中文摘要：

针对逆变器开关元件的开路故障,提出一种级联H桥多电平逆变器故障诊断与容错控制策略。在不改变级联H桥多电平逆变器电路拓扑的情况下,通过快速傅里叶变换（fast fourier transform,FFT）和主元分析（principal component analysis,PCA）对逆变器原始开路故障数据进行了预处理和特征提取,构建贝叶斯网络（Bayesian netw ork,BN）对级联H桥多电平逆变器开关元件的故障进行快速诊断,根据诊断的结果,基于变载波和调制波电压重构容错控制方法,使逆变器输出电压仍能满足系统平稳运行的要求,通过仿真与试验验证了该策略具有良好的诊断及容错控制性能。

英文摘要：

To solve the open circuit faults of the switching device in multilevel inverters, a fault diagnosis and fault-tolerant control strategy was proposed for a cascaded H-bridge multilevel inverter. The fast fourier transform （FFT） and the principal component analysis （PCA） were utilized to reprocess and feature extraction respectively without changing the circuit topology of the cascaded H-bridge multilevel inverter. The faults of cascaded H-bridge multilevel inverters could be fast diagnosed with constructing Bayesian network（BN）. According to the fault diagnosis results, output voltages of the multilevel inverter could still meet the demands to keep the system operating smoothly. The way was based on a voltage reconstruction fault tolerant control method by changing the modulation waves and carder waves, and the performance of the strategy was verified by simulation and experiment.