共查询到20条相似文献,搜索用时 31 毫秒
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Chen Y. Dickens J. Mankowski J. Kristiansen M. 《Dielectrics and Electrical Insulation, IEEE Transactions on》2009,16(4):971-978
Recent research efforts at Texas Tech University on impulse antenna phased array has needed to develop a reliable high voltage, high repetition rate switch that will operate with ultra low jitter. An ideal jitter of a small fraction of the risetime is required to accurately synchronize the array to steer and preserve the risetime of the radiated pulse. In [1], we showed the initial test system with sub-ns results for operations in different gases and gas mixtures. This paper discusses in detail 50 kV, 100 Hz switch operations with different gases. The effects of gases and gas mixtures have on switch performance which includes recovery rate and in particular jitter will be investigated. Gases tested include, dry air, H2, N2, and SF6, as well as H2-N2, and N2-SF6 gas mixtures. Switch jitter as a result of triggering conditions is discussed, also including a comprehensive evaluation of jitter as a function of formative delay in the various gases. The temperature of gas and its effects on switch jitter is also documented in this paper. A 50 Ω, 1 nF pulse forming line is charged to 50 kV and provides the low inductance voltage source to test the different gases. Triggering is provided by a solid state opening switch voltage source that supplies ~150 kV, 10 ns risetime pulses at a rep rate up to 100 Hz in burst mode. A hermetically sealed spark gap with a Kel-F - PCTFE (PolyChloroTriFluoroEthylene) lining is used to house the switch and high pressure gas. 相似文献
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本文设计了一台激光触发变压器型脉冲调制器并开展了单次及1Hz重频实验研究。该调制器由水介质同轴脉冲形成线、激光触发开关、脉冲变压器、假负载等组成。在调制器主开关导通电压为-795k V时,激光到达开关25ns后调制器主开关导通,在负载上得到了电压-402k V、电流26k A、脉冲宽度128ns的准方波高功率电脉冲。当调制器主开关分别为氮气、六氟化硫时对调制器激光触发气体开关的延时、抖动特性进行了实验研究,266nm激光触发时,氮气具有较小的延时和抖动;同时对自击穿和激光触发两种情况下负载电压的前沿特性进行了对比,最后对实验结果进行了分析。 相似文献
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开关在脉冲功率技术中极其重要,其已成为制约脉冲功率技术发展的主要技术瓶颈。为了满足高电压、大电流、高电荷转移量、电极烧蚀小、寿命长的要求,文中设计了一个由轴向磁场控制的旋转电弧间隙开关,研究了其电磁场分布及轴向磁场下电弧的运动机制,并进行了初步实验。结果表明此开关中的电弧确实在轴向磁场控制下做旋转运动,且运动速度很快,不需要对触发脉冲进行陡化就能得到纳秒级脉冲。实验放电波形比较稳定,分散性为2ns;开关电极表面的烧蚀小,有利于延长开关的寿命;开关工作参数为:电压23kV,单脉冲能量0.314MJ,峰值电流100kA,电荷转移量27.3C/脉冲。 相似文献
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Sullivan D.L. Kovaleski S.D. Hutsel B.T. Gahl J.M. 《Dielectrics and Electrical Insulation, IEEE Transactions on》2009,16(4):956-960
The use of laser targets as a method to decrease the required laser energy to trigger a laser triggered gas switch has been investigated at the University of Missouri. Target materials were identified based on durability, melting point, reactivity and reflection coefficient. Laser targets were placed into a cathode of a laser triggered gas switch. The switch was pulse charged by the Tiger pulsed power machine to between 185 kV and 330 kV. The switch was triggered by directing a 1064 nm or 266 nm wavelength laser pulse from an Nd:YAG laser onto a laser target to ablate material and create plasma, closing the switch. The goal of the project was to trigger a high voltage gas switch with less than 1 mJ of laser energy while maintaining a switch jitter comparable to present electrically triggered switches for LTD based systems. The study successfully demonstrated that triggering the switch using a 1 mJ infrared pulse and a graphite target resulted in a jitter less than 5 ns. Findings will be used in the design of switches for LTD based systems. 相似文献
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研究了一种应用于激光驱动源的大功率超高速半导体开关反向开关晶体管(RSD)的新结构,以实现ms、ns脉宽、MW以上的高重复率脉冲的产生和控制。RSD具有大面积快速均匀开通、可无限串联、功率大、换流效率高、寿命长的特点。利用单次脉冲试验平台研究了RSD的开通机理及高密度能量转换、允许通过的峰值电流、开通条件与预充、准静态损耗及其di/dt等多项特性。根据经验公式,对小直径RSD做极限电流试验,f 20mm的RSD堆体通过了19.9kA脉冲电流(脉宽30ms)。通过减小主回路电感考核了RSD的高di/dt 耐量特性,放电电压3kV时得到di/dt接近8kA/ms。 相似文献
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为了满足脉冲功率技术和脉冲电流试验技术对放电开关的要求,笔者设计了BaTiO3高介电常数的电介质沿面闪络伪火花开关的触发装置。通过对表面放电触发器的实验发现:在伪火花开关的工作气压范围内,高介沿面闪络触发器显示出很强的电荷发射能力和快速的电荷注入能力,在气压为7 Pa时,触发器能够在30 ns内释放1.5μC,触发电流的上升陡度为1.2×1011A/s,发射的电子数达到9.4×1012。对自放电电压为28 kV的伪火花开关,可靠工作的最低电压可降低到130 V,放电时延为35~100 ns,最小抖动为6~25 ns。 相似文献
