electrical cut-off signal intended for each first transistor,

- following receipt of the corresponding second signal, interruption of the current by at least one first transistor, and

- switching of the switching device in the second configuration.

Characteristics and advantages of the invention will appear on reading the following description, given solely by way of non-limiting example and made with reference to the appended drawings, in which:

[Fig 1] Figure 1 is a schematic representation of an example of a switching system according to the invention comprising a first example of a switching device according to the invention,

[Fig 2] Figure 2 is a flowchart of a switching process implemented by the switching device of Figure 1,

[Fig 3] Figure 3 is a schematic representation of a second example of a switching device according to the invention, and

[Fig.4] Figure 4 is a schematic representation of a second example of a switching system according to the invention. An example of a switching system 10 according to the invention is represented in FIG. 1. A second example of a switching system 10 will be represented and described later.

The switching system 10 has at least one input 1, 3 and at least one output 2, 4. In particular, the number of inputs 1, 3 is equal to the number of outputs 2, 4. In the example represented on the figure 1, the number of inputs and outputs is equal to two, however this number is likely to vary.

The switching system 10 is configured to receive a current on each of its inputs 1, 3, and to transmit each current to a respective output 2, 4.

Optionally, the switching system 10 also comprises a neutral input EN and one or more neutral output(s) SN, the switching system 10 being configured to conduct a current between the neutral input EN and the output(s) ( s) neutral SN and, in a manner known per se, to cut this current using a neutral switch S.

The switching system 10 is, moreover, configured to detect an electrical fault relating to at least one of the currents and to interrupt said current, or a plurality of the currents, in particular all the currents, in the event of detection of the fault.

The switching system 10 comprises at least one switching device 15, and in particular a switching device 15 for each pair formed by an input 1, 3 and an output 2.4.

In FIG. 1, the switching system 10 is a bipolar system, i.e. a system 10 with two poles, or with two electrical phases, without neutral.

A person skilled in the art can easily adapt such a switching system, for example, to mono-, bi-, tri- or quadri-polar installations, with or without neutral.

Each pole of the installation will be associated with a respective input 1, 3 and output 2, 4, with in particular a corresponding switching device 15, the neutral being associated with the corresponding input EN and output SN of the system 10.

The different switching devices 15 corresponding to the different poles of the system 10 are, for example, identical to each other.

Each switching device 15 comprises input 1, 3 and the corresponding output 2, 4 and is configured to conduct from input 1, 3 to output 2, 4 an electric current received at input 1, 3.

The current is, for example, a direct current, but is, in a variant, likely to be an alternating current. The current is associated with an electrical voltage between input 1, 3 and output 2, 4. Each switching device 15 is, moreover, configured to detect an electrical fault relating to the current that it conducts and to interrupt said current in the event of detection of the fault.

Each fault is, for example, excessive current intensity, short circuit, overvoltage, excessive temperature of an internal component, internal failure after circuit breaker self-test, undervoltage, abnormal shape of the voltage (non-sinusoidal for example on an AC network), or even an electric arc.

Each switching device 15 comprises, in addition to the input 1, 3 and the corresponding output 2, 4, a switching module 20 and a control module 25.

It should be noted that certain elements of the switching devices 15, in particular the control module 25, are likely, depending on the case, to be specific to a single switching device 15 or common to several switching devices 15.

Each input 1, 3 or output 2, 4 is configured to be connected to an electric current inlet or outlet conductor, for example to a conductive wire or cable, or else to an input or output terminal of another electrical device.

Switch module 20 has an electrical circuit connecting input 1, 3 to output 2, 4 and configured to conduct current between input 1, 3 and output 2, 4.

The electrical circuit comprises, connected in series, at least two first transistors 30 and 35 and a switching device 40. Optionally, the circuit further comprises a disconnector 45.

Optionally, the switching module 20 further comprises a peak limiter 50.

Each first transistor 30, 35 is a JFET transistor.

The acronym JFET, from the English "Junction Field-Effect Transistor" designates a field-effect transistor whose gate is directly in contact with the semiconductor channel connecting the source and the drain, the channel being interposed between two portions semiconductors having a type of doping different from that of the channel, so that the modification of the potential of the gate (connected to one of these two portions) tends to increase the size of the depletion zone which appears at the junction between the channel and said portions. Thus, if the voltage is sufficient, the channel is completely stripped and made electrically insulating.

Each first transistor 30, 35 is, in particular, an n-type channel JFET.

Each first transistor 30, 35 is on by default (or “normally on”). In other words, each first transistor 30, 35 is such that, in the absence of action on the gate of the first transistor 30, 35, the first transistor 30, 35 allows a current to flow between the source and the drain. The first transistors 30, 35 are arranged head to tail in the electrical circuit, that is to say the current flows from the source to the drain in one of the first transistors 30, 35 and from the drain to the source in the other first transistor 30, 35.

Thus, the expression “head to tail” designates first transistors 30, 35 connected in opposite directions.

In particular, each first transistor 30 is connected in a direction opposite to the direction of each first transistor 35.

