Characteristics and propagation of switching-induced stress waves in SiC MOSFET power modules

Switching-induced stress waves (SSW) are recognized as a promising non-invasive technology for real-time monitoring of power module packaging failures, though limited by the lack of a comprehensive understanding of their characteristics and propagation mechanisms. In this study, a dedicated SSW detection platform was developed for SiC MOSFET power modules, where the mechanical wave nature was verified through time-delay analysis. Dominant frequency components at 150 kHz and 270 kHz were identified using both piezoelectric ceramic and PVDF sensors. Experimental investigations further demonstrated that the time-domain parameters of SSW were predominantly influenced by bus voltage (U DC ), followed by load current (I R ), whereas principal frequency components remained stable across operational conditions. Propagation effects through the module were systematically analyzed via finite element modeling, revealing a 5.82% increase in signal amplitude and 5.88% spectral bandwidth expansion after transmission. These results confirm that sensor-captured signals can be effectively equated to original chip vibrations in defect-free propagation paths.