High voltage switch using series-connected IGBTs with simple auxiliary circuit

There is much need for high voltage solid-state-switches in a broad area of applications. To get a high voltage switch, the series-connection of a solid state device is usually used. The main problem in such high voltage switches is to guarantee the voltage balance across the device both at a static and dynamic transient state. This paper presents a simple and reliable voltage-balancing scheme of the high voltage switch stack using series-connected IGBTs. With the proposed method, using a simple voltage balancing circuit, high-voltage semiconductor switches are realized with working voltages of several orders of kilo-volts. The operation principle of the proposed circuit is explained and analyzed. Transient and static voltage balancing is tested on an experimental 20 kV/400 A switch with sixteen series-connected IGBT modules.