Bipolar Pulse Generator Research Articles

Design of a High-Frequency Irreversible Electroporation Bipolar Pulse Generator Based on H-Bridge Inverter With an Isolating Transformer

Design of a High-Frequency Irreversible Electroporation Bipolar Pulse Generator Based on H-Bridge Inverter With an Isolating Transformer

High-voltage pulse generator for time-of-flight mass spectrometry in electrospray thrusters.

Electrospray thrusters exhibit diverse operational modes based on the nature of ejected particles. Time-of-flight mass spectrometry is frequently employed to analyze the composition of the plume. This study introduces a novel converter-based bipolar high-voltage pulse generator aimed at producing synchronized bipolar high-voltage pulses with controllable voltage levels and frequencies, specifically tailored for the study of electrospray thrusters. The proposed topology generates bipolar high-voltage rails from a low-voltage power source through the forward-flyback with Cockcroft-Walton voltage multiplier topology. Subsequently, fast high-voltage MOSFETs are employed to generate high-voltage pulses. This paper outlines the operational principles and design methodologies of the pulse generator. Experimental verification corroborates its operational principles and functionalities, revealing that the pulse rise and fall times consistently remain below 30ns, while the voltage can be tuned within the range of 300-1000V. An electrospray thruster was employed to conduct a thorough and practical validation of the high-voltage pulse generator. This included generating time-of-flight curves and mass spectra of the plume, resulting in precise differentiation of all particles present.

Braiding Operations for a Topological Josephson Junction Array Using a Bipolar Current Pulse Generator Controlled by SFQ Logic Circuits

Braiding Operations for a Topological Josephson Junction Array Using a Bipolar Current Pulse Generator Controlled by SFQ Logic Circuits

All-Solid-State Synergistic Bipolar Pulse Generator for Gene Electrotransfer

All-Solid-State Synergistic Bipolar Pulse Generator for Gene Electrotransfer

A Bipolar Pulse Generator Without H-Bridge Controlled by a Magnetically Isolated Driver

A Bipolar Pulse Generator Without H-Bridge Controlled by a Magnetically Isolated Driver

A Bipolar Pulse Generator With High-Voltage Gain Based on Three-level Neutral-Point-Clamped Split-Source Inverter

A Bipolar Pulse Generator With High-Voltage Gain Based on Three-level Neutral-Point-Clamped Split-Source Inverter

A Magnetic Isolated Drive Circuit Based on Half-Bridge for Bipolar Marx Pulse Generator

A Magnetic Isolated Drive Circuit Based on Half-Bridge for Bipolar Marx Pulse Generator

Long-duration bipolar linear transformer driver based on a multi-turn half-bridge structure

All-solid linear transformer driver(LTD) generators are widely used to output unipolar high-voltage rectangular pulses in nanoseconds. However in some applications, the bipolar output is necessary and the size of the generator is limited, which is challenging for LTD topology because the size of the magnetic core is related directly to the amplitude and pulse duration of the output waveforms. In this paper, a bipolar long-duration pulse generator based on the topology of a linear transformer driver combined with a half-bridge and multi-turn structure is put forward. The half-bridge topology can output bipolar waveforms easily and can save the number of switches used in the generator. To eliminate the crosstalk voltage that appears during operation, a differential mode inductance is used to protect the circuit. A snubber circuit is applied to suppress the reverse overshoot. The multi-turn design is chosen to make the size more compact. However, the multi-turn usually leads to a lower rise speed. To improve the performance, an optimization method that improves the rising speed by changing the turns of each stage is discussed. The strategy is useful and can be applied on some other occasions. The generator can output bipolar waveforms whose amplitudes are 4 kV and the duration can be adjusted from 200 ns to 800 ns. The rise time can be limited to 70 ns. The size of the generator is 10 cm * 10 cm * 15 cm, which is compact compared to the generators put forward before.

Accumulation effect of active species in atmospheric-pressure plasma jet driven by nanosecond high-voltage pulses with MHz pulse repetition rate

With respect to successful applications of pulsed power in gas discharges, the enhanced generation of desired active species and control of plasma parameters as required are always decisive issues. In this study, a bipolar nanosecond high-voltage pulse generator with a maximum pulse repetition rate (PRR) of up to 1 MHz (i.e. a minimum pulse interval of 1 µs) in burst mode is developed, based on the principle of full-bridge converter and pulse transformer. This pulse source is used to generate an atmospheric-pressure plasma jet in Ar + 1%CH4 gas flow, and the influence of pulse intervals (from 1–10 µs) is explored. It is found that the pulse interval can strongly modulate the active species, i.e. a short pulse interval enhances the generation of C2 radial and H atom due to the accumulation effect, when the pulse interval is comparable with their lifetime, while it slightly suppresses the generation of Ar excited states and the energy fraction into electronic excitation. Reduced pulse intervals also prominently increase the energy fraction of vibrational excitation. This study demonstrates how the PRR effectively modulates active species and energy branching and enhances the generation of certain active species in atmospheric-pressure plasma driven by pulsed power.

