Reliability Study of Die Attachments in SiC Power Modules with Thermal Balancing Control

With active neutral point clamped (ANPC) inverter, the uniform power loss distribution on power modules can be achieved through thermal balancing control. In practice, adopting such control methods may increase the total power losses, potentially affecting the reliability of power devices. This paper presents an evaluation of the reliability of SiC power modules with and without thermal balancing in a three-level ANPC inverter. Specifically, this study focuses on the reliability of die attachments, which is a critical concern in power module reliability. Transient thermal-mechanical analysis is conducted via finite element analysis (FEA) following the JEDEC power cycling standard. Simulation results from this analysis are subsequently integrated into the Coffin-Manson model, estimating the lifetime represented by cycles. The results indicate that although thermal balancing effectively reduces peak junction temperatures, it simultaneously increases thermal-mechanical stress due to higher overall power losses. Finally, the estimated lifetime of the SiC half-bridge power module decreases. This study also aims to provide a foundational benchmark for assessing the effect of thermal balancing control on power module reliability in a more practical scenario.