【作者】 卜大鹏；

【导师】 廖敏夫；

【作者基本信息】 大连理工大学 ， 电机与电器， 2008， 硕士

【摘要】 开关元件是脉冲功率系统的核心元件之一,也是其主要技术瓶颈。真空触发开关作为能量的快速关合(释放)开关,是近年来非常有发展潜力的脉冲功率开关器件。本文以真空触发开关(TVS)的基本特性为主要研究对象,对其进行了理论分析与实验研究,设计和开发了场击穿型真空触发开关及其控制器。论文首先从真空触发开关场致发射击穿机理的分析出发,通过数学建模,引入热力学运动方程,建立真空触发开关的真空放电阴极斑点热传导模型,用来描述和估算真空触发开关的时延特性。然后以初始等离子体的产生与扩展机理为重点,讨论了真空触发开关的时延特性,对于采用氢化钛作为涂敷材料的沿面击穿型和场击穿型真空触发开关,分别进行了具体的仿真计算与分析。研究表明,应用所建立的阴极斑点热传导模型对沿面击穿型真空触发开关进行时延计算结果和Lafferty及Farrall的经典实验数据相吻合,证明了计算模型的正确性。为了验证所建立的场击穿型真空触发开关阴极斑点热传导模型的有效性,设计了场击穿型触发极结构,提出并研制出一种新型的触发源控制器。在新型触发源控制器的设计中,从基本高压脉冲发生回路和基本触发信号产生回路设计出发,采用陡化高压脉冲发生回路,利用三电极间隙产生陡化的高压触发脉冲来提高TVS的触发精度(触发精度在1μs之内),并采用光电隔离技术实现高低压的安全隔离,提高了触发电路的抗干扰能力。为了研究触发过程中的电弧特性,建立了一套LC试验主回路,以及电弧图像采集系统。为了验证所设计的场击穿型真空触发开关和控制器的参数特性,对建立的实验回路进行了大量实验来研究其基本工作特性如触发可靠性、触发时延与分散性、主间隙的导通特性。结果表明,场击穿型真空触发开关时延计算结果的与实验得到的结果较为接近,证明了计算模型的正确性。对TVS电弧的图象特性进行了分析,通过直观观测TVS导通过程中电弧形态的变化,可为深入研究TVS触发过程提供新的实验手段。更多还原

【Abstract】 The switch is the kernel component and the main technical obstruction of the pulsed power system (PPS). As an energy fast closing (releasing) switch, the TVS is considered as the most prospective switch in PPS. In this paper the fundamental characteristics of the TVS are theoretically and experimentally researched.The field-breakdown mechanism in TVS was analyzed. Based on introducing the behavior of heat in solids, the heat conduction model was set up for describing the heating process of the spots on the cathode, which occur in the TVS when triggered. The models can be used for explaining the initial plasma’s production and expansion mechanism and calculating the breakdown delay time on the improvement of the initial plasma produced by the trigger electrodes. For the TVS whose dielectric was coated with the TiH layer, the calculation using the heat conduction model was carried out. The calculation results confirm with Lafferty and Farrall’s experimental data very well.From the structure of the field-breakdown triggered vacuum switch (TVS) pole, a novel design for controlling the trigged vacuum switch is proposed. The field-breakdown triggered vacuum switch and its control system are constructed. Trigger a new source of the controller design, from the design of basic high-voltage pulses loop and basic trigger signal generating loop, steepened high voltage pulse generating loop is proposed in the novel controller of trigged source. In the TVS triggering circuit, a three-electrode-gap is used for providing steepened high voltage triggering pulse to improve the triggering precision (within 1 us). Then a main loop with LC and a system used to collect vacuum arc image are established.A lot of research is used to study their basic working characteristics, such as the trigger reliability, the delay time and its scatter decrease with the different triggered power, the characteristic of the main gap communicated and the image of the TVS arc. The experimental results show that the field-breakdown triggered vacuum switch delay time is close to the calculation model. Through visual observation on the changes of the TVS arc the analysis of the TVS arc image is a new experiment method.更多还原