Magnetic Compression Circuit Research Articles

Simplified High-Voltage Short-Pulse Power Modulator for DBD Plasma Application

Dielectric barrier discharge (DBD)-based plasma reactor and lamp are widely used for the growing areas of medical science, bacterial disinfection, pollution control, surface treatment, and so on. In this article, a simplified high-frequency, high-voltage short-pulse power modulator (HV-SPPM) is proposed for DBD plasma sources that are effectively capacitive loads. An energy discharge circuit (EDC) has been devised in the HV-SPPM to terminate the high-voltage pulses increase indefinitely for a capacitive load, which causes damage to the pulse power modulator. The HV-SPPM is using a wide bandgap (WBG) device without having a dissipative snubber circuit on primary side and magnetic compression circuit. The performance of the HV-SPPM has been validated experimentally by using a suitable DBD plasma-UV load. In the proposed HV-SPPM, a series diode with resistor has been introduced across the DBD plasma-UV lamp to damp out the sinusoidal oscillations between DBD capacitance and leakage inductance of the transformer. The HV-SPPM is capable to generate negative voltage pulses up to 6 kV and pulse width 800 ns with frequency variation up to 50 kHz. The proposed arrangement makes the HV-SPPM more compact, lightweight, simple, and highly efficient with very short rise and fall times voltage pulses suitable for the DBD plasma applications.

High voltage pulse generation using magnetic pulse compression

Abstract The paper presents an overview of a method of nanosecond-scale high voltage pulse generation using magnetic compression circuits. High voltage (up to 18 kV) short pulses (up to 1.4 μs) were used for Pulsed Corona Discharge generation. In addition, the control signal of parallel connection of IGBT and MOSFET power transistor influence on system losses is discussed. For a given system topology, an influence of core losses on overall pulse generator efficiency is analysed.

A Compact Repetitive Unipolar Nanosecond-Pulse Generator for Dielectric Barrier Discharge Application

Dielectric barrier discharge excitated by pulsed power is a promising approach for producing nonthermal plasma at atmospheric pressure, but pulsed power generators vary widely in performance and should be chosen according to application requirements. In this paper, a repetitive unipolar nanosecond-pulse generator is constructed using resonant charging and one-stage magnetic compression circuits, where IGBT and magnetic switches are the key units, respectively. The generator is capable of providing repetitive pulses with a voltage of up to 30 kV and duration of 70 ns at a 300 resistive load. Output pulse voltage can be adjusted by varying ac input voltage or trigger pulse-width. This compact and convenient generator has been used successfully to produce stable dielectric barrier discharge.

Inactivation of Bucillus Stearothermophilus by pulsed electric field

B. Stearothermophilus remains alive even under intense electric field, since spores formed are highly resistant to damage from electric field effects. This paper describes the effects of pulsed electric field on B. Stearothermophilus (ATCC no, 12980). An aqueous suspension of B. Stearothermophilus spores was placed between parallel planar electrodes and subjected to pulsed electric fields of up to 189 kV/cm, which are obtained from a high-voltage pulsed voltage generator. Either a Blumlein generator or a magnetic compression circuit with a semiconductor opening switch was used as the pulsed voltage generator. The spores that survived the treatment were detected by a colony counting method. The growth activities were measured using a microbial calorimetry technique. The temperature and pH of the spore suspension remained unchanged during the treatment. It was found that the growth activity of B. Stearothermophilus was affected by the pulsed electric field. while no remarkable lethal effect was observed in the range of up to 40 kV/cm.