大功率直流接触器在不同介质中开断电弧特性的实验研究

The rapid development of electric vehicles and the improvement of the power supply capacity of aviation systems pose higher demands on high-power DC contactors. In order to study the influences of the type and pressure of gases sealed in a DC contactor on the arc characteristics during the breaking process, a prototype of the bridge-type DC contactor with a one-way valve was designed and a DC breaking circuit experiment setup was built. The measured data under different gases and pressures, such as arc voltage, arc current, duration time, and arc energy were obtained. The influences of gas medium and pressure on characteristics of DC arc were analyzed in detail. The results show that the arc burning process of DC contactor can be divided into three stages, in which the duration of elongation stage when arc column is between the moving and static contacts accounts for more than 60% of the total arc burning time. When the pressure is 0.3 MPa, the arc duration of hydrogen, nitrogen and helium at 200 V/1 200 A is 1.20 ms, 1.42 ms and 1.54 ms, respectively. The peak voltage of hydrogen arc is much higher than that of other two kinds of gas arc, and the arc burning energy is the lowest, which shows that hydrogen has excellent arc extinguishing performance. When the pressure rises from 0.1 MPa to 0.3 MPa, the arc extinguishing performance of the three gases is significantly improved, which is reflected in the reduction of the arc burning time by 17%, the decrease of arc burning energy by 15%, and the acceleration of arc motion.