High-voltage and short-rise-time pulse-transformer with amorphous cores

A short rise time pulsed power transformer using cobalt-based amorphous alloy cores, which operates at high voltage (similar to 100 kV) and high repetition rate (similar to 4,000 pps), has been developed for application as a pulsed power modulator for copper vapor lasers. An output voltage of more than 80 kV, a rise time of 65 ns, and a transformation efficiency of 83% were demonstrated for the transformer with a 1:2 step-up ratio. Moreover, using a 1:3 step-up ratio, a maximum output voltage of over 110 kV was achieved. Circuit calculation indicated the impedance matching and coupling coefficient would be improved by the 1-turn primary coil and short magnetic path length from primary to secondary coil. This paper describes the design procedure, and the experimental and analytical results respecting the transformer characteristics.