High Voltage Square Research Articles

Soft Electrohydraulic Bending Actuators for Untethered Underwater Robots

Traditional underwater rigid robots have some shortcomings that limit their applications in the ocean. In contrast, because of their inherent flexibility, soft robots, which have gained popularity recently, offer greater adaptability, efficiency, and safety than rigid robots. Among them, the soft actuator is the core component to power the soft robot. Here, we propose a class of soft electrohydraulic bending actuators suitable for underwater robots, which realize the bending motion of the actuator by squeezing the working liquid with an electric field. The actuator consists of a silicone rubber film, polydimethylsiloxane (PDMS) films, soft electrodes, silicone oils, an acrylic frame, and a soft flipper. When a square wave voltage is applied, the actuator can generate continuous flapping motions. By mimicking Haliclystus auricula, we designed an underwater robot based on six soft electrohydraulic bending actuators and constructed a mechanical model of the robot. Additionally, a high-voltage square wave circuit board was created to achieve the robot’s untethered motions and remote control using a smart phone via WiFi. The test results show that 1 Hz was the robot’s ideal driving frequency, and the maximum horizontal swimming speed of the robot was 7.3 mm/s.

Development of electrostatic removal system for application in dust removal from Martian spacesuits

Dust removal from Martian spacesuits whilst on exploration activities is critically important for long-term Martian exploration missions. Martian dust is known to contain harmful particles which must be removed from Martian spacesuits to prevent entry into habitation zones on Mars, and prevent spacesuit wear. In this work, an Electrostatic Removal System was developed which utilised the phenomenon of dielectrophoresis to remove Martian dust from the outer layer of spacesuits. Dielectrophoretic forces were exerted on dust particles by an alternating electrostatic field which acted to remove the particles from a surface. The field was generated by applying high voltage square waves, produced by a MOSFET H-Bridge, across an array of parallel copper electrodes contained within an Electrostatic Removal Device. A theoretical model was derived to predict the effect of variables on the system performance, which was validated through experimental testing. This system demonstrated a high dust clearing performance of over 95% when the dust is in direct contact with the Electrostatic Removal Device’s surface. However, the system was not able to achieve dust removal from samples of Nomex, Teflon, and Kevlar, the three constituent materials of the outer layer of spacesuits. Further development is required for the system to become a viable option for the removal of Martian dust from spacesuits. Nonetheless, this system may prove effective in other applications such as dust removal from solar panels or optical devices, where the electrodes may be able to be integrated directly beneath the dust layer.

Electro-optic solution to overcome the transient regime of a cavity dumped UV laser source?

Laser marking is one of the main industrial applications of lasers. To mark many materials or to obtain patterns of small dimensions, triggered pulsed solid laser sources are increasingly used emitting in the fundamental in the infrared and to which two nonlinear (NL) stages are added to obtain an emission in the UV. The conversion efficiency as well as that of the marking then depends mainly on the peak power of the UV pulses generated. One of the solutions for obtaining a higher peak power is to reduce the duration of the laser pulses. To do this, it is possible to change the architecture of the laser cavity by switching from a Q-Switch operating mode (QS) to a cavity dumped mode (CD). With this architecture it is thus possible to reduce the duration of the pulses by an order of magnitude. This peak power gain is unfortunately achieved at the cost of a very long transient regime, up to a few tens of milliseconds, compared to the classic QS which generally only occurs for the first laser pulse. Unfortunately, laser marking is by nature based on chopped operation for the laser, which corresponds to working permanently in a transient state. Marking with a CD architecture laser is then often full of defects and therefore unacceptable in terms of quality. After a study of the problem specific to the use of a UV source with CD architecture in the context of marking, we propose an original solution to dissociate the chopped regime, specific to marking, from the transient regime of the laser. This solution is based on the use of an RTP (Rubidium Titanyle Phosphate RTiOPO4) electro-optical crystal placed between the laser output and the NL stages. This crystal is driven like a half-wave plate by high voltage square pulses of a duration corresponding to the duration of the marking laser pulse trains. This thus makes it possible to obtain laser operation in a stabilized regime, therefore outside the transient regime, and simultaneously chopped operation characteristic of laser marking. The new operating mode obtained is characterized in detail with the new marking performances which prove to be optimal and compatible with the requirements of a quality marking. In addition to making the CD architecture compatible with laser marking, this solution also makes it possible to adjust the average power, and therefore the energy of the laser pulses to adapt it according to the materials and this without changing the thermal behavior of the laser. Last advantage, by adjusting the extinction voltage applied to the RTP outside the cavity, it is also possible to keep a few milliwatts of the marking laser beam as the aiming beam, with the certainty of perfect alignment with the full power beam.

