On the Practical Design of a High Power Density SiC Single- Phase Uninterrupted Power Supply (UPS) System Cai Chen1, Yu Chen, member, IEEE, Yifan Tan, Jianming Fang, Fang Luo, senior member, IEEE and Yong KangAbstract－ this paper proposes a high power density SiC singlephase system potential for Uninterrupted Power Supply (UPS) applications. To get the high power density, the semiconductors, packaging, circuit topology and thermal design are synthetically considered. To increase the switching frequency and reduce the size of the passive components, the SiC MOSFETs and diodes are chosen; to minimize the parasitic inductances and eliminate the snubbers, the SiC bare dies are packaged as the Half-Bridge (HB) modules; to remove the bulky DC-link capacitors, the Full-Bridge inverter and the Active Power Filter (APF) are designed, and they are structured by using the fabricated SiC HB modules; and finally to dissipate the heat from such a compact enclosure in the cost-efficient way, the heat-sink of the modules and the forced air cool system are well designed, and the thermal 3D-Finite Element Analysis model is built to survey the best cooling configuration. A 2kVA prototype is built and tested, and the power density of the system is up to 58W/in3 and the maximal efficiency is up to 98.3%.