Pulsed Power System Research Articles

Barium Strontium Titanate-based multilayer ceramic capacitors with excellent energy storage and charge-discharge performance

Energy storage capacitors for advanced pulse power systems and high-power electric devices is a kind of important electronic components, the demand continues to grow, specifications are constantly being upgraded, and performance boundaries are continuously being pushed. Multilayer ceramic capacitors (MLCCs) for energy storage applications have received increasing attention due to the advantages of ultralow equivalent series inductance, equivalent series resistance, good frequency characteristics, strong voltage overload ability, and stable operability at high temperatures. However, the relatively low energy storage density significantly limits its broader applications. Here, 0.4Ba0.55Sr0.45TiO3-0.4Bi0.5Na0.5TiO3-0.2SrZrO3 (0.4BST-0.4BNT-0.2SZ) relaxor ferroelectric MLCCs are prepared at different heating rates. Excellent recoverable energy storage density of 10.3 J cm−3 and high energy efficiency of 93 % are achieved in fast-fired MLCCs under the electric field of 106.3 V μm−1. The impedance spectroscopy and thermally stimulated depolarization current technologies are employed to investigate the conductance mechanism of MLCCs, and the results can explain the effect of heating rate on the performance of MLCCs. In addition, the charge-discharge performances of fast-fired MLCCs are also thoroughly investigated, exhibiting great thermal and fatigue stability.

Toward Design Rules for Multilayer Ferroelectric Energy Storage Capacitors - A Study Based on Lead-Free and Relaxor-Ferroelectric/Paraelectric Multilayer Devices.

Future pulsed-power electronic systems based on dielectric capacitors require the use of environment-friendly materials with high energy-storage performance that can operate efficiently and reliably in harsh environments. Here, a study of multilayer structures, combining paraelectric-like Ba0.6Sr0.4TiO3 (BST) with relaxor-ferroelectric BaZr0.4Ti0.6O3 (BZT) layers on SrTiO3-buffered Si substrates, with the goal to optimize the high energy-storage performance is presented. The energy-storage properties of various stackings are investigated and an extremely large maximum recoverable energy storage density of ≈165.6Jcm-3 (energy efficiency≈93%) is achieved for unipolar charging-discharging of a 25-nm-BZT/20-nm-BST/910-nm-BZT/20-nm-BST/25-nm-BZT multilayer structure, due to the extremely large breakdown field of 7.5MVcm-1 and the lack of polarization saturation at high fields in this device. Strong indications are found that the breakdown field of the devices is determined by the outer layers of the multilayer stack and can be increased by improving the quality of these layers. Authors are also able to deduce design optimization rules for this material combination, which can be to a large extend justify by structural analysis. These rules are expected also to be useful for optimizing other multilayer systems and are therefore very relevant for further increasing the energy storage density of capacitors.

Enhanced energy-storage properties in (Bi0.5Na0.5)TiO3 ceramics by doping linear perovskite materials Ca0.85Bi0.1(Sn0.5Ti0.5)O3

For energy storage applications in Bi0.5Na0.5TiO3 (BNT)-based materials, the key challenges are the premature polarization saturation and low breakdown electric field (Eb), which confine the energy storage capacity of BNT and significantly restrict progress in advancing pulsed power capacitors. Hence, the cooperative optimization strategy of band structure and defect engineering was proposed, which successfully obtained a high recoverable energy density of 3.83 J/cm3 and an energy efficiency of 77.9 % in the Bi0.5Na0.5TiO3-0.12Ca0.85Bi0.1(Sn0.5Ti0.5)O3 (BNT-0.12CBST) ceramics. Doping the BNT matrix with CBST has been shown to not only reduce grain size but also enhance relaxor behavior, which collectively improves breakdown strength and delays polarization saturation. Furthermore, the x = 0.12 ceramic also exhibits a commendable discharge power density of 91.9 MW/cm3 and a transient discharge time of 40 ns. The higher resistivity and lower oxygen vacancy concentration are conductive to acquire superior breakdown electric field and energy storage performance. We determine the crystal structure, dielectric and ferroelectric properties of the studied ceramics in a wide range of temperatures and concentrations, and a phase diagram is constructed, which illustrates the complex phases present and their transformation behavior. Our work provides an effective strategy to optimize the energy-storage of dielectric ceramics, and shows great potential for practical applications in pulse power systems.

