Study On Key Technologies Of Plate PFN And Stacked Blumleins Based Long-pulse Power Generator

Long pulse production and time precise control are the new demands for the pulsed power generators(PPG) as the PPG driven high power microwave(HPM) is developing towards directions of long pulse and power combining. This dissertation presents a PPG technique routine based on stacked Blumlein lines and compact plate pulse forming network(PFN) with the advantages of long pulse production, precise control and compact construction. The key issues and key devices for the PPG technique routine are investigated and manufactured. Furthermore, the integration design and low voltage experiment for the PPG with 5 GW peak power and more than 150 ns pulse width are carried out. The detailed contents and innovative work are listed as follows.1. The short-circuit path and impedance increase method for the multiple gas switching stacked Blumlein lines are investigated. The existence of the short-circuit path is analyzed according to the circuit models. The equivalent model for the short-circuit path and impact on the output waveform are analyzed. In addition, the impedance increase method is investigated. The result shows that the choke scheme could increase the short-circuit impedance but not affect the triggering effect. Correspondingly, the impedance and permeability characteristics of the soft magnetic materials for the choke scheme are tested and analyzed.2. A multiplex solid-state high-voltage nanosecond trigger generator based on magnetic pulse compressor(MPC) is investigated and manufactured. Theoretical studies show that decreasing the relative jitter of the primary voltage and the first compression time are the practical and exclusive approaches to decrease to time jitter of the MPC. The drive circuit for the thyristors and thyristors closed transformer with fast risetime are constructed as the pre-boost circuit for MPC. The impact of the permeability on the maximum compression gain is analyzed and a three stages MPC is constructed. A 10 Hz repetition rate experiment is carried on the trigger generator. The results show that the trigger generator could produce four parallel high-voltage nanosecond pulses with the amplitude of 50.5 k V, the risetime of 25 ns and the pulse width of 60 ns. In addition, the time control parameters are tested with the delay of 8.329 μs, the dispersion time of 13.3 ns, the time jitter of 2.3 ns.3. A 100 k V Trigatron switch in tens of microseconds charging time is investigated and manufactured. Theoretical studies show that the field enhancement could improve the self-breakdown stability in tens of microseconds charging time but depress the trigger characteristics. Therefore, field enhancement factor should be set in a moderate value. Through simulation, the key parameters such as edge radius and the relative position of the trigger electrode are optimized. The self-breakdown and trigger experiments are carried out. The results show that the relative range of breakdown voltage is less than 6% under more than 4 atm and the trigger jitter in the range of 70%-90% of the self-breakdown voltage reaches to 2.1-0.8 ns.4. The compact plate PFN is investigated. Theoretical studies show that plate PFN could generate quasi-square wave with moderate rise time and flat top. Therefore, plate PFN could substitute the distributed parameter PFL and conventional PFN in 100-500 ns pulse production. The characteristics of commercial ceramic dielectric materials are analyzed and compared. The results show that N4700 medium is suitable for the storage capacitors in plate PFN. Correspondingly the endurance voltage and discharge tests of N4700 capacitors are carried out with 130 k V/65 μs impulse. The theoretical derivation and experimental verification for the characteristic parameters of L-C-L network structured plate PFN are carried. The results show that the mutual inductance from the adjacent electrodes has an import effect on the unit inductance and characteristic parameters.5. The integration design and low voltage experiment for the PPG are carried out. A four stages stacked Blumlein pulse generator with 5 GW output is designed. Meanwhile, the charging system is constructed with the risetime of 88 μs, the charging voltage of more than 150 k V. The control system is also debugged, with precise control of the time delay between the pulse charging and triggering. The experiments of two and four stages stacked Blumlein lines are carried out. The boost ratio is 1.89 and the pulse width is 188 ns in two stages stacked Blumlein lines. The boost ratio is 3.43 and the pulse width is 208 ns in four stages stacked Blumlein lines. The experimental results are analyzed. The unit inductance of the parallel layout plate PFNs is affected by the adjacent plate PFN, and the impedance and electrical length are increased as a result. Therefore, the boost efficiency is decreased and the pulse width becomes longer with the increase of stages. These results verified the feasibility of the technology routine.