A high-power semiconductor switch of high-voltage pulses with a rise time of nanosecond duration

The results of studies of new fast-acting semiconductor devices—deep-level dynistors intended for use in high-power devices of nano-and microsecond pulsed-power technology—are presented. The possibility of switching multikiloampere current pulses having a rise rate of 200 kA/μs with the use of a single device with a 12-mm-diameter structure is shown. A high-power switch based on an assembly of dynistors with an operating voltage of 12 kV connected in series is described. The switch is capable of switching current pulses with a 1200-A amplitude and a 4-ns rise time.     

An PBЕ-73C vacuum spark gap with a control circuit based on an inductive energy storage

The design and operating principle of a small (50 mm in diameter and 100 mm in height) РВЕ-73C vacuum spark gap are described. It is shown that it can be efficiently switched using a control circuit with a low (∼900 V) supply voltage, which is based on an inductive energy storage and a diode opening switch that forms a high-voltage igniting pulse with a rise time of nanosecond duration. The РВЕ-73C switching process is investigated at different rise times of igniting voltage pulses and different igniting current amplitudes. The results of tests of the spark gap operating in regimes of switching current pulses with an amplitude of 12 kA and a rise time of 800 ns are presented.     

Small switches of high-power microsecond pulses on the basis of high-voltage integrated pulse thyristors and reverse switch-on dynistors

A high-voltage switch on the basis of a small unit of series-connected high-voltage integrated pulse thyristors (HVIPTs), which were developed at the Ioffe Physical Technical Institute, was designed and investigated. At a power voltage of 25 kV, current pulses of microsecond duration with an amplitude of 2.8 kA and a rise time of 0.8 μs were switched. The attained current density through an HVIPT (5.6 kA/cm²) appreciably exceeds the permissible current density for conventional thyristors. It is shown that the developed HVIPT unit can be used in the triggering circuit of a high-power assembly of reverse switch-on dynistors (RSDs) at an operating voltage of 25 kV, which consists of 14 series-connected dynistors with a diameter of their structures of 24 mm. The RSD switch with a triggering circuit on the basis of HVIPTs allowed switching of rapidly rising current pulses with an amplitude of 20 kA and a duration of 150 μs. The small dimensions of the HVIPT unit (4 × 10 × 32 cm) and the RSD assembly (7 × 7 × 34 cm) determine the wide prospects for using them in high-power pulse technology.     

Direct coupling of pulsed radio frequency and pulsed high power in novel pulsed power system for plasma immersion ion implantation

A novel power supply system that directly couples pulsed high voltage (HV) pulses and pulsed 13.56 MHz radio frequency (rf) has been developed for plasma processes. In this system, the sample holder is connected to both the rf generator and HV modulator. The coupling circuit in the hybrid system is composed of individual matching units, low pass filters, and voltage clamping units. This ensures the safe operation of the rf system even when the HV is on. The PSPICE software is utilized to optimize the design of circuits. The system can be operated in two modes. The pulsed rf discharge may serve as either the seed plasma source for glow discharge or high-density plasma source for plasma immersion ion implantation (PIII). The pulsed high-voltage glow discharge is induced when a rf pulse with a short duration or a larger time interval between the rf and HV pulses is used. Conventional PIII can also be achieved. Experiments conducted on the new system confirm steady and safe operation.     

Studying dynistor switches with nanosecond switching times

The results of studying the process of switching deep-level dynistors (DLDs) with 16- and 24-mm-diameter structures in the modes of switching micro- and nanosecond pulses with amplitudes of several kiloamperes are presented. It is shown that the dynistor switching process is highly uniform. The results of DLD tests at a high repetition rate of switched current pulses are presented. The principle of constructing high-power DLD switches with independent triggering of dynistors, which is based on the use of a single-turn saturable-core choke in the power circuit and a saturable-core isolating transformer in the DLD triggering circuits, is described. A DLD switch with an operating voltage of 8 kV is considered, which can switch current pulses at a frequency of 2 kHz with an amplitude of 1.5 kA and a duration of 200 ns.     

Output voltage adjustment of a pulsed high-voltage nanosecond generator with inductive energy storage and a solid-state switching system

The possibility of adjusting the output voltage of a high-voltage nanosecond pulse generator with inductive energy storage and a solid-state switching system was investigated. All components of the adjustment system are installed in the low-voltage input circuit of the generator, whose voltage was less than 1000 V. The smooth adjustment of the output voltage in the range of 70–115 kV was achieved. The experimental setup and the obtained results are described.     

A High-Current Nanosecond Electron Accelerator with Inductive Energy Storage

A nanosecond electron accelerator with an output energy as great as 600 keV, a beam current of 16 kA, and an accelerating voltage half-height duration of ～180 ns is described. The accelerator is based on an inductive energy storage composed of two coils. A wire explosive current chopper is used in the inductive storage as a release. The circuit diagram of the accelerator is shown, the design for the accelerator is described, and results from its testing are presented.     

