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The design, construction, and operational characteristics of a low-impedance and low pulse drop transmission line transformer (TLT) are described in this paper. The multicore coaxial transmission line used for this transformer is different from traditional coaxial transmission line since its inner conductor consists of several high-voltage cables that are connected in parallel by using two metal disks placed at both ends of them. Simultaneously, the impedance of the coaxial transmission lines with ten cables designed in this paper is perfectly reduced from 60 to $13.5~\Omega $. Moreover, the transmission lines can withstand a high voltage of several tens of kilovolts with 13.9 mm in diameter. The transmission lines were then used to construct TLTs. The transformers are wound inductively in separated cylinders made of polypropylene to enhance the isolation from the input to the output of the transformers. Consequently, the pulse drop is substantially reduced, minimizing pulse distortion in the transformer. A three-stage TLT, whose input and output impedances are 4.5 and $40.5~\Omega $ , respectively, was developed with the transmission lines. The experimental results show that the three-stage transformer based on the low-impedance and low pulse drop design transmission lines can achieve a voltage gain factor of almost 3.0. [ABSTRACT FROM AUTHOR]

This paper has introduced two important indexes, turn-off surge voltage (TSV) on power switch and peak positive pole potential (PPPP) of storage batteries, which can be used to evaluate switching transient process of high-voltage energy storage system. Research on them is of great significance to power switch choice and high-voltage isolation design in engineering applications. Power switch response process at the turning off moment and transient process in freewheel stage have been analyzed by the established small-signal model of single power switch; then, a power switch test platform for hybrid energy storage system was built to verify it. Taking pulsed-power supply charging device with a novel inductor of low resistance and high inductance as a research object, this paper has analyzed dynamic process of the TSV and the PPPP at the turning off moment through establishing state space model of the whole system. Comparison shows that the numerical curves match the simulated curves well. Finally, the exactness of the employed model has been further verified in two pulse capacitor charging experiments. [ABSTRACT FROM AUTHOR]

This paper is devoted to the design, implementation, and test of a low cost, modular, and reliable pulsed high-voltage (HV) converter (dc chopper). The distinct characteristics of the present prototype refer to: adjustable voltage amplitude up to 7 kV, amplitude drop less than 4‰ for $2 \times 10$ A output peak current at 5 kHz, adjustable pulse frequency up to 5 kHz, adjustable duty cycle between 1% and 10%, rising/falling time around 100 ns, and jitter about 10 ns. In principle, 1-kV modules based on a fast MOSFET each are combined in series to form a completely modular push–pull switch configuration. Contrary to sophisticated optical fiber-based insulation techniques, the driving low-voltage stage of the power supply is magnetically coupled to the HV stage. The low-voltage stage defines and schedules the HV pulses by means of a microcontroller. The 7 kV is equally distributed along MOSFETs due to balancing networks of passive components. Zener diodes in parallel with MOSFETs provide sufficient protection against overvoltages. The power supply has been successfully tested on dielectric-barrier discharge-based plasmas which have nowadays continuous technological interest. [ABSTRACT FROM AUTHOR]

Nonlinear transmission lines (NLTLs) have been studied over the past several years to generate high-power radio frequency signals. Their operation consists of a lumped line based on the nonlinear behavior of the LC section components, capacitors or inductors, as a function of the applied voltage or current, respectively. However, considering high-power signals, the application of these devices using nonlinear ceramic capacitors as the capacitive lumped lines are restricted to frequencies around 100 MHz since at high voltages, parasitic impedances in the line structure limit the maximum operating frequency. On the other hand, the use of variable capacitance diodes has enabled the operation of NLTLs at higher frequencies. This paper provides the results of a study of NLTLs for RF generation based on silicon carbide Schottky diodes. The principle of operation and its simplified theory are presented. Initially, the voltage dependence of the diode capacitance is modeled. Experimental and simulation results are compared. Frequency oscillations around 200 MHz were generated. The extraction of the radio frequency energy is realized, and the radiation of the electromagnetic wave is performed using double-ridged horn antennas. Finally, some parameters are analyzed, and all results discussed. [ABSTRACT FROM AUTHOR]

Marx generator using all-solid-state devices has been studied for many years. Higher parameters are always the demand for new applications. Traditional all-solid-state Marx generator can output high voltage due to its series topology, but the current is always limited by the switch. In this paper, a stage-stage paralleled topology of Marx generator for high current has been proposed. Topology structure and driving mode comparison for current balance have been analyzed. The paralleled driving mode for the current balance and the shaping waveform has been proposed. For experiment, a four-stage-four-paralleled Marx generator with metal–oxide–semiconductor field-effect transistors (MOSFETs) has been constructed with output pulses 2.2 kV, 730 A (depending on the load), rise time of 31 ns, fall time of 56 ns, and adjustable pulsewidth from 400 to 800 ns. [ABSTRACT FROM AUTHOR]

This paper describes a study on the high-voltage compact solid-state pulsed-power modulator for parallel reactor operation. The current capacity of the pulsed modulator has been improved to drive multiple reactors in parallel. The pulse discharge switch uses the IXYK120N120C3 (1200 V/120 A) insulated-gate bipolar transistor for a high current output. The gate driver has been improved according to the characteristics of the replaced switch. The output specifications of the modified pulsed-power modulator are a maximum output voltage of 40 kV, a maximum output current of 300 A, a pulsewidth ranging from 1.5 to $5~\mu \text{s}$ , a maximum repetition rate of 3 kHz, and an average power of 13 kW. The modulator has the dimensions of $450 \times 475 \times 600$ mm3, a maximum peak power of 12 MW, and a maximum power density of 93 kW/L. A resistive load experiment and a plasma reactor parallel drive test were performed. Four parallel reactors were driven using one modulator. In addition, a 50% reduction in the concentration of toluene was obtained through the experiment of the toluene gas treatment using only parallel plasma reactors. [ABSTRACT FROM AUTHOR]

This paper presents a 100-kV high frequency transformer/rectifier package, which is capable of a dual output polarity operation. An H-Bridge inverter drives the primary of the high voltage (HV) transformer at a frequency of 20 kHz. The inverter is driven by a Microchip dsPIC33F digital signal controller using peak current mode control with adaptive slope compensation. The HV-tank has two HV-coax output cables with a grounded shield on each cable. If the center conductor of the coax cable designated as negative output is grounded, positive voltage is obtained from the coax cable designated as positive output and vice versa. This paper provides design details and experimental results from tests of the entire system. [ABSTRACT FROM PUBLISHER]

