Special AC Power Supply Design For Plasma Discharge & Study Of The Sterilization Experiment

The plasma excited by AC power supply has many advantages and it can work in a large range of air pressure and frequency parameters.Comparing with pulse pulse power supply,it has a large cost advantage,thus leading to its characteristics of irreplaceable in the discharge plasma.So the comprehensive research on the AC power supply and plasma is increasing.How to combine the design of power supply with the enhancement of plasma characteristics has become an important direction of plasma research and a difficult problem to be solved in industrial applications.Therefore,in order to have a further understanding of the influence of the parameters in the power supply on the discharge product,this paper developed an experimental high-voltage AC power supply,conducted the discharge test on the self-designed coaxial DBD device,and carried out relevant research.First,based on the UC3854 chip,the design of a regulated DC circuit is provided to provide a more stable DC voltage for the AC power supply,and to improve the higher-order harmonics of the input current,so that the power supply can be used for more powerful industrial applications.Medium,while reducing the cost of industrial applications.IGBT is used for inverter circuit design,KA962F driver chip is used for driver circuit design,and RCD absorption circuit is designed to suppress IGBT overvoltage.SG3525 chip is used for PWM circuit design,which can adjust a wide range of frequency and duty cycle.Secondly,experiment and analyze the design circuit.The output voltage of the DC voltage regulator circuit is 400V,and the voltage fluctuation is only about 4V,showing a relatively stable working state.Through the FFT analysis of the input terminal current waveform of different power sources such as traditional rectification,regulated power supply,board power supply and design circuit,the THD is 71.18%,28.44%,30.80%and 6.34%,respectively.In addition,the DC voltage regulator circuit does not change with the change of the input voltage.The change in the load size will not affect the voltage size,and the current will follow the power change.When testing the inverter circuit,the drive circuit realized high-speed driving with a rise time of 252ns and a fall time of 413ns.When the RCD circuit is tested under a 110V DC input voltage,the maximum overshoot voltage on one side is reduced from 36.1V to 13.6V,which has a significant suppression effect.In the experimental test of the whole machine,the load side can obtain an output voltage of 27.2k V peak-to-peak.By collecting the envelope of its high-frequency signal,it shows that the maximum voltage fluctuation is about 0.7k V.By conducting discharge tests at 4k Hz,6k Hz,12k Hz and 13.6k Hz,it is verified that the series resonant circuit has good frequency selection characteristics.Finally,the power supply system is used to drive the coaxial DBD discharge device to analyze the discharge effect and sterilized rules.By means of FTIR,we get three different modes according to different classification of products,including ozone mode,transition mode and nitrogen oxides mode.The sterilization results select the germination inhibition rate index as standard with the help of a microscope.Under the nitrogen oxides mode,the germination inhibition rate varies with the voltage rises,decreases with the increase of gas flow rate.The maximum average germination inhibition rate of 55.58%appear under the condition of 26 k V and 60 L/h.Combining the sterilization mechanism with the law of product,O₃ is the main sterilization material in the mode of ozone,the comprehensive effect of various oxides can sterilize under the nitrogen oxides mode.Besides,main sterilization material will change under different conditions.