Thermal Characterization of SiC Modules for Variable Frequency Drives

In this paper, the advantages of SiC power modules to reduce peak junction temperature and power cycling effects are presented. A detailed power loss calculation and thermal model is developed and tested on a 480 V, 190A, 150 HP variable frequency drive (VFD) with SiC modules. A comparison between the SiC module and an equivalent rated Si module is presented to demonstrate the reduction in power cycling effects, particularly at low speed operation. Infrared (IR) imaging results and an analytical explanations of the phenomenon is provided. These results show that SiC inverters can be used for high torque and low speed applications. Also, the reduction in junction temperature swing improves reliability.