The Impact and Optimization of Parasitic Capacitance in Silicon Carbide Power Module Switching Characteristics

This paper presents a frequency domain analysis method to investigate the influence of common-mode (CM) capacitance on the switching characteristics of silicon carbide (SiC) power modules. By establishing a frequency domain model during the device switching transient, the frequency response characteristics of voltage overshoot, oscillation and common-mode current affected by the CM capacitance are obtained. The underlying mechanisms of the impact of CM capacitance on the switching characteristics under different grounding conditions are clarified. Furthermore, a 3D packaging structure is proposed to effectively eliminate the capacitance in power modules. The electrical and thermal performance of the proposed structure are optimized through the integration of the cooling system and the decoupling circuit, and the CM capacitance characteristics are experimentally evaluated. The results demonstrate that the proposed 3D packaging structure can effectively eliminate the CM capacitance in power modules, providing a new solution for the integration of SiC devices in packaging.