Short Circuit Protection of Parallel SiC MOSFET Modules Based on Electro-Thermal Design with High-Temperature I-V Characteristics

We demonstrate the successful 19 kA short circuit protection of four parallel 1,200 V-600 A SiC MOSFET modules within the product configuration. The operation condition to protect the power modules is extracted by the analysis using the newly proposed electro-thermal device model with the I-V curve under a wide range of conditions (high temperature, high current and high voltage). One of the features of the proposed model is that the accurate I-V trajectory of the SiC MOSFET is described under the short circuit condition, taking the impact of the device junction temperature on the I-V curve into account. Accuracy of the proposed model is verified for the single SiC MOSFET module at first, comparing the simulated voltage and the current waveforms of the SiC MOSFET with the measurement result under real short circuit condition. Then, the short circuit behavior of four parallel connected SiC MOSFET modules is evaluated by using the proposed model. The operation condition to protect all the MOSFETs is determined taking the current imbalance and the voltage spike into account. The proposed model solves the weak short circuit capability of the SiC MOSFET and this model contributes to the prevalence of the highly efficient power electronics equipment using SiC power devices.