A DC contactor

Abstract

The embodiment of the invention discloses a DC contactor. The DC contactor comprises a contact unit, an arc extinguishing magnetic control assembly, an excitation magnetic coil system and an actuating system. With the DC contactor designed by the invention, an automatic magnetic field of the arc extinguishing magnetic control assembly can be generated, magnetic blow-out arc extinguishing of a DC arc is achieved, the dependence of a traditional high-voltage DC contactor on an external magnetic blow-out device is eliminated, and the influence of degradation failure, gassing, single strength and the like of the external magnetic blow-out device on DC arc extinguishing is prevented; and meanwhile, with the adoption of non-polarity DC magnetic blow-out arc extinguishing, the DC contactor has the advantages of high reverse DC load disconnection capability.

Description

technical field [0001] This application relates to the field of electricity, in particular to a DC contactor. Background technique [0002] High-voltage and high-current DC contactors are mainly used for switching on and off DC currents in various new energy fields, and are widely used in solar photovoltaic systems and other DC systems, such as the switching of DC side currents of photovoltaic inverters, vehicle-mounted systems such as urban rail, Metro, electric vehicles, charging piles, energy storage battery packs, and other uninterruptible power supplies, communications industries and other fields. [0003] Since there is no natural zero-crossing point for DC current, and the arcing time and overvoltage conditions of the arc are more severe when breaking, the breaking of DC current is much more difficult than the breaking of AC current. In order to improve the DC breaking capacity of DC contactors, high-voltage DC contactors often take measures to dissipate the DC arc e...

AI Technical Summary

Problems solved by technology

[0005] With the increasing power consumption of the electrical system in the application field, the requirements for the electrical capacity of the DC contactor are continuously increasing, and the requirements for the reverse current switching capability of the contactor are also more stringent. However, the magnetic blowing device of the traditional DC contactor is used as an external The components are arranged in a closed arc extinguishing chamber, which has a complex structure and high cost. At the same time, its arc extinguishing effect also has disadvantages. First, it is affected by the high temperature of the arc during the DC breaking process. The deterioration and loss of magnetism are serious, and the magnetic blowing effect is significantly reduced, resulting in a decrease in the DC breaking capacity; secondly, the magnetic blowing device mostly uses ferrite, NdFeB and other ferromagnetic materials, and more impurity gases will be precipitated during the breaking process. The saturated vapor pressure of the impurity gas is very high, which will lead to an increase in the DC arc voltage and arc energy, which is also very unfavorable to the breaking of the DC load; again, the magnetic field strength of the traditional magnetic blowing device remains unchanged, and the breaking of overload or too low DC The effect of magnetic blowing under load cannot be guaranteed

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