High Voltage Pulse Research Articles

A High-Voltage Pulse Modulator Composed of SiC MOSFETs/IGBTs in a Hybrid Connecting State

In order to solve problems such as a slow switching speed, a high switching power, a loss of pure IGBT modulators, and the weak withstanding load short-circuit ability of pure SiC MOSFET modulators used for vacuum loads, this paper proposes a new scheme for high-voltage pulse modulators based on SiC MOSFET/IGBT hybrid connecting circuits. It has a low power loss like the pure SiC MOSFET modulator and a strong withstanding load short-circuit ability like the pure IGBT modulator. Firstly, the principle circuit of the hybrid connecting modulator are discussed and chosen. And the basic working processes of the hybrid parallel-series modulator is described in detail. Secondly, three key points in this new scheme are analyzed and designed as follows: the static and dynamic voltage sharing; the actualizing of the ZVS process for IGBTs; the improvement of short-circuit protection for SiC MOSFETs. A modulator consisting of 16-stage 1200 V-SiC MOSFETs and 1200 V-IGBTs in hybrid parallel-series states is tested. Based on the sample circuit, the working data, such as high-voltage pulse waveforms of 10 kV/2 KHz/10 μs, static and dynamic voltage sharing, the driving control sequence, the U/I sequence of the IGBT, the short-circuit protection waveform, and the calculation, are obtained and discussed.

Evaluation of heart rate variability at 1-month after pulsed field ablation of atrial fibrillation and comparison with radiofrequency ablation

Abstract Background Pulsed Field Ablation (PFA) of atrial fibrillation (AF) is a nonthermal novel ablative modality in which high-voltage electric pulses are delivered to generate a high myocardial tissue-specific cellular death, with negligible consequences on surrounding structures including ganglionated plexi. The impairment of the cardiac autonomic ganglia after AF ablation with radiofrequency (RF) has been associated with an increase in mean heart rate (HR) and a reduction in heart rate variability (HRV) and might influence the long-term success of AF ablation. Little data is available on the effect of PFA on cardiac autonomic nervous function. Purpose The aim of this study is to investigate whether PFA ablation could lead to different values of HR and HRV compared to RF at 1-month post-ablation 24-hour Holter monitoring. Methods Between January to September 2023, we included consecutive patients undergoing AF ablation with PFA. According to our clinical practice, all patients performed a routine 24-hour Holter monitoring at 1-month post-ablation. Consecutive AF patients treated with RF were used as controls. Patients in treatment with antiarrhythmics or with documented recurrences of AF at 1-month post-ablation Holter monitoring were excluded. Results 22 consecutive PFA patients were compared to 22 consecutive RF controls. There were no differences in demographic, clinical and echocardiographic data between the 2 groups (Table 1). At 1-month post-ablation Holter monitoring (Table 2), PFA patients had significant higher values of VarIndex (2.18±0.9 vs 1.47±0.7, p=0.01), ASDNN/5min (52.37±15.93 vs 37.17±12.96, p<0.01), SDANN/5min (116.50±27.97 vs 96.03±28.38, p=0.04), and SD (128.95±31.31 vs 106.30±29.56, p=0.04). There was no difference in minimum HR (47.00±6.59 vs 50.29±10.25, p=0.21), mean HR (67.77±6.63 vs 69.24±9.71, p=0.56), and maximal HR (115.41±18.12 vs 110.81±16.44, p=0.39). Conclusions PFA leads to higher values of HRV parameters (i.e., VarIndex, ASDNN/5min, SDANN/5min, and SD) at 1-month post-ablation compared to RF. These data suggest a higher preservation of cardiac autonomic function with PFA, in contrast to RF. Whether the preservation of cardiac autonomic function with PFA might lead to higher rate of long-term AF recurrences remains to be determined.Table 1Table 2

Importance of the electrophoresis and pulse energy for siRNA-mediated gene silencing by electroporation in differentiated primary human myotubes

