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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]

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]

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]

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]

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]

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 a novel technique for the voltage droop compensation of long pulses in solid-state bipolar high-voltage Marx generators. Considering the modularity of Marx generators the compensation consists in adding one extra stage to perform as a pulsewidth modulation circuit. This stage voltage is added to the output positive or negative pulses, and an output LfCf filter is included to smooth the voltage pulse waveform. A five-stage laboratory prototype of this circuit has been assembled using 1200-V Insulated Gate Bipolar Transistors and diodes with 1000-V dc input voltage. The circuit was operated at 50-Hz bipolar pulse rate, giving 4-kV bipolar pulses, into a resistive load, with 100- \mu \texts pulsewidth and 9.5-ms relaxation time. The circuit was able to compensate 10% of bipolar pulse voltage droop. [ABSTRACT FROM PUBLISHER]

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]

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]

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]