High-power microwaves are generated using high voltage (HV) pulses, which are generated using a Marx generator connected to a peaking stage. The output of the peaking stage is the input to the half transverse electromagnetic (HTEM) horn-type antenna. This paper discusses the effect of isolation distance between HV tapered arm and the grounded reflector on the variation of characteristic impedance and gain with respect to the length, flair angle, and tapering angle of the antenna. This paper also discusses the radiation loss on the side and back of antenna. An experiment has been described using an available Marx generator and HTEM antenna. Using the experimental and simulation results, the optimal design parameters of antenna are obtained. [ABSTRACT FROM PUBLISHER]

In this paper, the detailed design of an ion pump power supply is presented. The ion pump power supply was designed based on an LCC resonant topology with high switching frequency to take advantage of a smaller transformer for isolation. Because the proposed ion pump power supply has a 7-kV, 50-mA specification, high-voltage insulation is required. In order to secure insulation reliability, the power supply was designed with eight separate transformers that share primary turns. The spacing between the primary turns and secondary turns allows for increases in the leakage inductance and parasitic capacitance of the transformer. A compact design can be achieved using the parasitic component generated by the proposed design as the resonant parameters of the LCC resonant converter. In addition, based on a trapezoidal approximation of the LCC resonant converter, the resonant parameters are designed to have trapezoidal shapes of the resonant current in order to reduce conduction loss. Finally, the results of the experiment indicate that the developed ion pump power supply can be used effectively in high-voltage and low-current applications. [ABSTRACT FROM AUTHOR]

The generation of high-power electromagnetic waves is one of the major applications in the field of highintensity pulsed power. The conventional structure of a pulsed power generator contains a primary energy source and a load separated by a power-amplification system. The latter performs time compression of the slow input energy pulse and delivers a high-intensity power output to the load. Usually, either a Marx generator or a Tesla transformer is used as a power amplifier. In the present case, a system termed "module oscillant utilisant une nouvelle architecture" (MOUNA) uses an innovative and very compact resonant pulsed transformer to drive a dipole antenna. This paper describes the ultracompact multiprimary winding pulsed transformer developed in common by the Université de Pau and Hi Pulse Company that can generate voltage pulses of up to 0.6 MV, with a rise time of less than 270 ns. The transformer design has four primary windings, with two secondary windings in parallel, and a Metglas 2605SA1 amorphous iron magnetic core with an innovative biconic geometry used to optimize the leakage inductance. The overall unit has a weight of 6 kg and a volume of only 3.4 L, and this paper presents in detail its design procedure, with each of the main characteristics being separately analyzed. In particular, simple but accurate analytical calculations of both the leakage inductance and the stray capacitance between the primary and secondary windings are presented and successfully compared with CST-based results. Phenomena such as the core losses and saturation induction are also analyzed. The resonant power-amplifier output characteristics are experimentally studied when attached to a compact capacitive load, coupled to a capacitive voltage probe developed jointly with Loughborough University. Finally, an LTspice-based model of the power ampli- fier is introduced and its predictions are compared with results obtained from a thorough experimental study. [ABSTRACT FROM AUTHOR]

High power pseudospark switches (PSSs) can control pulsed high voltage, high peak current discharges. In this paper, a PSS in series with a saturable inductor at the anode is investigated. The commutation process is analyzed with a time-resolved method. And the effects of the number of magnetic cores and anode voltages on discharge characteristics are studied experimentally. At the beginning of commutation process, when the anode voltage is 10.4 kV with four magnetic cores, the inductor is unsaturated, and there is a flat plateau of the forward voltage drop after the anode voltage drops rapidly to about 200 V, at the same time the current rise rate is 2.8 kA/ $\mu \text{s}$. When the inductor is saturated, there is a voltage spike that occurs at the end of the flat plateau, and the current simultaneously rises rapidly at the rate of 6.4 kA/ $\mu \text{s}$. The current sharp rise lags behind the voltage drop of the pseudospark gap, and the electrode erosion and energy dissipation reduce significantly. When the anode voltage is 15.6 kV, the commutation losses reduce by about 30% with seven cores in series at the anode. As a result, it is evident that the discharge process will speed up if the anode voltage is higher. And the trigger delay decreases by up to 8% when the anode voltage varies from 5.2 to 15.6 kV. Finally, in order to obtain a reproducible pseudospark discharge by the use of a saturable inductor, the number of magnetic cores has to be optimized for different anode voltages. [ABSTRACT FROM AUTHOR]

In this paper, a 25-kW bipolar pulsed-power supply for strategic mineral exploration has been described. A 500-V, 12.5-A unit module consisting of a highly efficient LCC resonant converter and a full-bridge-based bipolar pulse-switching unit is designed. The LCC resonant converter has a trapezoidal-shaped resonant current for reduced conduction loss. For achieving high power density, the leakage inductance of the transformer is used as resonant inductance without an external inductor. Moreover, the designed gate drive circuit based on the repetitive short pulse is proposed to operate the frequency range from dc to 8 kHz and reduce the size of the gate transformer. Four modules are connected in series and parallel in order to operate the power supply in either loop mode or grounded dipole mode. Depending on the load condition, the pulse power source capable of delivering the required high voltage and low current (2 kV, 12.5 A) or low voltage and high current (500 V, 50 A) is operated either in grounded dipole mode or loop mode, respectively. In order to satisfy the output voltage balancing of the four modules, the third wire is wound to compensate for the transformer of the LCC resonant converter. Finally, the design of the bipolar pulsed-power supply has been verified based on the experimental results of the field test. [ABSTRACT FROM AUTHOR]

In this paper, the implementation of a power supply for the generation of plasma, with the purpose of sterilizing a surface, is presented. A power supply based on a Class-E switching amplifier is proposed. This switch-mode amplifier is capable of producing a high-voltage and high-frequency output for plasma generation. In addition, a feedback mechanism is used to handle load variation. This is achieved through the characterization of the load at high voltages while generating plasma. Portability of the system is the primary goal of this paper. Thus, the implementation of a miniaturized circuit capable of achieving high efficiency and low power consumption at the same time is critical. The design and implementation of the complete battery-powered system, as well as the simulation and measurement results are discussed. [ABSTRACT FROM PUBLISHER]

