【作者】 李志强；

【导师】 钟辉煌；

【作者基本信息】 国防科学技术大学 ， 电子科学与技术， 2009， 博士

【摘要】 高功率微波的应用对脉冲功率技术和高功率微波源技术提出新的要求是向小型化和长脉冲方向发展。电感储能脉冲功率源和磁绝缘线振荡器(Magnetically insulated transmission line oscillator,简称MILO)作为各自领域内向该方向发展的重要候选者之一得到了广泛关注。本文在对新型电感储能脉冲功率源电路进行理论分析和数值计算研究的基础之上,研制了一台基于新方案的脉冲功率源,同时还研制了一个和该脉冲功率源相匹配的S波段15Ω锥形MILO负载,并进行了联调实验。本文的主要研究内容有以下几个方面:1)在研究传统电感储能脉冲功率源工作原理基础之上,开展了新型电感储能脉冲功率源工作原理的理论分析与数值计算研究。新方案的核心思想是利用传输线的延时隔离作用,将两个电感的放电时刻在时间上进行错开,从而起到改善输出波形质量的作用。采用等效电路的方法推导出了储能电感放电计算公式,表明新方案是将传统电感指数衰减放电波形转换成指数衰减放电波形和正弦阻尼振荡放电波形的叠加,从而达到改善波形质量的作用。同时,新方案还具有降低阻抗以及提高能量转换效率等优点。此外,还得到了当储能电感L2和传输线电容C2以及负载电阻RL所组成串联回路品质因数满足Q≈1时可获得最大能量转换效率的结论。PSpice电路仿真实验验证了理论分析结果。2)在理论分析和数值计算研究的基础之上,开展的原理性实验初步验证了理论设计的正确性。在此基础之上,再通过对关键部件的调研、选取、结构设计以及静电场分析等,研制了一台基于新方案的脉冲功率源。开展了该脉冲功率源电路参数测试工作并驱动水电阻假负载进行了实验研究,实验结果验证了电路仿真计算结果。3)在调研、比较和理论分析的基础之上,设计了S波段15Ω锥形MILO负载并开展了实验研究。从MILO的色散关系出发,设计了器件结构尺寸,并进行了模拟优化和实验研究。该器件在电压500kV,电流35kA的条件下获得了效率11%、功率2GW、频率2.65GHz的高功率微波输出。MILO在长脉冲情况下运行的研究结果表明,脉冲功率源输出电压波形质量差是造成微波波形质量较差的关键因素。对不同负载结构对微波输出性能影响的研究表明,采用石墨负载收集极是一个良好的选择。4)开展了新型电感储能脉冲功率源驱动二极管的实验研究。通过对所研制的脉冲功率源驱动虚阴极振荡器(Virtual cathode oscillator,简称VCO)、15ΩMILO、20ΩMILO等作为二极管负载的实验研究,明确了脉冲功率源的工作特性。对二极管电流和电爆炸丝根数与充电电压比值(n/Uc)的关系研究表明,存在最优的n/Uc,可使脉冲功率源获得最大的电流输出。调整陡化开关气压的研究表明,合理的开关气压是获得良好脉冲波形质量的保证。改变储能电感L2的研究表明,通过调整电感大小容易改变输出波形。对实验中出现的脉冲缩短问题进行了深入研究,明确了二极管击穿和电爆炸丝开关沿面爬电是发生脉冲缩短问题的主要原因。开展了驱动S波段15Ω锥形MILO的初步实验研究,在二极管电压300kV、电流22kA、脉冲宽度214ns的条件下,获得了功率200MW、脉冲宽度66ns的高功率微波输出。5)在理论分析和实验研究的基础之上,提出了紧凑化的设计思想,开展了紧凑化结构设计。详细介绍了紧凑化设计思路,对各关键部件进行了结构设计和静电场分析,得到了长不超过1m,直径不超过0.65m,技术指标为电压500kV、电流34kA、脉冲宽度160ns的紧凑化结构模型。另外还提出了全固态化设想并进行了电路仿真验证。更多还原

