Fast rise time pulsed power generator using IGBTs and coaxial magnetic pulse compression circuit

Abstract

All solid-state pulsed power generators, which are operated with long lifetime, compactness and high reliability, have been developed to be used for industrial applications, such as excimer laser, high energy density plasma (EUV sources) and pulse ozonizer. Moreover, requirements of these applications are repetitive operation and fast risetime voltage. Recently, semiconductor power device technology has improved the performance of fast high voltage switching and low switching loss. In particular, insulated gate bipolar transistor (IGBT) is highly efficient semiconductor switching device. However, the IGBT switch is still not sufficient to drive the pulse laser and the pulse ozonizer itself. In practical systems, semiconductor switches are used with the assistance of magnetic switches. We have studied and developed high repetition rate small size pulsed power generator for generation of discharge plasma. This generator consists of an IGBT switch circuit, a step-up pulse transformer and multi-stage magnetic pulse compression circuit (MPC) at the last magnetic pulse compression stage, has a coaxial configuration. This fast-rising pulsed power generator using a coaxial MPC has been developed for fast rise time output current. We use two kinds of magnetic core materials, a Co-based amorphous alloy and a nanocrystalline Fe-based soft magnetic alloy. Two kinds of magnetic cores were investigated in the coaxial MPC to evaluate loss of the magnetic cores, leakage current of saturable inductors, and circuit inductance. The pulsed power generator produced a pulsed-high-current of 3.7 kA with a rise time of 7 ns at a repetition rate of 1000 pulses per second (pps). This generator is able to generate an output voltage of about 20 kV with voltage rise time of less than 10 ns. We did the operation test and generate the streamer discharge with 1000 pps.