A Simple Transfer Capacitance Measurement Method of SiC MOSFET in High-voltage Applications

Accurate nonlinear capacitance measurement methods play an important role in the modeling of silicon carbide (SiC) MOSFET for transient switching analysis and design of high performance power electronics equipment. This paper presents an improved capacitance measurement method, which can obtain the transfer capacitance Crss of SiC MOSFET accurately. This method is based on the time-domain reflectometry theory during dynamic switching process, which is easy to design and be captured. Different from other existing methods, the influence of gate-drain stray capacitance caused by PCB wiring and probes is considered in the process of measurement, thus resulting in the minimization of errors produced by instrument and layout. Also, the impact of parasitic inductance in driver loop on measurement results can be counteract skillfully. In addition, the proposed method characterized by dynamic behavior can be used in high-voltage applications. The performance of this proposed method is verified and compared experimentally by a double-pulse test (DPT) platform.