BackgroundElectrotransfection is based on application of high-voltage pulses that transiently increase membrane permeability, which enables delivery of DNA and RNA in vitro and in vivo. Its advantage in applications such as gene therapy and vaccination is that it does not use viral vectors. Skeletal muscles are among the most commonly used target tissues. While siRNA delivery into undifferentiated myoblasts is very efficient, electrotransfection of siRNA into differentiated myotubes presents a challenge. Our aim was to develop efficient protocol for electroporation-based siRNA delivery in cultured primary human myotubes and to identify crucial mechanisms and parameters that would enable faster optimization of electrotransfection in various cell lines.ResultsWe established optimal electroporation parameters for efficient siRNA delivery in cultured myotubes and achieved efficient knock-down of HIF-1α while preserving cells viability. The results show that electropermeabilization is a crucial step for siRNA electrotransfection in myotubes. Decrease in viability was observed for higher electric energy of the pulses, conversely lower pulse energy enabled higher electrotransfection silencing yield. Experimental data together with the theoretical analysis demonstrate that siRNA electrotransfer is a complex process where electropermeabilization, electrophoresis, siRNA translocation, and viability are all functions of pulsing parameters. However, despite this complexity, we demonstrated that pulse parameters for efficient delivery of small molecule such as PI, can be used as a starting point for optimization of electroporation parameters for siRNA delivery into cells in vitro if viability is preserved.ConclusionsThe optimized experimental protocol provides the basis for application of electrotransfer for silencing of various target genes in cultured human myotubes and more broadly for electrotransfection of various primary cell and cell lines. Together with the theoretical analysis our data offer new insights into mechanisms that underlie electroporation-based delivery of short RNA molecules, which can aid to faster optimisation of the pulse parameters in vitro and in vivo.

Electric discharge process modelling when piston pins recovery in internal combustion engines

Introduction. The relevance of the topic of the presented article is determined by the improvement of the technology for repairing and restoring machine parts. Currently, the technology of restoring piston pins of internal combustion engines (ICE) by a high-energy method of plastic deformation of metal using the energy of a high-voltage pulse discharge in a liquid is widely used – the electrohydraulic effect, and on its basis electrohydraulic processing. The purpose of the article is to increase the efficiency of the method of restoring piston pins of internal combustion engines due to the use of the electrohydraulic distribution method.Materials and methods. The research methods such as the analysis of the degree of influence of the electrical parameters of the electrohydraulic distribution process on the amount of deformation of the piston fingers depending on the relevant material were used. The article discusses a mathematical model of the electric discharge process when restoring piston pins. The calculation method determines the modes and parameters of the process of electrohydraulic distribution of piston pins while maintaining their fatigue life, static strength and wear resistance.Results. In this work, the degree of influence of the electrical parameters of the electrohydraulic distribution process on the amount of deformation of the piston pins, depending on the product material used, is established. A mathematical model of the electric discharge process during the restoration of piston pins has been developed, and based on them, the modes and parameters of the process of electrohydraulic distribution of piston pins have been determined while maintaining their fatigue life, static strength and wear resistance.Discussion and conclusions. The studies have shown that exploding wires made of iron, copper, and tungsten are not effective in restoring piston pins with an internal radius of up to 10 mm. The pressure in the case of their use does not exceed 100 MPa. Exploding Al wires with a diameter of less than one millimeter have the greatest effect. In this case, the inductance of the circuit should be minimal, because this provides the largest share of the energy released in the discharge channel from all stored in the capacitor. This ensures the highest pressure in the channel. Based on the same considerations, the capacity should be limited to a range of 3-12 UF. This method can be applied to the restoration of other car parts.

Ferroelectric Hf0.5Zr0.5O2for Analog Memory and In‐Memory Computing Applications Down to Deep Cryogenic Temperatures

AbstractLow‐power nonvolatile memories operating down to deep cryogenic temperatures are important for a large spectrum of applications from high‐performance computing, electronics interfacing quantum computing hardware to space‐based electronics. Despite the potential of Hf0.5Zr0.5O2(HZO), thanks to its compatibility with complementary metal‐oxide‐semiconductor (CMOS) back‐end‐of‐line processing, only few studies of HZO‐based memory devices down to cryogenic operation temperatures exist. Here, analog ferroelectric memory stack fabrication with 10 nm HZO and their detailed characterization under wide range of pulse amplitudes and frequencies down to 4 K are reported. When operated at temperatures below 100 K, HZO devices can support high amplitude voltage pulses, yielding record highProf up to 75µC cm−2at ±7 Vp(14 Vpp) pulse amplitudes accompanied with frequency‐dependent memory window between 6 and 8 V. Devices show excellent endurance exceeding 109cycles of ±5 Vp(10 Vpp) andProf 30 µC cm−2without significant degradation of coercive voltages or loss of polarization at cryogenic temperatures. At least 20 reproducible analog states for temperatures below 100 K with almost ideal linearity of intermediate polarization states in both pulse directions is observed, demonstrating the high potential of analog cryogenic ferroelectric memories, essential for on‐line training in in‐memory‐computing architecture.

