Research On The Electro-explosive Plasma Switch Applied For Explosive Foil Initiator

Pulse power switch is a key device of exploding foil initiator system(EFIS).The switch,which including characteristics of high conductivity current,high switching speed,low inductance and low resistance,need to develop urgently.Although the traditional cathode vacuum switch can meet the electrical performance requirements of EFI,the high cost and low environmental adaptability of the switch can't meet the requirements of miniaturization and anti-impact of EFI.Development of switch with solid state,miniaturization and low-cost has become the key of the new generation EFI.The paper produced planar electro-explosive switch and one-shot switch of Schottky Barrier Diode(SBD)by MEMS.The design and integration methods,characteristics and trigger mechanism of the two switches have been studied.On the basis of planar electro-explosive switch of copper film,the Al/CuO multilayer film was deposited on the bridge area of trigger electrode to improve the performance of the switch.The software was used to optimize the switch electrode structure.The planar electro-explosive switches with different structure had been compared between constraint and no-constraint state.When the charging voltage is 1500 V,the peak current without constraint is 1142 A,which is 52.8%higher than that of the restraint state,The Al/CuO multilayer film can improve the current amplitude in the constraint state within a certain voltage range.The structure of the composite film had no significant effect on the peak current without the constraint.Through the direct fabrication of one-shot switch on the ceramic substrate,the preparation process had been simplified.Based on the experimental study of the characteristic of SBD electric explosion such as plasma charge flux,electron temperature and density,the trigger polarity effect of one-shot switch was analyzed.The results showed that there were four types of connections among SBD,top electrode and discharge capacitor.Type P.that anode of SBD contacted with the top electrode and cathode of SBD contacted with positive of capacitor would make it easier to turn on the switch.By the experiment of the one-shot switch,the influence on the characteristics of the switch was studied,including the dielectric material,the main voltage,the packaging material and the trigger diode.The results showed that the parylene C film as the dielectric material layer was better than that of polyimide(PI)film.The switch performance with different capsulation materials was that AB glue>HTPB rubber>704 glue.The peak current of switch was greater with larger SBD.When the charging voltage is 1400 V,the peak current of the one-shot switch is 1020 A.The peak current and resistance of the switch are related with main voltage,but there is no significant relationship among the rise time,inductance and main voltage.The peak current shows an increasing trend with improving the applied voltage.The influence of the trigger capacitor,different types of diodes on one-shot switch was analyzed.To ensure the switch act,trigger capacitor must offer a large enough current to generate sufficient initial plasma.As a trigger element SBD has a better effect than the PN junction diode.The change of arc temperature during the switching process was analyzed by using the method of the atomic emission spectroscopy double line technique.The results showed that the switch worked when the arc temperature was under the melting point of the tungsten.On the other hand,the switch ran out when the arc temperature was too high to induce the ablation of the switch electrode.The shock pressure of SBD electro-explosive was tested by Polyvinylidene Fluoride(PVDF)film.The process of shock pressure during SBD electrical explosion was obtained.By comparing with the dielectric yield strength,testing of SBD electro-explosive shock pressure can be used to judge the trigger condition of the switch.Based on the RLC circuit theory and the dielectric material conductivity model,the one-shot switch resistance model was established.The model can be used to reveal the effects of the circuit parameters on the peak current and the rise time of the switch.