Analysis of back electromotive force in RCEML

Compared with the rail electromagnetic launchers (EMLs), there is a strong magnetic coupling between the drive coils and the projectile of coil EMLs. This makes it possible that the coil EMLs have very high efficiency. When doing research on coil EMLs, we found that there was a significant downward trend of the current wave of the launcher system by use of batteries as a power source, which was considered as the effect of back electromotive force induced by the moving projectile. This paper investigates the inherent nature of the back electromotive force in reluctance coil electromagnetic launchers (RCEMLs). The equation of circular electric field round the projectile is theoretically derived; the finite element model to calculate the back electromotive force is established in ANSOFT MAXWELL, and the numerical conclusions is validated by Nd-Fe-B magnet experiment; the back electromotive force of RCEML is detected. In addition, the zero exit current mode of coil EML is proposed after analyzing the effect of back electromotive force and the current waveforms of the launcher system under conditions of different power supply voltages.