Research On Capacitor Discharge Unit Based On MOS Controlled Thyristor

A small capacitor discharge unit（CDU）based on MOS controlled thyristor and0.22μF high voltage ceramic capacitor was produced in this paper,and micro chip exploding foil initiators were produced,boron-potassium nitrate pellet（BPN）and hexanitrostilbene（HNS）were adopted in order to verify the ignition and initiation capabilities of CDU.The main research contents and conclusions are as follows:（1）The static characteristics and discharge performance of MCT were studied:conduction properties of MCT and cold cathode trigger tube were studied;the protection performances of fast recovery diode（FRD）,transient suppression diode（TVS）and gate resistor were studied;package form of MCT was studied,it was found that surface mount package is better than in-line pakage;the printed circuit board of CDU was designed and manufactured,the inductance of CDU is about 10nH,and the resistance is about 100mΩ.The peak current is 2.68 kA,and the current-rising-rate is 22.46 kA·μs^-1 under the condition of 0.22μF/1200V.After formula derivation and experiment verification,as the capacitance becomes smaller,then the peak current becomes smaller,the capacitor discharge time and the peak current rise time become shorter.As the discharge voltage increases,the peak current increases,the discharge period unchange.（2）Micro electromechanical system（MEMS）technology was adopted,such as photolithography,magnetron sputtering and spin coating.Silicon exploding foil initiators（Si-EFI）with two bridge foil structures were prepared in batches:Si/Au bridge foil is 0.7Ω,and Si bridge foil is 3.7Ω.Electrical explosion parameters and flyer motion were studied.The energy utilization ratio of 3.7Ωbridge foil is higher than 0.7Ωbridge foil.Light radiation of plasma generated by electrical explosion was observed through ultra-high-speed photography,the integrity of the flyer is greatly enhanced and the flyer appeares regular circle under the constraint of barrel.The relationship of energy and flyer velocity was analyzed,the threshold voltage of 3.7Ωbridge foil is 1.60kV,and the threshold voltage of 0.7Ωbridge foil is 1.80kV,because of the negative temperature effect of the silicon resistivity.（3）Si-EFI,MEMS-EFI and LTCC（Low Temperature Co-fired Ceramic）-EFI were adopeted,the ignition and initiation ability of CDU were characterized by boron/potassium nitrate and HNS-IV.The minimum ignition voltage of Si-EFI（0.7Ω）is 1.20kV,and the minimum ignition voltage of Si-EFI（3.7Ω）is 1.10kV.The simulation and experimental results show that the flyer velocity of 1500m/s is not enough to initiate HNS.It was found that MEMS-EFI is suitable for the CDU,which can detonate HNS at 1.10kV.LTCC-EFI can ignite BPN at 1.20kV,however,it failes to detonate HNS,because ceramic flyer prematurely broke in barrel.