A solid-state pulse power sub-nanosecond SiC DSRD-based generator with high-voltage and high repetition frequency for pulse discharge water treatment

Water treatment is one of the most important issues for all walks of life around the world. The unique advantages of the solid-state power electronic pulses in water treatment make it attractive and promising in practical applications. The output voltage, rising time, repetition rate, and peak power of output pulses have a significant impact on the effectiveness of water treatment. Especially in pulse electric field treatment and pulse discharge treatment, the pulse with fast rising time achieves the advantage of generating plasma without corona, which can avoid water heating effect and greatly improve the efficiency of the pulse generator. High repetition rate can significantly reduce the peak power requirement of the pulse in water treatment application, making the equipment smaller and improving the power density. Therefore, the study developed a high-voltage high frequency sub-nanosecond pulse power generator (PPG) system for wastewater treatment. It adopts SiC DSRD (Drift Step Recovery Diode) solid-state switches and realize modular design, which can achieve high performance and can be flexible expanded according to the requirements of water treatment capacity. Finally, an expandable high-voltage PPG for water treatment is built. The output parameters of the PPG include output pulse voltage range from 1 to 5.28 kV, rise time <600 ps (20%–90%), repetition up to 1 MHz. The experiment results of PPG application for pulse discharge water treatment is presented. The results indicate that the proposed generator achieves high-efficiency degradation of 4-Chlorophenol (4-CP), which is one of the most common chlorophenol compounds in wastewater. From experiment, the homemade system can degrade 450 mL waste water containing 500 mg/L 4-CP in 35 min, with a degradation rate of 98%. Thereby, the requirement for electric field intensity decreased. Through the further quantitative analysis, the impact of frequency, voltage, and electrode spacing on the degradation effect of 4-CP is confirmed.

Structure of Self-Powered Modular High-Voltage and High-Current Pulse Generator for Magnetron

Structure of Self-Powered Modular High-Voltage and High-Current Pulse Generator for Magnetron

The Enhancement of Tumor Ablation Effect by the Combination of High-Frequency and Low-Voltage Bipolar Electroporation Pulses.

Recently, combining short high-voltage IRE monopolar pulses with long low-voltage IRE monopolar pulses was shown to enlarge the ablation region. This finding indicates that combining HFBPs with low-voltage bipolar pulses (LVBPs), which are called composited bipolar pulses (CBPs), may enhance the ablation effect. This study designed a pulse generator by modifying a full-bridge inverter. The cell suspension and 3D tumor mimic experiments (U251 cells) were performed to examine the enhancement of the ablation effect. The generator outputs HFBPs with 0-±2.5 kV and LVBPs with 0-±0.3 kV in one period. The pulse parameters are adjustable by programming on a human-computer interface. The cell suspension experiments showed that CBPs could enhance cytotoxicity, as compared to HFBPs with no cell-killing effect. Even at lower electric energy, the cell viability by CBPs was significantly lower than that of the HFBPs protocol. The ablation experiments on the 3D tumor mimic showed that the CBPs could create a larger connected ablation area. In contrast, the HFBPs protocol with a similar dose generated a nonconnected ablation area. Results indicate that the CBPs protocol can enhance the ablation effect of HFBPs protocol. This proposed generator that uses the CBPs principle may be a useful tool for tumor ablation.

