Effects of Pulse Repetition Frequency and Voltage Slew Rate on The Uniformity of Air Dielectric Barrier Discharge

Abstract

To obtain uniform atmospheric pressure plasma in air, a nanosecond pulse power supply is used to excite a double layer dielectric barrier discharge (DBD) with indium tin oxide (ITO) glass as grounded electrode. The effects of pulse repetition frequency (PRF) and voltage slew rate on the discharge uniformity are investigated in the PRFs range of 500 Hz-11 <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$\mathbf{kHz}$</tex> and the rising edge time range of 50 ns-400 ns with fixed applied voltage amplitude. A digital image processing technique called the gray level histogram (GLH) is used to analyze the discharge images that are captured from the ITO glass side. The corresponding voltage-current waveforms are measured to assist in explaining the effect of the electrical parameters on the discharge uniformity. The findings demonstrate that the discharge is uniform when the PRF is less than 5 <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$\mathbf{kHz}$</tex> . The residual charged particles will cause the electrical field to degrade and the uniformity to diminish as the PRF increases. The electron avalanche merging and improved discharge uniformity are both facilitated by the rapid voltage slew rate, which can also increase the reduced electric field strength in space. Additionally, it is discovered that an increase in PRF would initially cause the peak values of the discharge current and gap voltage to increase (from 500 Hz to 3 <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$\mathbf{kHz}$</tex> ), followed by a reduction. The peak values of the discharge current and gap voltage fall as the voltage slew rate increases. These findings indicate that the reduced electric field strength and space charge, which may be used to measure the uniformity of air DBD, are affected by changes in the PRF and voltage slew rate.