Development of Bipolar Pulse Power Supply Based on Peak Closed-Loop Control Method

With the wide application of pulsed power technology in tumor ablation, sewage treatment, and other related fields, researchers have found that bipolar electrical pulses are more effective than unipolar electrical pulses. In this article, a new bipolar pulse generator is proposed, which combines the features of boost circuit and Marx circuit to significantly improve the boost ratio of output pulse and the tunability of pulse peak. In order to improve the load regulation rate and peak stability of bipolar pulse power supply, a bipolar pulse power supply based on peak closed-loop control method is designed in this article. The high-voltage pulse is attenuated, and its peak is sampled by the pulse peak sampling circuit, and the pulse peak voltage is fed back to the DSP controller for comparison with the set peak value, and the proportional integral differential (PID) adjustment is performed according to the voltage deviation, and the boost ratio of the pulse generator is changed to realize the constant peak output of the bipolar pulse. In order to verify the feasibility of the proposed bipolar pulse generator with peak closed-loop control scheme, simulation and experimental studies of the bipolar pulse power supply with five-stage peak closed-loop control were conducted. The results show that the output repetition frequency of 5 kHz, pulsewidth of 5– <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$10~\mu \text{s}$ </tex-math></inline-formula> , and peak pulse value within ±2.0 kV can be stabilized when the input voltage is 100 V.

Incident Angle Dependence of the Waveform of the Polarization-Sensitive Photoresponse in CuSe/Se Thin Film

The results of studying the waveforms of longitudinal and transverse photocurrent pulses generated in thin, semitransparent CuSe/Se films as a function of the angle of incidence (α) of a femtosecond laser beam at linear and circular polarizations are presented. It has been established that the durations of unipolar longitudinal photocurrent pulses at linear and circular polarizations of laser pumping do not depend on the angle α. It is shown that the evolution of the temporal profile of the helicity-sensitive transverse photocurrent with a change in α strongly depends on polarization. At linear polarization, the shape of the unipolar pulses remains virtually constant; however, at circular polarization, the generation of unipolar and bipolar pulses is possible, with the waveforms strongly depending on the angle α. The influence of the incidence angle on the waveforms of transverse photocurrent pulses is explained by the transformation of linear and circular polarization into an elliptical upon the refraction of light at the air/semitransparent film interface and by the interplay of photocurrents arising due to linear and circular surface photogalvanic effects in the film. The presented findings can be utilized to develop polarization and incidence angle-sensitive photovoltaic devices.

Voltage Gain Enhancement of Solid-State Pulse Modulator by Adapting Sequential cum Parallel Charging of Capacitors

This article proposes a new capacitor charging mechanism, “sequential cum parallel charging of capacitors (S+P-CC),” for enhancing the voltage gain of the pulse modulators. It also proposes a new high-gain pulse modulator, i.e., a modular bipolar pulse generator (MBPG). This article first introduces the charging mechanism, and then to show its feasibility, the mechanism is applied to the MBPG. The capacitors of the MBPG are charged using the proposed “S+P-CC” mechanism and suitably enabled the MBPG to achieve an enhanced voltage gain. In addition to the enhanced voltage gain, the MBPG also offers the following benefits: flexibility in generating the pulsed output at variable amplitude, polarity, width, and repetitiveness. To understand the concept, a detailed analytical approach is presented in the article, and to verify the correctness of the approach, 1.2-kV (pk-pk) pulse generating MBPG prototype consisting of two modules and two stages is designed and tested. The experimental results provided validate that the prototype successfully generated 2−10 μs, unipolar/bipolar pulses with a repetition rate of 10,000 pulses per second.

