中频条件下真空灭弧室的纵向磁场仿真

该文研究了中频400～800Hz条件下纵磁真空灭弧室内的磁场特性,利用Ansys Maxwell求解了三维瞬态纵向磁场分布.由计算结果可知:在电流变化的过程中,中心区域纵向磁场的变化明显滞后于其他区域.电流峰值时在触头片开槽交错放置的位置有磁场峰值区域,电流过零时中心区域有明显剩磁.当频率增加时,涡流效应更明显,使纵向磁场的磁感应强度值减弱.对中心点,频率提高导致过零时剩磁增加,磁场滞后相位更明显,影响电弧扩散.增加触头片开槽数可以减弱涡流效应,而增加触头杯座槽旋转角,触头中间平面磁感应强度的最大值近似线性增加.文中通过分析电弧形态和电压等实验结果验证了磁场滞后对真空灭弧室的开断能力的影响.

Simulation of Axial Magnetic Field in Vacuum Arc Interrupters at Intermediate Frequency

Characteristics of axial magnetic field (AMF) vacuum interrupters in intermediate-frequency (IF, 400-800Hz) power system of more electric aircraft is researched in this paper. The AMF distribution is solved by Maxwell. It can be concluded by the calculation as follows: In the process of current change, the axial magnetic field changes slower in the central region than in other regions. The peak area of the magnetic field is located between the interlaced slots, and there is a significant residual magnetic field in the center area at current zero. When the frequency increases, the eddy effect is so serious that the magnetic flux density of the AMF decreases. For the center point, the residual magnetic field is stronger and the lag phase is bigger on account of the frequency increase, which will prevent the arc plasmas from diffusing. The eddy effect can be reduced by adding the number of slot in the contact blade. The maximum of the magnetic flux density is increased approximately linearly by adding the rotation angle of contact. The influence of magnetic field hysteresis on the breaking capacity of the vacuum interrupter is verified by experiments including arc appearance and arc voltage.