The principle of coaxial transmission line pulse transformer and square-wave response of it.

Transmission line pulse transformers have been widely used in pulsed power technology. Traditional transmission line pulse transformers often use separate structures, which always introduces larger spurious parameters, and have lower voltage levels. In order to solve these problems, this note proposes a coaxial transmission line pulse transformer. A circular symmetric structure is used in the input and output ports of the coaxial transmission line pulse transformer, and there are no spurious parameters theoretically. Furthermore, this structure is suitable for hundreds of kilovolts high voltage applications. The structure and working principle of the coaxial transmission line pulse transformer are introduced in this note, and the circuit simulation research is conducted. The factors that affect the pulse transformation are analyzed. Furthermore, experimental studies of the square wave impulse response are conducted on an actual device. The result shows that the proposed coaxial transmission line pulse transformer can achieve the purpose of increasing the voltage amplitude while keeping the pulse waveform undistorted.

A Tesla-type repetitive nanosecond pulse generator for solid dielectric breakdown research.

A Tesla-type repetitive nanosecond pulse generator including a pair of electrode and a matched absorption resistor is established for the application of solid dielectric breakdown research. As major components, a built-in Tesla transformer and a gas-gap switch are designed to boost and shape the output pulse, respectively; the electrode is to form the anticipated electric field; the resistor is parallel to the electrode to absorb the reflected energy from the test sample. The parameters of the generator are a pulse width of 10 ns, a rise and fall time of 3 ns, and a maximum amplitude of 300 kV. By modifying the primary circuit of the Tesla transformer, the generator can produce both positive and negative pulses at a repetition rate of 1-50 Hz. In addition, a real-time measurement and control system is established based on the solid dielectric breakdown requirements for this generator. With this system, experiments on test samples made of common insulation materials in pulsed power systems are conducted. The preliminary experimental results show that the constructed generator is capable to research the solid dielectric breakdown phenomenon on a nanosecond time scale.