A gigawatt generator with an inductive energy storage discharge

A design of high-current nanosecond generators with discharge of an inductive energy storage into a 15 Ω resistive load and test data are presented. Parameters of the opening switch made as an electrical explosive current interrupter are optimized. When the voltage applied to the inductive energy storage is 50 kV, the amplitude of the load voltage is 500 kV, and the half-height pulse duration is 250 ns with a pulse power up to 20 GW.     

A compact semiconductor opening swith-based generator with a 300-kV output voltage and up to 2-kHz pulse repetition rate

A compact generator with a semiconductor opening switch (SOS-diode) shaping across resistive load pulses with an amplitude of up to 300 kV, duration of 30–50 ns, and a 300-Hz pulse repetition under uninterrupted operation and up to 2 kHz in a 30-s burst mode is described. The generator contains a thyristor charging device, magnetic compressor, and inductive storage with a semiconductor opening swith based on SOS-diodes. The average output power at a maximum pulse repetition rate and a 250kV-voltage is 16 kW. The overall dimensions of the generator are 0.85×0.65×0.42 m, the weight is about 115 kg.     

A multi-pulse mode of operation of a magnetocumulative generator

Experimental results of generating a nanosecond high-current pulse burst by a multiwinding dynamic transformer, which is based on the principle of recuperation of the energy stored in the single primary winding, and the method of the sequential magnetic-flux trapping by several secondary windings are described. The inductive energy storage with an opening switch is used to sharpen current pulses of the generator. Six small electric capacitors are in turn charged up to ∼300 kV for ∼100 ns with a time interval of 10 μs.     

A High-Voltage Pulse Generator with Inductive Energy Storage and Thyratron

A high-voltage pulse generator with an inductive energy storage is described. Its operation is based on the current interruption by a thyratron. It was shown that a T2-500/20 thyratron is capable of reliably interrupting the current with an amplitude of 800–850 A in an inductive energy storage, forming from a low-voltage (0.5–2 kV) power source voltage pulses with an amplitude of up to 90 kV and leading edge duration of 200–250 ns at the load.     

A KPU-200 movable capacitor installation

A movable electrophysical capacitor installation with a 250-kJ maximum bank energy, which generates intense neutron pulses, is described. A current pulse generator with a capacitive energy storage forms the basis of the installation. When the initial voltage at the capacitor bank is up to 35 kV, the installation ensures a flow of current pulses with amplitudes of up to 2 MA in a gas-discharge plasma-focus chamber, which is filled with an equal-component deuterium-tritium (DT) mixture. Under these conditions, the chamber is capable of repeatedly generating single fast-neutron pulses with an energy of 14.1 MeV, a duration of ～70 ns, and an integral yield over 1013 neutrons/pulse.     

A compact, low jitter, nanosecond rise time, high voltage pulse generator with variable amplitude

In this paper, a compact, low jitter, nanosecond rise time, command triggered, high peak power, gas-switch pulse generator system is developed for high energy physics experiment. The main components of the system are a high voltage capacitor, the spark gap switch and R = 50 Ω load resistance built into a structure to obtain a fast high power pulse. The pulse drive unit, comprised of a vacuum planar triode and a stack of avalanche transistors, is command triggered by a single or multiple TTL (transistor-transistor logic) level pulses generated by a trigger pulse control unit implemented using the 555 timer circuit. The control unit also accepts user input TTL trigger signal. The vacuum planar triode in the pulse driving unit that close the first stage switches is applied to drive the spark gap reducing jitter. By adjusting the charge voltage of a high voltage capacitor charging power supply, the pulse amplitude varies from 5 kV to 10 kV, with a rise time of <3 ns and the maximum peak current up to 200 A (into 50 Ω). The jitter of the pulse generator system is less than 1 ns. The maximum pulse repetition rate is set at 10 Hz that limited only by the gas-switch and available capacitor recovery time.     