Core‐shell TiO2@Au Nanofibers Derived from a Unique Physical Coating Strategy for Excellent Capacitive Energy Storage Nanocomposites

AbstractPolymer dielectrics have been widely employed in pulsed power systems, but their applications are severely restricted by the low energy density. Incorporating core‐shell nanofillers is one promising strategy to enhance the energy density of polymer dielectrics. Nowadays, core‐shell nanofillers are mainly prepared via chemical coating strategies, which always involve complex chemical synthesis procedures. Herein, a unique physical coating strategy is developed to prepare core‐shell TiO2@Au nanofibers consisting of monodispersed Au nanoparticles homogeneously anchored on the TiO2 nanofibers. Interestingly, the TiO2@Au nanofibers show outstanding dielectric energy storage boosting capability. Specifically, with merely introducing 0.1 wt.% TiO2@Au nanofillers, the TiO2@Au/PVDF composite exhibits a substantially enhanced breakdown strength of 749 MV m−1, which reaches 152.8% of PVDF. Meanwhile, a high dielectric constant of 10.2 (114.1% of PVDF) is obtained. Consequently, an ultrahigh energy density of 18.6 J cm−3, which is 250.1% of PVDF, is achieved. It is further revealed that the significant energy storage boosting effect is originated from the Coulomb blockade and micro‐capacitor effects of the TiO2@Au nanofibers. This work establishes a unique paradigm for the facile preparation of core‐shell nanomaterials, which have huge potential for both dielectric energy storage and other functional nanocomposites.

A high‐power electromagnetic source for disabling improvised explosive devices

AbstractUltra‐wideband (UWB) microwave sources driven by specialised pulsed power generators have experienced a considerable development in the last decade due to their wide domain of new applications such as defence or counter‐terrorism activity. The authors present the main findings of a research dedicated to the development of a pulsed power‐driven electromagnetic field source for disabling improvised explosive devices (IED). The pulsed power generator driving the source is a 13‐stage compact Marx producing voltage pulses reaching an amplitude of 0.5 MV, with a pulse repetition frequency (PRF) of up to 100 Hz. The generator is coupled to a bipolar pulse forming line, providing bipolar pulses with a dV/dt of around 1.6 MV/ns. This pulsed power system feeds an array composed of 16 Koshelev‐type UWB antennas through an impedance matching transformer. The resulting electromagnetic source is capable to produce pulsed electric fields (PEFs) having a figure‐of‐merit (FOM) of 1 MV. First, practical experiments were carried out to study the effects of the PEFs on targets. The targets used in the present study are M2B type flashbulbs, known to have the same susceptibility as the US army M6 detonator. Different configurations of wires (shielded, twisted, etc) with different lengths were used in connecting items inside these targets. The tests were performed by placing the flashbulbs at different distances to determine the essential parameters (i.e., amplitude, duration, and frequency range) of the PEFs required to trigger them. An overview of the experimental campaign and the main findings are also presented followed by conclusions.

Biocompatible neem gum-modified polyvinyl alcohol composite as dielectric material for flexible energy devices

In our pursuit of a flexible energy storage solution, we have developed biocompatible (bc)-NG/PVA composite polymers by combining neem tree gum (NG) with polyvinyl alcohol (PVA). This innovative bio-inspired approach harnesses NG's unique properties for both the bio-electrolyte and bio-electrode components. The resulting bc-NG/PVA composites exhibit superior dielectric strength and versatility, surpassing traditional inorganic ceramic dielectrics in advanced electronics and pulsed power systems. Our study investigates the dielectric characteristics, conductivities, electric modulus, and impedance parameters of Pure PVA and NG-doped PVA composites. Adding 5 % NG to PVA significantly boosts its conductivity from 10−8 S cm−1 to 10−4 S cm−1, while the dielectric constant of PVA/5 % NG composite jumps to 104.5 compared to pure PVA. These improvements position the composite films of 5 % NG added PVA as promising materials for diverse applications. The heightened performance of these NG-blended PVA composite materials underscores their potential as a valuable resource for flexible energy storage solutions.