According to one embodiment, the sources of the first two transistors 30, 35 are interposed between the drains of the first two transistors 30, 35 along the current path.

In the example of switching device 15 of Figure 1, the sources of the first two transistors 30, 35 are connected to each other at a point 55.

Optionally, the number of first transistors 30, 35 is different from two, for example equal to four, six or any even number.

In this case, the first transistors 30, 35 are divided into two groups of first transistors 30, 35, the transistors 30, 35 which belong to the same group being arranged in the same direction and successively connected in series to each other.

Alternatively, two or more pairs of groups are present, each pair comprising a group of first transistors 30 connected in series with each other and a group of first transistors 35 connected in series with each other, the two groups of the pair being connected in series to each other.

The different pairs of groups are connected in parallel to each other.

According to a variant, each pair comprises a single first transistor 30 and a single first transistor 35 connected in series, the pairs being connected in parallel with each other.

According to another variant, the electrical circuit comprises a plurality of groups of first transistors 30, 35, the groups being connected in series to each other.

Each group then comprises at least two first transistors 30 or at least two first transistors 35, the first transistors 30, 35 of the same group being connected in parallel to each other. In particular, each group contains only first transistors 30, 35 oriented in the same direction, and there is at least one group of first transistors 30 oriented in one direction and at least one group of first transistors 35 oriented in the other direction. . Thus, whatever the direction of the current, at least one of the groups of first transistors 30, 35 prevents the current from flowing. For example, the first transistors 30 of a group are all connected at one end to the same point as the first transistors 35 of a first neighboring group and optionally at the other end to the same point as the first transistors 30 or 35 d a second neighboring group.

Each first transistor 30, 35 is, for example, made of silicon carbide SiC. As a variant, at least one first transistor 30, 35, in particular each first transistor 30, 35 is made of another semiconductor material, for example of gallium nitride GaN or else of silicon. The material used depends in particular on the voltages and intensities of the currents that the switching device 15 is designed to withstand.

The switching device 40 comprises a first terminal 60 and a second terminal 65. The first terminal 60 is, for example, connected to one of the first transistors 30, 35.

The switching device 40 is configured to switch between a first configuration and a second configuration.

When the switching device 40 is in the first configuration, the switching device allows current to flow between the first terminal 60 and the second terminal 65.

When the switching device 40 is in the second configuration, the switching device electrically isolates the first terminal from the second terminal 65.

The switching device 40 is configured to switch between the first and the second configuration upon receipt of a first control signal from the control module 25.

The switching device 40 configured to be, by default, in the second configuration. In other words, in the absence of a first control signal transmitted by the control module 25, the switching device 40 is in the second configuration.

According to the embodiment shown in Figure 1, the switching device 40 is a relay comprising a first contact 70 and a first actuator 75.

The switching device 40 is, in particular, not sized to interrupt on its own the current flowing between the input 1, 3 and the output 2, 4. In particular, the switching device 40 is not configured to extinguish any electric arc appearing between the first contact 70 and one or the other of the terminals 60, 65. The switching member 40 is, for example, devoid of arcing chamber.

However, the switching device 40 is, for example, configured to prevent a current from flowing between the terminals 60, 65 if the voltage between the input 1, 3 and the output 2, 4 is applied between the terminals 60 and 65 . It should be noted that, according to possible variants, the switching device 40 is sized to extinguish the current on its own if necessary, for example by extinguishing any electric arc which would result therefrom.

The first contact 70 is electrically conductive and is movable between a first position and a second position, represented in FIG.

When the switching member 40 is in the first configuration, the first contact 70 is in the first position. When the switching device 40 is in the second configuration, the first contact 70 is in the second position.

When the first contact 70 is in the first position, the first contact 70 electrically connects the two terminals 60 and 65, for example by pressing against the two terminals 60 and 65.

When the first contact 70 is in the second position, the first contact 70 is distant from at least one of the terminals 60 and 65. Thus, the first contact 70 does not allow current to flow between the terminals 60 and 65.

Many types of mechanisms, in particular rotary ones, are likely to be used to ensure the mobility and guidance of the first contact 70.

According to possible embodiments, the relay 40 is a MEMS relay (from the English “Micro Electro-Mechanical System”, meaning “micro electromechanical system”). A MEMS relay is a relay of which at least a part of microscopic dimensions is made from semiconductor materials. For example, a beam of microscopic dimensions deforming under the effect of an electric field plays the role of first contact 70. very quickly, their switching times being typically of the order of 10 microseconds.

As a variant, the relay 40 is a relay of macroscopic dimensions of a known type.

The first actuator 75 is configured to move the first contact 70 between the first position and the second position following receipt of a first control signal, in particular a first electrical control signal, from the control module 25.

In particular, the first actuator 75 is configured to maintain the first contact 70 in the second position in the absence of a first control signal, and to move the first contact 70 into the first position and maintain it there when the first actuator 75 is supplied with the first control signal.

