Research On High-voltage Nanosecond Pulse Generator Based On Air-core Tesla Transformer

Nanosecond fast pulse sources with output voltages of several kilovolts and power GW levels have a wide range of applications,such as driving electron beam diodes to generate high-current pulsed electron beams for high-power microwave technology research;bombarding anodes with generated electron beams Z target,producing(sub-)seconds of high-energy X-rays for radiographic,deep-penetrating,industrial non-destructive testing or time-response calibration of nuclear detectors for transient physical processes;they can also be applied to biological and medical fields.In this paper,the compact high-pressure nanosecond pulse generation technology is studied by using the technique of "air core Tesla transformer+pulse-forming line(PFL)".The working principle of the air-core Tesla transformer and the coaxial PFL was analyzed through theoretical calculations.The approximate expression of the output voltage of the Tesla transformer under ideal conditions was obtained.The key factors affecting the output voltage waveform and the PFL were differently simulated by the PSpice software.Maxwell's electromagnetic field simulation optimizes the design configuration of the air-core Tesla transformer and calculates the equivalent capacitance of the secondary winding of the transformer;through the pressure equalizing ring design,the electric field distribution of the PFL and the high voltage output end of the transformer is optimized.The Maxwell software is used to perform 3D simulation on the optimized PFL to obtain the surface field intensity distribution and equivalent capacitance when the PFL is considered in the boundary.Based on the above theoretical analysis and simulation design,a high pressure nanosecond pulse generator based on an air-core Tesla transformer was developed.The device consists of a primary energy source,an air-core Tesla transformer,a nanosecond PFL,and a high pressure gas spark switch.The device(excluding the primary energy source)weighs 24.9 kG and has a maximum diameter of 280 mm and a length of 700 mm.The experiments show that,when the primary capacitor of 40 nF is fired at 20 kV,the peak voltage on the PFL is as high as 500 kV,generating a pulse with peak voltage of 390 kV,half high width of 1.8 ns and peak power of 1.52 GW on a 100 ohm resistor.