Linear transformer and primary low-inductance switch and capacitor modules for fast charging of PFL

Abstract

Abstract. A step-up linear pulse transformer and a modular primary powering system were developed for fast (≈350 ns) charging of a pulse forming line (PFL) of a high-current electron accelerator. The linear transformer is assembled of a set of 20 inductors with circular ferromagnetic cores and one-turn primary windings. The secondary turn is formed by housing tube walls and a voltage adder with a film-glycerol insulation installed inside of the inductors. The primary powering system assembles 10 modules, each of them is a low-inductance site of two capacitors of 0,35 µF and one gas switch mounted at the same enclosure. The total stored energy is 5.5 kJ at the charging voltage of 40 kV. According to test results, the equivalent parameters at the output of the transformer are the next: a capacity -17.5 nF, an inductance -2 µH, a resistance -3.2 Ohms. IntroductionLinear transformers take a special place among the variety of existing high voltage pulse transformers. They assemble a series set of one-turn transformers with primary windings fed separately and the common one-turn secondary winding. The coaxial version with the volume primary winding and the secondary winding formed by a common housing and a central stalk-voltage adder have the lowest possible induction and a minimal resistance of windings. It reduces both the energy transfer time and losses [1][2][3].The following are the design and the basic characteristics of linear pulse transformer with an output voltage of 800 kV and the modular capacitive energy storage in the form of low-inductance capacitorswitch modules, designed for fast (≈350 ns) charging of a pulse forming line of a nanosecond highcurrent accelerator.