线圈型电磁发射器反向电流分析及其对发射器系统的影响

线圈型电磁发射器利用驱动线圈和弹丸线圈的磁通耦合机制加速弹丸向前运动,磁通耦合的大小决定了弹丸的受力及其加速过程。然而高速运动的弹丸会造成其前部磁力线压缩,在驱动线圈内部产生与驱动电流方向相反的感应电流,抑制了电源的正常放电,导致发射器系统电流波形呈下滑趋势。针对该问题,从理论上导出了运动磁体周围环形电场分布方程,分析了运动磁体各项参数对感生电场的影响;运用有限元分析方法模拟了永磁体弹丸运动过程并利用钕铁硼柱体做了验证实验;运用线圈型电磁发射器实验平台测得了环形感应电流;通过分析不同电源电压条件下发射器系统电流分布提出了零电流输出模式的方案。

Analysis of Back Current in and the Effect Acting Coil Electromagnetic Launchers on the Launching System

During the coil electromagnetic launching process, the projectile is accelerated due to the mutu- al coupling of magnetic flux between the drive- and projectile coils, which determine the force acting on the projectile and also the acceleration process. However, high-speed movement of the projectile will cause the magnetic field lines compress in the front and back current induced in the drive coils which suppresses the normal discharge of power supply. This paper investigates the back current induced in drive coils due to the movement of projectile in coil electromagnetic launchers. The equation of circular electric field round the projectile is theoretically derived based on a hypothesis that all the magnetic dipoles are uniformly dis- tributed in the projectile; the finite element model to calculate the back current is established in ANSOFT MAXWELL, and the numerical result of which is validated by Nd-Fe-B experiment ; the back current of coil electromagnetic launcher is detected indirectly and the program of zero exist current mode is proposed after analyzing the current waveforms of the launcher system under conditions of different power supply voltages.