Repetition Frequency Sub-microsecond Uniform Pulse Power Source Of The Atmospheric Air Discharge Characteristic Research

Gas discharge plasma has been widely applied to some important industry field as environment pollution improving, materials modification, microelectronics industry, deposition and etching, plasma display panel. A homogeneous dielectric barrier discharge could be achieved in the atmosphere open air using a repetitive high voltage narrow pulse power source. The plasma is far from the balanceable state so much more particles with active chemical character and higher energy will be generated. The local over exothermic problems induced by temperature increasing which often existed in traditional continuous power system with high frequency or radio frequency has been efficiently solved using pulsed discharge. It has important industry application value for the excellence of convenient operating, simple configuration and needless of assistant special gas.Effects of leakage magnetic inductance and distributing capacitance of the pulse transformer, charging circuit and the capacitance of DC high voltage source upon output wave shape has been studied with circuit simulation software. Also, testing and measurement have been done for the repetitive high voltage narrow pulse modulator.80kV amplitude of the voltage was acquired using a load resistance with its value1.2kΩ. The pulse width was230ns with a rise time of124ns and the frequency can be adjusting from130Hz to998Hz continuously. The amplitude of the repetitive voltage fluctuates at the rate of5%to10%.An experimental device used to research the DBD (Dielectric Barrier Discharge, DBD) plasma characteristics excited by sub-microsecond pulse power in atmosphere air has been founded. Glass, PTFE (Polytetrafluoroethene) and plexiglass have been made use of the dielectric barrier materials. Homogeneous discharge has been obtained around130mm diameter area in atmosphere air using the three dielectric materials with gap distance at4.5mm,6.5mm and6.5mm respectively. There isn’t any filamentary discharge discovered by naked eyes or by camera with time of exposure at0.25s. Parameters such as gas gap voltage, discharge current, discharge power density and so on, has been calculated using Liu and Neiger’s equivalent circuit model for DBD, and these parameters were applied to study the DBD characteristics excited by sub-microsecond pulse power. The rate of electric change is determined by pulse amplitude and rise time of applied voltage, species and thickness of dielectric barrier, distance of gas gap and some other conditions. Effects of applied parameters onto discharge electrical characteristics and homogeneity of discharge will be studied by the way analyzing the effects of applied parameters onto the rate of electric change.Emission spectrums of plasma under different amplitude of applied voltages were measured by spectrometer. Rotational, vibrational temperature and also their changing rule following applied voltages were obtained by analyzing the emission spectrum. It is as basic works for a better understanding of the characteristics for atmosphere air DBD plasma excited by sub-microsecond pulse power.There are many advantages for the polymer film processing using plasma excited by pulse power in atmosphere air. Preliminary polymer film processing experiments and analysis for PTFE has been done adopting homogeneous DBD plasma excited sub-microsecond pulse. It is as a basic work for industry application.A electron avalanche model based on streamer discharge mechanism has been established in the work of this paper.Character of the electron avalanche development and the applied electric field influenced by the space charge field will be calculated and analyzed. The homogeneity of discharge influenced by electric field change rate will be stated through calculating the effects between electron avalanches with different initialization time.