Implementation of high-voltage switch using inductive energy for switch synchronization

For discrete semiconductor switches with smaller ratings stacked for high-voltage high-current applications, there is the need to ensure reliable gate synchronization of all the switches in the stack. The switching delay between the separate stages can be minimized through fast transfer of the control signals needed for synchronizing the switch or by reducing the effects of stray inductances. This paper describes the design of a HV switch which uses the inductive energy stored in the primary transformer for switch synchronization. In this design, single low-voltage power source provides control signal and sufficient current to drive the stacked insulated-gate bipolar transistors (IGBTs) at a sufficiently high gate — emitter voltage. The fast current transfer due to this inductive energy greatly improves switch turn-on delay time, allowing for reliable switch synchronization at fast speed. The designed HV switch was used as the modular unit of an SSPPM to apply rated pulse output voltage and current of 15 kV and 1.5 kA respectively to a load. The operation of the designed HV switch was verified through experimentation.