三电平有源电力滤波器IGBT开路故障诊断方法研究

摘要

针对三电平中点钳位式(Neutral Point Clamped,NPC)有源电力滤波器(Active Power Filter,APF)中功率器件IGBT开路故障的诊断问题,提出采用小波包分析故障信号,提取各频段能量系数作为故障特征,并利用网格搜索支持向量机(Support Vector Machine,SVM)进行分类的诊断方法.将所提方法应用于三个测试点进行测试,分别为逆变输出侧三相补偿电流、直流侧电容电压、电源侧三相电流,然后针对各信号的特点完成故障特征提取与故障类型识别,最后在谐波源三相整流桥触发角变化时进行了适应性实验,结果表明所提出的方法可分别基于三个测试点实现故障诊断,并且基于直流侧电容电压的测量方式对谐波源变化有良好的适应性.%Aiming at the problem of open-circuit fault diagnosis of IGBT in three-level neutral point clamped active power filter,this paper presents a diagnosis method which adopts wavelet packet to analyze fault signal,extract the energy coefficient of each frequency band as the fault feature,and use the grid search support vector machine (SVM)to classify the fault type.The proposed method is applied to three test points respectively,and the test points are the inverter output side of the three-phase compensation current,DC-side capacitor voltage,power supply side of the three-phase current.Then,the fault feature extraction and fault type recognition are completed according to the characteristics of each signal.Finally,the adaptive experiment is carried out when the triggering angle of the three-phase rectifier bridge alternates.The results show that the proposed method can realize fault diagnosis based on three test points respectively,and the measurement method based on the DC side capacitor voltage has good adaptability to the alternation of the harmonic source.