IGCT门阴极换流路径杂散阻抗在线监测方法研究

Study on the On-line Measurement of Stray Impedance of IGCT Commutated Path

集成门极换流晶闸管(integrated gate commutated thyristor,IGCT)换流路径杂散阻抗是评估其关断能力的重要参数,现有离线测量方法有诸多缺陷并且测试过程复杂,实时性差。该文主要针对IGCT换流路径杂散阻抗在线监测问题,结合IGCT关断过程,分析了换流路径杂散阻抗的构成;根据基尔霍夫电流定律(Kirchhoff’s current law,KCL)、基尔霍夫电压定律(Kirchhoff’s voltage law,KVL)推导了换流路径电压、电流方程,进而提出基于阴极集成印刷电路板(printed circuit board,PCB)式电流传感器的换流路径杂散参数在线监测方法;采用高速采集卡和LabVIEW软件,构建了测量系统;通过在高压、大电流加速老化测试平台上的实际测试,实现了mΩ级电阻与nH级电感的杂散阻抗准确提取,验证了在线监测方法的有效性。

The stray impedance of the IGCT’s commutated path is an important parameter for evaluating its turn-off commutated ability.The existing off-line measurement methods have many defects,complicated testing processes,and poor real-time performance.In this paper,the composition of the stray impedance of the commutated path is analyzed,aiming at the problem of online monitoring of the stray impedance of the commutated path combined with the IGCT turn-off process.Based on KCL and KVL,the voltage and current equations of the commutated path are given,and an online monitoring method of commutated path stray impedance based on a cathode integrated PCB current sensor is proposed.The measurement system is constructed using high-speed digitizers and LabVIEW software.Through the actual test on the high voltage and high current accelerated aging test platform,the accurate extraction of the stray impedance of mΩ class resistance and nH class inductor is realized,and the effectiveness of the online monitoring method is verified.