For example, the first actuator 75 is of a known type comprising a spring and an electromagnet, the spring tending to move the first contact 70 towards its second position and the electromagnet being configured, when powered by the first control signal, to exert, directly or indirectly, on the first contact 70 a force tending to move the first contact 70 towards its first position. However, many types of first actuators 75 are likely to be considered. For example, if relay 40 is a MEMS relay, actuator 75 is an electrostatic actuator.

The disconnector 45 is interposed between the switching device 40 and the output 2, 4. The disconnector 45 comprises a third terminal 80 connected to the switching device 40, a fourth terminal 85 connected to the output, a second contact 90, a second actuator 95 and a control device 100.

The second contact 90 is electrically conductive and is movable between a third position and a fourth position, represented in FIG.

When the second contact 90 is in the third position (or "ON position"), the second contact 90 electrically connects the two terminals 80 and 85, for example by pressing against the two terminals 80 and 85.

When the second contact 90 is in the fourth position (or "OFF position"), the second contact 90 is distant from at least one of the terminals 80 and 85. Thus, the second contact 90 does not allow the passage of current between the terminals 80 and 85.

Many types of mechanisms, in particular rotary, are likely to be used to ensure the mobility and guidance of the second contact 90.

Disconnector 45 is, in particular, configured to maintain insulation between terminals 80 and 85, even if the voltage between input 1, 3 and output 2, 4 is applied between terminals 80 and 85. For example, the distance between the second contact 90 and at least one of the terminals 80, 85, when the second contact 90 is in the fourth position, is such that an electric arc does not occur between the terminals 80 and 85 when the voltage is applied between these terminals. This distance is, in particular, greater than or equal to 3 millimeters (mm), but is likely to vary from one embodiment to another, in particular according to the voltage imposed between the various elements of the installation.

The second actuator 95 is configured to move the second contact 90 between the third position and the fourth position following receipt of a second control signal, in particular a second electrical control signal, from the control module 25.

In particular, the second actuator 95 is configured to maintain the second contact 90 in the fourth position ("OFF") in the absence of a second control signal, and to move the second contact 90 to the third position ("ON") and hold it there when the second actuator 95 is supplied with the second control signal. For example, the second actuator 95 is of a known type comprising a spring and an electromagnet, the spring tending to move the second contact 90 towards its fourth position and the electromagnet being configured, when it is powered by the second control signal, to exert, directly or indirectly, on the second contact 90 a force tending to move the second contact 90 towards its third position. However, many types of second actuator 95 are likely to be considered.

Optionally, the second actuator 95 is also configured to open the neutral disconnector S at the same time as the disconnector 45.

The control member 100 is configured to be actuated by an operator so as to act on the second actuator 95 so that the second actuator 95 moves the second contact 90 between its third and fourth positions.

In a manner known per se, the control member 100 is, for example, a rotary handle, or even a button, which can be moved by the operator between two positions to control the movement of the second contact 90.

Optionally, the control member 100 is furthermore configured so that, when it is moved by an operator so as to move the second contact 90 to its fourth position, to act on the control module 25 so that the control module 25 controls the interruption of the current by the first transistors 30, 35 and by the switching device 40.

Alternatively, the control unit 100 is configured to control the movement of the second contact 90 via the control module 25, for example by sending a signal to the control module 25 which controls the second actuator 95 in response. controller 110 is, for example, provided to receive from a sensor 102 information on the position of the control member 100.

According to optional embodiments, the control member 100 comprises a locking mechanism capable of maintaining the control member 100 in the position in which the control member 100 maintains the second contact 90 in the fourth position. Such a mechanism then allows the installation which is downstream of the device 10 to be locked out.

The sensor 102 is configured to detect a position of the control member 100, in particular to detect that the control member 100 reaches, during its movement, a position preceding the position in which the control member 100 drives the opening of the disconnector 45. The sensor 102 is, for example, an optical sensor provided to detect the passage in front of the optical sensor of a part of the control member 100 when the control member 100 reaches the position preceding the position in which the control member 100 causes the opening of the disconnector 45. The control module 25 is configured to detect the electrical fault and to control in response the interruption of the current by at least the first transistors 30, 35 and the switching device 40.

The control module 25 comprises at least one monitoring device 105, a controller 110, a main power supply 115 and, optionally, an auxiliary power supply 120.

In the example shown in Figure 1, a single controller 110, a single main power supply 115 and a single auxiliary power supply 120 are common to the different switching devices 15, however, as a variant, these elements of the different switching devices 15 are likely to be distinct from each other. According to another variant, several power supplies 115 and/or several power supplies 120 are likely to be present, to supply the controller 110 in a redundant manner and thus prevent the failure of one of them being sufficient to put the system out of service. 10.

Each monitoring device 105 is configured to monitor the current flowing in the switching device 15.

For example, each monitoring device 105 is configured to measure current intensity values and to transmit these values to the controller 110, for example in the form of an electrical signal whose voltage or intensity is a function of the current intensity. In this case, the monitoring member 105 is, for example, a torus, in particular a Rogowsky torus. However, other types of intensity sensors are likely to be used, for example Hall effect sensors, or even shunt sensors, among others.