In this paper, we present the first implementation of our 0–60-kV picosecond rise time 1–10-ns pulse generator. The pulse generator will be used in future work to generate a (sub-)nanosecond streamer plasma for air purification research. The first implementation of the pulse generator is a single-line pulse generator with an oil spark-gap, which generates 5 ns pulses with a 200 picosecond rise time and can operate at repetition rates of over 1 kHz into a 50 \Omega load. In this paper, we evaluate its performance and describe how we measure the very short pulses with an integrated and calibrated D-dot sensor. Furthermore, we present 3-D EM simulations of the 5 ns pulse generator and show that the simulations are in good agreement with the measurements. We previously described methods to flexibly vary the pulse duration of the pulse source by (artificially) changing the length of the pulse forming line (PFL). Here, we test these methods and find that changing the length of the outer conductor of the PFL and inserting magnetic material at the end of the PFL is a suitable method to change the pulse duration. Finally, we measure the breakdown voltages of the oil spark-gap and discover that higher pulse repetition rates are possible at higher oil pressures and smaller gap distances. [ABSTRACT FROM AUTHOR]

The role of irreversible electroporation using pulsed electric field is to generate high-voltage (HV) pulses with a predefined magnitude and duration. These HV pulses are applied to the treatment chamber until decontamination of the sample is completed. In this paper, a new topology for HV rectangular pulse generation for water disinfection applications is introduced. The proposed topology has four arms comprised of series-connected half bridge modular multilevel converter cells. The rectangular pulse characteristics can be controlled via the software controller without any physical changes in power topology. The converter is capable of generating both bipolar and monopolar HV pulses with microsecond pulse durations at high a frequency rate with different characteristics. Hence, the proposed topology provides flexibility by software control, along with hardware modularity, scalability, and redundancy. Moreover, a cell’s capacitance is relatively small, which drastically reduces the converter footprint. The adopted charging and discharging process of the cell capacitors in this topology eliminate the need of any voltage measurements or complex control for cell-capacitors voltage balance. Consequently, continuity of converter operation is assured under cell malfunction. In this paper, analysis and cell-capacitor sizing of the proposed topology are detailed. Converter operation is verified using MATLAB/Simulink simulation and scaled experimentation. [ABSTRACT FROM AUTHOR]

The influence of gas pressure and electrical parameters on low-pressure plasma has been investigated in this paper. A fast intensified charge-coupled device (ICCD) imaging is utilized to examine the dynamics of plasma bullet and plasma plume length at different pressure and plasma parameters. The experimental results reveal that the gas pressure has great influence on both the length of the plasma and on the propagation velocity of the plasma bullet. By increasing the gas pressure from 15 to 15 000 Pa, both the length of the plasma jet and the velocity of the plasma bullet first increase and then decrease. The maximum value of plasma plume occurred at 100 Pa, in which the propagation velocity gets the maximum value of 5\times 10^6 m/s. Further increasing the gas pressure to 15 000 Pa results in decrease in both the plasma length and bullet velocity. Relative to voltage, the frequency of the applied pulse voltage has a different impact on the plasma propagation at different gas pressures. While a higher voltage induces a longer plasma plume and a faster propagation velocity at both 30 and 2000 Pa, increasing the frequency has little influence on plasma at 30 Pa but reduces the plasma length and propagation velocity observably at 2000 Pa. In addition, an exotic plasma plume structure is observed by ICCD. A possible hypothesis is discussed here to explain this phenomenon. These experiments may lead to a more precise control of the low-pressure plasma, warranted for advanced materials technologies. [ABSTRACT FROM AUTHOR]

One of the critical components of high energy density pulsed power systems used to generate short high-voltage and high-power impulses is gas-filled plasma closing switch (PCS). In recent years, significant research efforts have been aimed at finding environmentally friendly gases which can be used in the PCSs, and several gases including dry air, nitrogen, carbon dioxide, argon, and their mixtures have been considered as potentially suitable working fluids in such switches. However, the lack of knowledge of the breakdown characteristics of complex switching topologies filled with these gases limits their practical applications. Therefore, further investigation of the breakdown performance of PCSs is required, in order to establish their applicability for practical use in high-voltage pulsed power systems. This paper reports on the investigation of the breakdown characteristics of a triggered PCS topology with corona discharge electrodes. The self-breakdown voltage of the switch, variation in the self-breakdown voltage, time to breakdown, and jitter have been obtained for the switch filled with “zero grade” air, N2, CO2, and an Ar/O2 mixture up to a pressure of 10 bar (abs). It was shown that the switch can provide a stable breakdown performance with jitter as low as ~1 ns. [ABSTRACT FROM AUTHOR]

This paper describes the design and implementation of novel trigger circuit (23 kV, $1.7~\mu \text{s}$ , and 0.66 J/pulse) for xenon flash lamp driver. The design is based on a modified flyback circuit in the discontinuous conduction mode to take advantage of both generating the high voltage from the resonance with output capacitor and connecting the series with main pulse circuit using the flyback transformer which can carry the full current of several kiloampere at high-voltage side. This design eliminates the requirement for additional high-voltage protection devices in a xenon flash lamp driver. In addition, the unique high-voltage flyback transformer is designed with high turn ratio and low leakage inductance. The detailed design procedure for the resonant circuit at the output side of the flyback circuit with the permissible range of the parasitic component of the transformer is described on the basis of simplified analysis of resonant circuit. To verify the proposed design, computer simulation based on PSpice software and experiments for the proposed triggering circuit with a main pulse circuit was performed. For the experiment, the trigger circuit is developed with the specification of maximum 23-kV, 0.66-J/pulse output and tested with a xenon flash lamp (Heraeus P4101) driver consisting of a 1.5-kV, 36-kJ/s main pulse circuit and a 2.5-kW (500 V, 5 A) simmer circuit. The experiment is performed in both triggering without the simmer mode and combining the simmer mode. From the simulation and experimental results, it is verified that the triggering circuit can be used effectively, as it exhibits reliable ignition. [ABSTRACT FROM AUTHOR]

High-power current sources with high dynamic performance, ultralow current ripple, and absolute reference tracking accuracy are the key elements for magnets (bumper and septum) that are used in accelerators. Similar requirements are also encountered in plasma research applications in fusion reactors, as well as plasma research for the future high voltage direct current circuit breakers. Therefore, the current source must be able to drive resistive/inductive and highly fluctuating loads without any compromise in its performance. In this paper, such a flexible, dynamic, and accurate current source is introduced, which able to provide amplitudes up to 30 kA and bipolar voltages up to 10 kV. The system’s operating concept is presented and its design procedure in order to fulfill a list of demanding specifications is demonstrated. In addition, a detailed description of its near-optimal, advanced control system is presented. Finally, the theoretical considerations are verified by extensive simulation results for various operating scenarios, including driving chaotic arc loads. [ABSTRACT FROM AUTHOR]

