Thermal profile analysis of Doubly-Fed induction generator based wind power converter with air and liquid cooling methods

Today, wind power generation system keeps on moving from onshore to offshore and also upscaling in size. As the lifetime of the wind power converter is prolonged to 20-25 years, this paper will investigate and compare different cooling methods for power modules - the air cooling and the liquid cooling seen from a thermal profile assessment point of view. Firstly, an analytical approach from loss profile to thermal profile for the power semiconductor is proposed and verified in a 2 MW Doubly-Fed Induction Generator (DFIG) based wind turbine system. Then, the typical air cooling and liquid cooling in wind power converter are analyzed and compared in terms of the mean junction temperature and the junction temperature fluctuation. It is concluded that the liquid cooling approach has a similar junction temperature fluctuation but gives a lower mean junction temperature than the air cooling approach.