The controller 110 is configured to detect the occurrence of an electrical current fault, for example from the measured values. The criteria for detecting the various faults are known per se, and sometimes established by standards, and are not described here.

The controller 110 is further configured to control a switching of each first transistor 30, 35. For example, the controller 110 is configured to generate, in response to the detection of a fault, a third electrical signal intended for each first transistor 30, 35, the or each third signal being capable of causing the current to be interrupted by the first transistor or transistors 30, 35.

Each third signal is, for example, an electric voltage between the source and the gate of the first transistor 30, 35, the voltage being such that the conductive channel of the said first transistor 30, 35 is pinched and therefore interrupted by the two depletion zones between which the channel is interposed. According to one embodiment, the controller 110 is electrically connected to each of the gates of the first transistors 30, 35 and to the point 55, so as to impose an electric voltage between the gates and the point 55, the potential of which is equal to the potential of the sources of the first transistors 30, 35.

Optionally, if two groups of transistors 30, 35 are present, each third signal is transmitted simultaneously at least to the transistors 30, 35 which are in the same direction, for example to all the transistors 30, 35.

The controller 110 is configured to generate the first control signal and to transmit it to the switching device 40 so as to maintain this switching device 40 in the first position.

The controller 110 is furthermore configured to control the switching of the switching device 40 from the first configuration to the second configuration in response to the detection of a fault, for example by interrupting the first signal.

The controller 110 is, moreover, optionally configured to control the switching of the disconnector 45 to its fourth position in the event of detection of a fault, for example by emitting or interrupting the second electrical signal.

According to one embodiment, the controller 110 controls the switching of the disconnector 45 to its fourth position by supplying electricity with the second signal to a conductive winding 125, so as to exert on the second actuator 95 a force causing the opening of the disconnector 45 by the second actuator 95.

It should be noted that many different means are likely to be used to allow the controller 110 to act on the disconnector 45 so as to cause it to switch.

The controller 110 is, for example, formed by a processor and a memory storing a set of software instructions, the software instructions leading to the implementation of an example of a switching method, described below, when they are put implemented on the processor.

As a variant, the controller 110 is formed by a set of programmable logic components, by one or more dedicated circuits, in particular one or more integrated circuits, or by any set of electrical or electronic components.

The main power supply 115 is configured to electrically supply the controller 110 and, optionally, the monitoring device(s) 105, with one or more supply currents generated from the electrical current(s) passing through the switching device(s) 15.

The auxiliary power supply 120 is configured to electrically supply the controller 110 and, optionally, the monitoring device(s) 105, with one or more supply currents generated for example from a reserve of electrical energy A1 such as a battery or a capacitor, or received from a source A2 external to the system 10, for example from an electricity distribution network .

The limiter 50 is connected in parallel to the first two transistors 30, 35 and is configured to prevent an electric voltage between the extreme terminals, for example between the drains, of the first two transistors 30, 35 from exceeding a predetermined voltage threshold. . Clippers 50 of multiple types are known to those skilled in the art, using for example a varistor or even one or more Zener diode(s). Such circuits are sometimes called “TVS”, from the English “Transient-Voltage Suppressor”, which means “transient signal limiter”.

A flowchart of the switching process is shown in Figure 2.

The method comprises an initial step 200, a step 210 of detecting a fault, a step 220 of controlling, a first step 230 of interrupting, a second step 240 of interrupting, a step 250 of switching and a step 260 of actuation.

During the initial step 200, the switching device 40 is in its first configuration and the movable contact 90 of the disconnector 45 in its third position. Further, controller 110 does not generate the third signal, and first transistors 30, 35 are therefore on.

Thus, an electric current flows between the input 1, 3 and the output 2, 4, allowing the generation of a power supply current by the main supply 115. The controller 110 uses the supply current to generate the first electrical signal which maintains the switching member 40 in its first configuration.

During the detection step 210, the controller 110 detects the occurrence of a fault, for example from current intensity values measured by the monitoring device 105.

In response to the detection of the fault, the controller 110 generates, for each first transistor 30, 35, the corresponding third control signal, and transmits each third control signal to the first transistor 30, 35 for which it is intended, during the control step 220. For example, the controller 110 imposes a predefined voltage between the gate and the source of each first transistor 30, 35, and maintains this voltage as long as the power supply of the controller 110 allows it.

During the first interrupt step 230, the controller 110 interrupts the first control signal. Optionally, during this step, the controller 110 also sends the second control signal to the second actuator 95 or, if applicable, to the winding 125. Optionally, the first control signal is interrupted after the expiry of a predetermined time delay, this time delay being measured from the emission of each third control signal.

The delay time is, for example, between 5 nanoseconds and 10 milliseconds, but is likely to vary from one mode of implementation to another.

As a variant, the first control signal is interrupted by the controller 110 after the controller 110 has measured that the intensity of the current flowing between the input 1, 3 and the output 2, 4 is less than or equal to a threshold in value absolute, in particular equal to zero.

The transmission of the second control signal, provided to control the opening of the disconnector 45, is for example simultaneous with the interruption of the first control signal.