In this paper, we present the final implementation of our 0–50-kV picosecond rise time 0.5–10-ns pulse generator. The pulse generator will be used in future work to generate a (sub)-nanosecond streamer plasma for air purification research. The pulse generator is a single-line pulse generator with an oil spark-gap (SG), which generates 0.5–10-ns pulses with a 200-ps rise time and can operate at repetition rates of over 1 kHz into a 50- \Omega load. It is an improvement over the first implementation of our nanosecond pulse generator that we designed and verified experimentally in previous work. In this paper, we evaluate the performance of the final design. Furthermore, we present 3-D electromagnetic simulations of the nanosecond pulse generator and show that the simulations are in good agreement with the measurements. A variation in pulse duration from 0.5 to 10 ns is possible and the output pulses are square shaped without the large plateau behind the main pulse that was present in the pulses from the first implementation of the nanosecond pulse generator. At high voltages, the pulse top becomes less flat due to a time-dependent mismatch in the spark-gap. Furthermore, investigation of electrode erosion of the oil spark-gap shows that the erosion rate of the electrodes is in the range of 200–600 \mu \mathrmcm^3 \cdot \mathrmC^-1 for the electrode that is mainly the cathode and 100–300 \mu \mathrm{cm}^{3} \cdot \mathrm{C}^{-1}$ for the electrode that is mainly the anode, respectively. This is almost an order of magnitude higher than most gas spark-gap studies show for brass electrodes. Therefore, electrode erosion in the oil spark-gap will be a limiting factor on the lifetime of the system. We designed a new electrode with a stainless steel head to increase this lifetime. [ABSTRACT FROM PUBLISHER]

This paper presents the design and experimental validations of a system of three new high-voltage (HV) pulsed-power converters for the H− sources. The system requires three pulsed voltages (50, 40, and 25 kV to ground) at 2-Hz repetition rate, for \(700~\mu \) s of usable flat-top. The solution presents ripple-free output voltages and minimal stored energy to protect the ion source from the consequences of arc events. Experimental results on the final full-scale prototype are presented. In case of short-circuit events, the maximal energy delivered to the source is in the Joule range. HV flat-top stability of 1% is experimentally achieved with a simple Proportional-Integral-Derivative regulation and preliminary tuned H− source (e.g., radio frequency control, gas injection, and so forth). The system is running since more than a year with no power converter failures and damage to the source. [ABSTRACT FROM PUBLISHER]

In this paper, a compact all-solid-state pulsed power modulator was designed based on Marx generator and pulse transformer. It is consisted of a six-stage Marx generator using power MOSFETs as switches to generate primary voltage pulses and a pulse transformer through a closed magnetic core to boost and convert the polarity of the output high-voltage (HV) pulse. A MOSFET driver circuit based on optical–electrical isolation was designed for controlling the Marx generator. It shows that the output pulse shapes, especially the rising and falling phases, are determined by the design of the pulse transformer such as its leakage inductance, distributed capacitance, magnetization inductance, and step-up ratio. The designed modulator is able to generate HV pulses with amplitude ranging from −35 to 35 kV, repetition frequency up to 10 kHz, minimum pulsewidth 250 ns. Various types of plasma discharges, including air microdischarge for local treatments, plate-to-plate air dielectric-barrier discharge, underwater discharge, are able to be driven with good reproducibility by this compact pulse modulator. [ABSTRACT FROM AUTHOR]

High-voltage (HV) pulse generators (PGs) are the core of pulsed electric field applications. Applying HV pulses produces electrical pores in a biological cell membrane, in which if the size of the pores increases beyond a critical size, the cell will not survive. This paper proposes a new HV-PG based on the modular multilevel converter with full-bridge submodules (FB-SMs). In order to alleviate the need of complicated sensorless or sensor-based voltage balancing techniques for the FB-SM capacitors, a dedicated self-regulating charging circuit is connected across each FB-SM capacitor. The individual capacitor charging voltage level is obtained from three successive stages, namely, convert the low-voltage dc input voltage to a high-frequency square ac voltage, increase the ac voltage level via a nanocrystalline step-up transformer, and rectify the secondary transformer ac voltage via a diode FB rectifier. The HV bipolar pulses are formed across the load in a fourth stage through series connected FB-SMs. The flexibility of inserting and bypassing the FB-SM capacitors allows the proposed topology to generate different pulse-waveform shapes, including rectangular waveforms with specifically reduced dv/dt and ramp pulses. The practical results, from a scaled-down experimental rig with five FB-SMs and a 1-kV peak-to-peak pulse output, validate the proposed topology. [ABSTRACT FROM PUBLISHER]

Nowadays, most of solid-state circuits are fabricated through the application of the 2-D electrode manufacturing technology (printed circuit). In this paper, solid-state pulse-forming modules using 2-D electrode manufacturing technology are presented to produce long pulse duration while less space volume is being occupied. First, on a glass–ceramic (dielectric constant 225) substrate with the dimension of 250~\text mm \times 95~\text mm \times 4 mm, as meander line is the usual delay-line circuit in printed circuit boards, the meander pulse-forming line is used to deliver a high-voltage pulse with pulse duration longer than 120 ns by simulation and test validation. Furthermore, we also discuss the double parallel meander-line and the “V” shaped meander-line in this section. Second, with the same substrate, the LC pulse-forming module is used to generate the high-power pulse with good square pulse quality. By changing the inductance L, this module can be adjusted to deliver pulses with different durations. Third, planar concentric ring PFL is proposed with simulation analysis. In simulation, the planar concentric ring PFL is designed using an attractive storage medium—Barium Titanate (BaTiO3 base- ceramics (dielectric constant ~1000). At last, a compact PFL based on the structure of multilayer ceramic capacitor is introduced, and can generate a quasi-square pulse in simulation. These various types of solid-state pulse-forming modules may be the potential component in the compact pulsed power systems to generate high-voltage, long-duration pulses. [ABSTRACT FROM AUTHOR]

The power supply based on pulse step modulation technology has been widely used as the high-voltage power supply (HVPS) for additional heating systems. The topology contains numbers of converters and multisecondary transformers. For the magnetizing inrush of the transformer and charging current of the converters connecting with the secondary windings of transformer, the power up of the power supply system is quite complex. There are resistor branches series with the transformer and each converter is used to limit the inrush current. A lot of resister branches and parallel contactors in the converter modules are required, and as a result the dissipation and electromagnetic interference inside the module are serious. In this paper, the soft-start circuit is simplified to only one resistor branch. The precharge circuits of the converters, which are connected to the secondary, are diverted from the inside of the modules to the primary winding of transformer. Since the multisecondary transformer powers up at the same time as converters, the capacitors in all converters will limit the ramp up rate of the transformer voltage, and the magnetic inrush current can be ignored. To analyze the characters of the precharge branches, all converters can be equaled as parallel during the soft-start process. The equivalent circuit, a series $RLC$ circuit, is proposed in this paper. A 1.2-kV power supply, contains 12 converters, with soft start has been built up in laboratory. Simulation and experiment results are shown to verify the theoretical analysis. A new soft-start circuit of 100-kV HVPS system was designed. [ABSTRACT FROM PUBLISHER]

