Reliability assessment of IGBT modules modeled as systems with correlated components

System modeling of electrical components for Wind Turbine (WT) applications is an important part for the overall WT reliability assessment. The presented approach is an approximate method for Insulated Gate Bipolar Transistor (IGBT) reliability estimation, modeled based on the parallel system configuration. The estimated system reliability by the proposed method is a conservative estimate. Application of the suggested method could be extended for reliability estimation of systems composing of welding joints, bolts, bearings, etc. The reliability model incorporates the correlation between the components in the reliability estimation though limit state functions and mechanical (failure-effect) correlations. The model is based on a physics of failure approach and a linear accumulated damage rule. To account model parameter variabilities, the First Order Reliability Method (FORM) technique was applied for the systems failure functions estimation. It is desired to compare the results with the true system failure function, which is possible to estimate using simulation techniques. Theoretical model development should be applied for the further research. One of the directions for it might be modeling the system based on the Sequential Order Statistics, by considering the failure of the minimum (weakest component) at each loading level. The proposed idea to represent the system by the independent components could also be used for modeling reliability by Sequential Order Statistics.