Lifetime Estimation of IGBT Power Modules for Reliability Study of Wind Turbine Systems

In this paper, a method for lifetime estimation of insulated-gate bipolar transistor (IGBT) power electronics (PE) modules in offshore wind turbine (WT) applications is presented. An extensive operational model of a multi-megawatt wind turbine (WT) and a ‘physics of failure’-based reliability model of a power electronic (PE) converter have been combined for the purpose of estimating the thermal loading and the lifetime consumption of the converter module. This integrated approach enables the observation of results and aspects that the previously used models have overlooked. The paper investigates a PMSG WT model equipped with a fully-rated back-to-back voltage source converter. The developed approach and its application is demonstrated with a thermal loading comparison between the machine side converter (MSC) and the grid side converter (GSC). The influence of both, the wind variability in one side and the grid condition from the other, on the converter thermal loading is an analysis that proves the extended applicability of the novel converter reliability model proposed here. The results show that this kind of modelling has a potential to be used for improvement in the design process as well as in the O&M of the power electronics systems in WTs.