一种三电平变流器故障诊断及容错控制策略

A Fault Diagnosis and Fault-tolerant Control Strategy for Three-level Converter

针对中点箝位(NPC)三电平变流器的开关器件故障问题,此处提出一种NPC三电平变流器IGBT开路故障诊断方法与软件容错控制策略。首先,分析了NPC三电平变流器IGBT开路故障时的运行状态,选取直流侧3个桥臂相电压和输出三相电流作为故障初始数据,通过互补集合经验模态分解(CEEMD)算法和能量占比特征提取方法得到故障特征矩阵。然后,将特征矩阵输入参数改进后的1D-CNN框架并实现IGBT的开路故障定位。故障定位后,针对IGBT单管故障提出一种基于空间矢量脉宽调制(SVPWM)的容错控制策略,通过切换空间矢量使得NPC三电平变流器容错运行。最后,搭建仿真和实验平台,验证了所提故障诊断和容错策略的可行性和可靠性。

Aiming at the problem of switching device fault of neutral point clamped(NPC)three-level converter,an IGBT open-circuit fault diagnosis and software fault-tolerant control strategy is proposed for NPC three-level convert-ers.Firstly,the operating state of the NPC three-level converter with ICBT open-circuit fault is analyzed and the DC-link phase voltages of the three bridge arms and the output three-phase currents are selected as the initial fault data.The fault feature matrix is obtained through the complementary ensemble empirical mode decomposition(CEEMD)al-gorithm and the energy ratio feature extraction method.Then,the feature matrix is input into a modified ID-CNN framework to achieve IGBT open-circuit fault localization.After fault localization,a fault-tolerant control strategy based on space vector pulse width modulation(SVPWM)is proposed for the single IGBT fault.By switching the space vec-tors,the NPC three-level converter can continue to fault-tolerant operation.Finally,the simulation and experimental platform is built to validate the feasibility and reliability of the proposed fault diagnosis and fault-tolerant strategies.