Exploiting the Converter Efficiency as Application-level Health Estimation Precursor

Due to the uncertainties linked to the lifetime estimations of power converters and in particular the uncertainty introduced by extrapolating the accelerated test results to other usage conditions, which has a significant impact on the failure distributions and thereby introducing a failure probability inhibiting a variance of several years. Due to this relatively large variance, the lifetime estimations lack sufficient precision, which can induce misleading system risk rates, when considering unique cases under study. The state-of-the art is currently seeing an increasing research output which are in favour of basing reliability studies of physics-of-degradation methodologies, where changes in the electro-thermal parameters are used as health precursors. The physics-of-degradation based methods are restricted to considering a single component. Due to the impracticability of monitoring each of the power electronic components concurrently, there is an essential need for a for a method which can monitor the health status of the entire converter. This paper proposes a method, which makes use of the converter efficiency to monitor the parameter shift of multiple components and which can be used at the application-level to gain precision, when stating the operational lifetime of power converters. Finally, the degradation rate trends of the power electronic components are used as indicators, of when the end-of-life of the converter is reached.