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