Development Of Repetitive Frequency Bipolar Marx Pulse Generator And Study On Plasma Jet Characteristics

With the continuous development of plasma technology,the application fields of atmospheric pressure and normal temperature plasma are expanding,such as surface modification of materials,biomedicine and environmental treatment.The plasma jet has greater utility in the plasma generation mode because of the separation of its discharge region from the working region.In plasma jets,the pulse generator as an excitation source to excite the plasma has its unique advantages.In order to study the characteristics of atmospheric pressure plasma jet at normal temperature,it is necessary to develop a pulse generator for related experiments.At present,the solid-state switch of the pulse generator has the advantages of compact structure,simple control and long life compared with the conventional spark switch,so the all-solid pulse generator has significant advantages.In this paper,a new type of bipolar Marx high-repetition pulse generator is developed based on the requirements of atmospheric pressure plasma jet and the structure of Marx pulse generator,and it is applied to plasma jet experimental research.In this paper,the circuit topology of a novel bipolar Marx high-repetition pulse generator is proposed based on the Marx pulse generator.The working principle of the pulse generator is analyzed,and the circuit simulation model is built in the PSpice simulation software.The feasibility of the circuit topology of the pulse generator is verified by a simulation model.After calculation and simulation,it is proved that the stray inductance and capacitance are related to the rising edge of the output waveform of the pulse generator and the waveform oscillation.Then,according to the design parameters and principles of the pulse generator,key components such as solid state switches,storage capacitors,and fast recovery isolation diodes are selected.The driving circuit of MOSFET is designed,and the high and low voltage isolation module and driver chip in the circuit are selected.The 40-channel control circuit board is designed based on FPGA and electro-optical conversion circuit,and the integrated modular design improves the resistance of low voltage signal.Interference ability.Finally,the performance test of the bipolar Marx high-repetition pulse generator was carried out.The parameters of the output pulse after the pulse generator test were: repetition frequency 1kHz,pulse width 200ns-10?s,pulse amplitude ±5kV The rise time is 100 ns and the fall time is 80 ns.Due to the voltage tolerance of the device and the single-phase flow limitation of the diode,the bipolar Marx high-repetition pulse generator cannot achieve the originally designed voltage amplitude parameter,rise and fall time adjustment and tail cut function.Therefore,based on the bipolar Marx high-repetition pulse generator,a bipolar Marx high-repetition pulse generator based on matrix control is improved.The circuit topology feasibility of the pulse generator is analyzed,and the circuit simulation model is established.The simulation verification circuit can realize the voltage amplitude,pulse width,repetition frequency,rise and fall time adjustment and tail cutting function.Inductance is used to isolate the bipolar Marx high-repetition pulse generator based on matrix control,so the core of the inductor is selected and calculated.Then the pulse generator prototype is tested.When the pulse generator is superimposed at 10 levels,the parameters of the output pulse are: the maximum pulse output amplitude is ±9kV,and the highest repetition frequency is 1kHz,which can realize the rise time of the output pulse.Flexible adjustment with fall time.Finally,the experimental study of atmospheric pressure and normal temperature plasma jet using bipolar Marx high-repetition pulse generator as excitation source was carried out.Exploring the factors affecting the length of the plasma jet lays the foundation for the application of plasma jets.It was verified that the bipolar Marx high-repetition pulse generator can meet the needs of further research on plasma jets.The re-frequency bipolar pulse generator designed in this paper has high output voltage and wide output pulse width,and reduces the requirements for isolated power modules.It is compact in structure,flexible in multi-parameters,and has tail-cut function.It has a good application prospect in the study of atmospheric pressure plasma jet at normal temperature.