A Pseudospark Gap in the Inductive-Energy-Storage Circuit

A pseudospark gap is described that is capable of interrupting a current of up to 1 kA and shaping voltage pulses with an amplitude of up to 110 kV and rise time of 100 ns. Analytical expressions for calculating the energy released in the device at the switching-off stage and the efficiency of the generator with an inductive energy storage system are obtained. The characteristics of the pseudospark gap and of a similar-design thyratron connected in the same circuit are compared. It is found that the turn-off time of the pseudospark gap is shorter than that of the thyratron by a factor of 2.5.     

High-power switches based on reversely switched-on dynistors for high-voltage pulse technologies

The results of comparative investigations of commercially produced reversely switched-on dynistors (RSDs) with an operating voltage of 2 kV and 76-mm-diameter structures are presented. The studies were performed in the mode of switching current pulses with an amplitude of 200 kA and a duration of 300 μs. The electric scheme of the power circuit of the generator of high-power high-voltage pulses with a switch on the basis of an assembly of RSDs is considered. RSD switches with an operating current of 250 kA and operating voltages of 12 and 24 kV are described. Some results of using RSD switches in high-voltage pulse technologies are presented.     

Arc development of triggered vacuum switch with multi-rod electrode system

Triggered vacuum switch (TVS) is one of the important switch apparatuses in the high pulsed power system, which takes the vacuum as insulation and arc-extinguishing medium of main gap. The conduction of TVS is the arcing process of vacuum arc in practice. So, it is meaningful to research on the vacuum arc characteristics for the high current application of TVS. A six-gap rod electrode system is studied in this paper. It is made up of 3 pairs of rod electrodes, i.e., spatially interleaved rods of opposite polarity on a ring. The arc development under different high currents is tested and discussed, based on the electrical characteristics of the vacuum arc voltage and arc resistance. The variety of arc voltage shows the parallel arcing and the transfer process in the multi-channel, which is benefit to maintain the diffusion of vacuum arc. A TVS sample based on multi-rod electrode has carried high current of 225 kA in peak and charge transfer of 45 C in a pulse.     

Investigation of high-voltage integral pulse thyristors in single-pulse and pulse-train modes

The results of studying the switching capabilities of recently developed high-voltage integral pulse thyristors (HIPTs) with a working area of 0.45 cm² and an operating voltage of 3 kV are presented. A silicon chip of a thyristor consists of a large number of microthyristor cells that are enabled strictly synchronously with a control-current pulse, thus providing low switching energy losses and allowing a current of up to 8 kA at a pulse duration of 1.5 μs to be switched within 500 ns in a single-pulse mode. The HIPT switching-off time is several microseconds when, after a power-current pulse terminates, a field-effect transistor with a low (tens of milliohms) channel resistance closes the emitter–base circuit. The low switching energy loss and the short switching-off time made it possible to use HIPTs in the mode of switching current pulses with an amplitude of 500 А at a frequency of 50 kHz.     

An experimental stand for investigating protective devices for high-voltage overhead lines

An experimental stand for investigating and testing lightning protection devices for aerial power lines is described. The stand is composed of an oscillation circuit modeling a power line with an industrial frequency of 50 Hz, a voltage of up to 10 kV, and a current amplitude in the circuit as high as 10 kA; a generator of short single current pulses with a voltage of up to 25 kV and a current amplitude of up to 30 kA, modeling a lightning discharge; and commutation, control, and diagnostic systems. The stand is used to investigate elements of multi-chamber arrester systems for protecting high-voltage overhead lines.     

一种新型采样点控制方法的提出及电路设计和仿真

介绍了利用辅助线圈实现反馈的反激式开关电源的控制原理,以及采样点控制电路在其中的作用,在此基础上提出了一种新颖的单端输入采样点控制电路。其优点是：电路总是动态的修正每个周期的采样时间点,使之与脉冲宽度的相对位置保持不变,这样可以大大减小控制偏差,从而获得高的控制精度。     

The Coaxial Shunt for Measurement of Current Pulses of Artificial Lightning with the Amplitude up to ±220 kA

The improved construction of the coaxial shunt SC-300M intended for measurement of decaying sine and aperiodic pulses of artificial lightning current with amplitudes up to ±220 kA is described. The results of tests of the instrument shunt in the high-current discharging circuit of power high-voltage generator of lightning current (g.l.c.) under pulsed A-component with the first amplitude -198 kA corresponding to time ≈35 µs and an action integral of the simulated pulse of current of lightning discharge equal to ≈2.38 × 10⁶ J/Ω are presented. The quantity of electricity under single action on the shunt by a current pulse of artificial lightning with logarithmic decrement of oscillations ≈2.06 that passed through the current-carrying elements of its construction was ≈-9.9 C. It was shown that, simultaneously with registration of pulsed A-component of lightning current, the shunt, owing to using of a matching voltage divider at the end of its cable communication line, allows also to measure normalized amplitude-time parameters of aperiodic shortened long-term C*-component of artificial lightning current (-568 A; ≈5 ms;τ_C* ≈18 ms; -16 C) that was being formed in the discharging circuit of the generator.     

