| Transmission line pulse transformer (TLT), having outstanding performance in high frequency, conforms to modern pulse power technology (PPT) of being compact, repetitive and solid. Nowadays, TLT has attracted extensive attention. In this thesis, a 4-stage TLT is developed based on the theoretical analyses on TLT, the optimization of secondary line inductance, and the method to design TLT. The research results set basis for the wide application of TLT to PPT.The detailed work includes the following:1. A basic TLT theory has been analyzed.A general TLT theory has been analyzed. The process of wave transmission of a 2-stage TLT has been analyzed in detail, and then generalized to n stages. The undesireable effect to the output result caused by secondary lines is also pointed out. Particularly, after the carefully examination of TLT's gain, the results manifest that the number of stages should not be too large, generally not larger than 10. Besides, the frequency response of TLT has been carefully analyzed. The results indicate that TLT has an exceptional high-frenquency response, and it works up to 1 GHz if parameters are suitable.2. An optimization of TLT's secondary inductance is investigated in detail.Two typical topologies of TLT, i.e., with coupling between stages and without, are analyzed and discussed, and the expressions of output are derived. In order to design a compact TLT, an optimization of each secondary line inductance is presented. For TLT without coupling between stages, the optimal values of the n-stage inductance is n-1 times of the second stage, and the inductance is equal for TLTs with coupling between stages. Having been optimized, the volume of magnetic core used for TLT is the least. At last, a comparison of the outputs of several structures is presented. The result indicates that the topology of mutually coupling between stages is more suitable to the designing of compact TLT; the topology of non-coupling is simpler and more beneficial to the low output impedance of TLT.3. Numerical simulations on TLT have been conducted.The results of numerical simulations have verified the theorectial ananlysis that the electrical length of transmission lines has influence upon the output pulse. Generally, transmission line with a length less than a half of the pulse width will cause pulse distortion to the output. Forthermore, the inductance and capacitance at the joints are also harmful to the rise-time and fall-time performance of TLT. Joints should be short, and TLT should be keeping far from the conductors connecting to ground.4. A 4-stage TLT is developed.Experiments of low voltage on TLT have been conducted before high voltage versions. A 4-stage TLT with diameter 300 mm, height 450 mm, and mass 45 kg is developed. Through a Blumlein pulse generator, a pulse with voltage up to 10 kV, duration (FWHM) of 150 ns and rise-time about 20 ns is injected into the TLT. At the output terminal of TLT, pulse with amplitude 40 kV, pulse width 150 ns and rise-time slightly larger than 20 ns is obtained. By far, this type of pulse transformer with such performance has not been reported. |
