Development Of Nanosecond Pulse Generator Based On Blumlein Transmission Line

Pulse power technology not only plays more and more important role in military and high-tech research, but also exhibit good application potential in many fields,such as industry, biomedicine and environment protection and so on. But so far, there is no one commercial nanosecond pulse generator. Therefore, it has vital scientific significance and the application value to develop nanosecond pulse generator with high performance. This thesis developed a nanosecond pulse generator based on blumlein transmission line according to pulse power technology and the spark switch technologyThe principle that Blumlein transmission line generates high-voltage pulse was analyzed theoretically from the view of points of transmission of electromagnetic wave and its equivalent circuit. The circuit simulation result with software Pspice validates the theoretical analysis. The influence of stray parameters in Blumlein-type pulse generator on the output pulse was also simulated. The results have show that stray inductance in discharge loop, stray capacitance between the two terminals of load and the stray capacitance between the front end of load and the earth slow the rise rate of front edge and fall rate of back edge, and the rise time and fall time are approximately in direct proportion to the stray parameters. The stray resistance in discharge loop leads to fall step by step at the end of pulse. The stray inductance in output loop results in overshoots at the front and back edge. Although the stray capacitance between the back end of load and the earth can also cause overshoot at the rise edge of pulse, the back edge of pulse is distorted and the fall time increases greatly. The simulation provides reference for the development of pulse generator and improving the rise edge of pulse.The air pressure, gap distance, field type and electrode structure of field distortion spark switch were studied in detail. Reasonable insulation structure reduced the size of the switch. The field distribution in the gap was simulated with software Femlab, and the result validates the rationality of electrical design. The characteristic of the switch were calculated theoretically. The switch was design concretely in mechanical size and then machined. The experiments were carried out to study the influence of working voltage ratio and triggering voltage on breakdown time delay as well as its jitter. The triggering range and triggering threshold were also studied. The experimental results indicated that the time delay was less than 100ns and jitter less than 10ns when the air pressure less than 2atm, voltage ratio larger than 80% and triggering voltage larger than 15kV. Moreover, the triggering range was larger than 55% and triggering threshold less than 10kV. The experimental results indicated that the switch can meet the design demand.In the last part, the design of each part of the Blumlein-type nanosecond pulse generator and the prototypical assembly were completed. The components were selected and their parameters were calculated. A resistor divider for measuring triggering voltage and its corresponding pulse source for step response experiment of divider were designed. The Blumlein-type nanosecond pulse generator was debugged overall and the output waveform was measured in laboratory. The result shows the equipment can satisfy the design requirements, which indicates the equipment lays a foundation for practical application.