电子束轰击炉高压电源故障分析及对策

Fault Analysis and Countermeasures for High Voltage Source of Electron Beam Bombarding Furnace

电子束轰击炉运行过程会产生高压放电现象,严重时可能损坏高压整流硅堆。通过深入分析,指出其成因是由于高压整流变压器漏感较大和系统采用大电感高压滤波,当高压放电时电子束流剧增,三相桥式整流电路运行于一种强迫延时换相角αp=30°和换相重叠角γ≥60°的故障状态,时间过长必然导致高压整流硅堆热损坏。为此提出3点改进措施:直流高压输出端设置扼流电抗器以抑制电子束流的上升速度;控制电路检测直流高压输出的下降突变信号,快速判断高压放电的发生;高压电源供电回路串接晶闸管,用于软起动及快速切断供电电源。实践证明:对高压整流硅堆损坏的原因分析是正确的,所采取的应对策略是有效的。

High-voltage （HV） discharge phenomena, which appear in the working process of electron beam bombar- ding furnace（EBBF）, may result in failure of HV silicon rectifier stack （SRS） in the worst cases. After thorough analysis, it is concluded that, due to the relatively large leakage inductance of rectifying transformer and large inductor of the HV filter, the three-phase HV-SRS is forced to work in a fault state of forced delay commutating angle αp = 30° and overlapping angleγ≥60° when HV discharge happens and electron beam current （EBC） surges. To handle this issue, three measures were taken： 1 ） a choke reactor was inserted at the HV output to restrain the EBC ris- ing rate; 2） a specified control circuit was designed to quickly evaluate the occurrence of HV discharge; 3） a thyristor was series-connected to HV power supply loop for its soft starting and fast turning off. Application results show that the analysis about the HV-SRS＇s failure is correct and the measures taken against this failure are effective.