Parasitic Parameters Design Consideration and Its Optimization Technique of High-Voltage Pulse Transformer for Ignition Module

Parasitic Parameters Design Consideration and Its Optimization Technique of High-Voltage Pulse Transformer for Ignition Module

Electrical engineering equipment for generating and measuring of complete pulse current of artificial lightning in the conditions of high-voltage electrophysics laboratory

Goal. Decision of problem scientific and technical task on the reliable generating and measuring in the conditions of high-voltage electrophysics laboratory basic component of complete pulse current of artificial lightning with the rationed amplitude-temporal parameters (ATPs) with the use of the modernized generator of current of lightning of type of UITOM-1. Methodology. Bases of the applied electrical engineering, electrodynamics and electrophysics, electrophysics bases of technique of high-voltage and high pulse currents, bases of high-voltage pulse technique and measuring technique. Results. Information, which specify on a decision at Research and Design Institute «Molniya» of National Technical University «Kharkiv Polytechnic Institute» problem scientific and technical task, related to the reliable generating and measuring in the conditions of high-voltage electrophysics laboratory of complete pulse current of artificial lightning, which contains pulse A- (repeated pulse D-), intermediate B- and long-term C- (shortened long C*-) components of this current, is resulted, ATPs which answer the hard technical requirements of normative documents of the USA of SAE ARP 5412: 2013, SAE ARP 5414: 2013 and SAE ARP 5416: 2013. Short information is indicated about the applied electrical circuits of separate high-voltage generators of pulse currents of condenser type of GIC-A (GIC-D), GIC-B and GIC-C (GIC-C*), which it is worked as synchronous appearance on the general electrical loading in composition the modernized powerful high voltage generator of complete pulse e current of artificial lightning of type of UITOM-1, and in-use high-voltage measuring facilities which contain the heavy-current low-resistance shunts of type of SHK-300 for simultaneous registration with their help on examinee on stability to lightning devices objects of aviation and space-rocket technique of ATPs proper component of complete i pulse current of artificial lightning. Technical examples are resulted and the row of results of practical application of the indicated domestic powerful high-voltage proof-of-concept electrophysics equipment is described at the tests of elements of some aircrafts (ACs) on resistibility to the direct action on them of complete pulse current of artificial lightning with rationed ATPs. Originality. A problem is formulated and having the important applied value in area of aviation and space-rocket technique for the leading countries of the world scientific and technical task on the reliable generating and measuring in the conditions of high-voltage electrophysics laboratory indicated component of complete pulse current of artificial lightning with rationed ATPs and concrete electro-technological ways and hardware are indicated for its successful decision. Practical value. The use of the modernized powerful high-voltage generator of complete pulse current of artificial lightning of type of UITOM-1 developed in practice and created in Ukraine will allow to conduct the real verification on resistibility to the action of lightning of different side systems, devices and construction elements, containing metallic and composition materials, both again developed and modernized ACs, that will be instrumental in the increase of vitality of such ACs in the extreme terms of their flight and stay in an electrical active earthly atmosphere with flowing in it storm electrical discharges. References 30, tables 3, figures 20.

Irreversible electroporation promotes a pro-inflammatory tumor microenvironment and anti-tumor immunity in a mouse pancreatic cancer model.

Pancreatic cancer is a significant cause of cancer-related mortality and often presents with limited treatment options. Pancreatic tumors are also notorious for their immunosuppressive microenvironment. Irreversible electroporation (IRE) is a non-thermal tumor ablation modality that employs high-voltage microsecond pulses to transiently permeabilize cell membranes, ultimately inducing cell death. However, the understanding of IRE's impact beyond the initiation of focal cell death in tumor tissue remains limited. In this study, we demonstrate that IRE triggers a unique mix of cell death pathways and orchestrates a shift in the local tumor microenvironment driven, in part, by reducing the myeloid-derived suppressor cell (MDSC) and regulatory T cell populations and increasing cytotoxic T lymphocytes and neutrophils. We further show that IRE drives induce cell cycle arrest at the G0/G1 phase in vitro and promote inflammatory cell death pathways consistent with pyroptosis and programmed necrosis in vivo. IRE-treated mice exhibited a substantial extension in progression-free survival. However, within a span of 14 days, the tumor immune cell populations reverted to their pre-treatment composition, which resulted in an attenuation of the systemic immune response targeting contralateral tumors and ultimately resulting in tumor regrowth. Mechanistically, we show that IRE augments IFN-γ signaling, resulting in the up-regulation of the PD-L1 checkpoint in pancreatic cancer cells. Together, these findings shed light on potential mechanisms of tumor regrowth following IRE treatment and offer insights into co-therapeutic targets to improve treatment strategies.