A superconducting magnetic-energy storage system as a source of high-power current pulses with constant amplitude

A facility is described that allows generation of long current pulses with a virtually constant amplitude by a superconducting inductive (magnetic) energy storage with a 5-MJ energy content. The design of this facility ensures the possibility of changing the parameters of an output current pulse by varying the inductances of the magnetic-system’s sections and their electromagnet coupling. This approach allows not only the stabilization of the current pulse but also a severalfold increase in the initial current value. The electric insulation of the storage’s coil can withstand a voltage higher than 200 kV, and a special system of multielectrode current leads can transfer a power of up to 250 MW at a 1.3-kA current from the cold zone (4.2 K) into the warm (300 K) zone almost without energy losses. The current can be increased to 10 kA by changing the connection of the facility’s sections. The facility has been tested in six full-scale experiments and is ready for further tests as a component of electrophysical facilities of various purposes.     

High voltage ultrawide band pulse generator using Blumlein pulse forming line

A high voltage ultrawide band pulse generation system has been developed to radiate intense and ultrawide band electric fields for the examination of effects of the electric fields on the operation of electronic devices. As major components of the system, a helical strip∕wire type of air-cored pulse transformer and a triaxial type of Blumlein pulse forming line have been designed and fabricated to amplify and shape the output pulse, respectively. For the construction of a compact system, the pulse transformer and the Blumlein line are installed in a single cylindrical container. An ultrawide band TEM horn antenna has been fabricated to radiate the Blumlein output pulses to electronic devices. A number of experimental results demonstrate that the system is capable of providing an output pulse whose voltage is greater than 300 kV, pulse duration is ~5 ns, and rise time is ~500 ps with repetition rate of 10 Hz. The peak-to-peak value of electric field intensity of a radiated pulse is also measured to be approximately 42 kV/m at a distance of 10 m away from the antenna.     

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 pulse-compression-ring circuit for high-efficiency electric propulsion

A highly efficient, highly reliable pulsed-power system has been developed for use in high power, repetitively pulsed inductive plasma thrusters. The pulsed inductive thruster ejects plasma propellant at a high velocity using a Lorentz force developed through inductive coupling to the plasma. Having greatly increased propellant-utilization efficiency compared to chemical rockets, this type of electric propulsion system may one day propel spacecraft on long-duration deep-space missions. High system reliability and electrical efficiency are extremely important for these extended missions. In the prototype pulsed-power system described here, exceptional reliability is achieved using a pulse-compression circuit driven by both active solid-state switching and passive magnetic switching. High efficiency is achieved using a novel ring architecture that recovers unused energy in a pulse-compression system with minimal circuit loss after each impulse. As an added benefit, voltage reversal is eliminated in the ring topology, resulting in long lifetimes for energy-storage capacitors. System tests were performed using an adjustable inductive load at a voltage level of 3.3 kV, a peak current of 20 kA, and a current switching rate of 15 kA/micros.     

Optimization of high-voltage devices for energy compression of nanosecond pulses

Designs of compact converters intended for compression of high-voltage pulses with durations of a few nanoseconds and operating in a traveling wave mode were examined. The energy compression unit contained two lines-high-impedance and forming-with a high -pressure gas spark discharger used as a switch. A traditional serial connection of lines was replaced by a parallel connection to increase the energy compression efficiency. The power of the initial pulse (amplitude, 145 kV; half-height duration, 4 ns; and rise time, 1.5 ns) at a load of 45 Ω was increased by a factor of 1.8, while the calculated value was 2.5. The amplitude was as great as -195 kV, and the power was 17% higher relative to the circuit with a serial connection of lines. When shaped, the pulse was compressed in time to 0.8 ns. Two modifications of devices converting the initial pulse with an amplitude of -160 kV and a rise time of 0.3 ns into pulses with amplitudes of -210 and -250 kV and durations of 0.80 and 0.45 ns, respectively, were tested. Waveguide components of the converters were developed, with which it was possible to minimize the dimensions of the device in order to avoid excitation of higher harmonics while maintaining the electric strength.     

