Abstract：The electromagnetic rail launch system was mainly composed of a pulse power supply and a launch device. It was limited by the saturation of the magnetic material, the low conductivity of the rail, the current skin effect and proximity effect. So, the inductance gradient of the device was low and the resistance gradient of the rail was high, resulting in low launch efficiency of the system. The system also had the characteristics of time-varying parameters, multi-field coupling, and short-duration pulse operation, so it was difficult to carry out accurate dynamic simulation calculation of the whole system. In order to improve the launch efficiency of the device, this paper established an equivalent circuit model of the system including the pulse power supply and the launch device, and given the extraction method of dynamic parameters, and analyzed the factors affecting the launch efficiency. Firstly, the concept of kinetic energy resistance Rk was introduced through theoretical derivation, and the kinetic energy of the armature was converted into resistance loss. According to the working characteristics in the launching process, the circuit model of two working stages of armature acceleration and armature arcing at the time of exiting the bore was established. Secondly, based on the series circuit model, according to the energy equivalent principle, a mathematical model of the system energy efficiency ηe, energy equivalent resistance R*k., loss equivalent resistance R* and current equivalent duty cycle D was established. According to the mathematical model, a DC pulse equivalent circuit model was established. In addition, considering the change of the barrel parameters during the armature movement, the velocity equivalent frequency was introduced, and using finite element simulation software to perform frequency sweep analysis of eddy current field to convert armature motion model into static frequency sweep model. Then, the curves of the rail inductance Lu, the resistivity Ru and the inductance gradient La’ as a function of frequency were obtained. The whole system electrical simulation model was established for simulation analysis, and the theoretical model, simulation model and experiment were compared, the results showed that the error between the three launch efficiency was less than 3%. Finally, the factors affecting the efficiency of the single launch experiment was analyzed, and it showed that the energy equivalent resistance R*k. was too small and the loss equivalent resistance R* was too large, which was the main reason for the low launch efficiency of the device: One was that due to the low gradient of the system inductance, the energy equivalent resistance R*k. was only 40.3% of the system loss resistance R*. In addition, the inherent loss of the system other than the loss of the rails accounted for 74.3% of the loss equivalent resistance R*. At the same time, the excessive outlet current leaded to a large residual magnetic field energy of the system, which further aggravated the additional energy consumption of the system. The design direction of launch efficiency optimization was given: increasing the inductance gradient, reducing the system loss resistance, and reducing the outlet current to reduce the residual magnetic field energy. The DC pulse equivalent circuit model was established by introducing the concept of kinetic energy resistance and the energy equivalence principle. The simulation model of the whole system was established after extracting time-varying parameters from the finite element model. The equivalent circuit model, system simulation and test results are compared and analyzed to verify the correctness and effectiveness of the equivalent circuit and simulation system. Finally, it provides a research method for the efficiency analysis and optimal design of electromagnetic launcher system.
翟小飞, 李鑫航, 刘华, 彭之然. 电磁轨道发射系统电路模型及发射效率研究[J]. 电工技术学报, 2023, 38(11): 2841-2849.
Zhai Xiaofei, Li Xinhang, Liu Hua, Peng Zhiran. Research on Circuit Model and Launch Efficiency of Electromagnetic Rail Launch System. Transactions of China Electrotechnical Society, 2023, 38(11): 2841-2849.
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2023, Vol. 38 
