基于Prony算法的三电平逆变器开路故障诊断方法

针对传统基于信号分析的中性点箝位(NPC)逆变器故障诊断方法存在频谱易泄露,及难以分析非稳态、非线性故障信号的问题,提出一种基于Prony算法的三电平逆变器开路故障诊断方法。首先,采用小波变换对原始测量信号去噪预处理,克服Prony法对噪声敏感的缺点。其次,通过Prony分析拟合逆变器的三相电流信号,提取其幅值、频率、相位、衰减因子四维故障特征。然后,应用支持向量机(SVM)对中性点箝位逆变器故障进行分类。最终,在仿真平台上验证文中所提算法,仿真结果表明,对中性点箝位逆变器开路时瞬变非线性电流信号可以有效的提取故障特征,实现单、双管的开路故障诊断。

Open circuit fault diagnosis method of three-level inverter based on Prony Algorithm

Aiming at the traditional fault diagnosis method of neutral point clamped inverter(NPC) based on signal analysis, it is prone to spectrum leakage and has the problems of signal nonlinearity and unsteady state. An inverter open-circuit fault diagnosis method based on the Prony algorithm is proposed. Firstly, wavelet transform is used to denoise the original measurement signal to overcome the disadvantage that the Prony method is sensitive to noise. Secondly, the Prony analysis method is used to extract the four-dimensional fault characteristics of amplitude, frequency, phase, and attenuation factor by fitting the three-phase current signal of the inverter. Then, a support vector machine (SVM) is used to classify the neutral point clamped inverter faults. Finally, the proposed algorithm is verified on the simulation platform. The simulation results show that the transient nonlinear current signal of neutral point clamped inverter can effectively extract the fault characteristics and realize the open circuit fault diagnosis of single and double transistors, and this method is fast and accurate in diagnosis.