基于雪崩三极管的高重频高压纳秒脉冲产生方法综述

激发大气压脉冲等离子体通常对施加脉冲的要求是k V级幅值、ns级前沿和宽度、k Hz级重复频率,尤其要求脉冲前沿和宽度尽量小,雪崩三极管脉冲产生电路非常适合于这样的要求。本文综述了基于雪崩三极管的脉冲产生方法。首先介绍了雪崩三极管的基本原理和研究概况,进而介绍了多管串联电路、多级Marx电路、多管并联电路以及脉冲截断电路四种典型电路结构的研究现状,分析了各电路的性能特点,并以多级Marx电路为例理论分析了影响输出脉冲幅值、前沿、后沿、脉宽、重复频率、效率和稳定性等参数的关键因素。最后介绍了多管串联Marx电路、多管并联Marx电路以及多路Marx并联电路三种组合型脉冲产生电路的研究进展,并对基本原理进行了分析。     

基于模块化Marx电路和传输线变压器的重频纳秒脉冲源设计

重频纳秒脉冲激励的大气压等离子体放电具有反应活性高等优点。设计了基于模块化雪崩三极管Marx电路和传输线变压器的重频纳秒脉冲源。计算不同Marx模块的导通时延和输出波形的抖动,研究了磁心数量、位置和形状对于输出波形的影响。磁心电感越大、外径与内径之比越大,且位于传输线变压器第一级和最高一级时对脉冲叠加效率的提升作用越明显。提出直接叠加和传输线变压器两种脉冲叠加方式组合的方法,进一步提高输出电压。整体脉冲源可以在50~300Ω负载产生2~14k V,高阻负载产生4~25k V,前沿3.8ns,脉宽7~15ns,重复频率0~10k Hz的重频纳秒脉冲电压,装置结构紧凑,参数调节灵活,方便携带。     

基于Marx电路的全固态纳秒脉冲等离子体射流装置的研制

研制一套具有快边沿纳秒脉冲等离子体射流装置。该装置由基于Marx电路的并带有尾切开关的全固态纳秒脉冲发生器和具有针环电极结构的等离子体射流装置组成。其中,纳秒脉冲源主要由直流电源、控制电路和主电路组成,主电路为10级模块化设计的Marx电路,使用MOSFET作为主开关和尾切开关;控制电路产生同步触发脉冲信号,通过光纤进行隔离后同步驱动MOSFET工作。输出纳秒脉冲电压参数为:幅值0~8k V可调,脉宽100~1 000ns,重复频率1Hz~1k Hz,上升沿30ns左右,下降沿50ns以内。等离子体射流装置使用氩气作为工作气体,其结构为针-环电极结构。搭建等离子体射流实验平台,并能够产生稳定的等离子体,为进一步探索大气压等离子射流的应用奠定了基础。     

Compact Subnanosecond Pulse Generator Using Avalanche Transistors for Cell Electroperturbation Studies

Research on the electroperturbation effects of ultrashort high field pulses in cancer cells requires subnanosecond rise time, high voltage pulses delivered to low impedance biological loads. Here we present a compact solid-state pulse generator developed for this application. The pulse is generated by switching a chain of avalanche transistors configured as a tapered transmission line from high voltage to ground. The system features a built in 1400:1 capacitively compensated resistive voltage divider. The divider, with a 3 dB point at 910 MHz, overcomes challenges in the direct measurement of the high frequency components of the output pulse. The generator is capable of producing a 0.8 ns rise time, 1.3 ns wide, 1.1 kV pulse into a 50 Omega load at a maximum repetition rate of 200 kHz. Techniques to implement physical layouting strategies to achieve subnanosecond rise times are outlined. Problems faced in integrating the subnanosecond pulse generator with a biological load are discussed. This pulse generator will be used in experiments aimed at electromanipulation of intracellular biomolecular structures.     