In the field of electromagnetic launch or other military research, the requirements for the power density of high-voltage capacitor charging power supply (CCPS) are increasing. The design of the cooling system becomes more difficult, especially in the intermittent operation mode, when the power supply exists transient heating process. As the main heating element of CCPS, the inverter unit is the key factor to influence the power density. In this paper, the main factors that influence the temperature rise of the device are analyzed, including the material and size of the heat sink. The rules between the above factors and the transient temperature rise are analyzed by Matlab simulation software. Then, the architecture model of inverter unit is established through ICEPAK software for simulation, which proves the accuracy of the regular. A basis for designing system level power supplies working in intermittent operating mode is provided through the transient thermal design of inverter unit’D The accuracy of the rule is verified through some load short circuit experiments with a 30-kW/6 kV charging power supply. [ABSTRACT FROM PUBLISHER]

The acceleration grid power supply (AGPS) is an important part of the neutral beam injector (NBI) system. With the increase in NBI power, the requirement for output voltage of the AGPS is becoming higher and higher, even reaching to 1000 kV. As the inverter-type high voltage power supply uses inverters located at the lower voltage side to regulate and cut off the output voltage, it is very suitable for high-voltage applications. The proposed scheme for the AGPS of the International Thermonuclear Experimental Reactor (ITER) NBI system comprises five stages, where each stage has an inverter-type power supply with an output voltage of 200 kV. This paper investigates the inverter-type power supply based on neutral point clamped three-phase three-level (TPTL) inverter and three-phase step-up transformer, which is equivalent to an insulated TPTL dc–dc converter connected with a dual dc link. In order to design a preferable controller for the inverter-type power supply, the topology and principles of the TPTL dc–dc converter with duty cycle modulation have been analyzed. It indicates that only when the converter operates at a large duty cycle, the output voltage ripple can be limited to ±5%. Hence, the small signal model of the converter at a duty cycle larger than 2/3 is established. Following the mathematical model, a single-loop PID controller has been designed and a 400 V/6 A prototype has been built. Simulation and experimental results verify the correctness of the theoretical analysis. The system achieves a lower output voltage ripple and fast dynamic response. [ABSTRACT FROM AUTHOR]

This paper proposes a new topology of a nanosecond, high voltage pulse generator devoted to pulsed corona discharge (PCD) reactor supply. The proposed topology is based on solid state, semiconductor switches and uses parasitic components of transformers. A prototype construction of the proposed generator loaded with a PCD reactor with 6.4-pF capacitance is able to generate high voltage pulses with maximum amplitude of 14 kV (using 5.4-kV supply and up to six modules of proposed topology, each equipped with a MOSFET transistor with 1-kV blocking capability) with voltage steepness of 730 V/ns. Obtained pulses are 65-ns long. The peak power delivered to the PCD reactor is >0.3~MW while the energy consumed reaches 7 mJ/pulse. This paper also compares two different mechanical constructions of such generators and gives an overview of analytical and numerical voltage waveform analyzes. [ABSTRACT FROM PUBLISHER]

In this paper, the authors examine the field emission performance of stainless steel polished to varying degrees, both before and after being coated with a nitrogen-implanted silicon oxynitride layer. The deposition procedure utilizes the simultaneous sputtering of silicon dioxide from a dielectric quartz window and ion implantation of nitrogen from an RF inductively coupled plasma. Here, the scanning field emission microscopy results indicate that prior to being coated, the number of emission sites increased drastically from 12 to more than 300 as the surface roughness increased from 4 to 64 nm, corresponding to polishing with 1-μm diamond paste to 15-μm (600 grit) silicon carbide paper. However, after being coated with nitrogen-implanted silicon oxynitride, all the samples displayed zero to five emission sites at electric field strengths at least three times higher than the uncoated stainless samples. Thus, neither the roughness of the underlying stainless steel nor that of the top surface of the coating had an effect on suppressing field emission. Depth profiling using Auger electron spectroscopy determined that the 0.24-μm-thick silicon oxynitride coating contained approximately 15% nitrogen. Fourier transform infrared spectroscopy of a coated silicon wafer confirmed this stoichiometry and bonding. The technical impact of this work is that coating the large contoured stainless steel surfaces with a nitrogen-implanted silicon oxynitride layer may eliminate the need for expensive labor-intensive polishing procedures currently used in high-voltage electrode structures, such as those found in electron injectors. [ABSTRACT FROM AUTHOR]

The objective of this paper is to investigate an influence of high-frequency high-voltage impulse conditioning on the back-to-back capacitor bank switching performance of vacuum interrupters (VIs). Nine identical 7.2-kV VIs were tested by 80 CO operations after the proposed conditioning. Test inrush currents were set to 0-, 2-, and 5-kA peak. The experimental results showed that this conditioning technology could make an impact on both prestrike and restrike characteristics of VIs. The complementary cumulative distribution function (CCDF) of the prestrike gap d\textrm {pre} followed complementary Weibull distribution. In contrast to VIs without conditioning, three typical prestrike gaps, i.e., CCDF 10% prestrike gap d\overline {10} , CCDF 50% prestrike gap d\overline {50} , and CCDF 90% prestrike gap d\overline {90}\vphantom {\sum RRR} , decreased by 39%, 19%, and 4% at most, respectively. Besides, the scattering of d\textrm {pre} decreased by 52% at most. Furthermore, the conditioning technology had an influence on the feature of restrike waveform through variation of field emission current. It could also reduce the restrike probability by 22.5% at most and made the entire restrikes occur between $0.5T$ and $5T$ during recovery voltage period ( $T=20$ ms). [ABSTRACT FROM AUTHOR]

