An optimized snubber design for three level inverter systems

In this paper a new circuit design for the protection of e.g. multi level converters is presented. The so-called ´optimized snubber design´ still comprises most of the positive features as a low number of components, improved efficiency due to the low snubber element and power semiconductor losses, reduced over-voltage across the semiconductor devices and no balancing problems. With these advantages, the new proposed snubber circuits can be used for high power inverters as well as the so-called flexible AC transmission systems (FACTS). The presented snubber circuit has been analyzed and confronted with different existing converter designs using a simulation environment. The simulation results are compared with the output of a standardized three level converter system to verify the advantages of the new snubber design