Optionally, if a neutral disconnector S is present, a command to cut the neutral disconnector S is sent during step 230.

During the second interruption step 240, the current is interrupted by at least one of the first transistors 30, 35.

Indeed, since the first two transistors 30, 35 are connected head to tail in the electrical circuit, at least one of the first transistors 30, 35 is effectively non-conducting under the effect of the corresponding third control signal whatever the direction. current, including if the current is alternating current.

In particular, current flows through the switching device 15 at the start of the second interrupt stage 240, and is interrupted by the switching of the first transistors 30, 35.

During the switching step 250, the switching device 40 switches to its second configuration. Optionally, the movable contact 90 of the disconnector 45 switches to its fourth position.

It should be noted that it is not the switching of the switching device 40 nor that of the disconnector 45 which causes the current to be interrupted. Indeed, the switching of the transistors 30, 35 being very fast, it generally takes place before the switching of the member 40 has been able to end. If component 40 is capable of switching very quickly, the aforementioned time delay ensures that transistors 30, 35 switch before component 40.

For example, the switch step 250 is implemented after the second interrupt step 240. Alternatively, the movement of the movable contact 70 begins before the current is interrupted by the first transistors 30, 35, but this interruption occurs before the appearance of an electric arc between the contact 70 and the terminal 65.

The actuation step 260 is implemented after the switching step 250. In particular, during the actuation step, following the interruption of the current by the first transistors 30, 35, the controller 110 is not electrically powered and therefore does not transmit a third signal to the first transistors 30, 35 which are therefore on, nor a second signal to the switching device 40, which is therefore in the second configuration.

Optionally, the neutral disconnector S is cut off during step 260, if such a neutral disconnector S is present.

During the actuation step 260, an operator acts on the lever 100 to close the disconnector 45 and thus electrically connect the terminals 80 and 85. However, although the first transistors 30, 35 are on, the switching device 40, being by default in the second configuration, prevents the passage of current.

Thus, the current is cut off quickly by the JFETs 30, 35 in the event of detection of an electrical fault. In addition, the switching device 40, being in the second configuration and therefore non-conducting by default, ensures the maintenance of this protection even when the control module is not electrically powered and therefore cannot maintain the JFETs 30 , 35 in their non-conducting state, for example if an operator actuates the lever 100. Thus, despite the use of first transistors 30, 35 passing by default, the electrical protection of the installation remains ensured even if the controller 110 n is not functional.

Moreover, since the JFETs break the current very quickly, the switching device does not have to be dimensioned in such a way as to allow this cut, but only the maintenance of the insulation. In particular, no electric arc appears even if the switching device is of the moving contact type, which limits its wear and therefore avoids the need for an interrupting chamber. In general, the switching device can have a high electrical conductivity since it does not have to break high currents, this role being played by the JFETs, which naturally have a very high conductivity. The electrical resistance of the switching device is therefore low.

In addition, the JFETs 30, 35 tend to saturate and thus limit the intensity of the current flowing through them when this intensity is very high, for example in the event of a short-circuit, and therefore thus participate in the protection of the network even before their cut. When the switching member 40 is a relay comprising a movable contact 70, the switching member 40 reliably allows effective isolation even in the absence of electrical power supply from the control module 25.

The use of a disconnector 45 separate from the switching device 40 allows an operator to manually interrupt the current without, however, by a reverse movement, the operator being able to cause the current to flow at a time when the controller 110, non-functional because for example not electrically powered, could not monitor the presence of a fault and cut off the current via the first transistors 30, 35.

In addition, disconnector 45 provides galvanic isolation between input 1, 3 and output 2, 4.

A rotary handle 100 is an effective way to allow the operator to control the disconnector 45.

When the sources of two of the first transistors 30, 35 are connected together, the controller 110 can simply control the switching of these two transistors 30, 35 by acting on the midpoint 55 and/or on the gate voltage of the transistors 30, 35, and therefore control the two transistors 30, 35 using a single signal.

SiC or GaN JFETs are suitable for safely conducting high currents.

If two groups of first transistors 30, 35 are used, the transistors 30, 35 of each group being connected in the same direction, several transistors necessarily participate at the same time in breaking the current, whatever the direction of the latter. Thus, the constraints relating to the sizing of the transistors 30, 35 are more limited since each must only support part of the current breaking function and must only withstand part of the total voltage which appears during this cut.

If several pairs of transistors 30, 35 or several pairs of groups of transistors 30, 35 are connected in parallel to each other, the total resistance between input 1, 3 and output 2, 4 is decreased.

A second example of switching device 15 is shown in Figure 3 and will now be described. The elements identical to the first example of FIG. 1 are not described again. Only the differences are highlighted.

It should be noted that if a single switching device 15 comprising a single switching module 20 and a single control module 25 dedicated to the single switching module 20 is represented, embodiments in which several switching devices such as that of Figure 2, comprising a single module of control 25 common or a plurality of control modules 25 each associated with one of the switching modules 20, are also envisaged.

The switching device 40 has no moving contact 70, and instead comprises at least two second transistors 130 and 135, of a non-conducting type by default, connected in series between the two terminals 60 and 65.

