Aging Detection for Capacitors in Power Electronic Converters

The aging detection of dc-link capacitors has great significance in enhancing the reliability of the power electronic converters in photovoltaic applications. This chapter summarizes the wear-out failure characteristics of capacitors, including degradation models and end-of-life criteria. Generally, two categories of methods are applied to define the end-of-life criteria of capacitors. One category is to construct the relationship between electrical and nonelectrical parameters. Another is to identify the failure status of capacitors using the structure change of capacitors. Some electrical parameters and nonelectrical parameters will change with the degradation of capacitors. Based on this, the chapter presents the condition monitoring procedure for capacitors. According to the dependence on the physical model of capacitors, two main categories of principles are generally used to estimate the electrical parameters of dc-link capacitors. One is the physical model-based method, and another is the data-driven-based method.