逆变器的电容老化故障诊断方法研究

Research on Capacitor Aging Fault Diagnosis Method of Inverter

针对逆变器电容老化故障的特征不明显、提取困难,且存在多分类、细分类问题,提出一种自适应白噪声完整集合经验模态分解(completeensembleempiricalmode decomposition with adaptive noise,CEEMDAN)与小波包能量熵(wavelet packet energy entropy,WPEE)结合的特征提取策略,并利用改进麻雀搜索算法(improvedsparrow search algorithm,ISSA)优化最小二乘支持向量机(least squares support vector machine,LSSVM)参数,完成故障诊断。首先,利用CEEMDAN处理相电压信号,获得模态分量(intrinsic mode function,IMF),根据相关系数、方差贡献率共同筛选IMF,将含噪的IMF去噪并重构,与不含噪的IMF构成纯净IMF组,然后利用小波包分析并对其分解获取故障特征明显的WPEE;其次,通过Iterative混沌映射与随机游走策略改进的SSA对LSSVM进行参数寻优,建立诊断模型;最后,以Z源逆变器为例进行验证。结果表明:所提方法能快速有效地提取电容老化故障特征,且诊断方法更快、故障识别率更高。

In order to solve the problems of multiple classification and subclassification,a feature extraction strategy combining adaptive white noise complete set empirical Mode decomposition and wavelet packet energy entropy was proposed.The parameters of least squares support vector machine are optimized by the improved Sparrow search algorithm.Firstly,the phase voltage signal was processed by CEEMDAN to obtain the modal component,and IMF was screened jointly according to the correlation coefficient and variance contribution rate.The IMF with noise was denoised and reconstructed,and the IMF without noise was formed into the pure IMF group.Then,WPEE with obvious fault characteristics was decomposed by wavelet packet analysis.Secondly,LSSVM parameters are optimized by using Iterative chaotic mapping and the improved SSA based on random walk strategy,and the diagnostic model is established.Finally,Z-source inverter is taken as an example for verification.The results show that the proposed method can extract capacitor aging fault features quickly and effectively,and the diagnosis method is faster and the fault recognition rate is higher.