The second transistors 130 and 135 are, for example, MOSFETs

The MOSFETs, according to the English acronym of "Metal Oxide Semiconductor Field Effect T ransistor", in French "transistor with field effect with metal-oxide-semiconductor structure or "transistor with field effect with insulated gate", are unipolar transistors .

The non-passing MOSFETs by default are said to be "enhancement", and are designed so that the application of a predefined electric potential on the gate leads to the accumulation in the channel of charge carriers which then allow the channel to be conductive, whereas in the absence of this potential the channel is devoid of free charge carriers and is therefore insulating.

In the example represented in FIG. 3, the two second transistors 130 and 135 are interposed between the two first transistors 30, 35 and connected to each other in series head to tail.

In particular, each second transistor 130, 135 is interposed between the source of a first transistor 30, 35 and point 55. For example, the drains of the two second transistors 130, 135 are connected to point 55 and the sources of these two second transistors 130, 135 are each connected to the source of a corresponding first transistor 30, 35 via a respective terminal 60, 65.

Furthermore, a diode 140 is connected in parallel between the source and the drain of each of the two second transistors 130, 135, the cathode of the diode being connected to the drain of the corresponding second transistor 130, 135 and the anode of the diode 140 connected to the source.

The gate of each second transistor 130, 135 is connected to the controller 110 so as to allow the controller 110 to turn on the second transistor 130, 135 by applying an electric voltage between point 55 (therefore the sources of the second transistors 130, 135) and the grille.

Point 55 is, for example, electrically connected to the drains of the two second transistors 130, 135 and to the gates of the two first transistors 30, 35, to allow the controller 110 to simultaneously control the two first transistors 30, 35 by the application of an electric voltage between point 55 and the gates of the first transistors 30, 35 before the switching off of the second transistors 130, 135. For example, point 55 is connected to a first point whose electric potential is fixed by controller 110 (for example fixed by the power supply of controller 110), while the gates of the second transistors 130, 135 are connected to a second point whose controller 110 is configured to modify the electric potential, the first point and the second point being connected by a predefined resistance.

The gates of the first transistors 30, 35 are connected to a third point whose controller 110 is configured to vary the electric potential. The third point is also connected to the first point by a predefined resistor.

Such an assembly makes it possible to separately control the MOSFETs 130, 135 and the JFETs 30, 35. In particular, it makes it possible to vary the voltage between the gate and the source of each of the JFETs 30, 35 without modifying the voltage between the gate and the source. the source of the MOSFETs, and thus to play on the conductivity of the JFETs 30, 35, in particular by imposing a slightly positive voltage (for example 2 V) between the gate and the source of the JFETs to increase their conductivity or by making the JFETs not -passages by imposing a negative voltage (for example -15V), without changing the behavior of the MOSFETs 130, 135.

Thus, the set of two second transistors 130, 135 and diodes 140 forms a switching device which is in its second configuration by default (in the absence of voltage imposed between the gate and the source of transistors 130, 135) but the application of a voltage causes each of the two transistors 130, 135 to switch to one of the two possible current flow directions, and therefore even if the current is alternating.

The operation of the second example is similar to the first example, the cutoff of the JFETs 30, 35 preceding the cutoff of the second transistors 130, 135, which therefore participate only in maintaining the cutoff and not in the interruption of a current in circulating, which therefore limits the stresses weighing on these second transistors 130, 135.

It should be noted that although the switching device 40 has been described, in the second example, as being formed of two transistors 130, 135 successively connected between the first two transistors 30, 35, which makes it possible to simplify the control of the switching module 20, the positioning of transistors 130 and 135 in the electrical circuit is likely to vary.

A switching device 40 with transistors, in particular with MOSFETs, allows faster switching than a moving contact relay, while providing insulation even in the absence of a control signal (ie in the event of failure or non- controller power supply 110). Additionally, the MOSFETS are small in size, which reduces the size of the system 10 compared to a system 10 using a relay 40. In addition, the MOSFETs are inexpensive.

According to one embodiment, the role of switching device 40 is played by the disconnector 45. In this case, the control means 100 do not act directly on the actuator 95, but act on the controller 110, which controls then the actuator 95 electrically. In particular, the electrical supply signal of the actuator 95 is cut by the controller 110 following the actuation of the control means by the operator.

It is thus avoided that the disconnector 45 is closed by the operator without the controller 110 being functional and not being able to ensure the breaking of the current if necessary via the transistors 30, 35.

Although the member 40 has been described here as comprising either a relay or a set of MOSFETs, it is obvious that other types of member 40 are likely to be used.

According to possible embodiments, an example of which is represented in FIG. 4, the switching system 10 comprises a single switching device 15 comprising a single input 1 and a plurality of outputs 2, as well as a single electrical circuit comprising at least two transistors 30, 35 between input 1 and each output 2.

In particular the two transistors 30, 35 or more are interposed between input 1 and a point 5 of the circuit to which all outputs 2 are connected.

A switching device 40 is interposed between each output 2 and point 5.

