Abstract : IGCTs can be used alone without a buffer circuit. However, 6kV and above high-voltage frequency converters require IGCTs to be used in series to achieve higher withstand voltage levels. In this case, a parallel buffer circuit is needed for the IGCT to operate safely. To design a series snubber circuit for a 6kV high-voltage frequency converter, this paper analyzes the characteristics of IGCTs and presents a specific method for designing the IGCT snubber circuit. The working effect of the snubber circuit is verified through experiments. Keywords : Snubber circuit, Series snubber, High-voltage frequency converter 1 Introduction High-voltage frequency converters are increasingly widely used due to their outstanding energy-saving effect. IGCTs (Integrated Gate Commutated Thyristor) have excellent switching characteristics and have become the preferred choice for high-voltage frequency converters. IGCTs are a new type of high-voltage, high-power power electronic switching device that combines a GCT (Gate Transformer) improved from a GTO (Gate Transformer Oxide) with an extremely low inductance gate driver. Compared with the traditional GTO, the GCT structure has been improved. In addition to structural differences, the difference between IGCTs and GTOs also lies in the extremely low gate-cathode stray inductance. This characteristic makes the di[sub]GQ[/sub]/dt value during IGCT turn-off two orders of magnitude higher than that of traditional GTO, reaching 3500A/us. Therefore, the IGCT has a very short storage time during turn-off, making the entire turn-off process safe and rapid. Similarly, its turn-on time is also significantly shortened. In my country, high-voltage drive motors are mainly at the 6kV level, and the highest withstand voltage level of a single IGCT currently cannot meet the requirements. Therefore, to ensure device safety, in our developed three-level structure 6kV high-voltage frequency converter, a scheme of two IGCTs connected in series is adopted to obtain a higher withstand voltage level. However, using devices in series can cause voltage equalization problems, which can compromise device safety. To ensure the high reliability of IGCT operation, a series buffer circuit is essential in the design of high-voltage frequency converters. This article will analyze in detail the design method of the IGCT series buffer circuit. [b][align=center]For details, please click: IGCT Series Buffer Circuit Design in 6KV Variable Frequency Speed ​​Control System[/align][/b]