The Experiments of Voltage Balancing Methods in IGBTs Series Connection

To the affections of series IGBTs operation, the working process and characteristics of two kinds of simple, reliable voltage-balancing circuits are analyzed and compared. In the case of non-synchronous of gate signal, RCD snubber can not suppress the dynamic over-voltage during the switch transients observed from the experiments. The RCD active gate control is discussed in detail includes signal delay and the component parameters on the dynamic voltage balancing. A qualitative relationship of the component parameters to the voltage balancing is given. The experimental results show that the RCD active gate control method can inhibit the over-voltage effectively, and an acceptable voltage sharing is achieved in the series connection.