三电平逆变器的功率管开路故障诊断

三电平变换器因其输出谐波小、开关应力低等优点而受到广泛关注，而对变换器故障情况的诊断处理是变换器能可靠、高效运行的前提。该文针对三电平变换器的拓扑，通过理论分析和仿真实验，对变换器中的各功率管开路故障诊断进行研究。以二极管钳位三电平半桥逆变器为例，分析三电平变换器在功率管开路下的电路工作情况及故障表现形式，并由此提出根据检测逆变器输出侧PWM电压和输出电流极性来诊断功率管开路故障的故障识别方案。最后通过仿真和实验验证该方法的正确性和有效性。该方法相对于已往的功率管开路故障诊断方法，具有诊断迅速、可靠性高的优点。

Open-circuit Fault Diagnosis of Transistor in Three-level Inverter

Due to the advantages such as low output distortion and low switching losses, three-level inverter attracts great attentions in a long period, in the meanwhile, the diagnosis about the fault of converters is the prerequisite of the reliable and effective operation of converters. Through analysis and simulation, this paper did some research about the open-circuit fault diagnosis of transistors in three-level inverter. Using the three-level diode-clamped inverter as an example, operation mode and behavior patterns of inverter under open-circuit fault situation were analyzed. The concept of fault diagnosis using output PWM voltage and polarity of output current was also introduced. Through simulation and experiment, the validity of this method was testified. Comparing to the former methods proposed, this method has the advantages of quick response to fault and high reliability.