Improved Analysis Model of SiC Power MOSFET with Staged Critical Parameters

Abstract

Silicon carbide (SiC) metal-oxide-semiconductor field-effect transistors (MOSFETs) have great advantages in improving the power density and performance of power converters due to the high switching frequency, high operating voltage. However, the increase in switching frequency is also increasingly inflicted the voltage and current stresses to the parasitic elements of the SiC MOSFET, which restricts the device’s optimal performance. In addition, many parasitic elements of SiC MOSFET are coupled with each other during the switching process, which makes the analysis complicated and calculation cumbersome. This paper presents an analytical model for SiC MOSFETs, which identifies and selectes the dominant elements and key variations of each stage separately according to the change stages of major variables. The complexity of the model is reduced while the accuracy is guaranteed. Using this model, the voltage and current switching rate of SiC MOSFET can be quickly solved, and the impact mechanism of each critical parameter can also be revealed clearly. A double pulse test circuit composed of a 600V/20A SiC MOSFET is set up and experimental results are obtained to verify the accuracy of the proposed analytical model.