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气体触发开关是脉冲功率电路的重要组成器件。针对工程中对低抖动、长寿命气体触发开关的需求,结合三电极场畸变型触发开关,设计一种拥有较多孔隙的多环型触发极结构。对三种主电极-触发极分别为平板-多环、平板-圆盘、球冠-圆盘的开关进行击穿特性实验研究,结合电场仿真对比分析实验结果。实验结果表明:在22.4k V/40ns的触发脉冲和5.0~7.5k V的工作电压下,平板-多环结构的开关时延及抖动比较稳定,开关时延基本在81.0~84.5ns之间,抖动为0.8~1.1ns。平板-多环电极结构开关时延、抖动均明显优于平板-圆盘结构,其开关时延、抖动与球冠-圆盘结构基本相同但使用寿命优于球冠-圆盘结构。 相似文献
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基于反向开关晶体管(RSD)的工作原理,提出采用脉冲变压器隔离的直接式触发高压RSD,以解决系统对触发开关要求较高的问题。脉冲变压器的作用是隔离主放电回路的高压,同时在有限的时间内给RSD提供足够的预充电荷且经过一定的时间延迟后饱和。据此,利用变压器等效电路对其进行了设计,得到了变压器及电路的相关参数。利用电路仿真软件Saber仿真脉冲变压器的饱和特性,并进行了实验验证。最后以10kV电压通过RSD对负载放电为例,验证方案的可行性,得到峰值为12kA、底宽15μs、di/dt为2kA/μs的主电流。实验完毕,经测试,器件完好无损。 相似文献
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The authors developed a new type of commutating element that can be used repeatedly in order to develop fault current limiters (FCLs) to be operated on distribution lines. Operating tests were carried out on the commutating element combined with a conducting element in a circuit equivalent to the line voltage of 6.9 kV and the short-circuit current of 12.5 kA. The FCL was able to limit the actual peak current to 12 kA, or one third under a peak current of 32.5 kA without the use of the FCL. The authors present the operating principle of the new commutating element and results of the tests. The commutating element employs stainless steel resistors operating in a SF6-N2 gas mixture 相似文献
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Elizondo J.M. Rodriguez A.E. Honig E.M. 《Dielectrics and Electrical Insulation, IEEE Transactions on》1995,2(3):368-375
High current density (>100 A/cm2) electron beam diodes operating beyond 250 kV/cm in a 1 cm gap configuration are described. The principal features of the electron source are the high current density and high field without the onset of vacuum arcs or arc collapse prior to gap closure. The electron beam diode was controlled by a variable pulse-width output Marx generator. Fields to 600 kV/cm were applied for 25 to 30 ns, and to 300 kV/cm during space-charge limited current conduction at pulse lengths of 100 to 120 ns. Evidence of the transition to space-charge limited unipolar flow and transition to bipolar space-charge limited flow was obtained. Traces of the typical behavior and the different transitions are shown. Beam uniformity was measured by using a set of Faraday cups. The Faraday cup setup was then used to demonstrate suppression of electron emission from surfaces coated with a dielectric film 相似文献
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Kazunori Satou Akira Sugawara Takayuki Itou Kouichi Itagaki 《Electrical Engineering in Japan》2000,132(3):8-13
The switching time and arc‐ignition probability of a sustained main discharge in a laser trigger vacuum gap were measured. The third harmonic beam of an Nd:YAG pulse laser (wavelength 355 nm, energy 5 mJ/pulse, power density 4 × 107 W/cm2) was used to trigger the gap. The main electrodes 85 mm in diameter were made of oxygen‐free copper. The gap length was 1.6 mm and the experimental chamber was evacuated to about 1.3 × 104 Pa by a turbomolecular pump. The UV beam from the laser was focused at normal incidence onto the grounded cathode. The switching time decreased and the arc‐ignition probability increased with increasing applied voltage. The switching time was 326 ns at 15 kV with a circuit inductance of 107 μH. Its jitter was 24.8 ns. The advantageous results obtained with the UV beam are compared to the previously reported data on triggered vacuum gaps. © 2000 Scripta Technica, Electr Eng Jpn, 132(3): 8–13, 2000 相似文献
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Hartmann W. Roemheld M. Rohde K.-D. Spiess F.-J. 《Dielectrics and Electrical Insulation, IEEE Transactions on》2009,16(4):1061-1065
