Development Of A Bipolar Nanosecond Pulse Generator Based On Magneticpulse Compression And Its DBD Application

In recent years,non-equilibrium plasma at atmospheric pressure has attracted more attention because of its unique advantages.In order to study the characteristics and regularity of dielectric barrier discharge(DBD)under nanosecond bipolar pulse which can enrich the theoretical study of high frequency bipolar discharge,it is of great academic significance to develop a high voltage and high repetition rate bipolar nanosecond pulse generator.First,the principle of bipolar magnetic pulse compression(MPC)is explained,which is based on full bridge inverter circuit,pulse transformer,and magnetic switch,and the parameters of the system are calculated.According to the system design order,the parameters of the discharge circuit,which are composed of sharpening capacitor,saturation magnetic switch and load,are calculated.Based on the description of the skin effect of the pulse transformer winding,the suitable winding conductor is selected.The leakage inductance of three different winding structures is calculated,which is helpful to select the appropriate winding structure.The design of full bridge inverter circuit is related to the stability of the whole system,this paper describes the design and implementation of the discharge blocking RCD snubber circuit for IGBT protection.As for the design of magnetic switch,two kinds of materials with good performance at high frequency were measured using the single winding measurement method.Finally,the Co-based amorphous core is chosen as the magnetic switch.Secondly,this paper uses Model Editor in PSpice software to establish the measured magnetic core model,and studies the influence of the relevant circuit parameters on the output voltage waveform,especially the rise time.And some suggestions on the design of the magnetic compression system are presented.According to the simulation results and the measured waveforms,the leakage inductance of the transformer and the saturation magnetic switch inductance can be introduced.As a result,the nanosecond pulse generator produces a pulse on a resistor,with an amplitude of 5–13 kV,a rise time of approximately 100 ns,a repetition frequency of 0 to 10 kHz.Finally,this paper studies the plasma characteristics under high frequency bipolar pulse.The discharge process in a period is analyzed by measuring the current and voltage waveforms during discharge,and the discharge process is further verified by the Lissajous curves of discharge charge and voltage.At the same time,by the analysis of Lissajous curve,the equivalent capacitance of the DBD discharge model is obtained and compared with the theoretical value.In order to study the relationship between the discharge characteristics and frequency of DBD under high frequency bipolar pulse voltage,the relationship between the initial discharge voltage and the frequency is measured.Through the calculation and derivation of the DBD circuit,the regularity of the conduction current varying with the frequency is obtained,and the reasonable conjecture is given,which enrich the theory of high frequency discharge.