Method for obtaining junction temperature of power semiconductor devices combining computational fluid dynamics and thermal network

Abstract Keeping the highest junction temperature of Insulated Gate Bipolar Transistor (IGBT) modules below the critical temperature is key to ensuring the stability and reliability of power supplies in accelerator facilities. However, the existing junction temperature extraction methods are not suitable for liquid cooling IGBTs and can be improved in terms of speed and accuracy. In order to investigate the junction temperature of IGBT modules and the characteristics of their water-cooled plates, an electro-thermal model combining the thermal network method and the computational fluid dynamics analysis is proposed. The accuracy of the model is improved, because the power loss is corrected by the double-pulse test, and the thermal resistance of the cold plate is refined by computational fluid dynamics simulation. The thermal network method guarantees that the model is fast and can be easily applied to various operating conditions. The method is used to analyze the performance of two cold plates, select the cooling conditions, and further increase the switching frequency on the premise of ensuring the reliability of the IGBT module. The accuracy of the method has verified by experimental results, and the applicable conditions and the estimated junction temperature error are also analyzed.