Hybrid low loss voltage balancing method for series connection of IGBTs

The demand for high voltage switches can be achieved by connecting power devices in series. The main problem associated with series connected devices is the unequal sharing of the switch voltage by each device. In this paper, a hybrid voltage balancing method suitable for use with series strings of IGBT is described. The method combines active gate control with passive snubber circuits to yield a simple gate control circuit and to minimise the switching power losses. Simulations show that the method is capable of good voltage balancing during turn-off and turn-on transients.