US-12620542-B2 - Electrical protection devices and systems

US12620542B2US 12620542 B2US12620542 B2US 12620542B2US-12620542-B2

Abstract

An electrical protection system has connection terminals, separable electrical contacts, a switching mechanism and at least one power switch connected in series with the separable electrical contacts, the switching mechanism including a displaceable control member. The electrical protection system further includes an electronic control circuit coupled to the at least one power switch and a sensor coupled to the control member for measuring a position of the switching mechanism. 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 in which the electrical contacts separate.

Inventors

Eric Domejean
Jérôme BRENGUIER
Frédéric Court

Assignees

SCHNEIDER ELECTRIC INDUSTRIES SAS

Dates

Publication Date: 20260505
Application Date: 20220519
Priority Date: 20210520

Claims (14)

1 . 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 to the separable electrical contacts to switch the separable electrical contacts to the open state, an electronic control circuit coupled to said at least one power switch, a sensor coupled to the control lever to measure a position of the switching mechanism, wherein the electronic control circuit is configured to switch said at least one power switch to an off state when the sensor detects that the switching mechanism has reached a position preceding a position from which the separable electrical contacts separate, wherein a movement of the control lever of the switching mechanism is configured to cause an angular offset between the rotation of the control lever and moving to the open state of the separable electrical contacts, wherein the angular offset enables compensating for a reduction in a clearance of the separable electrical contacts caused by wear of the separable electrical contacts.
2 . The electrical protection system as claimed in claim 1 , wherein the electronic control circuit is configured to switch said at least one power switch to the off state when an electrical fault is detected by a measuring circuit.
3 . The electrical protection system as claimed in claim 1 , wherein the electrical protection system comprises an internal electrical power supply configured to electrically power the electrical control circuit using the electrical voltage across the connection terminals.
4 . The electrical protection system as claimed in claim 1 , wherein said at least one power switch is a MOSFET.
5 . The electrical protection system as claimed in claim 1 , wherein said at least one power switch is normally open.
6 . The electrical protection system as claimed in claim 1 , wherein the electronic control circuit comprises a plate-shaped substrate and a conductive plate making contact with a metal backing of said corresponding at least one power switch, said at least one power switch and its respective conductive plate being mounted on one or each face of the substrate.
7 . The electrical protection system as claimed in claim 6 , wherein at least one of the conductive plates comprises a segment configured to form a fixed electrical contact that interacts with a mobile electrical contact to form together said separable electrical contacts.
8 . The electrical protection system as claimed in claim 1 , wherein the switching mechanism is a toggle mechanism.
9 . The electrical protection system as claimed in claim 1 , wherein the electrical protection system is configured such that, to close the separable electrical contacts, the control lever is configured to be moved to the corresponding position by a user, this movement, by way of a link rod of the switching mechanism, driving a hook of the switching mechanism to rotate, the hook becoming hooked on a tripping bar of the switching mechanism, the link rod then driving a deck of the switching mechanism to rotate until the separable electrical contacts close.
10 . The electrical protection system as claimed in claim 1 , wherein the electronic control circuit is configured to switch said at least one power switch to an off state when the sensor detects that the switching mechanism has reached a position immediately preceding a position from which the electrical contacts separate.
11 . An electrical protection device comprising a casing and the electrical protection system as claimed in claim 1 , wherein the electrical protection device is a miniature circuit breaker.
12 . The electrical protection device as claimed in claim 11 , wherein the electronic control circuit and said at least one power switch are housed in a dedicated compartment inside the casing.
13 . The electrical protection device as claimed in claim 11 , wherein the width of the casing is a multiple of 9 mm.
14 . An electrical protection device comprising a casing and the electrical protection system as claimed in claim 1 , wherein the electrical protection device is an air circuit breaker.

Description

TECHNICAL FIELD The present invention relates to the technical field of electrical protection devices and systems, such as circuit breakers. PRIOR ART Many electrical switching devices of electromechanical type, such as air circuit breakers, and in particular miniature circuit breakers (MCBs) generally comprise a quenching chamber. The quenching chamber is configured to extinguish an electric arc that appears in the air between the electrical contacts of the device when the electrical contacts are separated after the device is tripped. The quenching chamber typically comprises a stack of metal plates that are superposed one above the other to lengthen and extinguish the electric arc. One or more apertures in the casing allow the quenching gases to be discharged from the device. However, in order to improve the performance of these protection devices, it has been proposed to replace the quenching chamber with an electronic breaking device comprising power switches based on semiconductor components. Such improved performance is advantageous, for example, in direct-current (DC) electrical systems comprising batteries of electrochemical accumulators, as the electrical protection devices of such systems must be capable, in the event of the occurrence of an electrical fault, of interrupting high-amplitude currents with a very rapid reaction time. These semiconductor-based protection devices must be capable of interrupting the electrical current with at least as much reliability as electromechanical protection devices. In addition, for safety reasons, these protection devices must be galvanically isolated. It is therefore advantageous to preserve separable electrical contacts as they allow an air gap to be formed when the device is in the open state (i.e., when the electrical contacts are separated, for example after the device has been tripped, or when a user wishes to isolate the installation located downstream of the protection device). Moreover, for the sake of compatibility with existing installations, it would be desirable for these protection devices to be able to be contained in a casing having the same size as the casings of switching devices of electromechanical type. There is therefore a need for electrical protection devices, such as circuit breakers, based on semiconductor components, which at least partially remedy these drawbacks. SUMMARY OF THE INVENTION To this end, 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 mobile control member and being coupled to the separable electrical contacts with a view to switching the separable electrical contacts to the open state, the electrical protection system further comprising an electronic control circuit coupled to said at least one power switch. The electrical protection system further comprises a sensor coupled to the control member and configured to measure a position of the switching mechanism, and the electronic control circuit is configured to switch said at least one power switch to an off state when the sensor detects that the switching mechanism has reached a position preceding a position from which the electrical contacts separate. By virtue of the invention, in the opening phase, the control circuit and the sensor allow the power switches to be switched to their off state before the electrical contacts are separated, this preventing the occurrence of an electric arc and thus allowing the current to be interrupted safely. In contrast, once the contacts are in the open position, the electrical contacts allow an air gap to be created. This prevents electrical current, such as leakage current from the power switches, or current resulting from a failure of these power switches, from being able to flow anew between the terminals after the device has been tripped. According to some advantageous but non-mandatory aspects, such an electrical protection device may incorporate one or more of the following features, taken alone or in any technically permissible combination: the electronic control circuit is configured to switch said at least one power switch to the off state when an electrical fault is detected by a measuring circuit;the electrical protection system comprises an internal electrical power supply configured to electrically power the electrical control circuit using the electrical voltage across the connection terminals;said at least one power switch is a MOSFET;said at least one power switch is normally open;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 su