In this paper, an improved regenerative snubber for three level GTO inverter is presented. A problem which is worse switching operations of neutral GTO's than those of upper/lower GTO's due to larger stray inductances is improved. Small capacitors are added between upper/lower snubber energy recovery capacitors and neutral point in order to reduce conduction pathes in snubber operations of neutral GTO's and small lossy snubbers are added to neutral GTO's for further improvement. With the considerations of all stray effects, a design methodology for optimum snubber design is suggested. Operation and analysis considered all stray effects are described and verified by computer simulation and experiment(4KVA, 1-pole).
