Switching characteristics analysis and power loss minimization of SiC BJT based on dual power supply RC driving circuit

Abstract

As a current driven power device, SiC BJT needs effective driving scheme, but the present schemes are either complicated or not parameter optimized. In this paper we give an optimized parameter design method based on dual power supply RC driving circuit. First, the detailed switching process of SiC BJT considering the loop parasitic parameters is presented. Then, the influence of the accelerating capacitor on the switching loss and driving loss of SiC BJT is analyzed. The theoretical and simulation analysis shows that as the accelerating capacitor increases, the driving loss of SiC BJT increases proportionally, while the switching loss decreases less. Finally, the switching process of SiC BJT was investigated experimentally at various accelerating capacitor values from 3.3 nF to 94 nF. It was found that with the increase of the accelerating capacitor, the total loss during the switching process first decreases and then increases. The total loss minimization during the switching process of SiC BJT can be achieved through properly selecting the accelerating capacitor.