Current monitoring electronic arc extinguishing device

Abstract

A current monitoring type electronic arc-extinguishing apparatus, which is a current monitoring type electronic arc-extinguishing apparatus suitable for conducting arc extinguishing on a mechanical switch (SW1). The apparatus comprises a power semiconductor device (TR1) connected to the mechanical switch (SW1), wherein at least one current transducer (CT1) is connected to the mechanical switch (SW1), and the current transducer (CT1) is used for detecting whether the mechanical switch (SW1) is switched off; the output end of the current transducer (CT1) and the control end of the power semiconductor device (TR1) are connected to a control circuit (A); and the control circuit (A) controls the power semiconductor device (TR1) to be switched off when the current transducer (CT1) detects that the mechanical switch (SW1) is switched off. The current monitoring type electronic arc-extinguishing apparatus has the advantages of short thyristor conduction time and high reliability.

Description

technical field [0001] The current monitoring electronic arc extinguishing device of the present invention belongs to the field of electricity, in particular a current monitoring electronic arc extinguishing device suitable for arc extinguishing in contactors, relays, circuit breakers and other mechanical switches. Background technique [0002] At present, in the electrical control system, mechanical switches such as contactors and relays are widely used to control the on-off of the load. However, due to the arc extinguishing grid used for ordinary arc extinguishing, it needs to pull the breaking arc to a certain length before it can work. The effect is poor, and the arc is large when the load is switched on and off, which leads to the disadvantage that the contacts are easily burned. [0003] For this reason, arc extinguishing devices for mechanical switch arc extinguishing have appeared, such as the patent No. CN01201907.0, named "electronic arc extinguisher"; Contactor p...

AI Technical Summary

Problems solved by technology

[0002] At present, in the electrical control system, mechanical switches such as contactors and relays are widely used to control the on-off of the load. However, due to the arc extinguishing grid used for ordinary arc extinguishing, it needs to pull the breaking arc to a certain length before it can work. The effect is poor, and the arc is large when the load is switched on and off, which leads to the disadvantage that the contacts are easy to burn out

[0003] For this reason, arc extinguishing devices for mechanical switch arc extinguishing have appeared, such as the patent No. CN01201907.0, named "electronic arc extinguisher"; Contactor passive switch drive controller", disclosed by the two patents, adopts the method of parallel connection of thyristor and contactor mechanical switch, the control circuit of the two patents is connected with the control terminal of the thyristor, and provides a thyristor before the contactor mechanical switch is broken. Conduction control signal, during the breaking process of the mechanical switch of the contactor, when the mechanical switch is breaking, the filter capacitor of the control circuit is discharged to delay, and the control signal for delaying the turn-on of the thyristor is turned off, the thyristor is cut off, and the arc-free breaking process is completed , since there is an uncertain delay time from the power loss of the control coil of the contactor to the breaking of the mechanical switch, in order to ensure that the thyristor is turned off after the mechanical switch is broken to ensure reliable arc extinguishing, the thyristor needs to be turned on for a long time (usually within several More than 10 milliseconds), this kind of arc extinguishing control method, which adopts the control method of delaying the closing of the control signal after the mechanical switch is broken, will inevitably increase the unnecessary and redundant conduction working time of the thyristor, and the long conduction working time of the thyristor will lead to the overload of the entire arc extinguishing device Poor capability and low reliability. At the same time, the working power of the control circuits of the above two patents must be provided by the drive circuit of the mechanical switch (which serves as the synchronization signal of the control circuit), so it is not applicable to mechanical switches without drive circuits such as circuit breakers.

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