基于Park变换的三电平逆变器开路故障诊断

针对现有二极管钳位式(NPC)三电平逆变器开路故障诊断方法存在计算量大、准确率受噪声和负载等影响的问题,提出了一种基于Park变换的三电平逆变器开路故障诊断方法。对三电平逆变器三相输出电流进行Park变换,计算平均电流Park矢量;利用滑动窗口取得单周期电流信号,根据逆变器电路结构分析IGBT故障时输出电流变化;采用迭代法确定平均电流Park矢量模值的阈值,结合相角和模值进行三电平逆变器功率管13种开路故障的识别和定位。仿真结果表明,该方法故障诊断准确率达到了98.31%。与传统的开路故障诊断方法相比,该方法不需要对13种开路故障数据进行学习和训练,大大减少了计算量,提高了故障诊断效率和准确率。

Open-circuit fault diagnosis of three-level inverter based on Park transformation

In view of problems that existing neutral point clamped(NPC)three-level inverter fault diagnosis method needs large amount of calculation and its accuracy is affected by noise and load,an open-circuit fault diagnosis method of three-level inverter based on Park transformation was proposed.Park transformation is carried out on three-phase output current of the three-level inverter to calculate average current Park vector;sliding window is used to obtain a single-cycle current signal,and output current change is analyzed in case of IGBT fault according to inverter circuit structure;iterative method is used to determine threshold value of average current Park vector modulus,and 13 kinds of open-circuit faults of three-level inverter power tube are identifid and located combining phase angle and modulus.Simulation results show that the fault diagnosis accuracy of the method reaches 98.31%.Compared with traditional open-circuit fault diagnosis method,the proposed method does not need to learn and train the data of 13 kinds of open-circuit faults,which greatly reduces calculation amount and improves efficiency and accuracy of fault diagnosis.