Development of a Self-Coupling High-Voltage Square Waveform Pulse Transformer

Development of a Self-Coupling High-Voltage Square Waveform Pulse Transformer

Effect of pulsed electric field treated on quality of curd.

Pulsed electric field (PEF) is a potential pre-treatment technique to improve the quality of milk by reducing its microbial load. The present study aims at addressing this issue with respect to a popular fermented dairy product, that is, curd. Milk was treated with high voltage and frequency (55 kV and 90 Hz) square waves of pulse width 900 µs for 100 s. Curd samples were prepared with conventional heat treatment (CHT), PEF-treated milk subjected to CHT (PT-CHT), and PEF-treated milk (PT). PT samples resulted in curd with higher acidity (0.17 ± 0.005% LA) and microbial load (6.65 ± 0.27 log CFU/g), while the PT-CHT samples resulted in curd with better whey holding capacity. The firmness recorded for CHT, PT-CHT, and PT was 1.15 ± 0.05, 1.32 ± 0.04, and 0.91 ± 0.03 N, respectively. PT-CHT showed a higher viscosity index, that is, 0.207 ± 0.005 g. Sensorial properties showed the acidic nature of PT-curd with greater syneresis and softer texture resulted in its poorer sensory scores for texture. Shelf-life analysis showed no significant difference between curd prepared using the CH and PT-CHT up to 12 days. The study demonstrated the potential of employing PEF with CHT for improving the texture and shelf life of curd without impacting its quality.

Ionization wave propagation and cathode sheath formation due to surface dielectric-barrier discharge sustained in pulsed mode

This work deals with the experimental study of a surface dielectric-barrier discharge, as a part of the ongoing interest in the control of plasma induced electro-fluid dynamic effects (e.g. plasma actuators). The discharge is generated using a plasma reactor consisting of a fused silica plate which is sandwiched between two printed circuit boards where the electrodes are developed. The reactor is driven by narrow high voltage square pulses of asymmetric rising (25 ns) and falling (2.5 μs) parts, while the discharge evolution is considered in a temporarily and spatially resolved manner over these pulses. That is, conventional electrical and optical emission analyzes are combined with high resolution optical emission spectroscopy and ns-resolved imaging, unveiling main characteristics of the discharge with a special focus on its propagation along the dielectric-barrier surface. The voltage rising part leads to cathode-directed ionization waves, which propagate with a speed up to 105 m s−1. The voltage falling part leads to cathode sheath formation on the driven electrode. Τhe polarization of the dielectric barrier appears critical for the discharge dynamics.