基于同步信号的多路延时IGBT驱动电路设计

基于同步信号设计了一种可实现相互之间高压隔离的IGBT多路延时驱动电路系统,并应用到Marx电路中,实现了可柔性调节的阶梯型脉冲高压输出。试验结果表明,延时驱动电路可实现最大30μs的延时,且具有IGBT驱动电压欠压保护、自给反向栅压等功能,同时场效应管的存在抑制了栅射极电压振荡。驱动信号高压隔离变压器为单原边多副边结构,简单紧凑,通过副边数目的增减,可驱动不同级数的Marx电路,具有扩展性好的优点。过流保护电路反应速度快,IGBT关断可靠,可在2μs之内抑制短路电流继续上升。该驱动电路应用于10级的Marx电路中,实现了峰值电压10 kV,脉冲宽度30μs,最大电压阶数10阶的脉冲高压输出。     

基于现场可编程门阵列的全固态高压ns脉冲发生器

为研究ns脉冲电场诱导肿瘤细胞的凋亡效应,结合Marx发生器原理和全固态开关技术,研制了一套基于现场可编程门阵列(FPGA)的多参数可调全固态高压ns脉冲发生器。该发生器主要包括高压直流电源、Marx电路、FPGA控制电路和负载4部分。Marx电路采用金属氧化物半导体场效应晶体管(MOSFET)作为控制开关代替传统的火花间隙开关,用二极管代替电阻。FPGA产生多路同步触发脉冲信号,通过光纤进行隔离后可作为MOSFET的原始控制信号,同步驱动多个MOSFET。FPGA控制电路控制充电电压和输出脉冲的宽度、频率,并具有保护功能。实验结果表明,该脉冲发生器可产生幅值(0～8kV)连续可调、脉宽(200～1 000ns)灵活可变、频率(1～1 000Hz)独立可控,前沿35ns的高压ns脉冲,为进一步探索ns脉冲电场生物医学效应奠定了基础。     

封装形式对瞬态电压抑制器件电磁脉冲防护特性的影响(英文)

Adding transient voltage suppressor(TVS) transistors to an electric circuit is an important method to protect it from the fast-risetime electromagnetic pulse(FREMP) damage. The package form of the TVS transistors influences the volume, response time, and power consumption of the circuit. However, the influence of the package form on the clamp voltage of TVS transistors affected by FREMP is not considered yet. In this article, the results of the experiment comparing the influence of package form are described, where the rectangular pulses with rise time shorter than 1 ns are used to test protection performance of three different TVS transistors, which have the same framework but different breakdown voltages. The influence of the different package forms on the clamp voltage is analyzed by using the fitting model. It is found that the package form of TVS transistors has less influence on the current characteristics of their protection performance, but more on the voltage characteristics. It is concluded that the diameter or width of the TVS transistors is the main factor determining the clamp voltage. Thus, the diameter or width of the TVS transistors should be big enough to ensure the stabilization of clamp voltage, but, at the same time, fit the allowing volume.     

Characteristics of a fast rise time power supply for a pulsedplasma reactor for chemical vapor destruction

Rotating spark gap devices for switching high voltage direct current (DC) into a corona plasma reactor can achieve pulse rise times in the range of tens of nanoseconds. The fast rise times lead to vigorous plasma generation without sparking at instantaneous applied voltages higher than can be obtained with DC. The resulting energetic plasma is effective for destroying a variety of molecules. The spark gap circuit configuration plays an important role in the effectiveness of the plasma generation. A single-gap circuit is effective for generating moderate peak voltages, but is limited by a multiple sparking phenomenon. A double-gap circuit can achieve equal peak voltages with every spark, but with a reduced number of pulses, compared to the single gap. Both configurations have an upper voltage imposed by the changing impedance of the reactor as voltage and frequency are varied. The pulse characteristics are reported for both types of circuits. The general performance of the reactors for destruction of some compounds with both circuits is also reported     

一种超宽带窄脉冲信号发生器的设计

宽度窄、幅度大的脉冲生成是探地雷达系统中要解决的关键问题之一.本文在比较了几种不同实现电路的优缺点,详细分析了雪崩三极管原理的基础,提出利用雪崩三极管的雪崩特性,实现超宽带、窄脉冲的生成.文中给出了电路原理图和实验结果,电路分为正、负脉冲2部分,可生成底宽为纳/亚纳秒级、正、负脉冲的峰-峰值高达160 V的窄脉冲信号,并且脉冲拖尾的振荡起伏小,很好地满足了雷达系统的宽度窄、幅度大的要求.电路结构简单、参数可调、移植性强、适用范围广.     

