Establishing an Equivalent Circuit of a Quasihomogeneous Discharge Atmospheric-Pressure Plasma Jet with a Breakdown-Voltage-Controlled Breaker and Power-Supply Circuit

To simulate the I-V diagram of plasma homogeneous and filamentary discharge with equivalent circuit model more accurately, this study employed a breaker and passive circuit components and calculated the discharge parameters, such as equivalent discharge resistances and potential distribution etc., in atmospheric-pressure plasma jet (APPJ). In addition, this study calculated the gas-gap and dielectric capacitances of the APPJ and added a power supply equivalent circuit. Compared with other circuit models that adopted switches or a time-controlled current source to simulate the discharges, our present circuit model used a breakdown-voltage-controlled breaker for the homogeneous discharge and resistors with high-frequency switches for the filamentary discharge. We employed potential simulation to obtain the equivalent dielectric capacitance in the APPJ and then derived the gas-gap capacitance. We also replaced the ideal sine wave power supply with the equivalent circuit of the common double-peak-waveform power supply. The MATLAB Simulink was used to construct an equivalent circuit model and the discharge area ratio, breakdown voltage and filamentary equivalent resistance were obtained via I-V waveform fitting. We measured the plasma I-V waveform with a 20-kHz frequency, various voltages (6, 12, and 15 kV), a gas flow rate of 30 SLM, and two types of gas (Ar and He). The simulated and experimental I-V waveforms were very close under different conditions. In summary, the proposed equivalent circuit model more meaningfully describes the plasma physics to simulate homogenous and filamentary discharge, achieving results that were compatible with our experimental observations. The findings can help with investigating plasma discharge mechanisms and full-model simulations of plasma.