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The influence of electromagnetic induction coil launcher (EICL) system parameters on the launch performance was analyzed, and a method for measuring the launch performance of an EICL system with a muzzle velocity and energy conversion efficiency was proposed. The EICL system mainly includes a pulse power supply and launcher. The parameters of the pulse power supply mainly include the discharge voltage and the capacitance value of the capacitor bank. The structural parameters of the launcher mainly include the bore size of the launcher, the air gap length between the armature and the drive coil, the length and width of the drive coil, and the trigger position of the armature. Change in single or multiple parameters in the launch system will influence the launch performance. The influence of single or multiple parameters on the launch performance was summarized, and the physical law as analyzed. The influence law of the EICL system parameters on the launch performance was obtained, which lays a theoretical foundation for the optimization design of EICL. Finally, experimental verification was carried out by a single-stage test platform.

Electromagnetic coil launcher is a kind of special linear motor. In order to study the trigger principles of multi‐stage electromagnetic coil launcher, based on the electromagnetic field theory, the paper deduced the field‐circuit coupling magnetic field control equations of multi‐stage synchronous inductive coil with the consideration of inter‐stage coupling, and analyzed the distribution law of magnetic lines of force, air‐gap magnetic field and current density for multi‐stage electromagnetic coil launcher. The following conclusions were reached: the largest part of magnetic flux was at the intermediate stages of multi‐stage electromagnetic coil launcher; each stage of drive coil compensates for the magnetic field of the upper coil, thus making a stable air‐gap magnetic field; the induced current density was mainly distributed in the tail and surface of the armature; according to anti‐electromagnetic shock design principle of multi‐stage electromagnetic coil launcher (namely, the requirement for small fluctuation of electromagnetic force), the basic principle of multistage trigger was summarized, that is the principle of keeping air‐gap magnetic field and induced current constant. Thus, the design foundation was laid for the operation of multistage electromagnetic coil launcher. © 2021 Institute of Electrical Engineers of Japan. Published by Wiley Periodicals LLC.

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Linear permanent magnet (PM) brushless dc motor (LPMBDCM) is used for electromagnetic catapult, which may offer significant advantages, in terms of efficiency, high speed and accelerations of heavy payloads, capability of high forces, and so on. In this paper, an LPMBDCM, which is constructed of transverse flux stator and PM mover, is investigated. First, the launch specifications and technical features under the condition of pulse power input are presented. Then, the magnetic circuit parameters including the calculation of the mutual and leakage inductance are derived, and the rated work performances are analyzed. The rated input voltage, current, thrust, and power efficiency are 4000 V, 18041 A, 1.389 MN, and 0.97, respectively, which can meet the requirements of electromagnetic catapult. The availability and reliability are validated as the temperature rise per launch is lower than 1°C, and the demagnetization of the PM would not happen with high pulse current. Finally, to validate the characteristic of the basic design, the system simulation model including the power supply and power conditioning is built using of Simulink, and the launch trajectory is simulated by the model, which shows the launch can achieve a speed of 99.47 m/s along the distance of 99.47 m within 1.51 s. A small-scale prototype machine is fabricated and the validity of the proposed method has been verified by the experimental results.Index Terms-Electromagnetic catapult, linear motor, magnetic circuit parameters, permanent magnet (PM).