一种用于脱硫脱硝的毫微秒脉冲电源的研制

电晕法烟气脱硫脱硝要求快速窄脉冲供电方式．介绍了一种新颖毫微秒波头脉冲电源，其输出电压波形．前沿上升时间小于20ns、脉宽小于100ns、基压和脉冲幅值分别可调，并且脉冲能显转移率和电源自身的能量效率也分别达到95％和70％以上．     

用于水中灭藻的高压脉冲电源的研究

等离子体在环境保护方面应用广泛,为给灭藻装置提供高压快速脉冲使其产生等离子体,设计了一台新型结构的脉冲电源。提出了Marx发生器与磁脉冲压缩电路相结合的电路结构,引入了小容量储能电容来控制输出脉冲的能量,基于PSpice软件进行仿真分析来改善电路参数和结构,各开关的动作采用单片机控制。仿真得到峰值7.5kV、上升沿30ns、重复频率100Hz、一个脉冲内能量0.7J的脉冲电压。     

适用于探地雷达应用的低过冲平衡脉冲发生器

设计了一种新型的超宽带ns级低过冲平衡脉冲发生器.该脉冲发生器包含驱动电路、雪崩三极管脉冲电路和脉冲整形电路3部分,驱动电路用以锐化触发脉冲;雪崩三极管脉冲电路采用独特的晶体管级联结构产生大幅度的高斯脉冲;脉冲整形电路利用并联端接电阻网络和肖特基二极管减小信号反射,最后使用巴仑产生平衡的高斯脉冲,该电路最高可以在300 KV脉冲重复频率下正常工作.测量结果表明,在100 KV脉冲重频时该脉冲发生器可以输出一对峰峰值为230 V、前沿为1.3 ns的平衡脉冲,并有着极小的振铃和过冲.这些特征说明,该脉冲发生器在探地雷达应用中有着更深探测距离和更快数据处理速度的优势.     

A repetitive high voltage pulse adder based on solid state switches

A repetitive high voltage pulse adder based on solid state switches with isolated recharge is described. All capacitors in the modulator are recharged separately through a corresponding magnetic core transformer by a common high frequency power supply. This circuit configuration simplifies the insulation design and arrangement. This scheme is suitable for high frequency pulse discharge due to its high charge efficiency. At the same time it retains the inherent switch protection capability similar to a solid-state Marx modulator. In our present work, a 22-stage test modulator has been built and successfully operated at output voltage of 20 kV with repetitive rate of 20 kHz, rise time of 150 ns and pulse width of 3 ?s. The primary experiments verified the system feasibility.     

A past hybrid system for PD measurement

A fast partial discharge (PD) measurement system is described, which employs analog as well as digital signal processing to achieve high sensitivity and discharge pulse resolution with low spectral distortion. Data on apparent charge, time of pulse occurrence and instantaneous applied voltage are stored in memory for subsequent information retrieval and treatment. The PD measurement system is designed to provide an integrated response to rapid rise time pulses of 1 to 2 ns, with suitable filtering added to reject extraneous noise     

一种纳秒级脉冲源的仿真及研制

对一种以射频三极管为主要元件的脉冲产生电路进行了计算和试验研究,研制了用于模拟PD信号试验的放电源,设计了储能电容为10pF和20pF的两种脉冲电路,讨论了放电源中主要器件雪崩三极管的雪崩效应理论,推导出三极管雪崩过程的简化模型,用电路仿真软件Pspice仿真分析该电路中储能电容和电源电压对脉冲波形的影响。详细讨论了实际制作过程中的注意事项和元器件的选择方法。实测储能电容为10pF和20pF的PD源脉宽分别为980ps和1180ps,幅值分别为8.9V和11.6V。结果表明,理论和仿真分析的结论一致。     

1MV/100kA快脉冲直线型变压器驱动源装置设计

快脉冲直线型变压器驱动源(LTD)技术是一种可以直接获得<100ns脉冲上升时间的新型脉冲功率技术,在Z箍缩、闪光照相和高功率微波等领域具有重要的应用前景。为了掌握LTD装置设计技术,基于已经研制完成的100kV/100kA快脉冲LTD原型模块,设计了输出电压/电流分别为1 MV/100kA的快脉冲LTD装置。装置由10级LTD模块串联而成,系统总储能为20kJ,次级采用真空磁绝缘传输线结构。装置直径约1.5m,长度约2.2m。根据10级LTD模块串联装置系统电路分析和数值模拟,结果表明在10Ω负载上的输出电压约为1.08MV,上升时间约51ns,脉宽为168ns。同时还针对磁绝缘传输线锥形和直筒形阴极结构建立了简化模型,采用PIC粒子模拟编码对其进行粒子模拟,结果表明,2种结构在负载端的输出电压均约为1MV,输出阻抗接近10Ω,同轴传输线间隙的电子流能够实现磁绝缘。     

