Compact High-voltage Pulse Generator Research Articles

Microcontroller‐based pulse signal controller development for compact high voltage pulse generator: Practical development in food treatment technology

The momentum of pulsed electric field (PEF) in maintaining food quality has increased due to its ability to treat food without the use of thermal elements. To achieve this, high pulse voltage must be used in conjunction with the pulse signal controller. Therefore, this paper presents the development of advanced pulse signal controllers using Arduino Uno. It can produce an adjustable pulse width from 63 ns (min) to 4 ms (max) along with an adjustable gap between pulses from 1 µs (min) to 10 s (max). A laboratory experiment was performed on a NaCl solution to record its performance in producing the desired pulse attribute. The results show that the pulse signal controller successfully delivers the intended pulse. A clean 4.25 A square pulse electric current was recorded in the absence of abnormal effects. This proves that the proposed method works as expected and also proves the concept presented. Practical applications The practical application of this research is more to the development of advanced electroporators that can meet current demand. It can produce pulses as low as 63 ns to 4 ms (maximum). By using the microcontroller available in the local market, it can reduce development costs while providing a reliable pulse. In addition, the pulse generated is also TTL and CMOS compatible and makes it useful for driving any digital switching device such as MOSFET and IGBT. Extensive applications are not limited to PEF, but also other pulse applications. Therefore, this study is very worthwhile to be implemented and commercialized besides being able to produce PEF treatment technology that is cheap, reliable, and robust.

Compact High-Voltage Pulse Generator for Pulsed Electric Field Applications: Lab-Scale Development

Square wave pulses have been identified as more lethal compared to exponential decay pulses in PEF applications. This is because of the on-time which is longer causes a formidable impact on the microorganisms in the food media. To have a reliable high-voltage pulse generator, a technique of capacitor discharge was employed. Four units of capacitor rated 100 μF 1.2 kV were connected in series to produce 25 μF 4.8 kV which were used to store the energy of approximately 200 J. The energy stored was discharged via HTS 181-01-C to the load in the range of nano to microseconds of pulse duration. The maximum voltage applied was limited to 4 kV because it is a lab-scale project. The electrical circuit diagram and the development procedure, as well as experimental results, are presented.

A Nanosecond High-Voltage Pulse Generator Based on Artificial Double Forming Lines

The results of experimental studies of a compact high-voltage pulse generator are presented. The generator is based on two artificial double forming lines in a collapsed circuit, which are switched by gas spark gaps; it also contains a peaking gas spark gap, transmission lines filled with a liquid dielectric, and a load equivalent. The characteristics of this generator were studied in the charging-voltage range of up to 100 kV. When the voltage pulse duration from the forming line was 100 ns, current pulses with an amplitude of 18 kA and a rise time of ~18 ns were obtained across an ohmic load.

Design of a High Voltage Pulse Generator with Large Width Adjusting Range for Tumor Treatment

The unique biological effects stimulated by short pulsed electric field have many applications in tumor treatment, such as irreversible electroporation, electrochemotherapy, gene transfection and immune therapy. These biological effects require high voltage pulses with different pulse width in the range from nanoseconds to hundreds of microseconds. To fulfill this requirement, a compact high voltage pulse generator has been designed based on a switchable capacitor array and a SiC MOSFET switching array. The proposed pulse generator has one output channel with an adjustable pulse width from 100 ns to 100 µs, an amplitude range from 0 kV to 2 kV, a repetition rate less than 1.2 kHz and a voltage drop less than 5%. The mechanism of the stacked switches circuit was investigated, in connection with a switchable capacitor array. The introduction of a switchable capacitor array extends the pulse width from nanosecond scale and microsecond scale compared with other similar design methods. The pulse generator has been designed in simulation and implemented in experiment. The developed pulse generator provides a convenient and economical tool for the further studies of the unique biological effects stimulated by different pulsed electric fields for tumor treatment.

A Digital Controlled Pulse Generator for a Possible Tumor Therapy Combining Irreversible Electroporation With Nanosecond Pulse Stimulation.