【Abstract】 The applications of high power microwave require that the pulsed power technology and high power microwave source technology develop towards the direction of miniaturization and long pulse. As one of important candidates in their respective fields, an inductive energy storage pulsed power source and a magnetically insulated transmission line oscillator (MILO) have attracted the attention of many researchers. In this dissertation, based on the theoretical analysis and simulation calculation of the working mechanism and operation properties of the novel inductive energy storage pulsed power source, an experimental inductive energy storage pulsed power souce has been designed and fabricated, at the same time, a MILO which can be used as a matching load of the pulsed power source has also been studied. Experiments of using this pulsed power source to drive the MILO have also been carried out.This dissertation mainly consists of the following aspects.1) Based on the systematic study of the traditional inductive energy storage pulsed power source, the theoretical analysis and simulation study of the working mechanism and operation properties of the novel inductive energy storage pulsed power source have been carried out. The basic thought of the novel technology is that by the help of the delay time of the transmission line, the beginning times of the different inductors discharge can be isolated, so that the output waveform can be improved. Considering the transmission line as a capacitor, the novel principle circuit has been simplified and the discharging formula of the inductor has been derived. The formula shows that the novel technology changes the traditional pure exponentially decayed discharging waveform into a combination of an exponentially decayed discharging waveform and a sinusoidally damped oscillation discharging waveform, which is the very reason why the waveform is improved. Further numerical calculation indicates that the novel technology also has the advantages of decreasing the output impedance and increasing the energy transfer efficiency. Additionally, when the RLL2C2 circuit quality factor Q≈1 is satisfied, the maximum energy transfer efficiency can be obtained. Circuit simulation results are in agreement with the theoretical results.2) Based on the theoretical and simulation study, the theory of the new design has been proved by the principle experiments. Through the survey, choice, structure design and static electrical field ananlysis for the key parts, an experimental device has been designed and fabricated. Measurements of the circuit parameters and experiments of the water resistance dumy load by the pulsed power source have also been carried out. Experiments with the dumy load have validated the simulation results. 3) Based on the investigation, comparison and analysis, an S-band tapered MILO with an impedance of 15Ωhas been designed and studied experimentally. Through the dispersion curve of the MILO, preliminary structure parameters were designed. With the help of the PIC code and the electromagnetic analysis software, the optimized structure parameters have been obtained. Micorwave with an averaged power of 2GW, a frequency of 2.65GHz and an efficiency of 11% has been achieved under the diode voltage of 500kV and the current of 35kA in the improved structure.The study of the MILO under the long pulse operation shows that the poor diode voltage waveform results in the poor microwave waveform. The effect study of different load structures on the output feature indicates that the graphite load is a better choice for long pulse operation.4) The diode driven by the experimental device has been studied experimentally. Operation properties of this device have been obtained through the experimental study of its driving different diode loads such as the virtual cathode oscillator (VCO), the MILO with the impedance of 15Ωand another MILO with the impedance of 20Ω. The study of the relation between the diode current and the ratio of the electrically exploded wires number and the charging voltage shows that there exists the optimal value of n/Uc which can make the pulsed source get the maximum current output. The study of adjusting gas pressure in the chopping switch shows that reasonablely controlling the gas pressure is the promise for the better output waveform. The study of changing the energy storage inductive value (L2) shows that the output waveform is easy to be changed by adjusting the inductive value. The pulse shortening is caused by the diode breakdown and the surface flashover of the electrically exploded opening switch through the study of pulse shortening phenomena. In the experimental study of this device’s driving the S-band MILO with the impedance of 15Ωto generate high power microwave, an output with an averaged power of 200MW and the pulse width of 66ns has been obtained under the diode voltage of 300kV,the current of 22kA and the pulse width of 214ns.5) Based on the theoretical analysis and experimental study, a concept about the compact structure design has been presented and the preliminary integrated design has been carried out. Through the especial structure design and the static electric field analysis of the key parts, a structure model of the pulsed power source with the length of less than 1m and the width of less than 0.65m has been obtained, which can be worked safely under the diode voltage of 500kV and the current of 34kA. Additionally, a concept design of a full solid state source has also been presented and simulated.更多还原