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In the launch process of the multistage synchronous induction electromagnetic launcher (SIEL), the armature is usually accelerated step by step. Due to the impact of high instantaneous electromagnetic force and large acceleration fluctuation, some kinds of sensitive loads may be damaged during the launching process. To reduce the harm that caused by the abovementioned issue, this article proposes an optimized armature and an asynchronous pulse discharge scheme to smooth the acceleration curve based on the toroidal reconnected electromagnetic launcher (TREL). First, a mathematical coupling model of the single-stage TREL is built to describe the energy conversion relationship between the driving coils and the armature. Then, the dynamics characteristics of the TREL model based on two armature structures and two discharge schemes are analyzed through the finite-element method. Finally, the simulation results demonstrate that the large acceleration fluctuation of the armature can be effectively cut down with the proposed methods. [ABSTRACT FROM AUTHOR]

This article presents a new single-stage TL-shaped electromagnetic launcher (SS-TL-EL), which improves the configurations of the driving coil and armature on the basis of the traditional synchronous coil launcher. Compared to the traditional single-stage synchronous electromagnetic launcher (TSSSEL), it can achieve a higher launching efficiency. In this model, due to the configuration of the T-shaped driving coil and L-shaped armature; therefore, there are more parameters can be derived to optimize the model and improve the launching efficiency. The finite-element method is used to simulate the model, and the comparison between TSSSEL and SS-TL-EL is completed under the same inductance, capacitance, capacitance-voltage, and armature mass. The simulation results show that SS-TL-EL has the larger eddy current, radial magnetic field density, and the wider current distribution area. In order to verify this feasibility of the concept, an SS-TL-EL and a TSSSEL were established and tested, and their launching model is simulated and analyzed. The experimental results show that the launching effects of SS-TL-EL are in agreement with the simulation results in general. The comparison of experimental results indicates that SS-TL-EL has a better launching effect than the TSSSEL under the same conditions. [ABSTRACT FROM AUTHOR]

Synchronous induction coilgun (SICG) has attracted more and more attention due to its advantages of simple manufacturing and no physical contact between armature and barrel. The armature, as an important component of SICG, will directly affect the launch speed and energy conversion efficiency. According to the distribution characteristics of eddy current and electromagnetic force, a new structural armature is proposed in this paper. The proposed inner conical armature is characterized by the maximum thickness at the tail end and the minimum thickness at the front end, with a gradual decrease in the thickness along the axial direction. The simulation results reveal that the proposed armature not only increases the mutual inductance between the armature and the drive coil but also enhances the electromagnetic force and weakens the armature capture effect. The experimental results verify that, compared with a traditional armature weighing 56.5 g, the new structure armature weighing 58.0 g enables higher muzzle velocities using the same set of pulsed power supply and drive coil, providing higher efficiency. [ABSTRACT FROM AUTHOR]

Researches on the synchronous parallel discharge of multimodule pulsed power supply have confirmed that it can output large pulse currents with high amplitude. For electromagnetic railguns, excess current may cause orbital erosion and other problems, and the ideal driving current is rectangular pulse currents. Therefore, the asynchronous discharge of multimodule superconducting pulsed power supply (SPPS) is studied in this paper to reduce the amplitude and increase the pulsewidth for driving an electromagnetic railgun. A toroidal SPPS based on eight coupled high-temperature superconducting pulsed power transformers and a dynamic simulation model of electromagnetic railgun is established. The simulation results show that armature currents with different amplitude and pulsewidth can be obtained by adjusting the trigger delay time of each module. With the increase of the trigger delay time, the amplitude decreases but the pulsewidth increases. With a set of trigger delay time, the asynchronous discharge of the eight-module SPPS can output an approximate rectangular pulse current with amplitude of 126 kA. The armature and projectile with a total mass of 50 g can be accelerated to 346 m/s, giving the efficiency of 16.2%. [ABSTRACT FROM AUTHOR]

In this paper, a new structure of coilgun with stepped coil winding was designed. The performance of this structure was investigated and compared to the conventional coilgun with uniform diameter stator coil (UDSC) winding. It can be seen from the results that the trigger position of this new structure moves forward with respect to the conventional coilgun. In order to compare the results, the inductance of the two coils is set to the same. If the initial voltage of the capacitor is lower, as the armature at the optimum trigger position, the muzzle velocity of armature in the conventional UDSC coilgun is relatively larger. Conversely, if the initial voltage of the capacitor is higher, the muzzle velocity of armature in the new structure coilgun is relatively larger. According to the simulation results with the increase of voltage, the difference is more and more obvious. Through the single-stage preliminary experiment in our laboratory, the results were in good agreement with the simulation results. And the trigger position is more forward, so the interaction time between the armature and the coil will be longer. Besides, the coil with stepped structure will increase the efficiency of the coilgun when the voltage level is higher. [ABSTRACT FROM AUTHOR]

Multipole field electromagnetic launcher (MFEL) is a new type of coilgun that can produce larger radial magnetic field compared to the axial magnetic field, the axial acceleration force of coilgun mainly come from radial magnetic field. Because of the similarity of the magnetic fields between inner and outer regions of MFEL, this paper proposed a double-armature MFEL. One armature coaxial with the drive coil placed inside of MFEL; the other armature coaxial with the drive coil placed outside of MFEL. A single-stage double-armature MFEL was studied by simulation and experimental methods. The simulation results indicated that the muzzle velocity of the double-armature launch is similar to that of the single-armature launch, and the efficiency of double-armature MFEL is obviously larger than that of single armature. To verify the conceptual feasibility, a small-size single-stage double-armature capacitor-driven MFEL was built and tested. The inner small armature weighs 63.13 g, the outer big armature weighs 88.38 g. The experimental results on single-armature launch show good consistency with the simulation results, but there is a little gap between the experimental results on double-armature launch and the simulation results. The causes of the existing differences are considered to be mainly from the consistency difference between the six driving coils and the mutual influence between the inner and outer armatures. [ABSTRACT FROM PUBLISHER]

The thrusts of a cylindrical linear synchronous motor with an HTS coil magnet as the excitation system were measured the first time and will be presented in this paper. The HTS coil magnet is made of second generation YBCO wire. The coil is a double pancake coil consisting of 34 turns wire. The inner diameter, outer diameter and height of the coil are 20, 30 and 13 mm, respectively. The armature of the motor is three phases, and the inner diameter is 40 mm. It is made of copper windings. With a direct current of 40 A for the HTS coil magnet and a RMS current of 10 A for the armature, a peak thrust of 3.8 N was measured at the temperature of 77 K and a radial gap of 5 mm between the armature and the excitation system. Effects of armature current, coil current, running time, magnetizers and seams between magnetizers were also studied. In the experiments, the peak thrusts of different types of HTS coil magnets were about from 1.3 times to 8 times as strong as the peak thrust of the coreless coil magnet under the same conditions. [ABSTRACT FROM AUTHOR]