Reliability is a critical criterion for multi-MW\ud
wind turbines, which are being employed with increasing\ud
numbers in wind power plants, since they operate under harsh\ud
conditions and have high maintenance cost due to their remote\ud
locations. In this study, the wind turbine grid-side converter\ud
reliability is investigated regarding IGBT lifetime based on\ud
junction temperature cycling for the grid-side press-pack IGBT\ud
3L-NPC-VSC, which is a state-of-the art high reliability\ud
solution. In order to acquire IGBT junction temperatures for\ud
given wind power profiles and to use them in IGBT lifetime\ud
prediction, the converter electro-thermal model including\ud
electrical, power loss, and dynamical thermal models is\ud
developed with the main focus on the thermal modeling\ud
regarding converter topology, switch technology, and physical\ud
structure. Moreover, these models are simplified for their\ud
practical implementation in computation platforms. Finally, the\ud
converter lifetimes for wind power profiles are predicted using\ud
the IGBT lifetime model available. Hence, the developed electrothermal\ud
model’s suitability for the lifetime predictions is shown.Peer ReviewedPostprint (published version