Prototype Design Of Various Arc Extinguishing Medium DC Contactors And Experimental Analysis

The DC power supply and distribution systems,such as electric vehicles,all-electric aircrafts,and photovoltaic power generation,have been rapidly developed and accompanied by the rapid rise of new energy fields in China.DC contactor,with the advantages of low power consumption and high sensitivity for breaking the DC circuit is an important switching device.So its electrical life and reliability are directly related to the success of the equipment operation,and even endanger the safety of personal and property.When the DC contactor contacts open,arcs are unavoidably generated.If the high-temperature arcs burn seriously,the surface of the contact will be ablated and the contact material will be lost,resulting in failure of the breaking.Therefore,studying the arcing characteristics of DC contactor arc is the core of improving its reliability and electrical life.This paper studies the influence of multi-physical factors such as pressure,magnetic field and breaking speed on DC arc characteristics in different arcing media,and finds the parameters that are most favorable to extinguish arc by experiments and simulation methods,it helps to reveal DC switch short circuit breaking process of H₂ and other dielectric.In this paper,the structure of the experimental prototype is designed that combining with the research status at home and abroad and the existing DC contactor products.The prototype can realize the function of arc extinguishing medium and pressure can be changed,the strength of the arc blowing magnetic field and the contact breaking speed can be adjusted,and the installation and operation are convenient,even the actual working process of the DC contactor can be simulated.The prototype experiment circuit is built as a 220V/200A DC resistive circuit;the hardware detection circuit design includes the design of the acquisition card,sensor,conditioning circuit and other aspects;the electronic control acquisition system is based on Lab VIEW software development,including the control module,data acquisition module,data processing module,data display modules,etc,which can complete the control of the experimental process,data acquisition and data real-time display and storage.In terms of experiments,the arc development process is divided into the arc starting phase,the arc striking phase,the arc blowing phase and the arc extinguishing phase by analyzing the typical characteristics of DC arc voltage,current and power waveforms,and explaining the characteristics of each phase;studying the breaking capacity of different arc extinguishing media?H₂?N₂?H_e?,selecting the media with good breaking performance?H₂?N₂?to further study the pressure,magnetic field,breaking speed,and the mixing ratio of various arc extinguishing media.Analyzing the influence of multiple physical factors on DC breaking to find the best method of breaking.In terms of simulation,using the first kind of boundary condition,MHD dynamic simulation is performed on the arcing process of the arc,and the key factors affecting the arc characteristics are studied,in addition simulating analysis of the dynamic process of typical H₂,N₂ arc breaking experiments and the breaking capacity of specific conditions.Suppleme-nting certain phenomena and movements of the arc which can provide certain reference for the design of sealed DC contactors.