Bi0.5Na0.5TiO3-based energy storage ceramics with excellent comprehensive performance by constructing dynamic nanoscale domains and high intrinsic breakdown strength

Lead-free ceramic-based dielectric capacitors show huge potential in electrical energy storage in pulsed power systems due to their fast charge/discharge rate, ultrahigh power density and environmental friendliness. However, unsatisfied charge/discharge performance characterized by inferior recoverable energy storage density (Wrec generally <5 J/cm3) has become a key bottleneck to restrict their applications in cutting-edge energy storage devices. In this paper, we focus on simultaneously realizing ultrahigh Wrec and efficiency (ƞ) in eco-friendly Bi0.5Na0.5TiO3 (BNT)-based dielectric ceramics via chemical doping. Interestingly, highly dynamic polar nanoregions (PNRs) and nanodomains are constructed by incorporating Sr0.7Nd0.2TiO3 (SNT) into 0.94BNT-0.06BaTiO3. Of great importance, the resulting relaxor ferroelectrics (RFEs) exhibit high bulk resistivity, submicron grain size and wide band gap due to high level of SNT doping accompanying with 1 at% Nb donor doping. Therefore, excellent energy storage properties with ultrahigh Wrec∼8.08 J/cm3 and ƞ∼92.1% are achieved due to coexistence of large polarization difference (ΔP=Pmax−Pr) and giant dielectric breakdown electric field (Eb∼540 kV/cm). Furthermore, excellent temperature/frequency/cycling stability characterized by ΔWrec < ±4% and Δη < ±2% ensure the energy storage applications of the studied dielectric ceramics over an enormous range of scales.

Comparative Study of Different High Voltage Switches Used in Pulsed High Voltage Application

High-voltage switches play a crucial role in pulsed power applications, where the efficient and reliable control of highvoltage pulses is required. This study aims to compare different types of high-voltage switches commonly used in pulsed power systems including electromechanical switches, vacuum switches, gas-filled switches, triggered spark gaps and solidstate switches. The comparison study focuses on key performance parameters such as voltage handling capability, current carrying capacity, turn-on time, and repetition rates are considered to provide a comprehensive study and analysis of the switch’s suitability for different pulsed power applications. Gas-filled switches such as spark gaps, thyratrons and ignitrons have been used in pulsed power systems due to their high voltage handling capability and low switching losses. However, they suffer from a limited lifetime and require maintenance and periodic replacement. Solid-state switches, i.e. Silicon-Controlled Rectifiers (SCRs), Insulated Gate Bipolar Transistors (IGBTs) and Metal Oxide Semiconductor Field Effect Transistors (MOSFETs) offer advantages in terms of longevity, reliability, and reduced maintenance. However, they have limitations in high-voltage applications and exhibit higher switching losses. The findings of this comparison study will assist researchers, engineers, and system designers in selecting the most appropriate high-voltage switch for pulsed power applications, considering the specific requirements and constraints of the system. This will ultimately contribute to the advancement and optimization of pulsed power technologies across a wide range of scientific, industrial, and strategic applications.

The Cascade of High-Voltage Pulsed Current Sources

Currently, pulsed adders are used as pulsed voltage sources maturely. However, their use as pulsed current sources is significantly limited due to circuit impedance and the characteristics of power devices. This paper presents a simple yet effective design for a pulsed current source, incorporating a solid-state Marx pulsed adder as the primary power source and an inductor for energy storage. In the pulsed current source, a Marx pulsed adder produces high voltage to charge the inductor. Then, the stored inductance energy is converted to generate current pulses on the load; the amplitude of the pulsed current is unaffected by the load impedance within a certain range. The pulsed current source can be designed as a standard module, and several modules can form a cascade system for producing current pulses with higher voltage. Finally, a pulsed current source was developed, which can produce adjustable current pulses with high voltage. The design principles, control methods and the effects of the distribution parameters are described. The feasibility of the cascade pulsed power system was validated in experiments. Nine modules were connected to generate pulses of current 10 A on a 15 kΩ resistor.