In the event of detection of a fault concerning a current supplied by an output 2 to an installation downstream of the output 2 in question, the controller 110 controls the cut-off of the current between input 1 and point 5, as well as the switching of each switching member 40 to its respective second configuration.

Then, the controller 110 commands the transistors 30, 35 to again let the current flow between input 1 and point 5, and switches back each of the switching elements 40 which do not correspond to output 2 with which the fault is associated. in its first configuration. On the other hand, the switching device 40 which corresponds to output 2 with which the fault is associated remains in its second configuration.

Thus, the breaking of the current in the event of a fault remains ensured despite the use of a single controller 110 and above all of a single set of transistors 30, 35, while the breaking of the currents associated with the outputs 2 which have not given rise to a fault is very short. The structure of the switching system 10 is therefore simplified compared to cases where the current to be sent to the various outputs 2, 4 would be supplied to several inputs 1, 3 each associated with a separate switching device 15 comprising its own set of transistors 30, 35 and its own switching device 40.

Such an embodiment is particularly conducive to the use of MEMS relays as switching devices 40, allowing rapid switching and therefore very short interruption of currents 2 which have not been associated with faults.

It should be noted that, as mentioned above, in the event of detection of a fault, the breaking of the current by the first transistors 30, 35 is controlled and effective before the switching device 40 and/or the disconnector 45 are each switched to their configuration in which they prevent the passage of current. This in particular avoids having to size these members 40, 45 to cut off the current, in particular to cut an electric arc which would occur if the members 40, 45 were operated to cut off the current while the current is flowing.

Generally speaking, this is the case regardless of the reason for the power outage. In other words, the controller 110 is configured to systematically cut off the first signal (which causes the switching device 40 to switch to its second configuration) at a time such that one of the first transistors 30, 35 at least, in particular the first two transistors 30, 35 have switched to their non-conducting state before the switching device 40 switches to its second position. For example, the first signal is interrupted after or at the latest at the same time instant when the current is cut by the first transistor or transistors 30, 35. This is the case for example if an external signal commands the controller 110 to cut off the current, for example if it is desired to cut off the current to work on a downstream installation.

When the system 10 starts up, if the member 100 is in a position in which it closes the disconnector 45, the controller 110 controls the switching of the switching member 40 from its second configuration (in which it prevents the passage of current ) until its first configuration (allowing the passage of current). Once the switching device 40 is in its first configuration, for example after a predetermined time period sufficient to allow this switching has elapsed, then the controller 110 controls the passage of each first transistor 30, 35 to its state passing.

In the event of action by an operator on member 100 to cut off the current, sensor 102 detects that member 100 is approaching the position in which member 100 causes disconnector 45 to open. this position is reached, the sensor 102 transmits to the controller 110 a signal which causes the emission of the third signals then, after a predetermined delay, cuts the first signal, so that the current is interrupted by the first transistors 30, 35 before the cut off the first signal. In addition, the sensor 102 is configured so that the current break by the transistors 30, 35 takes place at a time when the moving contact 90 is in contact with the two terminals 80 and 85, and before the moving contact moves away from one of these two terminals 80, 85. Thus, the interruption of the current is carried out by the transistors 30, 35 and not by the disconnector 45.

When the member 100 is switched back by the operator to restore the current, the controller 110 commands the closing of the member 40 before commanding the switching of the transistors 30, 35 into their on state by cutting off the third electrical signal.

It should be noted that although a switching device 15 in one piece is shown in the figures, according to a possible variant, the modules 20 and 25 are likely to be located in different parts and distant from one another. the other, but communicating with each other, of the switching device 15.

For example, the switching device 15 comprises a first device comprising the switching module 20 and a second device comprising the control module 25. In this case, the first device (or “switching device”) comprises for example a first housing and the second device (or “control device”) comprises a second box that is distinct and in particular remote from the first box.

The control device 25 is configured to transmit to the switching device 20 the various electrical signals, for example via an electrical conductor such as a cable.

Claims

1. Electrical switching device (15) comprising an input (1, 3), an output (2, 4), a switching module (20) and a control module (25), the switching module (20) being capable of conducting an electric current between the input (1, 3) and the output (2, 4), the control module (25) being configured to detect an electrical fault and to control the interruption of the current by the switching (20) in the event of detection of a fault, characterized in that the switching module (20) comprises an electrical circuit configured to conduct the current between the input (1, 3) and the output (2, 4) , the circuit comprising, in series, at least two first JFET transistors (30, 35) normally on head to tail and at least one switching element (40) comprising a first terminal (60) and a second terminal (65), the the switching member (40) being configured to switch between a first configuration and a second configuration, the switching member (40) per placing the passage of current between the first terminal (60) and the second terminal (65) when the switching element (40) is in the first configuration, the switching element (40) preventing the passage of current when the switching member (40) is in the second configuration, the switching member (40) being in the second configuration by default, the control module (25) being configured to generate at least a first electrical signal capable of maintaining the switching device (40) in the first configuration, the control module (25) being configured to, in the event of detection of a fault, generate at least a second electrical cut-off signal intended for a first transistor (30, 35), each second signal being able to control the interruption of the current by the corresponding first transistor (30, 35), the control module (25) being configured to interrupt the first signal in response to the detection.

