Reliability Analysis of High-Voltage IGBT Series Components Considering Dynamic Voltage Imbalance

Differences in device parasitic parameters and the discrete parameters of peripheral circuits can cause dynamic voltage imbalances during the switching transients of insulated gate bipolar transistor (IGBT) series components. To address the adverse effects of dynamic voltage imbalance on the switching characteristics and operational reliability of series components, this paper proposes a reliability analysis method for IGBT series components considering dynamic voltage imbalance. Firstly, the theoretical effects of dynamic voltage imbalance on the power loss of IGBT series components are analyzed. Secondly, an equivalent circuit simulation model of IGBT series components is developed, wherein dynamic voltage imbalance is simulated by introducing driving synchronization differences. The impact of this imbalance on the switching characteristics and thermoelectrical performance of the series components is then analyzed through simulation. Finally, a reliability analysis method is proposed to evaluate the influence of dynamic voltage imbalance on the failure rate of series components under various operating conditions. The results indicate that dynamic voltage imbalance most significantly affects the IGBT device that turns off first in the series configuration, resulting in its highest failure rate. Furthermore, as the degree of dynamic voltage imbalance increases, the failure rate disparity among series IGBT devices widens, with higher switching frequencies exacerbating this difference.