This paper describes the design and implementation of a three-phase resonant converter with low ripple and high control accuracy. Based on a three-phase LCC-type resonant converter—which has advantages of low ripple, high-efficiency, and high-power density compared with a single-phase converter—a high-voltage power supply with low ripple (<0.1%) was designed. In addition to the general merits of an LCC-type resonant converter operating at continuous conduction mode—including soft switching, low conduction loss, and current source characteristics—the proposed scheme uses only one phase under a light-load condition by having different leg designs of the gate drive circuit and snubber parameters. This allows the design to overcome the operational constraints of the general LCC-type resonant converter. The distinctive design of the three-phase converter structure provides high efficiency and low ripple not only during rated operation, but also under light-load conditions. In order to analyze the high performance of the proposed scheme from no load to rated load, a PSPICE simulation was carried out. Comparison results with a conventional LCC-type resonant converter based on a single-phase structure are analyzed from the viewpoints of output ripple, losses, and operable load range. Using the proposed converter, a 20-kV, 20-kW high-voltage dc power supply design and implementation was presented with a superior gate drive circuit. Finally, the superiority of the proposed converter was verified through a simulation and experimental results. It was experimentally confirmed that the developed power supply achieves high performance in terms of efficiency (98%), operable load range (0.5–20 kV), and low ripple (0.05%), with a high power density. [ABSTRACT FROM PUBLISHER]

This paper describes a modular solid-state switching cell derived from the Marx generator concept to be used in topologies for generating multilevel unipolar and bipolar high-voltage (HV) pulses into resistive loads. The switching modular cell comprises two ON/OFF semiconductors, a diode, and a capacitor. This cell can be stacked, being the capacitors charged in series and their voltages balanced in parallel. To balance each capacitor voltage without needing any parameter measurement, a vector decision diode algorithm is used in each cell to drive the two switches. Simulation and experimental results, for generating multilevel unipolar and bipolar HV pulses into resistive loads are presented. [ABSTRACT FROM PUBLISHER]

To supply the cathode voltage for the two gyrotrons (140 GHz/1 MW/3 s) of the electron cyclotron resonant heating system on HL-2A, a high-voltage power supply (HVPS) based on pulse step modulator (PSM) with rated output of 80 kV/200 A has been built. Because the storing energy of the PSM HVPS is much lower than traditional HVPS, it is beneficial to load protection. In the PSM HVPS, there are eight dry-type multiwinding transformers; each transformer has 14 secondary windings. The main insulation of the multiwinding transformer reaches to 150 kV. There are 112 switch power supplies in the PSM HVPS; the output voltage can be regulated from 0 to 80 kV by modulating their delay time and pulsewidths. To realize two gyrotrons parallel operating and respective quick protection for the loads, two solid-state high voltage modulators (SSHVM) based on insulated gate bipolar transistor are applied in the power supply. The over-current and over-voltage protection are executed by turning off the PSM HVPS and the SSHVM. The protection time is <10~\mus . A fully digital controller based on digital signal processor and field programmable gate arrays has been developed to ensure the stability of the output voltage of the PSM HVPS. The design circuit and elements are described, and the test results of the PSM HVPS are given in this paper. [ABSTRACT FROM PUBLISHER]

The main characteristics of reversely switched dynistor (RSD) are infinite series, long lifetime, turning on in microseconds to nanoseconds, high-current rise rate (100 kA/\mus), and ability of passing through large current (several kiloamperes). With these advantages, RSD has a great potential of application in repetition rate pulsed power technology and the future HVdc field. To resolve the problem of residual voltage of RSD caused by insufficient precharge, which leads to nonuniform turn-on of RSD, this paper, based on the conduction mechanism of RSD devices, describes precharge circuit design requirements and establishes a second order circuit model to study the resonant triggering circuit of RSD. It is found that reducing precharge inductor can effectively increase precharge current, resulting in reducing the turn-on voltage of RSD. Finally, design for three improved circuit topologies (full-bridge, intense pulsed, and two-step triggering circuit) are presented and experiments show that these improved circuit topologies can enhance the precharge efficiency and reduce the turn-on voltage of RSD. [ABSTRACT FROM PUBLISHER]

Since bipolar high-voltage pulses is more effective in the treatment of air purification, water treatment, and other applications than unipolar pulses, a newly developed bipolar high-voltage rectangular pulse adder is proposed with a new control strategy. The structure of the all solid state pulse adder based on the half-bridge structure has been improved by changing the driving signal of the MOSFETS in the main circuit to obtain high-voltage rectangular narrow pulses. Magnetic ring transformers with a common primary winding and rectifiers were employed to charge capacitors under a high frequency. Improved phase shift control strategy is proposed, which makes it possible to generate unipolar or bipolar pulses with or without chopping off over resistive and capacitive loads. The bias voltage in the pulse removed and the size of magnetic cores is reduced. A nine-stage laboratory prototype is assembled. Experimental results show that unipolar and bipolar rectangular pulses with an amplitude of 4 kV, frequency of 12 kHz, pulsewidth of 600 ns– $4~\mu \text{s}$ , and rise time of 80 ns are obtained over different loads. [ABSTRACT FROM AUTHOR]

The trigger voltage is usually high in traditional three-electrode gas switch, which makes the trigger system large and complex in large-scale pulsed power system such as linear transformer driver. In this paper, a three-electrode gas switch triggered by microhollow cathode (MHC) discharge is put forward, which can be operated stably under low trigger voltage. MHC discharge is a kind of microplasma with the characteristics of low trigger voltage (several thousand volts), high electron density, and high gas pressure discharge. In this switch, three MHC triggers sharing the same cathode are designed as the third electrode of the switch in the middle. Positive and negative high voltages are applied to two main electrodes, respectively. The breakdown characteristics of MHC discharge triggered by pulse voltage are first studied. The trigger voltage can be as low as 8 kV at 0.3 MPa in pure N2 with the discharge peak current up to 80 A. A circuit simulation model describing breakdown process of MHC is also built. Then two operating modes of the switch, three-electrode mode (T-mode) and two-electrode mode (D-mode), are analyzed. The stable operation with the charging voltage from ±35 to ±50 kV is realized under different working coefficients from 64% to 92% and different trigger voltages from 8 to 15 kV. The turn-on parameters including delay time, jitter, and turn-on time are studied that the delay time and jitter of D-mode are longer than that of T-mode under the same condition. At last, the improvement of MHC trigger for the stable operation of D-mode with shorter delay time is described. [ABSTRACT FROM PUBLISHER]

This paper presents generalized dynamic models for Marx derived multilevel half-bridge bipolar modulators. This high-voltage topology uses modular Marx multilevel converter diode ( \textM^\mathrm 3 CD) cells to generate positive and negative (bipolar) pulses or unipolar (positive or negative voltage pulses). The developed models are tested in transient studies of pulse voltages and currents in the load. Simulation and experimental results are presented and compared. [ABSTRACT FROM PUBLISHER]