The irreversible electroporation with microsecond electric pulses is a new ablation technique adopted in the tumor therapy worldwide. On the other hand, the nsPEF (nanosecond pulsed electric field) has been proved to provide a means to induce immunogenic cell death and elicits antitumor immunity, which is under intensive in-vitro and in-vivo studies and in clinical trials. Normally, one needs two different types of electric pulse generators for producing the pulses in the ranges of nanosecond and microsecond, respectively. In order to realize these two types of tumor treatments in complementary and optimize electrical pulse parameters, we have developed a compact high-voltage pulse generator with a wide pulse width tuning range, based on a capacitor discharging configuration digitally controlled by a silicon carbide MOSFET switching array through a pair of optic-coupler drivers. The developed digital pulse generator is capable of adjusting: pulse width over 100-100μs, voltage over 0-2kV and repetition rate up to 1.2 kHz. The pulse generator is designed in simulation, implemented and verified in experiments. The pulse generator is shown to deliver a complementary treatment on Murine melanoma B16 cell lines, i.e., triggering the cell early apoptosis under the 300ns pulse stimulation while a complete killing under the 100ns pulses. The pulse generator is further demonstrated to induce antitumor immunity in a preliminary in vivo study on the mice model.

A control unit of the cold-cathode thyratron with a high pulse repetition rate

A compact high-voltage pulse generator is designed for control of TDI thyratrons in grounded-cathode thyratron-switching circuits. The unit is the part of the pulse voltage generator for charging a double forming line of the frequency electron accelerator. The unit is controlled from the GZI-6 external generator with a maximal repetition rate of 50 s−1. The unit produces negative-polarity firing voltage pulses with a ∼18-kV/μs rate of pulse rise and allows one to fire simultaneously two TDI4-100k/75PD thyratrons. The scatter of amplitudes of currents of thyratrons, connected in parallel without additional current-dividing circuits, does not exceed 1%. The efficiency factor of the control unit is approximately 85%. The active elements of the control unit are the thyristor and the TGI-500/16 low-power pulse hydrogen thyratron.

A compact high-voltage pulse generator with opening insulated-gate bipolar transistor switch and a high pulse repetition rate

A small-size high-voltage (∼20 kV) microsecond pulse generator, which is based on a pulse transformer and loaded into a reactor with a pulse corona discharge, is described. Insulated-gate bipolar transistors (IGBTs) that form the switch are used in the low-voltage circuit of the generator. When the switch is open, voltage pulses with an amplitude of up to 1000 V are created across it and, hence, across the primary winding of the transformer. The pulse repetition rate of the generator is ∼20000 pulses/s.

A compact high-voltage pulse generator based on pulse transformer with closed magnetic core

A compact high-voltage nanosecond pulse generator, based on a pulse transformer with a closed magnetic core, is presented in this paper. The pulse generator consists of a miniaturized pulse transformer, a curled parallel strip pulse forming line (PFL), a spark gap, and a matched load. The innovative design is characterized by the compact structure of the transformer and the curled strip PFL. A new structure of transformer windings was designed to keep good insulation and decrease distributed capacitance between turns of windings. A three-copper-strip structure was adopted to avoid asymmetric coupling of the curled strip PFL. When the 31 microF primary capacitor is charged to 2 kV, the pulse transformer can charge the PFL to 165 kV, and the 3.5 ohm matched load can deliver a high-voltage pulse with a duration of 9 ns, amplitude of 84 kV, and rise time of 5.1 ns. When the load is changed to 50 ohms, the output peak voltage of the generator can be 165 kV, the full width at half maximum is 68 ns, and the rise time is 6.5 ns.

A Compact High-Voltage Pulse Generator for Plasma Applications

The design and construction of a compact high-voltage pulse generator for providing input electron beam power for the LAP/INPE 32 GHz gyrotron and for treatment of metal and polymer materials by plasma immersion ion implantation (PIII) are described. The generator was built on a circuit category of Pulse Forming Network (PFN), consisting of nine LC sections with L = 270 μH and C = 2.5 nF. The instrument was designed to produce a flat 30 kV, several Amps pulse in 15 μs pulse length with pulse repetition frequency (PRF) of 8 to 100 Hz. By means of a resonant charging inductance it is possible to gain an output voltage with a factor of 1.8 higher than the voltage supplied by the pulse generator. The generator is fed with sine-wave, constant current source, and a 60 kV, 15 mA switching power supply.