title: Thyristor stack for pulsed inductive plasma generation.
abstract: A thyristor stack for pulsed inductive plasma generation has been developed and tested. The stack design includes a free wheeling diode assembly for current reversal. Triggering of the device is achieved by a high side biased, self supplied gate driver unit using gating energy derived from a local snubber network. The structure guarantees a hard firing gate pulse for the required high dI/dt application. A single fiber optic command is needed to achieve a simultaneous turn on of the thyristors. The stack assembly is used for switching a series resonant circuit with a ringing frequency of 30 kHz. In the prototype pulsed power system described here an inductive discharge has been generated with a pulse duration of 120 micros and a pulse energy of 50 J. A maximum power transfer efficiency of 84% and a peak power of 480 kW inside the discharge were achieved. System tests were performed with a purely inductive load and an inductively generated plasma acting as a load through transformer action at a voltage level of 4.1 kV, a peak current of 5 kA, and a current switching rate of 1 kA/micros.
authors.affiliation: Plasmaphysics Group, Institute of Applied Physics, Johann-Wolfgang-Goethe University, 60438 Frankfurt am Main, Germany.
authors.forename: C
authors.initials: C
authors.lastname: Teske
authors.forename: J
authors.initials: J
authors.lastname: Jacoby
authors.forename: W
authors.initials: W
authors.lastname: Schweizer
authors.forename: J
authors.initials: J
authors.lastname: Wiechula