Effects of the spacing between plasma channels on the fracture behavior of red sandstone under high-voltage pulse discharge

In rock engineering, high-voltage pulse technology has attracted attention because it offers environmental protection, controllable energy, and repeatable discharge. It is necessary to study the fracture behavior of rock under high-voltage pulse discharge (HVPD) for the parametric design of rock breaking thereby. HVPD experiments were conducted in red sandstone samples with the plasma channel spacing ranging from 26 to 66 mm at intervals of 10 mm. The stress wave generated by HVPD was obtained from the current waveform measured by Rogowski coils. In combination with numerical simulations, the distribution characteristics, propagation process, and formation mechanism of fractures were analyzed. The results showed that after two applications of HVPD at different positions, the sample was both broken down and two plasma channels and radial fractures centered around them were formed within. The stress wave decays exponentially with the increase of the distance from the plasma channel. When the spacing between plasma channels is less than or equal to 46 mm, fracture coalescence occurs between the two plasma channels; thereafter, the fractures formed by the second HVPD face resistance to propagation towards the fracture area formed by the first HVPD. In addition, numerical simulation results indicate that the second HVPD will generate significant tensile stress in the middle region of the two plasma channels, leading to near-horizontal fracture coalescence. When the spacing between plasma channels increases to 56 mm and 66 mm, the tensile stress induced by the second HVPD in the middle region of the sample is small, and it is difficult to form fracture coalescence between the two channels.

Analysis of the solid breakdown characteristics under high voltage pulse

As an efficient breakage technology, high voltage pulse breakage technology (HVP) has been an attractive topic due to its selective advantages. Typically, HVP is conducted in water and it is believed that the breakdown strength of water is higher than that of solids, and the discharge channel will be formed in solids under short voltage front rise time. The location of the discharge channel is important for understanding and optimizing of HVP. The study focuses on solid breakdown and the location of the discharge channel. The breakdown type during the HVP process is analyzed, the breakage characteristics of solid particles are investigated, the breakdown parameters are compared between water and solid, and the influence of solid composition on breakdown type is revealed. Under the settled conditions of this study, the results showed that: the discharge channel is easier to be formed inside the solid particle with the particle in contact with the electrode. And the discharge channel is formed in water with water gap between the solid and the electrode. The location of the discharge channel is affected by solid composition and the electrical breakdown probability can be improved with other compositions embedded in solid particles.

An Investigation of the Efficient-Precise Continuous Electrochemical Grinding Process of Ti-6Al-4V.

Titanium alloys have many excellent characteristics, and they are widely used in aerospace, biomedicine, and precision engineering. Meanwhile, titanium alloys are difficult to machine and passivate readily. Electrochemical grinding (ECG) is an ideal technology for the efficient-precise machining of titanium alloys. In the ECG process of titanium alloys, the common approach of applying high voltage and active electrolytes to achieve high efficiency of material removal will lead to serious stray corrosion, and the time utilized for the subsequent finishing will be extended greatly. Therefore, the application of ECG in the field of high efficiency and precision machining of titanium alloys is limited. In order to address the aforementioned issues, the present study proposed an efficient-precise continuous ECG (E-P-C-ECG) process for Ti-6Al-4V applying high-pulsed voltage with an optimized duty cycle and low DC voltage in the efficient ECG stage and precise ECG stage, respectively, without changing the grinding wheel. According to the result of the passivation properties tests, the ideal electrolyte was selected. Optimization of the process parameters was implemented experimentally to improve the processing efficiency and precision of ECG of Ti-6Al-4V. Utilizing the process advantages of the proposed process, a thin-walled structure of Ti-6Al-4V was obtained with high efficiency and precision. Compared to the conventional mechanical grinding process, the compressive residual stress of the machined surface and the processing time were reduced by 90.5% and 63.3% respectively, and both the surface roughness and tool wear were obviously improved.

A study of pulsed high voltage driven hollow-cathode electron beam sources through synchronous optical trigger

In this study, a pulsed, high voltage driven hollow-cathode electron beam sources through an optical trigger is designed with characteristics of simple structure, low cost, and easy triggering. To validate the new design, the characteristics of hollow-cathode discharge and electron beam characterization under pulsed high voltage drive are studied experimentally and discussed by discharge characteristics and analyses of waveform details, respectively. The validation experiments indicate that the pulsed high voltage supply significantly improves the frequency and stability of the discharge, which provides a new solution for the realization of a high-frequency, high-energy electron beam source. The peak current amplitude in the high-energy electron beam increases from 6.2 A to 79.6 A, which indicates the pulsed power mode significantly improves the electron beam performance. Besides, increasing the capacitance significantly affects the high-current, lower-energy electron beam more than the high-energy electron beam.