Impact of Loading Effect from Liquid Foods on the Performance of Unipolar and Bipolar Square Pulse Generator

Impact of Loading Effect from Liquid Foods on the Performance of Unipolar and Bipolar Square Pulse Generator

Research on the Bipolar Microsecond Pulse Generator Using the Multistage Resonant Charging

In this article, a bipolar pulse generator based on multistage resonant charging has been proposed, which can deliver microsecond-range pulses for medical and industrial applications. The main circuit consists of two sets of identical Marx generators connected back to back with the load between them. It can flexibly output bipolar pulses with adjustable amplitude, pulse width, and frequency. In this research, six eight-stage Marx generators have been employed to verify the performance of the proposed bipolar pulse generator. From the experimental results, the proposed generator can deliver pulses with the amplitude of ±10 kV to no-load and a resistive load of 50 <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\text{k}\Omega $ </tex-math></inline-formula> . The repetitive frequency can be adjusted from 1 Hz to 1 kHz, and pulse width can be adjusted from 0.2 to <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$400~\mu \text{s}$ </tex-math></inline-formula> with 50 ns rising and falling time. The relaxation time between the positive and negative pulses can be determined from 0.2 to 400 <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\mu \text{s}$ </tex-math></inline-formula> . In the high-voltage field, the proposed Marx generator can deliver higher output voltage pulses and has smaller voltage differences between stages than the traditional solid-state Marx generator.

Co-effect of dielectric layer material and driving pulse polarity on the spatial emission intensity distributions of micro dielectric barrier discharge

A micro concentric ring device with asymmetric dielectrics (glass and n-silicon) is driven by a bipolar pulse generator with 20 kHz frequency, 1 μs pulse width, 50 ns rising/falling time, and 3.6 kV peak-to-peak voltage, and the spatial emission intensity distributions in the device are investigated. The experiments are operated at 133 mbar pure argon. The spatial-temporal microplasma evolution recorded by intensified charge-coupled device illustrates that ‘edge emission’ arises in the microchannels when the electrode (indium tin oxide) on which the glass dielectric is located acts as the cathode. However, when the electrode (conductive silver paste) adjacent to the n-silicon acts as the cathode, ‘center emission’ is induced. The dielectric materials’ properties (relative permittivity and secondary electron emission coefficient), synergistically with the pulse polarity, which determines the influence of the residual long-living particles generated by previous discharge on the subsequent discharge, are inferred to be responsible for the distinct spatial emission intensity distributions at different pulse polarities. When the n-silicon is situated on the cathode, the high permittivity of n-silicon repels the electric field into plasma, which means that the electrons can obtain more energy in the first half of their journey. Furthermore, the high secondary electron yield of n-silicon makes it possible to provide more seed electrons for microdischarge. This mechanism of electrons dynamics leads to the occurrence of ‘center emission’. When the positive half period of the bipolar pulse arrives at the n-silicon, the residual charged particles generated by the previous discharge will induce a reversed electric field in the channel center to impair the applied electric field and bring about the ‘edge emission’, but this cannot emerge in the microdischarge powered by the unipolar pulse. Investigation of spatial emission intensity distributions of microplasmas is important for the comprehension of devices based on micro-structure techniques.

Solid-State Bipolar Linear Transformer Driver Using Inductive Energy Storage

There have already a lot of circuit topologies for pulsed power generators using semiconductor switches. In this article, a novel circuit topology concept that can generate bipolar pulses based on linear transformer driver (LTD) topology is presented. Different from traditionally capacitive energy storage (CES) method, we utilize magnetic core as inductive energy storage (IES) medium to accumulate inductive energy before releasing pulses. The repetitive bipolar pulsed power generator is capable of operating in high repetition without reset circuit, because positive magnetization and negative magnetization can lead the magnetic core always back to initial state after every period. In this article, a three-stage laboratory prototype of bipolar IES-based LTD is designed and assembled using six existed CES-based LTD modules, which can generate ~2.4 kV bipolar peak pulses, 55 ns pulsewidth on a <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$150~\Omega $ </tex-math></inline-formula> resistive load with charging voltage of 80 V. Finally, this proposed three-stage LTD is evaluated under burst mode to verified the high repetition capability of this bipolar IES-based LTD. As a result, this generator can operate at repetitive frequency of 400 kHz without reset.

All-solid-state bipolar pulsed generator based on linear transformer driver and push-pull circuit.

