Study of Snubber Circuits in the Voltage Source Converter Based on Series-Connected IGBTs

The DC voltage of the VSC is very high and it is necessary to connect several IGBT in series. Some snubber circuits have to be used to restrain the over-voltage of IGBTs so as to avoid its damage and the snubber circuit will increase the current stress too. The over-voltage of IGBT in the converters is studied in the paper firstly. Then, the common snubber circuits used in series-connected IGBTs are discussed and compared. A simulated model is set up in Saber to study the snubber circuit at last, the results show that the RC snubber circuit is more suitable for series-connected IGBTs.