A high-voltage fast transient pulse termination load using a 10-mm distributed ceramic-carbon-rod resistor has been developed. It is capable of measuring a pulse's voltage amplitudes up to 100 kV and a rise time less than 300 ps. A difficulty for the development of the high-voltage ultrawideband (UWB) termination device is the compromise of the resistive element size considering opposite characteristics of the high voltage and the wideband frequency. A smaller resistor shows the better high-frequency performance but the worse high-voltage insulation characteristic. Many previous studies in the area of pulsed-power development have used a nonscaled load device for the pulse termination; nevertheless, a mismatch between a source and a load impedance results in significant misunderstanding of the output voltage in a high-voltage fast transient pulse measurement. In this paper, we propose a newly developed high-voltage UWB coaxial load improving impedance characteristics of a nonscaled load device. Physical length of a rod resistor is far longer than a wavelength of an input pulse so that the impedance linearly increases in the moving direction of the incoming pulse. The proposed log-scaled coaxial load device with a distributed ceramic-carbon-rod resistor has a property of compensating impedance variations, which is caused by the usage of an electrically long rod resistor, by means of diminishing coaxial characteristic impedance exponentially along the resistor. This diminishing coaxial structure makes it possible to maintain consistent impedance through the entire load device. Experimental results show good agreement with expectations in aspects of the voltage standing-wave ratio under 1.25 : 1 from dc to 10 GHz; peak impedance variations under 10% with the final converged impedance of 54.86 \Omega; and negligible reflections when injecting the repetitive pulsed input with amplitudes from 15 to 100 kV, a rise time below 300 ps, and repetition rates under 10 kHz. [ABSTRACT FROM PUBLISHER]

The paper describes a system for digitization and optical transmission of thermal measurements on high voltage devices in high vacuum environmental conditions and presents the tests conducted on a prototype. The system has been designed in particular to satisfy such technical requirements as to be mounted on the grounded grid of the SPIDER facility (a 100-keV/60-A particle accelerator) and to withstand frequent fault conditions in which the voltage of the grid transiently rises up to some tens of kV. The system is based on a circuit which samples and transmits the signals to the central acquisition system while preserving the signals and avoiding any electrical links between the high voltage device and the vacuum vessel. Moreover, the system has to be designed so as to minimize the electromagnetic noise affecting the low amplitude signals from the thermocouples (TCs). The circuit design is presented, describing the layout and the electronic components for the acquisition of the TC signals and for the data transmission via optical fiber. When SPIDER is operational, with up to 1-h pulse duration, the circuit is powered by a battery, which is in turn recharged by the energy coming from a photovoltaic cell when SPIDER is not operational and the circuit is not acquiring. Data are digitally transmitted according to RS-232 protocol for easy interfacing to the central data acquisition system. The circuit has been tested to check its proper operation, with particular care devoted to the data transmission and the recharging phase. The results are reported and discussed. [ABSTRACT FROM PUBLISHER]

Spacecraft charging, as a field, is continually being recharged by new developments in understanding, new materials and technologies, and new approaches to both new and old problems. I will discuss some of the new frontiers in understanding spacecraft charging in this paper, as well as referencing relevant papers from the 11th Spacecraft Charging Technology Conference. Spacecraft charging is highly material-property dependent. For example, the secondary electron emission, photoemission, bulk electrical resistivity, and surface resistivity are important parameters that help determine the extent of spacecraft charging (both on the surface and inside the spacecraft) in any given environment. Our understanding of these material properties is one of the new frontiers in spacecraft charging. I will discuss how these fundamental material properties have been found to depend on the following: proper measurement techniques, temperature, radiation flux, electric field, surface treatment, surface contamination from plumes and outgassing, surface modification through arcing and vacuum exposure, and synergistic effects. Modeling of spacecraft charging is a second new frontier. New developments in modeling have both improved our understanding of spacecraft charging and enabled us to model situations that are dynamic and geometrically complex. New schemes for treating both space and time variations of fields, particle fluxes, and spectra have made our modeling more precise and accurate. Now, many more spacecraft are being launched into low Earth orbit and the radiation belts. Modeling charging effects more accurately in those orbits will become more important than ever. A third new frontier in spacecraft charging is novel mitigation techniques. Surface materials and simple passive devices that emit electrons as fast as they are collected seem to make real-time charge mitigation cheaply and reliably achievable for the first time. Novel solar cell configurations and coverglass materials promise to make arcing, both of the primary electrostatic discharge (ESD) type and sustained arcing between cells or strings, a thing of the past. Superconducting cables may obviate the high voltages that lead to arcing. New cooperation between spacecraft and solar array manufacturers and spacecraft charging experts may help to prevent the spacecraft charging mistakes of the past. Furthermore, the final frontier is dealing with new materials and higher power requirements. Lightweight spacecraft materials are, in some cases, prone to exacerbate charging or arcing and may allow transmission of electromagnetic interference into sensitive electronics. New solar cell active materials may increase the effects of arcing on solar cell and solar array performance, even for primary ESD events. Higher power requirements may require longer transmission cables, which may increase the need for higher voltages, making arcing more likely. If superconducting cables become a reality, magnetics may become very important for spacecraft control and stability. What will happen to a superconducting cable if it must carry the increased current in an arcing event of very short duration? [ABSTRACT FROM PUBLISHER]

This paper presents a new device generating high-voltage pulsed cold atmospheric plasma jets. With these plasmas, the quantity of atomic oxygen (and, accordingly, the chemical activity) is a lot higher than that in previous researches. The main characteristic of the new device is the usage of three tubular needle-type electrodes connected in parallel. By applying high-voltage pulses (with 20–30-kV amplitude, duration of hundreds of nanoseconds, and hundreds of pulses per second), three independent discharges are formed in the discharge room. The plasma-forming gas is He, with a low quantity of oxygen introduced through the high-voltage electrodes. Each discharge has an optimal percentage of 0.5% vol. \O2 in He, which maximizes the quantity of atomic oxygen in the plasma. The plasmas of the three discharges unite to a single jet though, which contains a quantity of atomic oxygen that is a lot higher than that of the plasma of each discharge. The emission spectra of the plasma jets show the maximization of the intensity of the O I 777 nm line when a concentration of 1.5% vol. \O2 in He (three times higher than so far) is introduced in the plasma-forming gas. [ABSTRACT FROM PUBLISHER]

