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The armature is an important part affecting the energy conversion efficiency of a reluctance accelerator. In this paper, six kinds of soft magnetic materials are chosen and four structures are designed for the armature. At first, the circuit and magnetic force are theoretically analyzed. Then the armatures with different materials and structures are used in the simulation, and the performances are compared and analyzed. At last, the experiment verifies the theory analysis and simulation design. It is concluded that the saturation flux density and conductivity of the material are the key factors affecting the armature force, and the optimization of armature structure can effectively restrain the eddy current, reduce negative force and improve efficiency. Compared with cutting slits in solid armatures, laminating the sheets radially can reduce the eddy current more efficiently. Although slitting can prevent the eddy current to a certain extent, meanwhile, it will decrease the magnetic force because of the losing of magnetized volume and the surface area. Hence, choosing the high saturation flux density material and making out the armature with radially_laminated sheets will improve the efficiency of the reluctance accelerator. In this paper, the silicon steel radially_laminated armature is a better choice for the armature design of the reluctance accelerator.

Lagrangian description of electrical circuit model of a reluctance type accelerator system is introduced. The effectiveness of the general purpose magnetostatic finite element analysis (FEA) tools on the introduced model is demonstrated. Electrical equivalent circuit model of the system lays out many properties of the system in terms of voltage, current, power or energy distributions of electrical components, and also electrical equivalent of the mechanical components, in an easily perceivable form. These type of actuators are simple mechanisms when they are in steady state. However, when they are in transient, their dynamics may become very complex. The aim of the study is to show how this approach allows many researchers without the full electromagnetic background, to model and understand the dynamics of the reluctance type linear or rotary motor or actuators whether they are saturated or not. To exhibit the validity of the proposed model and solution of dynamic behaviors with FEA, it is verified on a basiccapacitor discharge type driver circuit including the electromagnetic accelerator coil and projectile.

In this paper, an improved discharging circuit was proposed to quicken the decay of the current in the drive coil in a reluctance accelerator when the armature reaches the center of the coil. The aim of this is to prevent the suck-back effect caused by the residual current in drive coil. The method is adding a reverse charging branch with a small capacitor in the traditional pulsed discharging circuit. The results under the traditional circuit and the improved circuit were compared in a simulation. The experiment then verified the simulations and they had good agreement. Simulation and experiment both demonstrated the improved circuit can effectively prevent the suck-back effect and increase the efficiency. At the voltage of 800 V, an efficiency increase of 36.34% was obtained.

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This paper proposed the use of a ringer, a self-switched inductive storage system, for applications involving reluctance accelerators, a kind of electromagnetic launcher, and compatible with applications where portability is a requirement. There will be shown three different useful approximations for the analysis of the ringer, employed as a power source for a reluctance accelerator. First, it described the equations governing the que behavior of an ideal unloaded ringer, and then the equations for the ringer with an uncoupled inductive load, and ultimately a Lagrangian model for the ringer as an inductive power source for a reluctance accelerator, capable to make predictions about the currents through the circuits and the exit speed of the projectile for a given firing. The accuracy of the predictions made with the third approximation, the Lagrangian model, was tested experimentally. [ABSTRACT FROM AUTHOR]