A junction temperature estimation method of SiC power module for real time application in a traction inverter

SiC MOSFET is a kind of promising power device for transportation electrification. In electrified vehicles, SiC inverters show strong competitiveness for its high efficiency and power density, especially for high-performance applications. A SiC power module generally consists of multiple MOSFET dies and Diode dies. Junction temperature estimation of different dies in different operation points is a critical problem for practical applications. In this article, power loss of SiC devices in a motor inverter is analysed and calculated in the time scale of switching period. Subsequently, a junction temperature estimation method combining 1D foster thermal model and 3D FEM thermal model is proposed. The maximum junction temperature in a SiC power module can be estimated with low computational burden. Working boundary with varying sine current amplitude and switching frequency can also be obtained for real-time control of motor inverters. The effectiveness and practicability of the proposed method is verified with transition simulation.