The absence of current-zero points in the direct current (dc) waveform of high voltage dc (HVDC) circuit breakers makes the interruption process more severe than the case of conventional ac networks with sinusoidal currents. In this way, in the current HVDC networks, a parallel precharged capacitor is inserted to inject the reverse current into the interruption chamber of the vacuum circuit breaker and create the artificial current-zero points. In this paper, a novel method for reverse current injection has been proposed. In this method, two separate helical flux compression generators (HFCGs) have been applied to generate the reverse current and an intense axial magnetic field (AMF), respectively. Numerical simulation of high-current vacuum arc (VA) in the presence of very strong AMF has been presented. For this purpose, the magnetohydrodynamic equations describing the behavior of the VA are coupled to a simple circuit analysis and the previously developed multiphysics model of HFCG. The results indicate that the explosively driven current injection set can make current-zero points properly in a typical HVDC network and lead to successful interruption of fault current. This method needs much less volume and cost in comparison to the parallel precharged capacitor sets. [ABSTRACT FROM AUTHOR]

In this paper, the surface creepage of high voltage self-breakdown switch which is used in 500-kv pulse modulator is analyzed in theory by employing the method of distributed element equivalent recurrent circuit. Moreover, the field distortion of the connecting ring of the switch is simulated by using software. According to the theoretical analysis, several methods to avoid surface creepage are obtained: 1) the outer housing of the switch should have high surface resistivity; 2) when the surface breakdown electric field is a constant, it is better to decrease the diameter of the electrode and to increase outer diameter and thickness of the outer housing; 3) in order to avoid field distortion, it is recommended, as far as possible, not to use metal connecting ring on the outer housing of the switch; and 4) there should be a clean environment for switch to work. [ABSTRACT FROM AUTHOR]

In power modulators for pulses in the microsecond range, transformers are often used for generating high output voltages. With standard topologies, the transformer is usually only excited in a unipolar direction, i.e., the flux density B swings between zero and a value close to the saturation flux density. By applying a reset circuit, the flux density B in the transformer is set to a value close to the negative saturation flux density before the pulse, so that the flux density could swing between the negative and positive saturation values during the pulse. This allows one to halve the core area and reduce the core volume/weight as well as the losses. In this paper, the operating modes of three different reset circuit topologies (the standard and a new advanced passive as well as an active one) and the corresponding waveforms are explained. Furthermore, the three topologies are compared with respect to the losses/complexity based on a design for a solid-state modulator with 20-MW output power and 200-ky output voltage. [ABSTRACT FROM AUTHOR]

Nonthermal plasma created by high-voltage dc power supply can be used to collect precharged suspended particulates, whereas nonthermal plasma generated by high-voltage pulsed power supply is used to remove harmful gases in the air, but how to increase the efficiency is not clear. In this paper, it is novel to apply magnetic: field to air purification to increase the purification efficiency. Effect of magnetic field is analyzed. It can be concluded that purification efficiency can be improved significantly along with the application of magnetic field. [ABSTRACT FROM AUTHOR]

This paper presents a power electronics converter to generate bipolar high-voltage pulses using low-voltage dc source. Converter is designed based on charging of different capacitors by a predetermined switching pattern and their discharging on the load for pulsed power applications. Low number of power electronics devices and bulky transformer elimination are main advantages of the proposed converter. According to new findings, bipolar high-voltage pulses may lead to higher efficiency in many applications, such as food sterilization industry. The proposed pulse generator generates bipolar controllable pulses with a modular circuit structure based on a capacitor-switched network. Experimental results are presented to verify the analysis. [ABSTRACT FROM AUTHOR]

Miniaturized high-voltage power converter techniques might offer an improved outlook for the development of compact accelerator technologies. We view the identification of materials and circuits that provide both high-voltage isolation and efficient power coupling characteristics to be the primary engineering challenge. A lithium niobate resonant piezoelectric transformer was mated to a voltage multiplier circuit, and the input–output terminal characteristics were investigated. This paper considers the piezoelectric transformer-coupled voltage multiplier circuit as a black box and reports on the input impedance, output voltage, power conversion efficiency, and transient charging capacity. We found that the circuit was well suited to the charging capacitors of arbitrary size to voltages well over ten kilovolts at power-conversion efficiencies approaching 20%. The circuit was also quite capable of driving a vacuum diode to high voltage. The piezoresonant transformers coupled to output power conditioning circuits appear to be good candidates for producing high voltage in a small footprint. [ABSTRACT FROM PUBLISHER]

In this paper, we present a design approach of a single-line nanosecond pulse source by using a thorough analytical investigation and by verification with CST MICROWAVE STUDIO. Through detailed analysis and simulation, we arrive at a design for a fast rise time variable pulse duration pulse source which is able to produce 1–10 ns pulses with tens of kilovolt amplitude and less than hundreds of picoseconds rise time. This variable pulse duration is achieved by using telescopic antennas and ferrites in the pulse-forming line of the pulse source. Finally, we present a first implementation of a 5-ns pulse source with an oil spark gap for fast switching. [ABSTRACT FROM AUTHOR]

In this paper, we present a solid state 0–120 kV microsecond pulse charger for our nanosecond pulse generator refid="ref1"/. The pulse-forming line (PFL) of our nanosecond pulse generator must be charged with microsecond pulses to prevent pre-firing of its oil spark gap. The pulse charger consists of two identical compact pulse charger modules with integrated electronics. The electronic circuits are mounted on a compact printed circuit board and consist mainly of a number of parallel connected insulated-gate bipolar transistors (IGBTs) that switch a primary capacitor bank into a pulse transformer. Each pulse charger module can generate 60 kV microsecond pulses at 1 kHz repetition rate. When connected in series, they are able to deliver up to 120 kV into a 100 pF load. This 100 pF load is the PFL of our nanosecond pulse generator at its maximum length of 1 m. The pulse charger is able to operate in a harsh electromagnetic interference environment as a result of its compact layout and optical triggering of the IGBTs. [ABSTRACT FROM PUBLISHER]

High Voltage Technology Demonstration Satellite HORYU-II is a nanosatellite (30-cm cubic shape, 7 kg) developed by students at the Kyushu Institute of Technology. One of the objectives of this satellite is orbital demonstration of high-voltage technologies. The satellite with the highest voltage generation in low earth orbit (LEO) has been the International Space Station, generating 160 V. In orbit, especially LEO, the use of high voltage over 200 V induces arcing. HORYU-II is aimed to demonstrate new designs of solar array that can generate the power, free of arcs, by producing 300 V via a specially designed solar array itself, not via a conventional dc/dc converter. If successful, HORYU-II will become the first spacecraft in the world that achieves 300 V photovoltaic power generations in space. In this paper, we describe the detail of the mission payload development and verification. Preliminary flight results obtained since the satellite's launch on May 18, 2012 to the sun-synchronous orbit at 680-km altitude are also briefly presented. [ABSTRACT FROM PUBLISHER]