Design, development and characterization of Blumlein Pulse Forming Line based pulsed power system for High Power Microwave source research

This paper describes a complete cycle of designing, developing, and characterising a Pulsed Power System (PPS) and generating microwaves using the relativistic source. For low impedance relativistic High Power Microwave (HPM) sources, Blumlein Pulse Forming Line (BPFL) based high voltage pulsed power systems are the most suited. An HPM source such as a virtual cathode oscillator (VIRCATOR) operating in nanosecond durations consists of a primary voltage source that charges a Marx pulse generator’s capacitor bank over a long time. The requirements of a diode load are met by compressing the output pulse width of a Marx generator by a BPFL. This article describes the novel design, construction and characterization of a circulating De-Ionized (DI) water insulated BPFL pulsed power system. A novel approach of insulating gas filled Marx generator of this class/rating is attempted. A pulse power system consisting of high pressure gas insulated Marx generator and circulating DI water-based BPFL was developed and experimented with the resistive load as well as HPM source. The PSPICE simulation of the Blumlein circuit for various load conditions is described. Criticalities in the design of end bushings are elaborated along with the development and testing of a compact BPFL-based pulsed power system.

Improving Charge Storage of Biaxially-Oriented Polypropylene Under Extreme Electric Fields by Excimer Uv Irradiation.

Biaxially-oriented polypropylene (BOPP) is one of the most commonly used materials for film-based capacitors for power electronics and pulsed power systems. To address the pressing issue of performance-limiting loss under extreme electric-fields, here we demonstrate a one-step, high-throughput, and environment-friendly process based on very low-dose ultra-violet irradiation from KrCl (222nm) and Xe2 (172nm) excimer. The performance of commercial BOPP is boosted in terms of withstanding electric-field extremes (Weibull breakdown strength 694 to 811V μm-1 by 17% at 25°C and 428 to 651V μm-1 by 52% at 120°C), discharged energy density, and conduction losses. Importantly, the depth profile of space charge is precisely measured in-situ with a high resolution of 500nm by laser induced pressure pulse. Consequently, the space charge effect and electric-field distortion are reduced and related to the improved polymer films. It is demonstrated that energetic UV photons act as scissors for BOPP chains and dissociate oxygen molecules leading to the more thermally stable oxygen-containing structures, as deep traps to impede charge migration. This work provides a promising approach to produce polymers with customized microscopic characteristics that is compatible with the assembly lines of polymer-based capacitors. This article is protected by copyright. All rights reserved.

Improving Energy Storage Properties of KNN Ceramic through Composition Modification

In this study, (1−x)K0.5Na0.5NbO3−xBa0.5Sr0.5(Zn1/3Nb2/3)O3, [(1−x)KNN-xBSZN] lead-free relaxor ceramics were fabricated by a conventional solid-state reaction method. XRD and Raman spectra confirm the R-C phase transition of the ceramics. The incorporation of BSZN effectively suppresses grain growth, enhanced the electrical resistivity, and improved the relaxation behavior. By analyzing the ferroelectric property of the sample under breakdown field, it is found that when x = 0.08, the ceramic demonstrates the smallest variation in polarization (∆P = 12.43 μC cm−2), the highest recoverable energy storage density (W rec = 0.8 J cm−3) and energy storage efficiency (η = 58.8%). The enhancement of energy storage is attributed to the introduction of BSZN, which effectively suppresses grain growth and improves the relaxation behavior of the ceramics. The results show that the ceramic enables be used in pulsed-power systems at low electrical field.

Ultrafast charge‐discharge and enhanced energy storage properties of lead‐free K0.5Na0.5NbO3‐based ceramics

AbstractFor dielectric capacitors in pulsed power systems, ultrafast charge‐discharge rates and good energy storage performances are essential. The relatively low efficiency η and the low energy density of potassium sodium niobate ceramics will restrict their applications. In this work, a local distortion of the crystal structure of ceramics is made by introducing the Bi and Ce ions, promoting the growth of polar nano‐regions, resulting in more obvious relaxation behavior and lower remnant polarization Pr. The average grain size is reduced, further increasing of breakdown strength. Eventually, fine comprehensive energy storage performances and good mechanical properties are simultaneously obtained. Enhanced recoverable energy storage density Wrec (∼5.30 J/cm3) and a high energy storage efficiency η (∼76.81%) are achieved in 0.970(K0.5Na0.5)NbO3‐0.030CeBiO3 (KNN‐0.030CB) ceramics with an ultrafast discharge rate t0.9 (31 ns) and a high current density (1008.5 A/cm2). All of these results indicate that this work provides a resultful way to design excellent comprehensive properties for advanced energy storage materials.

