The reliability of DC-link capacitors in urban rail transit is considered as a major challenge because of significant maintenance impact. In this article, the DC-link capacitor reliability is researched in metro traction drive system. In the small timescale of control level, the current harmonics of multiple operating conditions and different control methods in the DC-link capacitor are discussed. The power loss is simulated by the capacitor harmonics of current and equivalent series resistance (ESR) in multioperating conditions. Considering electrothermal coupling, the time-ordered and continuity of thermal stress are analyzed to evaluate the hot spot temperature dynamic conformed to the reality. Combining with the analysis of electrical stress and thermal stress, a multitimescale capacitor reliability evaluation method is proposed. It is divided into four steps: the discrete small timescale, the single route timescale, the daily operation timescale, and the whole lifetime cycle. In the different timescales, the lifetime distribution changes with the dynamics of the complex mission profiles, so as to estimate the lifetime bottleneck of the DC-link capacitor banks with different control methods by the Weibull distribution. In addition, experimental validation is provided to verify the accuracy of the proposed method.

中文翻译：

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地铁牵引驱动系统直流母线电容器组的多时间尺度可靠性评估

由于重大的维护影响，城市轨道交通中直流母线电容器的可靠性被认为是一项重大挑战。本文对地铁牵引传动系统中直流母线电容器的可靠性进行了研究。在控制水平的小时间尺度上，讨论了直流母线电容器中多种工况和不同控制方法的电流谐波。在多操作条件下，功率损耗由电流和等效串联电阻 (ESR) 的电容器谐波模拟。考虑电热耦合，分析热应力的时序性和连续性，评估符合实际的热点温度动态。结合电应力和热应力分析，提出了一种多时间尺度电容器可靠性评估方法。分为离散小时间尺度、单路径时间尺度、日常运营时间尺度、全生命周期四个步骤。在不同的时间尺度上，寿命分布随着复杂任务曲线的动态变化，从而通过威布尔分布估计不同控制方法的直流母线电容器组的寿命瓶颈。此外，还提供了实验验证以验证所提出方法的准确性。从而通过威布尔分布估计不同控制方式下直流母线电容器组的寿命瓶颈。此外，还提供了实验验证以验证所提出方法的准确性。从而通过威布尔分布估计不同控制方式下直流母线电容器组的寿命瓶颈。此外，还提供了实验验证以验证所提出方法的准确性。