Development of a High-Voltage Pulsed Electric Field Sterilization Power Supply Using a New Topology Circuit

Traditional thermal sterilization technology is easy to implement and safe, but it will destroy food nutrition and change food taste. Therefore, people began to turn their attention to non-thermal sterilization. High-voltage pulsed electric field sterilization technology is one of them; it has attracted much attention because of its high efficiency and little damage to food. Different types of loads will cause serious trailing of the pulse falling edge. In view of this situation, this paper proposes a new topology circuit that combines a solid-state switch with a half-bridge Marx generator. It can be used for high-voltage pulsed electric field sterilization. By improving the structure of the classical Marx circuit, the high-voltage pulse power supply of the new topology circuit has the characteristics of steep rising edge and short falling edge delay; does not require isolation inductance or isolation resistance, which solves the isolation problem between the DC charging power supply and the high-voltage terminal; and has a good voltage-clamping function and load adaptability. The working process of the topology circuit under resistive, capacitive and inductive loads and the voltage clamping effect when the solid-state switch does not work properly in the discharge process are analyzed in detail. The power supply is composed of an adjustable DC power supply, five-stage half-bridge Marx generator and control protection circuit. A field programmable gate array (FPGA) is used as the controller to generate control signals, and optical fiber isolation is used to provide control signals for the main loop. The power supply can output a high-voltage square wave pulse with a voltage amplitude of 10 kV, maximum pulse number of 1000 per second, maximum pulse width of 20 μs, pulse rise time of smaller than 300 ns and short pulse drop time, and the repeated voltage amplitude, frequency and pulse width are adjustable, which can meet the requirements of a high-voltage pulse sterilization experiment.

Ion Bunching in Square-Wave-Driven Mobility Capillary Electrophoresis-Mass Spectrometry.

The ion-bunching effect was typically produced for ion beams in the gas phase, such as in ion accelerators. In this work, ion bunching was generated for ions in a liquid channel, specifically in a mobility capillary electrophoresis-mass spectrometry (MCE-MS) setup. MCE was recently developed and coupled with MS for ion separation and the precise measurements of ion hydrodynamic radius and effective charge in solution. In conventional MCE, a DC high voltage is applied, which serves as the separation voltage. In this study, square waves were employed to replace this DC voltage, and the ion-bunching phenomenon was observed and characterized in both simulations and experiments. After applying a high voltage square wave, cations and anions would be bunched and concentrated at the positive and negative half cycle of the square wave, respectively. Accordingly, ion signal intensities detected by the following mass spectrometer could be increased by up to ∼50 folds for the aspartic acid anion. This square wave could also dissociate metal adduct cations from nucleic acid anions, which results in stronger nucleic acid ion intensities (up to ∼10 folds) with cleaner backgrounds.

Design and implementation of high voltage square wave power source with variable DC-offset and study its effect on atmospheric-pressure plasma

Design and implementation of high voltage square wave power source with variable DC-offset and study its effect on atmospheric-pressure plasma

Impact of pulsed electric field treated milk on quality of paneer and khoa.

The present work was undertaken to investigate the feasibility of pre-treatment of raw milk with Pulse Electric Field (PEF) treatment before its entry into the processing chain. A custom-designed and fabricated PEF applicator was used for the non-thermal treatment protocol. Raw milk was treated under three treatment protocols, viz., conventionally heat treatment (CHT), PEF treated milk subjected to conventional heat treatment (PT-CHT) and PEF treatment (PT). For the PT protocol, milk was subjected to high voltage (55 kV) square wave of pulse width 900 µs, for 100 s at a frequency of 90 Hz. The treated milk was then converted to two popular products, namely and paneer and khoa, which were evaluated for its physico-chemical, microbiological, sensory quality and shelf stability. Since khoa is a heat desiccated product, it was evaluated only against PT-CHT and CHT treatments. It was observed that PT treatment resulted in paneer with softer body with higher whiteness index, compared to other experimental samples. The PT treatment did not affect the product acceptability and the product had a shelf stability of 12 days under refrigeration, as against 16 days for CHT and PT-CHT treatment. The treatment protocols for milk did not significantly affect the quality and shelf life of khoa. Thus, there is wide future scope to used pulsed electric fields treatment synergistically with conventional heat treatment for inactivation of microorganisms, with better retention of nutritional and physical properties of product which has potential to save considerable amount of energy and time during processing of product.

