Research On Pancake-coil Electromagnetic Launch System

With the continuous upgrading of anti-armor weapons,the protection of traditional passive armor to tanks and armor vehicles appears to be "getting half the result with twice effort".Although the active protection technology can implement an active attack to intercept the incoming target,the active protection technology's launch energy greatly limits its response capability to the coming danger.Based on active protection technology and electromagnetic launch technology,active electromagnetic armor protection technology can make up for the shortcoming of active protection technology and effectively intercept high-speed targets with its sharper response capability.In order to better guide the research and design of active electromagnetic armor protection technology,the pancake-coil electromagnetic launch system is chosen as the research object to study the launch system of active electromagnetic armor protection.The work having done and the research results obtained are as follows;1)The construction of the pancake-coil electromagnetic launch experimental platform was completed,and the TVS conduction characteristics as well as the experimental system circuit was tested by discharge experiments.The accidents of the breakdown occurring between the launching pedestal and launching coil and the explosion of the high voltage package for triggering the TVS resulted in the improvement for the insulation of the launcher and the grounding of the experimental system.2)In order to protect the pulse capacitor and TVS,the experimental system circuit of a freewheeling circuit with a high power diode connected in series as a freewheeling switch has been studied,and the problem that the TVS cannot extinguish the arc normally has been solved by connecting the reverse current cutoff diode stack with the TVS in series.After many experiments,it is proved that the improved experimental system circuit with freewheeling circuit can withstand 9.4kV high voltage.3)The finite element software Maxwell was used to establish a proportional three-dimensional model of the pancake-coil electromagnetic launcher,and an external excitation circuit model was established based on the experimental system circuit with the freewheeling function.By comparing the current waveform obtained by the simulation under the typical working condition of 9.4kV with the experimental result,it was proved that the established simulation model and circuit excitation model were relatively accurate,and the simulation results could reflect the reality of the experimental system to a certain extent.4)Through simulation,it was estimated that when the applied voltage of the capacitor is 9.4kV,the launch speed of the experimental system is up to 8.45m/s.When the applied voltage is 9.4kV,the position of the strongest magnetic field in the launching pedestal during the launching process is always at the bottom of the inner cavity of the launching pedestal.The magnetic field in the central part of the launching coil is the largest,and it can be concluded that the central part of the coil is prone to deformation.The displacement of the launching plate is small,the magnetic field is always concentrated in the middle field of the launching plate along the radius during the launching process,and the decline of the magnetic field at the edge of the launching plate is slower than the rest.5)The effects of different capacitor parameters on the motion of the launching plate are studied by simulation.The spatio-temporal distribution of the pancake-coil electromagnetic launcher's and its surrounding magnetic field and the Electromagnetic-Structure coupled field of the launcher were simulated respectively under specific launch conditions.The results show that increasing the voltage and capacitance of the storage capacitor can increase the launching speed of the launcher and the system energy conversion rate,and reduce the time for the plate to reach its maximum speed.However,the duration of the electromagnetic force impacting on the launching plate by increasing the capacitance of the capacitor is significantly shorter than the duration of the electromagnetic force by increasing the capacitor voltage.The energy conversion rate of the pancake-coil electromagnetic launch system increases with the increase of the charging voltage or capacitance of the storage capacitor,but as the storage capacitor parameters increase,the increase rate of the energy conversion rate of the system decreases.Under the launch condition of capacitor with charging voltage of 50kV and capacitance value of 32?F,the maximum launching speed of pancake-coil electromagnetic launch system is 291.7m/s,and the maximum energy conversion rate is 26.6%.During the process that the launching plate is accelerated to 291.7 m/s,the launching coil and the launching plate are severely deformed,so the material and structure of the launch components need to be further optimized.