Research on Equivalent Test Method of Mechanical Fatigue Aging Life of Press-Packed IGBT Device Used in Circuit Breaker

Press-pack IGBTs (PPI) are receiving increasing attention in high-voltage and high-current applications. At present, the research on the mechanical fatigue failure of chips for PPI devices used in direct current circuit breaker (DCCB) is still immature, and there is no method to predict the fatigue failure life of PPI chips. In this paper, the method of simulation calculation is used to study the variation of strain of the chip when the PPI device for DCCB is switched off. Simulation results show that when a short-circuit fault happen, the short-circuit current causes the chip to expand, which can cause the chip to have a strain amplitude. Based on the Coffin-Mason formula, the strain amplitude is used as an equivalent variable so that an equivalent experimental method for calculating the fatigue failure life of the PPI is proposed.