Study On The Compact Pulse Forming Network

Pulsed power technology has been widely used in the field of national economy and national defense technology,and is developing rapidly under the strong demand for traction.Due to the actual need,such as portable,high-power pulse source is developing in the direction of the compact and miniaturization,and miniturization of the pulse forming device can realize to a large extent the miniaturization of high-power pulse source.Therefore,I intend to study the compact structure of the PFN(Pulse Forming Network)to satisfy the demands of the compact and miniature high-power pulse source.Firstly,the working principle of single-line type and Blumlein type PFN were analyzed by the method of wave process.Then,in the case of considering the mutual inductance,the linear,L and U1 connecting structures of the PFN were simulated by PSpice software.At the same time,the three-dimensional models of five different connecting structures of PFN were established and simulated with the transient field-circuit synchronous collaborative simulation methodology,and its experiment were carried out.The experimental results showed that the rise time of PFNs with the five different connecting structures was about 45 ns,and its half-high widths were 175 ns,170 ns,166 ns,158 ns and 154 ns,respectively.But the flat-tops of the output waveform were more fluctuant,the maximum fluctuation were 9.8%,13.3%and 18.9%of the flat top of the linear-type PFN’s output pulse.The optimal design of U1-type PFN was studied with the transient field-circuit synchronous collaborative simulation methodology.The simulation results showed that the maximum fluctuation at the top can be reduced from 21.2%to 5.3%by adding the shield and increasing the inductance value of the 6th network.The optimized output waveform of the U1-type PFN can meet the requirements of the high-power pulse source.Secondly,the effect of the parasitic parameters of the components on the quality of PFN’s output waveform and energy transfer efficiency of PFN were analyzed.The parasitic parameters of the components in the PFN include the inductance of the switching and load,the resistors of the inter-stage inductance,and the ESL and ESR of the capacitors.In order to clarify the effect of the parasitic parameters of the components on the quality of PFN’s output waveform and energy transfer efficiency of PFN,control variable method was used.The followed results were obtained:the introduction of any parasitic parameter would change the discharge waveforrm of PFN,at the same time,with the reduction of energy transfer efficiency.The rise time and the pulse half-high width of PFN was mainly determined by the L,and the ESL,ESR and RL were the secondary factors.The RL would decrease the amplitude of the top of the pulse waveform and increase the tail of the main pulse.At the same time,the ESL would cause the pulse waveform to produce overshoot,while the ESR and RL was conducive to reduce the anti-peak coefficient.From the energy point of view,the RL was the most important factor in reducing the energy transfer efficiency.The ESL and ESR were the secondary factors.The L was the smallest factor,and could be ignored.Finally,the linear,L,S1,S2,Ul,U2 and U3 connecting structures of the PFN based on MLCC were designed.The three-dimensional models of seven different connecting structures of PFN were established and simulated with the transient field-circuit synchronous collaborative simulation methodology,and the energy of three U-type PFNs’s main pluse were calculated.The result showed that the energy of the U3-type PFN’s main pulse was the largest,and the energy of the U2-type PFN’s main pulse was the second,and the energy of the U1-type PFN’s main pulse was the smallest.Seven different connecting structures of the PFN based on MLCC were produced and experimented,and the experimental results showed that its top voltage were 13 V,which was 86.7%of the theoretical voltage.At the same time,the resistors of the inter-stage inductance decreased the amplitude of the top of the linear-type,L-type,S1-type and S2-type PFNs’s pulse waveform.Since the resistors of the SI-type and S2-type PFNs were larger than that of the linear-type and L-type PFNs,the amplitude of its top were more serious.In addition,the energy of three U-type PFNs’s main pluse were calculated,and the order of its energy were consistent with the simulation results.Besides,the reason why the simulation results of U2-type and U3-type PFNs were inconsistent with its experimental results were analysed.When the simulation models adjusted were the same as the experimental models,the simulated waveforms could basically predict the experimental waveforms.The above results showed that the effect of the shield on the energy of U1-type PFN’s main pulse was stronger than that caused by the loss,and the feasibility of optimizing the U-type PFN’s output pulse waveform by adding the shield was preliminarily verified.