Modeling of Electromagnetic Railgun and Analysis of its Performance

Document Type : Original Article

Authors

1 Faculty of Electrical Engineering, Shahid Rajaee Teacher Training University

2 Power Engineering Department, Faculty of Electrical Engineering, Shahid Rajaee Teacher Training University, Tehran, Iran

Abstract

Since railgun is an electro-mechanical system, it is not easy to simultaneously solve the electrical and mechanical equations. In this paper, a method based on a circuit model is presented for the analysis of the railgun, in which, its equivalent circuit is extracted and the differential equations describing its behavior are obtained. Using the 4th order Runge-Kutta method solution to theses equations, railgun simulation is performed. The main advantage of the proposed method is that due to its calculation speed, it can be easily used in the sensitivity analysis and design optimization, while these issues are almost impossible with finite element method, due to their slowness. Then, by employing the proposed method, the system has been simulated and its behavior has been studied. Also, the effect of the railgun structural parameters’ variations on the velocity, efficiency and force applied to the armature has been investigated. To validate the proposed method, the point to point 3-D finite element method is employed. The results of the finite element method are close enough to the results of the proposed method, confirming the accuracy of the latter.  

Keywords


[1]     J. F. Kerrisk, “Current distribution and inductance calculations for rail-gun conductors,” Los Alamos Nat. Lab., Los Alamos, NM, Rep. LA–9092-Ms, 1981.
[2]     Bok-ki Kim and Kuo-Ta Hsieh, “Effect of rail/armature geometry on current density distribution and inductance gradient,” IEEE Transactions on Magnetics, vol. 35, no.1, pp. 413-416, 1999.
[3]     A. Keshtkar, “Effect of rail dimension on current distribution and inductance gradient,” IEEE Transactions on Magnetics, vol. 41, no. 1, pp. 383-386, 2005. 
[4]     M. S. bayati, A. Keshtkar, and A. Keshtkar, “Transition study of current distribution and maximum current density in railgun by 3D FEM and IEM,” IEEE Transactions on Plasma Science, vol. 39, no. 1, pp. 13- 17, 2011. 
[5]     J. Gallant, “Parametric study of an augmented railgun,” IEEE Transactions on Magnetics, vol. 39, no. 1, pp. 451-456, 2003.
[6]     K. T. Hsieh, “Numerical study on groove formation of rails for various materials,” IEEE Transactions on Magnetics, vol. 41, no.1, pp. 380-382, 2005.
[7]     T. G. Engel, J. M. Neri, and W. C.Nunnally, “Efficiency and scaling of constant inductance gradient DC electromagnetic launchers,” IEEE Transactions on Magnetics, vol. 42, no. 8, pp. 2043-2051, 2006.
[8]     A. Keshtkar, S. Mozaffari and A. Keshtkar, “Effect of rail tapering on the inductance gradient versus armature position by 3D-FEM,” Transactions on Plasma Science, vol. 39, no. 1, pp. 71-74, 2011.
[9]     B. Tang, Q. Lin, and B. Lin, “Research on thermal stress by current skin effect in a railgun,” Transactions on Plasma Science, vol. 45, no. 7, pp. 1689-1694, 2017.
[10]  S. A. Taher, M. Jafari, and M. Pakdel, “A new approach for modeling electromagnetic railguns,” Transactions on Plasma Science, vol. 43, no. 5, 2015.
[11]  K. S. Yang, S. H. Kim, B. Lee, S. An, Y. H. Lee, S. H. Yoon, I. S. Koo, Y. S. Jin, Y. B. Kim, J. S. Kim, and C. Cho, “Electromagnetic launch experiments using a 4.8-MJ pulsed power supply,” Transactions on Plasma Science, vol. 43, no. 5, pp. 1358-1361, 2015.
[12]  A. Keshtkar, S. Bayati and A. Keshtkar, “Derivation of a formula for inductance gradient using intelligent estimation method,” IEEE Transactions on Magnetics, vol. 45, no. 1, 2009.
[13]  A. Keshtkar, L. Gharib, M. S. Bayati, and M. Abbasi, “Simulation of a two-turn railgun and comparison between a conventional railgun and a two-turn railgun by 3-D FEM,” Transactions on Plasma Science, vol. 41, no. 5, 2013.