Surge Current Analysis of High-Power Press Pack Diodes: Junction Temperature and Forward-Voltage Modeling

In recent years, the use of high-power semiconductor devices has gained growing demand across various applications, including data centers, electric vehicles, and traction systems. However, increasing power densities may increase challenges in ensuring the reliability of devices, particularly under high surge currents. These surge events may result in excessive power dissipation and rapid temperature increases, leading to device performance degradation and potential failure. Therefore, accurate temperature estimation is critical. However, existing approaches in the literature are mostly oversimplified and constrained by static I–V characteristics, limiting their accuracy. To encounter these limitations, this article proposes a forward-voltage-based temperature evaluation methodology for high-power diodes subjected to 10 ms surge events. The proposed model integrates rated electrical parameters with thermal simulation data to enable the accurate estimation of dynamic slope resistance and forward voltage during transient surge operation. The proposed framework shows strong agreement with the experimental results and provides a reliable tool for surge capability assessment. This approach enhances device modeling accuracy under very-high-current stress and offers valuable insights for electro-thermal design and thermal management in next-generation power semiconductor devices. Keywords: surge current analysis; semiconductor devices; thermal characterization; junction temperature prediction; electro-thermal simulation; forward-voltage Modeling