| National defense and civil applications require the pulsed power system (PPS) withfeatures of compactness and solid-state. The structure of stacked Blumlein line (SBL) isbeneficial to the compact PPS due to its combination of energy storage, pulse formingand voltage multiplication. Ceramic for energy storage has wide potential for PPSapplications due to its essential characters such as high energy storage density, stabledielectric constant and excellent environmental adaptability. Therefore, SBL usingceramic for energy storage is an important technology approach to achieving compactand solid PPS. Five significant issues, i.e., the correlated theory of the SBL, thestructure optimization of the SBL; the breakdown characteristics of the ceramic,multi-switch triggered in synchronization, and the facility of a3-stage SBL usingceramic for energy storage, are studied and analyzed systematically in this dissertation.The main content involved is depicted as following.1. The correlated theory of the SBL is studied systematically through the analysisof its pulse forming process (PFP) and parasitic impedance. In the PFP analysis, thetransmission and reflection coefficients in each junction point of SBL are calculated,and the analytical expression of the output pulse for a lossless SBL is obtained by usingLaplace transform. A circuit model is developed for analyzing the influence of theparasitic impedance. The calculation results indicate that the voltage multiplication isbasically equal to the stage number as the ratio of the Blumlein impedance to theparasitic one decreases.2. For combining the SBL structure with its circuit parameters, the characteristicparameters of a parallel-plate SBL are calculated through the coding in Method ofMoment (MoM), and the effects of structural parameters on the output pulse are studiedthrough a3D SBL model developed in CST Microwave Studio. The results indicate:1)coupling impedances in parallel connection with the impedances formed betweenadjacent electrodes decrease the SBL matching impedance;2) the smaller ratio ofdielectric thickness to electrode width, the more benefit to improving the voltagemultiplication and the energy efficiency;3) the structure with a high ratio of length towidth is advantageous to a plane wave forming and transmission in a parallel plateBlumlein, so as to producing a rectangular pulse with good quality across a matchingload;4) it is beneficial to alleviating the electric-field enhancement located the electrodeedges in a parallel-plate SBL when the dielectric is wider than the electrode;5) as onlyincreasing the dielectric thickness, the output pulse duration is kept unchanged, but thepulse front and tail edges are stretched severely, and some oscillation emerges in thepulse flat-top.3. The influence of the ceramic dielectric discontinuity on the ceramic SBL is analyzed. The results indicate two aspects of this influence:1) the internal gap of theceramic is likely to result in the decrease of the ceramic breakdown strength (BDS) dueto the non-uniform distribution of electric field inside the parallel SBL, and the mostjeopardous gap is the one with a shape of triangle cross-view;2) the permittivitydifference of ceramic slabs deteriorates the output pulse flat-top quality of the ceramicSBL, and the best case is that each Blumlein has the same electric length by adjustingthe location of different ceramic slabs.4. Experimental system is built for testing the breakdown characteristics of theceramic. Four influence factors of the ceramic BDS, such as electrode configuration,dielectric surroundings, charging source and repetitive rates, are studied and analyzed.The results indicate:1) the maximum ceramic BDS among all the tests is26.01kV/mmunder conditions of semi-sphere electrode, glycerin surroundings, and single μs pulse;2)the vacuum flashover BDS tested under dc charging condition is slightly higher than theone under pulsed condition;3) the condition of pulse charging in high repetition rate cancause the thermal accumulation inside the ceramic, then ceramic melted, and fastformation of breakdown channel, thereby reducing the ceramic BDS.5. A SBL using ceramic for energy storage is proposed based on the small ceramicslab with dimensions of95×95×4mm3, and the output pulse waveforms are simulatedin different dielectric surroundings. The results indicate that this structural facility isappropriate to work in the surroundings with low permittivity, such as transformer oil orvacuum. The performance of the facility affected by switch working behavior isanalyzed. The results indicate that the dispersity of closure time of multi-switch resultsin ladder distortions within the front and tail edges of the output pulse, meanwhiledecreasing the ceramic BDS.6. A transmission line pulse transformer (TLT) is developed, and the testing resultsdemonstrate that the TLT is capable of splitting a narrow pulse into3subpulses with thesame parameters, i.e.,20kV voltage amplitude,12ns pulse width, and5ns rise time.By using the3subpulses, we have achieved3switches synchronizedly triggered in thens range.7. The facility of a3-stage SBL using ceramic for energy storage is developed andtested. After the3-stage SBL is dc charged up to4kV, a32ns quasi-rectangular pulseof11.4kV is measured across a10dummy load under the condition of the3switchestriggered in synchronization. The voltage multiplication is about2.9, and the energyefficiency is about90%. The effects of three factors, i.e., switching condition, chargingsource, and working surroundings, on the facility performance are experimentallystudied. The results indicate:1) multiple synchronized pulses can effectively improvethe closure time synchronicity of the multi-switch;2) the pulse with voltagemultiplication of2.7and energy efficiency of79%is achieved across the matched loadunder ns pulse charging condition;3) the effect of different working surroundings on the performance of the facility is tested, and the results demonstrate that the facility isappropriate to be operating in the surroundings with low dielectric constant. |
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