Wide Flat-topped High-voltage, Long Pulse Forming

Pulse Forming Network (PFN) is the best choice to produce long duration voltage pulse as well as current up to a few kilo-amperes. In this article, PFNs based on Blumlein and Marx structures are introduced , and the deviations of components which can affect the output waveforms are also studied. Some expected results are derived by experiments too.By studying the characteristics of PFNs, the influence of the parameters on output impedance and pulse duration are clarified.Numerical simulations show that when the components deviations are less than 5% , the deviations can be neglected. The inner inductor of capacitor would introduce worse effects on pulse top. So, it is better to choose low inner inductor capacitors. The inductor introduced by line of earthing contributes more influence on Blumlein structure than on Marx structure. Deviations of inductors provide much more influence than deviations of capacitors.Devices are designed according to the simulation. A PFN device based on Blumlein structure was built which can generate a long pulse with 3 s flat-top. With Blumlein structure and 12Q load, the PFN can produce a pulse with equal voltage to charged voltage and more than 3kA pulse current. The results of the experiment show that the PFN works smoothly and the rips of the top of pulse are less than ?%. Another PFN device based on Marx structure was also built which can generate a long pulse with 3jJ,s flat-top. With Marx structure and matched load, the PFN can produce a pulse with enhanced voltage equal to N/2 charged one. The experiment results show that the PFN works smoothly and the rips of the top of pulse are less than +1%.