Design and development of ultrasonic bipolar square-wave pulser for non-destructive testing of concrete structures.

This paper provides design and development details of the generation of bipolar High Voltage (HV) square wave pulses for the excitation of low frequency ultrasonic transducers. Such a circuit is required for the purpose of ultrasonic inspection of components, particularly where high energy is required to insonify the attenuative medium, such as concrete. A HV (±350 V) square wave pulse has been generated by an ultrafast complementary Metal Oxide Semiconductor Field-Effect Transistor (MOSFET) pair, which is driven by high speed MOSFET drivers. The generated bipolar square wave pulse has been utilized to energize a 108 kHz ultrasonic transducer to operate in the pulse-echo mode for the evaluation of a concrete test block. The receiver amplifier filters the received low-amplitude echo signals, which are reflected back from a discontinuity, and amplifies further for signal to noise ratio enhancement. The pulser board designed has been tested and evaluated for its functionality to measure ultrasonic velocity in the highly attenuative concrete medium up to a depth of 1 m. The measured value of acoustic velocity was compared with the value obtained from the commercially available ultrasonic pulse velocity instrument, and the values obtained are within ±5%.

Development of a Generator of High-Voltage Pulses Based on SOS-Diode and the High-Current Cold Thyratrons with the Auxiliary Glow Discharge for Feeding of Inflectors IC VEPP-5

An Injection Complex (IC) was designed in Budker Institute of Nuclear Physics in Novosibirsk in frame of a program of super high luminosity electron-positron facility VEPP-5. The stability of its operation is determined, among other things, by an injection-extraction system and, consequently, by generators of inflectors. For stable operation of the Injection Complex, these generators must produce pulses with maximum amplitudes of the output voltage of 50 kV and current in the load of the inflector 2 kA, the instability of the flat top less than 5% and its duration in the range from 20 to 92 ns; temporary stability of the generator should be ±2 ns and the output pulse’s front—less than 50 ns. In addition, it must be able to adjust the output voltage amplitude in the range of 10–100% [1]. This paper presents the results of the design sample of a generator of high-voltage nanosecond square pulses based on SOS-diode and the high-current cold cathode thyratrons (pseudospark switches).

A novel broadband capacitor voltage divider for measurement of ultrafast square high voltage pulse transmitted in transmission line

This paper studies a new type of broadband capacitive voltage divider, which is used to measure the high voltage square wave pulse with sub-nanosecond front in a transmission line. The low-frequency characteristics of traditional capacitive dividers are extended by adding sampling resistors, and the high-frequency gain caused by stray capacitors of sampling resistors is eliminated by adding compensation capacitors, which greatly broadens the bandwidth of capacitive dividers. The findings show that when the sampling resistance is 6.1 kΩ and 12 kΩ and the equivalent grounding capacitance is about 15 pF and 30 pF, respectively, the bandwidth of the divider is 180 kHz to 2 GHz and 100 kHz to 2 GHz, which can meet the test requirements of the high voltage square wave pulse with sub-nanosecond front and dozens of nanosecond pulse width.

Cascade volumetric acceleration of electrohydrodynamic flows

Method of cascade volumetric acceleration of electrohydrodynamic flows at atmospheric pressure air using high-voltage rectangular pulse generator was developed and investigated. The charged particles generated by dielectric barrier or corona discharge and accelerated by synchronizing the ion cloud movement with electric field change of the accelerating electrodes. To implement synchronous switching, a two-channel high-voltage square wave generator was used. It consists of 4 high-voltage switches combined in pairs in a half-bridge circuit and operates at frequency from 100 Hz to 100 kHz and voltage of up to 10 kV. Due to the controlled turning on and off of the switches, the minimum duration of high-voltage pulses is less than 200 ns. The generator is loaded with a two-phase multistage volumetric acceleration system of ion clouds.