直流电晕电流时域脉冲特性的统计分析

为了研究直流正负电晕电流时域脉冲的特性,基于实验室开发的高频电晕电流高压端测量系统,开展了不同条件下直流正负电晕的线板放电实验。基于大量实验数据,统计、对比了正、负极性电晕脉冲的幅值、上升时间、半波时间和重复频率等特征参数随导线电压及导线半径变化的规律。实验结果表明：导线电压对单个正、负脉冲波形的影响较小,主要影响脉冲的重复频率;负脉冲的上升时间平均值为20~30 ns,半波时间的平均值为90~110 ns;正脉冲的上升时间平均值为40~50 ns,半波时间的平均值为140~160 ns;随着导线电压的升高,正、负脉冲重复频率均迅速增大,但相同电压下,正脉冲的重复频率显著小于负脉冲的重复频率,负脉冲重复频率约为正脉冲的15~25倍。     

基于MOSFET的固体调制器研究

固体调制器能产生短脉冲、快上升沿、快下降沿、大电流,并能工作在兆赫兹频率下,因此是脉冲功率技术的一个重要发展方向.介绍了由功率金属氧化物半导体场效应晶体管(MOSFET)器件组成的固体调制器的基本工作原理.采用单片机和CPLD作为硬件核心设计了脉冲信号发生器,作为同体调制器的触发信号源.通过对驱动电路的仿真,确定了由集成驱动芯片组成的驱动电路的主要参数;设计了6个MOSFET并联的开关模块.实验表明,其具有良好的静态、动态均流效果.最终设计的调制器由3个开关模块叠加而成,在800V充电电压下,可以得到最短脉宽为33.8ns,前沿为13.9ns,幅度为2.20kV的脉冲.在多脉冲情况下,脉冲的一致性良好.     

Compact CMOS active quenching/recharge circuit for SPAD arrays

Avalanche diodes operating in Geiger mode are able to detect single photon events. They can be employed to photon counting and time‐of‐flight estimation. In order to ensure proper operation of these devices, the avalanche current must be rapidly quenched, and, later on, the initial equilibrium must be restored. In this paper, we present an active quenching/recharge circuit specially designed to be integrated in the form of an array of single‐photon avalanche diode (SPAD) detectors. Active quenching and recharge provide benefits like an accurately controllable pulse width and afterpulsing reduction. In addition, this circuit yields one of the lowest reported area occupations and power consumptions. The quenching mechanism employed is based on a positive feedback loop that accelerates quenching right after sensing the avalanche current. We have employed a current starved inverter for the regulation of the hold‐off time, which is more compact than other reported controllable delay implementations. This circuit has been fabricated in a standard 0.18 µm complementary metal‐oxide‐semiconductor (CMOS) technology. The SPAD has a quasi‐circular shape of 12 µm diameter active area. The fill factor is about 11%. The measured time resolution of the detector is 187 ps. The photon‐detection efficiency (PDE) at 540 nm wavelength is about 5% at an excess voltage of 900 mV. The break‐down voltage is 10.3 V. A dark count rate of 19 kHz is measured at room temperature. Worst case post‐layout simulations show a 117 ps quenching and 280 ps restoring times. The dead time can be accurately tuned from 5 to 500 ns. The pulse‐width jitter is below 1.8 ns when dead time is set to 40 ns. Copyright © 2015 John Wiley & Sons, Ltd.     

A Simplified Model for Parameter Estimation and Circuit Analysis of Inductive-Adder Modulator

In this paper, we propose a simplified model for easy estimation of design parameters and quick analysis of fast pulsed inductive adder modulators. Analytical method is used to deduct the simplified circuit model. This model offers an easy way to understand the behavior of the inductive-adder modulator circuits and provides designers a helpful tool to estimate critical parameters such as pulse rise time, system impedance, number of adder stages, etc. Computer simulations demonstrate that parameter estimation based on simplified circuit model is fairly accurate as compared to original circuit. Further more, this approach can be used in early stage of system development to assist the feasibility study of the project and to aid geometry selection and parameter selection of critical components.