Non-destructive Characterization of Parasitic Capacitances in Full-Bridge Power Module

SiC MOSFETs are preferred over Si-based power devices due to their low switching loss and ability to operate at high switching frequency. However, they have drawbacks such as higher noise emissions due to high 𝑑𝑣/𝑑𝑡 during switching transients. The common-mode conducted emissions are caused by displacement current flowing through the parasitic capacitance between switching nodes and ground. This paper proposes a non-destructive method for identifying parasitic capacitances in a full-bridge power module (FBPM) using a combination of time- and frequency-domain measurements. An equivalent circuit model for noise analysis is presented, and parasitic components are characterized for FBPM operating as a single-phase inverter. For validation, calculated parasitic capacitances are compared with values obtained from finite element method (FEM) simulation of 3D model of FBPM.