Design of High-Voltage Square Pulse Generator Based on Cascade Switches and Time-Delay Driver

In the application of pulsed-power technology, capacitive loads require that high-voltage pulses have fast front and back edges. Using multiple semiconductor switches, insulated gate bipolar transistors (IGBTs) in series with discharge high-voltage capacitors can generate high-voltage pulses. By adding a group of truncation switches, square pulses with fast back edges can be obtained. A novel drive circuit using many transformers with their primary windings in series is proposed to generate two groups of reverse driving signals by changing the dotted terminals on the secondary sides. The dead time between these signals is realized by adding some time-delay circuits. In terms of drive control, both the discharging switches and the truncation switches are triggered synchronously since the primary windings of all transformers are connected in series, which ensures the synchronism of driving signals. Time-delay drive circuits are added to the secondary sides of transformers to ensure a proper dead time between the two groups of driving signals for both discharging and truncation switches. Moreover, all driving power is provided from the single driver on the primary side, greatly simplifying the drive circuit. The voltage balancing of cascade IGBTs is realized by using resistor–capacitor–diode (RCD) snubber circuits. Experiments were carried out over resistive and capacitive loads. Square pulses with a voltage amplitude of 10 kV, a pulsewidth of $8~\mu \text{s}$ , a rising time of 157 ns, and a falling time of 78 ns were obtained on a 20- $\text{k}\Omega $ resistive load. The voltage amplitude, pulsewidth, and frequency are continuously adjustable.

Development and Test of a 400-kV PFN Marx With Compactness and Rise Time Optimization

Repetitive high-voltage square pulses are of great importance for producing long-pulse electron beams and high-power microwaves. One of possible technologies for the generation of such pulses is a Marx generator using pulse forming network (PFN) stages, often combined with a pulse sharpening technique to reduce the rise time to a few nanoseconds (peaking stage). This paper presents an innovative design, named the “zigzag design,” for the optimization of the compactness and of the rise time of 400-kV–85-ns PFN-Marx. Thanks to this design, the 16 stages of this generator, which delivers an open circuit output voltage of 720 kV, fit in a 650-mm length. For a slightly overmatched load ( $Z_{\mathrm {load}} = 100 ~\Omega$ ), the output voltage reaches 400 kV with a rise time as less as 5 ns. The inductance reduction associated with the innovative zigzag design, which allows this sharp rise time with no need for a peaking stage, is described. The 85-ns plateau duration of the pulse is given by the PFN construction of each stage, which is based on six ceramic capacitors (2.1 nF–45 kV) connected within a strip line. The 16 PFN stages are housed in a 360-mm diameter gas pressurized vessel. Burst mode operation for a duration of 10 s at a pulse repetition frequency of 100 Hz is reported, for a resistive load and for the electron beam diode of a X-band relativistic backward-wave oscillator (BWO). To reach further compactness, the BWO system is integrated on side of the generator vessel and a U-shaped gas pressurized line connects both systems through a compact conical vacuum insulator.

SOIMUMPs micromirror scanner and its application in laser line generator

A SOIMUMPs 1-D rotation micromirror is presented. The micromirror is driven by electrostatic vertical comb-drive actuators to work at resonant mode to scan a laser beam. The residual stress in the metal film coated on the SOI device layer is used to generate vertical offset in the comb-drive actuators with the combs located far from the rotation axis to increase the torque. A concave lens is designed to put after the micromirror to amplify the laser beam scanning angle, as well as to compensate for the curvature of the micromirror. A micromirror-based scanning system is used to build a laser line generator with a continuously adjustable fan angle, which solves the limitation of a fixed fan angle in conventional laser line generators. Prototypes of the micromirror and the laser line generator are fabricated and measured. A driving circuit that can generate a high-voltage square wave driving signal with adjustable amplitude and frequency is designed. All the parts are integrated in a 44 mm×88 mm×44 mm box and powered with a single 5-V power supply. The optical scanning angle under 100 V with or without the concave lens is 27 deg and 12 deg, respectively, at a resonant frequency of 900 Hz.

