并联全桥隔离DC-DC变换器开路故障诊断

Open-circuit Fault Diagnosis for Parallel Operated Full-bridge Isolated DC-DC Converter

单相电力电子变压器是实现铁路牵引系统高效化、轻量化的有力选择,其中并联全桥隔离DC-DC变换器是保证稳定直流输出的重要组成部分。为保证DC-DC变换器的可靠运行,文章针对其单个IGBT开路故障,提出了一种基于状态估计的单管开路故障诊断方案,即通过建立系统的混合逻辑动态模型和状态估计模型,对DC-DC变换器级在正常和单管开路故障下的估计残差进行分析,根据残差包含的故障信息实现单管开路故障诊断。最后,基于RT-LAB半实物实验平台,对提出的故障诊断方案进行验证,仿真实验结果表明,该诊断方法能在IGBT发生开路故障后的4个开关周期内实现故障开关的有效定位。

Single-phase power electronic traction transformer （PETT） is the power device to realize higher efficiency and reduction of weight in railway traction system, and parallel operated full-bridge isolated DC-DC converters are an important part of single-phase PETT to realize a stable DC-voltage output. In order to ensure the reliability of DC-DC level, in this paper, an open-circuit fault diagnosis method based on state estimator was proposed for open-circuit fault of a single IGBT. Through establishment of mixed logic dynamic （MLD） model and state estimator model, estimator residuals of the DC-DC level were analyzed under normal and faulty conditions. According to the residuals including information of the fault, fault diagnosis was achieved. Finally, the proposed fault diagnosis method was verified in a hardware-in-loop （HIL） experimental platform with RT-LAB simulator. Experimental results show that the diagnosis method can effectively locate the fault switch in four switching cycles after open-circuit fault of IGBT.