Silicon carbide (SiC) semiconductor devices have received extensive attention with the better performance of the wide band gap material. It is necessary to compare with their silicon (Si) counterparts due to SiC semiconductor devices are new. In this paper, a test platform based on buck converter is constructed to test the switching characteristics of SiC MOSFET, Si CoolMOS and IGBT, the input voltage of which is 400 V, the output current of which is 4–10 A. Switching waveforms, switching times, switching energy losses, dv/dt, di/dt and reverse recovery characteristic of internal diodes of three devices are presented. Finally, theoretical efficiencies and tested efficiencies of a 2 kW dual active bridge (DAB) converter are compared.