High-voltage pulsed generator for dynamic fragmentation of rocks

A portable high-voltage (HV) pulsed generator has been designed for rock fragmentation experiments. The generator can be used also for other technological applications. The installation consists of low voltage block, HV block, coaxial transmission line, fragmentation chamber, and control system block. Low voltage block of the generator, consisting of a primary capacitor bank (300?μF) and a thyristor switch, stores pulse energy and transfers it to the HV block. The primary capacitor bank stores energy of 600 J at the maximum charging voltage of 2 kV. HV block includes HV pulsed step up transformer, HV capacitive storage, and two electrode gas switch. The following technical parameters of the generator were achieved: output voltage up to 300 kV, voltage rise time of ～50?ns, current amplitude of ～6?kA with the 40?Ω active load, and ～20?kA in a rock fragmentation regime (with discharge in a rock-water mixture). Typical operation regime is a burst of 1000 pulses with a frequency of 10 Hz. The operation process can be controlled within a wide range of parameters. The entire installation (generator, transmission line, treatment chamber, and measuring probes) is designed like a continuous Faraday's cage (complete shielding) to exclude external electromagnetic perturbations.     

A high-current nanosecond electron accelerator with a semiconductor opening switch

A compact nanosecond electron accelerator with an output energy of up to 4000 keV, a pulsed power of 100–180 MW, a beam current of 0.25–1.1 kA, and a pulse energy of 5–7 J is described. The accelerator operates with a pulse repetition rate of 200 Hz and ensures an average beam power of up to 1 kW. A nanosecond generator with a solid-state switching system, which is based on magnetic stages of pulse compression and a semiconductor opening switch, is used as a supplying device. The design and electric circuit of the accelerator are described, and test results are presented.     

A Driver of Rapidly Rising Current Pulses Based on a Semiconductor Opening Switch

The possibility of using a semiconductor opening switch based on -800 diodes as a driver of a pulse current for a capillary discharge in a circuit with an inductive energy storage is investigated. It is established that, in the operation in a one-contour circuit at a voltage in the main circuit of up to 40 kV, the current switched to the load reaches 0.75 kA per diode, and this fraction is above 50% of the maximum current in the first half-period. The opening switch has exhibited good operation stability.     

空气直流断路器开断特性的分析验证

针对直流断路器在开断过程中电弧熄灭比较困难的问题,对空气直流断路器的开断特性进行了分析研究。分析了如何有效的缩短电弧的燃烧时间,研究了时间常数对断路器开断能力、电弧电流上升率的影响及断路器开断电流的大小与燃弧时间的关系。基于上述研究分析,制造出了样机,并利用高压直流试验台模拟不同的短路故障电流对直流断路器进行了多次开断试验测试,获得了很多试验数据,研究结果表明:断路器在额定电压为DC1800 V,能够可靠切除短路故障电流达到80 k A,断路器开断电流随着时间常数的增大而减小,燃弧时间随着开断电流的增大而减小。     

Compact inductive energy storage pulse power system

An inductive energy storage pulse power system is being developed in BARC, India. Simple, compact, and robust opening switches, capable of generating hundreds of kV, are key elements in the development of inductive energy storage pulsed power sources. It employs an inductive energy storage and opening switch power conditioning techniques with high energy density capacitors as the primary energy store. The energy stored in the capacitor bank is transferred to an air cored storage inductor in 5.5 μs through wire fuses. By optimizing the exploding wire parameters, a compact, robust, high voltage pulse power system, capable of generating reproducibly 240 kV, is developed. This paper presents the full details of the system along with the experimental data.     

Three-electrode gas switches with electrodynamical acceleration of a discharge channel

High voltage, high current, and high Coulomb transfer closing switches are required for many high power pulsed systems. There are a few alternatives for closing switches, for example, ignitrons, vacuum switches, solid-state switches, high pressure gas switches (spark gaps), and some others. The most popular closing switches up to date are spark gaps due to relatively simple design, robustness, easily field maintenance, and repair. Main drawback of spark gaps is limited lifetime, which is related directly or indirectly to erosion of the electrodes. Multichannel switches and switches with moving arc have been proposed to prevent the electrodes erosion. This study investigates switches, where a spark channel is initiated in a three-electrode layout and then the spark accelerates due to electrodynamic force and moves along the extended electrodes. At a given current amplitude, the diameter of the extended electrodes allows to control the spark velocity and hence, the erosion of the electrodes providing the required lifetime. The first switch is designed for 24 kV charging voltage and approximately 4 C total charge transfer. This spark gap was tested at 25 kA peak current in 40 000 shots in a single polarity discharge and in 20 000 shots in bipolar discharge. Second spark gap is designed for 24 kV charging voltage and approximately 70 C total charge transfer. It was tested in 22 000 shots, at a current of 250 kA with a pulse length of 360 mus. In this paper, we present design of these spark gaps and trigger generator, describe the test bed, and present the results of the tests.