Thermal analysis for optimized selection of cooling techniques for SiC devices in high frequency switching applications

The inception of wide bandgap power semiconductors has paved way for the evolution of highly efficient power switches. A deep understanding about the thermal characteristics of the SiC power device is essential to utilize its advantages in terms of higher thermal and power handling capability. The primary objective of this paper is to establish an accurate thermal model by proposing and comparing different methodologies for thermal analysis of commercially available SiC device, which in turn will aid to select optimum cooling techniques for higher system efficiency. Exponential curve fitting technique was exploited to deduce the parameters for RC equivalent network model. A high frequency sinusoidal pulse width modulated SiC MOSFET inverter with a fixed load was considered for electro-thermal analysis using a unified software platform PLECS. The effect of switching frequency on heat sink volume was established through simulation studies with imbibed datasheet parameters of a commercial power device. Finally, a 3-D model of the commercially available SiC power MOSFET in SOT-227B package was built to analyse the device heat dissipation profile for an optimized cooling choice. The proposed modelling approach serves to provide a platform for the thermal optimization of power devices and can be extended to other semiconductor devices. (paper)