摘要
维持和提高焊接电弧的稳定性是变极性GTAW焊接的关键。对于采用两级逆变的变极性焊接电源,二次逆变电路拓扑及其控制策略对输出电流极性切换过程和焊接电弧的稳定性具有显著影响。在分析变极性GTAW焊接电弧稳定问题的基础上,提出了维持和提高焊接电弧稳定性的措施。通过增加电流极性切换速度,在电流过零瞬间维持电弧空间的温度和残余电离度;小电流焊接时,在电流极性切换之前叠加电流脉冲,以提高电弧空间的温度和电离度;在电流过零熄灭瞬间,叠加足够高的电压脉冲,使电弧能够立即再引燃。进而,通过对全桥式二次逆变电路拓扑、半桥式二次逆变电路拓扑及其控制策略的分析,指出了它们的适用范围、存在的不足以及改进的途径。
During the variable polarily GTAW welding process,it is the key to maintain and improve the arc stability.Referring to a variable polarity GTAW welding power＇ supply with two stage inverters,the secondary inverter topologies and their relevant control strategies have greatly influence on the characteristics of the output current commutating process and the arc stability.In this paper, the arc stabilizing mechanism of variable polarity GTAW welding proc, ess is analyzed,and then the methods to maintain and improve the arc stability are proposed.By increasing the commutation rate of output current,the temperature and the degree of gas ionization in arc zone can be held when current zero-crossing.In the case of welding with a small current,the temperature and the degree of gas ionization can even be increased by adding a current pulse just belbre the polarity exchange.And also,a high voltage promotes the arc reigniting when eun＇ent zero-crossing.After analyzing the full-bridge and half-bridge topologies of the secondary inverter as well as their relevant control strategies ,their applicable limits,existing disadvantages and improving ways are pointed out,
出处
《电焊机》
北大核心
2009年第2期24-29,共6页
Electric Welding Machine
关键词
变极性焊接电源
二次逆变
全桥电路
半桥电路
稳弧
avariable polarity welding power supply
secondary inverter
full-bridge circuit
half-bridge circuit
arc stabilization