2. Switching device according to claim 1, wherein the switching member (40) comprises a first actuator (75) and a first contact (70) electrically conductive, the first contact (70) being movable between a first position and a second position, the first contact (70) being in the first position when the switching member (40) is in the first configuration and being in the second position when the switching member (40) is in the second configuration, the first contact (70) conducting the current between the first terminal (60) and the second terminal (65) when the first contact (70) is in the first position, the first contact (70) being separated by at least one of the first and second terminals (60, 65) when the first contact (70) is in the second position, the first actuator (75) being configured to hold the first contact (70) in the first position when the actuator (75) is energized with the first electrical signal.

3. Switching device according to claim 1, in which the switching device (15) comprises two second MOSFET transistors (130, 135), of the non-conducting type by default, in series head to tail between the first terminal (60) and the second terminal (65), each second transistor (130, 135) conducting current when the second transistor (130, 135) is energized by a respective first signal and preventing current from flowing in the absence of the first signal.

4. Switching device according to any one of claims 1 to 3, wherein the circuit further comprises a disconnector (45) connected in series with the first transistors (30, 35) and with the switching member ( 40), the disconnector (45) comprising a third terminal (80), a fourth terminal (85), a second contact (90), a second actuator (95) and a control member (100), the second contact (90 ) being movable between a third position and a fourth position, the second contact (90) conducting current between the third terminal (80) and the fourth terminal (85) when the second contact (90) is in the third position, the second contact (90) being distant from at least one of the third and fourth terminals (80, 65) when the second contact (90) is in the fourth position, the second actuator (95) being configured to move the second contact (90) between the third position and the fourth position when the control member (100) is operated by an operator.

5. Device according to claim 4, wherein the control member (100) is a rotary handle.

6. Device according to any one of claims 1 to 3, comprising a control member (100) operable by an operator to control the cutoff, by the control module (25), of the first signal.

7. Device according to any one of the preceding claims, in which each first transistor (30, 35) comprises a source, a drain and a gate, the sources of two of the first transistors (30, 35) being interposed, along the current path, between the drains of said two first transistors (30, 35).

8. Device according to any one of the preceding claims, in which the number of first transistors (30, 35) is greater than or equal to four, the first transistors (30, 35) being divided into pairs of groups of first transistors (30 , 35), each group containing at least one first transistor (30, 35) the first transistors (30, 35) of each group being connected successively to each other in series in the same direction if the group comprises more than one first transistor (30, 35), each first transistor (30, 35) of a group being in the different direction from the first transistor or transistors (30, 35) of the other group of the same pair, each group of a pair being connected in series to the other group of the pair, the pairs being connected in series to each other.

9. Device according to any one of the preceding claims, in which the first transistors (30, 35) are made of SiC or GaN.

10. Device according to any one of the preceding claims, comprising a single input and a plurality of outputs (2), each output (2) being connected to a single point (5), the first transistors (30, 35) being interposed between the input (1) and the said single point (5), the switching module (20) comprising, for each output (2), a respective switching device (40) interposed between the output (2) and the said single point (5).

11. Device according to any one of the preceding claims, comprising a switching device and a control device, the switching device comprising the switching module (20), the control device comprising the control module (25) , the switching device and the control device being remote from each other and being configured to communicate with each other.

12. Switching system (10) configured to transmit a plurality of currents between respective inputs (1, 3) and outputs (2, 4), to detect an electrical fault relating to at least one of said currents, and to interrupt at the minus the corresponding current in the event of detection of an electrical fault, comprising a plurality of switching devices (15) according to any one of the preceding claims.

13. A method of switching a current, implemented by an electrical switching device (15) comprising an input (1, 3), an output (2, 4), a switching module (20) and a module of control (25), the switching module (20) being able to conduct an electric current between the input (1, 3) and the output (2, 4), the switching module (20) comprising an electric circuit configured to conduct the current between the input (1, 3) and the output (2, 4), the circuit comprising, in series, at least two first JFET transistors (30, 35) normally on head to tail and at least one switching device (40) comprising a first terminal (60) and a second terminal (65), the switching device (40) being configured to switch between a first configuration and a second configuration, the switching device (40) allowing the passage of current between the first terminal (60) and the second terminal (65) when the switching element (40) is in the first configuration tion, the switching member (40) preventing the passage of current when the switching member (40) is in the second configuration, the switching member (40) being in the second configuration by default, the method comprising steps of:

- generation (200), by the control module (25), of at least one first electrical signal capable of maintaining the switching device (40) in the first configuration,

- detection (210) of an electrical fault by the control module (25),

- following the detection of a fault, interruption (220) of the first signal by the control module (25) and generation (230) by the control module (25) of a second electrical cut-off signal intended for each first transistor (30, 35),

- following receipt of the corresponding second signal, interruption (240) of the current by at least one first transistor (30, 35), and

- switching (250) of the switching member (40) in the second configuration.