Implementation of an Economical and Compact Single MOSFET High Voltage Pulse Generator

The high voltage load applications need very compact generators for the production of fast rising high voltage pulses and are invited in many applications including plasma soft X-ray, ion beam, PEF technology and microwave generators. From the right beginning several technologies have been introduced, Pulse Forming Networks, up to Marx generators. This paper also presents such type of square pulse generator based on power semiconductor device which simplifies the size of the conventional pulse generators. The high electric field intensity square pulses varying in magnitudes in the range of kilovolts with ms to µs pulse widths have been successfully used in many research fields. The advancements in power semiconductor devices, such as power MOSFETs, IGBTs are becoming most suitable for high switching speed high voltage pulse generators. These semiconductor devices are more reliable to control high voltages and currents when implemented in typical circuits. The voltage and current capabilities are increased by connecting the power switches in series and parallel respectively which need aided circuit for protection, equal voltage distributions. This paper presents the design and implementation of such a compact, portable high voltage µs pulse generator based on single power MOSFETs thus avoiding auxiliary circuits. A single CoolMOSTM RF Power MOSFET IXZR08N120B is selected as main switch in this work to produce the high voltage square pulses and is triggered using the suitable high-speed driver DEIC420 with low jitter at higher frequencies. The designed high voltage pulse generator which has variable pulse widths ranging from 2µs to 200μs with a variable pulse magnitude of 1kV is implemented in our laboratory. Keywords: CoolMOSTM Device, High Speed Driver DEIC420, Power Switch, Pulse Generator, RF Power MOSFET, Schmitt Trigger

A novel generator for high-voltage bipolar square pulses with applications in sterilization of microorganism

In this paper, we propose and design a novel generator for the high voltage square pulses with the changeable polarities in order to reach the requirements and the needs for the intended experiments on sterilization of microorganism. The major component of our circuits is a non-trivial combination between a half bridge Marx generator and an H bridge in series, combining with the DSP control unit, which can adjust the voltages, frequencies, pulse widths and polarities, and also tolerate various loads. More precisely, we illustrate the design and operation principles for each module in the constructed circuit and analyze the system performance with various loads. The effectiveness and correctness of our proposed circuit and methodologies have been verified and demonstrated by both PSIM simulation results and our own prototype. In this paper, we also show the stability and reliability of the pulse generator we proposed in terms of various load conditions and operation safety respectively. Furthermore, we also observe that the key parameters based on our constructed pulse generator can be easily adjusted which include voltages, frequencies, pulse widths and polarities. We hope that our work will stimulate the further investigations on design and analysis of pulse generators with a focus on modularization and miniaturization.

Square wave modulation of a mirror lens for ion isolation in a Fourier transform electrostatic linear ion trap mass spectrometer

Isolation of ions is a critical step in tandem mass spectrometry experiments. In electrostatic linear ion trap mass spectrometers, isolation is typically performed either using a timed ion selector, or by using a periodic electric field orthogonal to the axis of ion motion. In the latter case, the frequency of the field is matched to an ion of interest and the phase is such that the field is zero when the ions of interest are passing through the affected region. The periodic field method has the advantage that it is easier to isolate a single ion from a complex mixture. Here we describe an isolation method that produces essentially identical results to the orthogonal field method, but does not require the addition of any electrodes to the ion path. Instead, the periodic signal (a high voltage square wave) is applied to a lens that is a constituent of one of the ion mirrors. The square wave alters the energy of contaminant ions causing them to be lost from the trap. We demonstrate isolation of ions from a complex mixture using the square wave modulation technique. We also demonstrate an isolation resolution of 200 by isolating isotopes of a small molecule. We also characterize the performance of this method as a function of amplitude and time. An amplitude as low as 200V applied for 1ms can result in high-quality isolations using this method. We also discuss important considerations for those wishing to implement the method on other instruments.