All-solid-state linear transformer drivers (LTDs) are widely used in high-voltage repetitive nanosecond-pulsed generators, and only a few LTD generators can output bipolar rectangular waves currently. Furthermore, owing to the large reverse overshoot when the output pulse width is long, fewer LTD generators can achieve a rectangular wave output with a microsecond pulse width. In this study, a bipolar LTD circuit topology based on a push-pull circuit is proposed for irreversible electroporation. In this topology, a single-stage LTD module has four push-pull branches in its primary winding to achieve a bipolar output and a short-circuited winding with two resistor-capacitor-diode snubbers to suppress forward/reverse overshoot. A single-stage LTD module and a 12-stage LTD have been tested, and the results show that they can output bipolar rectangular pulses with variable parameters. When the output pulse width is 100ns to 1 µs, the maximum output voltage amplitude is 5.74 kV, the rise time is 29.1ns, and the reverse overshoot at 1 µs is 2.9%. When the output pulse width is 1-8 µs, the maximum output voltage amplitude is 2.93 kV, the rise time is 24.3ns, and the reverse overshoot at 8 µs is 11.3%.

High-Frequency and High-Voltage Asymmetric Bipolar Pulse Generator for Electroporation Based Technologies and Therapies

Currently, in high-frequency electroporation, much progress has been made but limited to research groups with custom-made laboratory prototype electroporators. According to the review of electroporators and economic evaluations, there is still an area of pulse parameters that needs to be investigated. The development of an asymmetric bipolar pulse generator with a maximum voltage of 4 kV and minimum duration time of a few hundred nanoseconds, would enable in vivo evaluation of biological effects of high-frequency electroporation pulses. Herein, from a series of most commonly used drivers and optical isolations in high-voltage pulse generators the one with optimal characteristics was used. In addition, the circuit topology of the developed device is described in detail. The developed device is able to generate 4 kV pulses, with theoretical 131 A maximal current and 200 ns minimal pulse duration, the maximal pulse repetition rate is 2 MHz and the burst maximal repetition rate is 1 MHz. The device was tested in vivo. The effectiveness of electrochemotherapy of high-frequency electroporation pulses is compared to “classical” electrochemotherapy pulses. In vivo electrochemotherapy with high-frequency electroporation pulses was at least as effective as with “classical” well-established electric pulses, resulting in 86% and 50% complete responses, respectively. In contrast to previous reports, however, muscle contractions were comparable between the two protocols.

Research of micro EDM/ECM method in same electrolyte with running wire tool electrode

A micro rod machining method which can switch between electrical discharge machining (EDM) and electrochemical machining (ECM) by attaching/detaching a diode to/from a bipolar pulse generator in parallel to the working gap was newly developed using a wire electrode made of tungsten. The problem of the wire electrode wear was eliminated by the use of the wire electrochemical turning (WECT) method in which the tungsten wire electrode is continuously running. The ultra-short bipolar pulse current was generated by the electrostatic induction feeding method where a pulse voltage is coupled to the working gap through a feeding capacitance. The machining characteristics of three types of wire guide; disk-shaped WC guide, laminated wire guide and cylindrical acrylic guide, were studied. The experimental results showed that the cylindrical acrylic guide has the best machining characteristics without the influence of guide wear and with less stray current flowing through the working gap. Using the cylindrical acrylic guide, the influences of the feeding capacitance C1, and the total amplitude of the pulse voltage on the machining characteristics were studied. Finally, a stainless steel SUS 304 micro-rod with a high aspect ratio of 14 was fabricated efficiently by using the EDM and ECM modes for rough and finish machining in sequence with the same setup, pulse generator, and neutral electrolyte.

A Compact High-Power Ultra-Wideband Bipolar Pulse Generator

A compact high-power ultra-wideband bipolar pulse generator based on a modified Marx circuit is designed, which is mainly composed of a primary power supply, Marx generator, sharpening and cutoff subnanosecond spark gap switches, and coaxial transmission lines. The Marx generator with modified circuit structure has thirty-two stages and is composed of eight disk-like modules. Each module consists of four capacitors, two spark gap switches, four charging inductors, and a mechanical support. To simplify the design of the charging structure and reduce the number of switches, four groups of inductors are used to charge the capacitors of the Marx generator, two of which are used for positive voltage charging and the other two for negative voltage charging. When the capacitor of each stage is charged to 35 kV, the maximum output peak voltage can reach 1 MV when the Marx generator is open circuit. The high-voltage pulse generated by the Marx generator charges the transmission line and forms a bipolar pulse through sharpening and cutoff switches. All transmission lines used for bipolar pulse generation have an impedance of 10 Ω. When the 950 kV pulse voltage generated by the Marx generator is fed into the transmission line, the bipolar pulse peak voltage can reach 390 kV, the center frequency of the pulse is about 400 MHz, and the output peak power is about 15.2 GW.