Pulse operation mode of inertial electrostatic plasma confinement devices

The paper discusses the operation features of the inertial electrostatic plasma confinement (IEC) devices in the pulsed high voltage mode. The pulse operation mode offers significant advantages in IEC devices, which are associated with high discharge currents that are inaccessible for continuous operating modes. However, the implementation of such operating modes is associated with a number of physical limitations and technical difficulties.A stand with an IEC chamber powered by a high-voltage pulse transformer and a unit for gas preliminary ionization in the IEC chamber has been developed. In the chamber, ions are accelerated from a background glow discharge. A study of the burning background discharge in the IEC chamber, background discharge current Ipre influence on the duration of current and voltage pulses of the main discharge and the delay between them was carried out. The results of the neutron yield measuring in an IEC chamber operating in pulsed mode are presented at a charging voltage up to 105 kV, a discharge current amplitude of several tens of amperes, a preionization current of 8 mA, and a pulse repetition rate from single to 300 Hz. A stable neutron flux with an energy of 2.5 MeV at a level of 106 neutrons/s was experimentally obtained.

Electroporation of Chlorella vulgaris with laboratory devices capable of generating arbitrary waveform pulses

The influence of pulsed electric fields with different waveforms on the electroporation of Chlorella vulgaris was investigated in this research. A pulsed power generator that can produce high-voltage pulses with arbitrary waveforms was developed. This device was utilized to generate pulsed electric fields of nine different waveforms (rectangle, bipolar rectangle, sine, half-sine, exponential decay, exponential increase, oscillation superimposed on rectangle, two-step rectangle, and triangle) with the same amplitude (17.5 kV/cm) and energy (0.27 J/pulse) for the electroporation of Chlorella vulgaris. The results showed that the pulse waveform played a significant role in the electroporation, which could be explained by the duration of transmembrane potential above threshold Δφth and by the frequent and rapid changes in the electric field above threshold Eth. Among the nine pulses, the oscillating superimposed rectangular pulse and half-sinusoidal pulse had the highest electroporation rate, with an improvement of about 40% compared to the conventional rectangular pulse.

Simulation and Experimental Study on the Rock-Breaking Process Induced by High-Voltage Electric Pulse

Simulation and Experimental Study on the Rock-Breaking Process Induced by High-Voltage Electric Pulse

Driver circuit with high-voltage pulse and high-frequency excitation for the cell of optically pumped sensors.

Helium optically pumped sensor is widely used in the application for the detection of weak magnetic fields, and the cell is the core component of that, which needs an external excitation signal to ignite and maintain its luminosity, and its luminosity affects the sensitivity performance of the sensor. To improve the performance of the cell and reduce the power consumption of the system, which is the largest power consumption component in the sensor, this study presents the design of a driver circuit for a helium cell based on a high-voltage pulse source and high-frequency excitation source and uses a T-type impedance matching circuit to realize the efficient transmission of energy. The experimental results demonstrate that the driver circuit can effectively light up the helium cell, in which the pulse voltage of the high-voltage excitation is more than 1.0kV, the output power of the high-frequency excitation signal is in the range of 0-6W, and it is easy to adjust the output power of the high-frequency excitation signal to optimize the sensitivity of the sensor with an the optimal power density of 1.1 W/cm2 and a sensitivity of 29.4 pT/Hz1/2 is obtained. The driver circuit method designed in this study is also suitable for other inert gases to generate metastable atoms.

Experimental study of cavitation development in liquid in pulsed non-uniform electric field under the action of ponderomotive forces

In this paper, the Rayleigh scattering method is used to study the formation of cavitation in water in a pulsed inhomogeneous electric field when a nanosecond high voltage pulse is applied to a needlelike electrode. The observational results confirm the theoretical picture of cavitation development under the action of electrostrictive ponderomotive forces. The values of the negative pressure, the average size of the cavitation nanovoids, and their concentration were obtained from these measurements, which are in agreement with theoretical estimates.