VSC-HVDC送端换流器IGBT开路故障诊断方法

为了实现VSC-HVDC系统送端换流器IGBT开路故障的在线诊断,首先基于送端换流器拓扑结构得到了换流器开关函数模型,给出了基于开关函数的三相电压残差定义;然后推导了2类单桥臂IGBT开路故障和4类双桥臂IGBT开路故障下的三相电压残差计算公式,分析了IGBT开路故障的电压残差特征。基于此,通过设定电压残差阈值和IGBT故障标志,提出了基于电压残差的送端换流器IGBT开路故障诊断方法。最后,对所提诊断方法进行了半实物实验验证,实验结果表明,所提方法能够准确诊断出各类单桥臂IGBT开路和双桥臂IGBT开路故障,且具有一定的抗干扰性能。

IGBT open-circuit fault diagnosis for VSC-HVDC rectifier

In order to realize the online diagnosis for IGBT open-circuit fault in VSC-HVDC rectifier,firstly,switching function model of the rectifier based on the topology of the rectifier was obtained,and the definition of three-phase voltage residual based on the switching function was given.Then,the three-phase voltage residual calculation formulas of two types of single-bridge IGBT open circuit and four types of double-bridge IGBT open-circuit faults were derived,and the voltage residual characteristics of IGBT open-circuit faults were analyzed.By setting the voltage residual threshold and the IGBT fault flag,a method for IGBT open circuit fault diagnosis based on voltage residual was proposed.Finally,the proposed method is verified by PSCAD/EMTDC platform.The simulation results show that the proposed method is able to diagnose single bridge and double bridge IGBT open-circuit faults accurately.