Optimal design of short circuit robustness for high voltage and high power IGBTs

The high-voltage and high-power IGBTs employed in the power grid must not only simultaneously satisfy the requirements of elevated voltage and reduced saturation voltage drop, but also exhibit strong short-circuit robustness during system failures, thereby posing a challenge in industrial design. This study investigates the shape of impurity concentration distribution in the IGBT buffer layer formed by different process combinations, as well as its impact on the static performance and short-circuit robustness of IGBT. Furthermore, an analysis is conducted to identify the underlying factors contributing to this influence. The simulation results demonstrate that the selection of a buffer layer with an appropriate concentration distribution enables the achievement of low on-state voltage and high short-circuit robustness in IGBTs. Based on this design, 4500 V/3000 A press-pack IGBT devices were fabricated, successfully passing the limit short-circuit current test at 14500 A. Leveraging these advanced 4500 V/3000 A press-pack IGBT devices, a prototype of a flexible DC converter valve with a rating of 30 kV/3 kA was developed, facilitating the replacement process for high-voltage and high-power IGBT devices in domestic power grid applications.