An explosively driven high-power microwave pulsed power system

The increased popularity of high power microwave systems and the various sources to drive them is the motivation behind the work to be presented. A stand-alone, self-contained explosively driven high power microwave pulsed power system has been designed, built, and tested at Texas Tech University's Center for Pulsed Power and Power Electronics. The system integrates four different sub-units that are composed of a battery driven prime power source utilizing capacitive energy storage, a dual stage helical flux compression generator as the main energy amplification device, an integrated power conditioning system with inductive energy storage including a fast opening electro-explosive switch, and a triode reflex geometry virtual cathode oscillator as the microwave radiating source. This system has displayed a measured electrical source power level of over 5 GW and peak radiated microwaves of about 200 MW. It is contained within a 15 cm diameter housing and measures 2 m in length, giving a housing volume of slightly less than 39 l. The system and its sub-components have been extensively studied, both as integrated and individual units, to further expand on components behavior and operation physics. This report will serve as a detailed design overview of each of the four subcomponents and provide detailed analysis of the overall system performance and benchmarks.     

A high-voltage power supply based on a distributed capacitive energy storage

For the corpuscular plasma heating in the MST plasma device (Madison, United States), an injector of hydrogen atoms with 25-keV energy, equivalent at omic current of >45 A, and 20-ms pulse duration was designed and put into operation at the Budker Institute of Nuclear Physics (Novosibirsk, Russia) in 2009. The pulse repetition rate is 5 min. The output current of the ion source in the atomic injector exceeds 50 A. A high-voltage source with a 1.5-MW power was design ed for the high-voltage powering of the atomic injector. The run duration of the power supply with rated characteristics is >20 ms. The power supply is based on a distributed capacitive energy storage, which allows the power consumption from the industrial network to be reduced down to 10 kW at a pulsed load power of 1.5 MW. The high-voltage power supply smoothly regulates the output voltage from 0 to 30 kV and is capable of being quickly deenergized if high-voltage breakdown of the load takes place. The diagram and structural components of the high-voltage power system of the atomic injector are described, and its test results are given.     

High-frequency pulse generators based on SOS diodes with subnanosecond current cutoff time

Compact high-voltage generators with a pulse power of 100–500 MW, an output voltage of 150–400 kV, a pulse duration of 3–6 ns, and pulse repetition rates of 300–400 Hz and up to 5 kHz in a steady-state and a 30-s-long burst mode, respectively, are described. The output power-amplification unit is based on an inductive storage and SOS diodes with subnanosecond current cutoff time. Physical processes in the semiconductor structure of a SOS diode operating in the subnanosecond current cutoff mode are considered. The generator circuit designs and their test results are presented.     

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.     

Generation of High-Voltage Subnanosecond Pulses with a Peak Power of 700 MW and Repetition Frequency of Up to 3.5 kHz

Test results of a combined subnanosecond modulator with an output impedance of 45 , which incorporates an all-solid-state high-voltage nanosecond charging device (with an inductive energy storage and a semiconductor opening switch) and a pulse sharpener with gas-filled gaps, are presented. The sharpening and cutting spark gaps filled with hydrogen at a pressure of 100 atm ensured the formation of stable pulses with amplitudes of –(180–200) kV and durations of (400–700) ps at a repetition frequency of up to 3.5 kHz. An average output power of 1.4 kW was achieved for the modulator's burst-mode operation with a number of pulses in a packet of 10⁴at a maximum pulse repetition rate.     

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.     

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.     

A semiconductor opening switch-based quasi-rectangualr pulse generator operating into a low-impedance load

A generator with a semiconductor opening switch (SOS-diode) operating into a low-impedance load of 4–5 Ω is studied. The amplitude of quasi-rectangular pulses is 50 kV at a half-height duration of 100 ns. The energy is applied from an intermediate storage via a spark gap to the output generator stage. The output pulse is formed by solid-state components.