Optimizing electrical performance of low hysteresis Sr0.7Bi0.2TiO3 energy storage ceramic

Dielectric capacitors with rapid discharge rates and high power density are the basis for advanced pulsed power systems. Sr0.7Bi0.2TiO3 (SBT) is expected to be used in energy storage capacitors owing to the small hysteresis and high energy storage efficiency (η). Nevertheless, the low breakdown strength (BDS) limits the enhancement of energy storage density. This study explores the potential of Ho2O3-modified SBT to address this limitation. Introducing Ho reduces oxygen vacancies, decreases electrical conductivity, and increases thermal conductivity, thus enhancing BDS. The enhancement mechanism of electrical performance is studied through microscopic morphology analysis, structural refinement and numerical simulation. The Sr0.7Bi0.15Ho0.05TiO3 exhibits remarkable properties, including ultra-low loss tanδ (0.1 %), ultra-high η (95.8 %), and outstanding thermal, frequency, and cycling stability in energy storage properties. Additionally, Sr0.7Bi0.15Ho0.05TiO3 possesses a high power density (67.9 MW/cm3) and a rapid discharge rate (0.03 μs). The findings indicate that Sr0.7Bi0.15Ho0.05TiO3 is a prospective material for energy storage capacitors.

Enhancing energy storage efficiency in lead-free dielectric ceramics through relaxor and lattice strain engineering

Dielectric capacitors with high power density and fast charge-discharge speed play an essential role in the development of pulsed power systems. The increased demands for miniaturization and practicality of pulsed power equipment also necessitate the development of dielectric materials that possess high energy density while maintaining ultrahigh efficiency (η). In particular, ultrahigh efficiency signifies minimal energy loss, which is essential for practical applications but challenging to effectively mitigate. Here, we demonstrate a strategy of incorporating heterovalent elements into Ba(Zr0·1Ti0.9)O3, which contributes to achieving relaxor ferroelectric ceramics and reducing lattice strain, thereby improving the comprehensive energy storage performance. Finally, optimal energy storage performance is attained in 0.85Ba(Zr0·1Ti0.9)O3-0.15Bi(Zn2/3Ta1/3)O3 (BZT-0.15BiZnTa), with an ultrahigh η of 97.37% at 440 kV/cm (an advanced level in the lead-free ceramics) and an excellent recoverable energy storage density (Wrec) of 3.74 J/cm3. Notably, the BZT-0.15BiZnTa ceramics also exhibit exceptional temperature stability, maintaining fluctuations in Wrec within ∼10% and η consistently exceeding 90% across the wide temperature range of −55 °C to160 °C, and under a high electric field of 250 kV/cm. All these features demonstrate that the relaxor and lattice strain engineering strategies have been successful in achieving high-performance lead-free ceramics, paving the way for designing high-efficiency dielectric capacitors with a wide temperature range.

A computational study on the effects of fast-rising voltage on ionization fronts initiated in sub-mm air and CO2\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$_{2}$$\\end{document} gaps

Gas discharge and breakdown phenomena have become increasingly important for the development of an ever-growing number of applications. The need for compact and miniaturized systems within power, pulsed power, semiconductor, and power electronic industries has led to the imposing of significant operating electric field stresses on components, even within applications with low operating voltages. Consequently, the interest in gas discharge processes in sub-millimeter and microscale gaps has grown, as the understanding of their initiation and propagation is critical to the further optimization of these technologies. In this work, a computational study of primary ionization fronts has been conducted, which systematically investigated the role of voltage rate-of-rise in point-plane and point-point electrode geometries with an inter-electrode gap maintained at 250 μ\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\\upmu$$\\end{document}m and a needle radius of 80 μ\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\\upmu$$\\end{document}m. Using the hydrodynamic approach with the local mean energy approximation, along with simplified plasma chemistry, simulations have been performed under positive and negative ramp voltages, rising at 50, 25, 16.67, 12.5, and 10 kV/ns in synthetic air and in pure CO2\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$_{2}$$\\end{document}. Results on the developed electric field, electron densities, and propagation velocities are presented and discussed. Effects on the cathode sheath thickness scaling with voltage rate-of-rise have been additionally analyzed, the mechanisms behind these effects and their potential impacts are discussed. The work conducted in this study contributes towards an increased understanding of the gas discharge process, under fast-transients and nonuniform electric fields, with relevance to microelectromechanical, power, and pulsed power system design.

