Analysis and simulation of pulse transformer considering leakage inductance and capacitance

Abstract

Pulse transformers capable of transmitting substantially rectangular voltage pulses, with durations of less than one millisecond, were developed for radar application, NLC klystron pulse modulator, driving a microwave amplifier, x-rays for medical and industrial use, gas lasers for plasma technology and plasma immersion ion implantation [1–7]. Several application of them, need medium or high voltage pulses (1 up to 700kV) that medium or high voltage pulse transformer increases the output pulse voltage to the value required for the load. The usually large number of turns in the secondary winding (the transformer ratio is frequently 1:10), together with the insulation gap between windings and between winding layers increase the value of the equivalent parasitic elements (leakage inductance and inter-winding capacitance). These elements extend the pulse rise time and cause overshoot and oscillations. Hence, the design of the pulse transformer is critical, not only because all materials must sustain the medium or high voltage across them, but also because the output pulse shape depends heavily on several transformer parasitic parameters that are difficult to master [8].