In order to handle high voltage with limited voltage rating self turn-off devices, it is necessary to give a simple and reliable series connection technique of these devices, especially IGBTs for high voltage applications. This paper proposes a snubber circuit to guarantee the voltage balance for IGBTs in series connection both at static and dynamic transients. The proposed circuit features with simple control at the gate side, unlimited number of devices in series, high reliability and low loss. The simulation and experimental results verify these advantages. A 10A/3000V prototype with three series-connected IGBTs have been designed and implemented. It has exhibited excellent dynamic voltage balance and an accepted overshoot level with LC snubber circuits and auxiliary clamp circuits.
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