To investigate the efficiency of submerged pulse corona (SPC) discharges in water we built a laboratory scale, parallel-plate reactor that is part of a closed loop water circulation system. A pulsed voltage is applied across the electrodes. One of the electrodes is coated with a porous ceramic layer to create local field enhancements to initiate corona discharges. For energization of the SPC reactor a pulse generator was developed which is based on a capacitor discharge initiated by a semiconductor switch. A pulse transformer, followed by two magnetic pulse compression stages, produces voltage pulses with amplitudes of up to 30 kV at a pulse width of 0.3 μs. Simulation of the circuit behavior leads to good agreement with voltage and current measurements. Details of the pulse generator and first experimental results concerning the efficiency of radical production are presented. Depending on the conductivity of the water to be treated, pulse currents of > 600 A at a voltage of 20 kV to > 30 kV are obtained for electrode sizes of around 50 cm2. The efficiency of the radical production is measured in terms of the hydrogen peroxide (H2O2) concentration, which is formed by recombination of hydroxyl radicals (OH.) at sufficiently high concentrations downstream of the plasma reactor. At pulse repetition rates of 20 to 100 Hz, H2O2 concentrations of several mg/l are produced, at efficiencies in the range of up to ?1 g/kWh. 相似文献
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Minamitani Y. Ohe Y. Higashiyama Y. 《Dielectrics and Electrical Insulation, IEEE Transactions on》2007,14(4):894-899
Nanosecond and sub-nanosecond high voltage pulses can provide new applications. A cancer treatment by an ultra-short pulse high electric field is one of them. High power pulsed microwave has been proposed to apply the high electric field for that treatment. This work focuses on the design of a compact high power pulsed microwave generator using a nanosecond pulse power generator for the cancer treatment. To obtain fast rise time of voltage and current for nanosecond pulses, a switch has to have low inductance. Water gap switches have this property. Since water has a dielectric strength exceeding 1 MV/cm, gap distances for switching can be reduced to several hundreds of micrometers, and still allow switching of tens of kV. The narrow gaps allow us to reduce the switch inductance. In this study, the water gap switch was built in a Blumlein pulse forming line. The Blumlein line was designed to provide a pulse of 1 ns and to match an impedance to 16 Omega of an antenna. By using the water gap switch in the Blumlein line, the voltage rise time obtained approximately 750 ps at 13 kV of a peak pulse voltage. An electromagnetic wave was radiated underwater by the loop antenna. A measuring antenna at 0.15 m and 0.4 m from the radiating antenna caught electric field intensities of 116 kV/m and 32 kV/m, respectively. A frequency element of 250 MHz had higher intensity. 相似文献
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Han Y. Lin F. Dai L. Li H. Wang L. Bo L. Long Z. 《Dielectrics and Electrical Insulation, IEEE Transactions on》2009,16(4):979-984
A compact pulsed power supply (PPS) system is important for the electromagnetic gun (EMG) system, which should supply high energy and large current. The paper presents the setup of compact PPS system based on high energy density capacitors. The PPS system includes ten 50 kJ modules, which can be triggered in sequence. Each module is composed of a capacitor (1000 μF/10 kV), a pulse shaping inductor (20 μH), a crowbar diodes with a crowbar resistor(30mΩ), as well as a main switch which can be a triggered vacuum switch?TVS? or thyristors. The peak value of the output current of each module is 70 kA. Characteristics of the TVS and thyristors are comparatively studied to determine their influence on the output current and energy. The requirements for the diode-stacks of the crowbar are fast-recovery, high voltage withstanding. A proper protection measure is used in order to protect the crowbar diodes from the damage of over-voltage when switch is fired. In the end, the overall discharge currents of the PPS triggered in sequence are presented. 相似文献