基于中点电流的ANPC逆变器故障诊断策略与容错控制

Fault Diagnosis Strategy and Fault-Tolerant Control of ANPC Inverter Based on Midpoint Current

有源中点箝位型(ANPC)逆变器具有输出波形畸变率低、传输效率高等优点,获得了广泛的应用,但大量的开关器件降低了逆变器的可靠性。分析了三电平ANPC逆变器在不同开关器件开路故障下的电流路径,得到不同故障下输出电平及输出电压空间矢量的变化情况。结合各矢量作用下中点电流与输出电流的关系,提出了一种基于中点电流的故障诊断方法。根据ANPC逆变器电路特点,对其桥臂器件和箝位器件提出了不同的容错模式,并提出了一种具有不降额容错能力的容错电路结构。通过搭建仿真模型及实验平台对提出的故障诊断方法及容错策略进行验证,仿真和实验结果验证了该故障诊断方法及容错策略的有效性。

Active neutral point clamped(ANPC)inverters are characterized by low output waveform distortion rate and high transmission efficiency,and have been wide use,but a large numbers of switching devices reduce the reliability of the inverter.The current path of a three-level ANPC inverter under different open-circuit faults of switching devices is analyzed,and the output level and output voltage space vector changes under different faults are obtained.Combining the relationship between the midpoint current and the output current under the action of each vector,a fault diagnosis method based on the midpoint current is proposed.According to the characteristics of the ANPC inverter circuit,different fault-tolerant modes are proposed for its bridge arm devices and clamp devices,and a fault-tolerant circuit structure with non-derating fault tolerance is proposed.The proposed fault diagnosis method and fault-tolerant strategy are verified by building a simulation model and experimental platform.The simulation and experimental results show that the fault diagnosis method and fault-tolerant strategy are feasible.