Enhanced Absolute Recovered Energy under Low Electric Field in All-Inorganic 0-3 Nanocomposition Thick Films.

Inorganic thick-film dielectric capacitors with ultrahigh absolute recovered energy at low electric fields are extremely desired for their wide application in pulsed power systems. However, a long-standing technological bottleneck exists between high absolute energy and large recovered energy density. A new strategy is offered to fabricate selected all-inorganic 0-3 composite thick films up to 10µm by a modified sol-slurry method. Here, the ceramic powder is dispersed into the sol-gel matrix to form a uniform suspension, assisted by powder, therefore, the 2µm-thickness after single layer spin coating. To enhance the energy-storage performances, the composites process is thoroughly optimized by ultrafine powder (<50nm) technique based on a low-cost coprecipitation method instead of the solid-state and sol-gel methods. 0D coprecipitation powder has a similar dielectric constant to the corresponding 3D films, thus uneven electrical field distributions is overcome. Moreover, the increase of interfacial polarization is realized due to the larger specific surface area. A maximum recoverable energy density of 14.62Jcm-3 is obtained in coprecipitation thick films ≈2.2 times that of the solid-state powder and ≈1.3 times for sol-gel powder. This study provides a new paradigm for further guiding the design of composite materials.

Simulation of effect of metal particles on breakdown process of three-electrode gas spark switches

Compared with two-electrode gas spark switch, three-electrode gas spark switch has the advantages of lower operating voltage, higher reliability and less discharge jitter, so it has been widely used in pulse power systems. However, due to the characteristics of pulse power technology, the gas spark switch is easy to cause ablation on the electrode surface during use, and the metal particles generated by ablation will significantly affect the stability and reliability of the switch. In this work the discharge process of the three-electrode gas spark switch under atmospheric pressure nitrogen environment is simulated first. In this model, the ionization coefficient near the trigger electrode is modified to compensate for the shortcomings of the local field approximation, and the relevant mathematical derivation process is given. The formation of the initial electrons is described by the field electron emission phenomenon, and the development process of electron collapse into the streamer is obtained. The physical mechanism of switch on is investigated, and the development process of each stage of switch discharge is described in detail. Then, the discharge process of the switch is studied when there are metal particles near the trigger. The study shows that the presence of metal particles enhances the electric field near the trigger and accelerates the formation of the initial electron cloud. In addition, in the presence of metal particles, the metal particles and the trigger will first break down, forming a high-density plasma channel after the breakdown, and becoming the source of the subsequent flow development. At the same time, because the metal particles on the channel have an obstructing effect on the streamer development, the streamer generates a discharge branch after contacting metal particles. In the end, the influences of metal particles of different shapes and sizes on the discharge process are discussed. The results show that metal particles with sharp shapes have stronger electric field distortion, when the electric field intensity is large enough, it may cause field emission on the surface of metal particle. And it is also made clear that the size of metal particle is small, the obstruction of the development path of streamer is small, and the streamers quickly converge behind the particles.

Improved energy storage properties of polypropylene-based composite dielectrics by introducing surface-charged BaTiO3@chitisan ultrafine constructions

Surface-charged BaTiO3@chitisan ultrafine constructions can effectively improve the energy storage properties of PP-based composite dielectrics through interfacial-regulation and trap introduction.

A High Vacuum, High Electric Field Pulsed Power Interface Based on a Ceramic Insulator

Improving the flashover voltage in a vacuum interface between a pulsed-power system and a vacuum region has been a goal for many years. The interface problem is difficult because of the electrical, mechanical, and vacuum issues that must be satisfied simultaneously. In this paper, according to the theories of vacuum flashover and the design rules for high electric field insulators, a ceramic insulated vacuum interface is presented. The electrostatic field along the ceramic surface was obtained by ANSYS simulations. By optimizing the field shaper and shielding rings, the electric fields were well distributed and the fields around the cathode and anode triple junctions were effectively controlled. The high voltage test was carried out on a ~40 GW, ~100-ns pulser, and results show that the vacuum interface can work stably with the hold-off voltage of 600 kV. The experimental results agree with the theoretical and simulated results. Finally, the influence of the surface treatment on the ceramic flashover characteristics was also discussed.