Measurement of Thermal Parameters of SiC MOSFET Module by Case Temperature

SiC-based wide bandgap semiconductor devices such as metal-oxide-semiconductor field-effect transistors (MOSFETs) are gradually replacing Si devices in industrial applications because of their excellent electrothermal properties. However, the reliability of these devices and the problem of the junction temperature estimation are concerns that are yet to be resolved for these applications. This article proposes a method to measure the Cauer-type RC thermal network parameters that consider the influence of degradation of the external cooling system using either two or four case temperature cooling curves. The proposed method simplifies the measurement not only of the junction temperature and the power loss but also of the thermal equilibrium condition and it is thus suitable for the application in a power converter. Experiments were performed to prove that the thermal network parameters obtained are both feasible and credible.