Measurement of high-current pulses is crucial in some special applications, e.g., electrodynamic accelerators (EA) and converters. In such cases, the current shunts have limitations concerning the frequency bandwidth. To overcome the problem, a method based on the shunt mathematical model is proposed. In the method, the solution of ordinary differential equations for the RL circuit is carried out in order to obtain the real current shape. To check the method, as a referee, a Rogowski coil dedicated to measuring high-current pulses was used. Additionally, the measurement results were compared with the mathematical model of the tested power supply system. Measurements were made for the short power supply circuit, which allows eliminating the nonlinearity. The calculations were carried out using a circuit model. In order to obtain the parameters of the shunt (resistance and inductance), it was modeled using an ANSYS/Q3D Extractor software. Comparison of calculation and measurement results confirms the correctness of our method. In order to compare results, the normalized root mean square error (NRMSE) was used.

Purpose: The purpose of this paper is to calculate and measure transients for two different constructions of electrodynamic accelerators (ironless and iron-core) supplied by a three-section power system (three capacitor banks). The optimization of power supply parameters (switch-on times and capacitances of individual sections) in terms of system efficiency has been carried out. Design/methodology/approach: Calculations have been carried out using a field-circuit model. For three-dimensional magnetostatic analysis, the Maxwell software and finite element method (FEM) were used, while for circuit model, the Matlab/Simulink software was implemented. For optimization of the supply system parameters, the genetic algorithm was used. The mathematical models were verified experimentally by using the original laboratory stand. Findings: The efficiency of the system is much higher in case of iron-core accelerator. In both cases, the results obtained for optimized supply settings are only slightly better than those obtained by simultaneously switching on the thyristors and for symmetrical capacity division. Research limitations/implications: Due to the presented field-circuit model, eddy currents in rails have been neglected. In the field model, there was no possibility to combine current flow calculations with moving of the projectile. Originality/value: Using the presented filed-circuit model, both electrical and mechanical transients could be calculated with sufficient precision. Thus, it could be used in the optimization of supply system. The solution time is low compared with the solution time of the transient field model.

The main objective of the research is to investigate, how the power supply parameters influence the kinetic energy of the movable element, called commonly a projectile or bullet. A calculation and measurement results of transient characteristics for an electrodynamic accelerator with permanent magnet support were presented in the paper. The calculations were made with using field-circuit model, which includes the parameters of the power supply, mass of the bullet and friction phenomenon. Characteristics of energy and muzzle velocity verso supply voltage (50 V to 350 V) and capacitance value (60 mF to 340.5 mF) were determined, as well. A measurement verification of selected points of calculation characteristics were carried out for investigated values of muzzle velocity. A good conformity between calculation and measurement results was obtained. Concluding, presented characteristics of the muzzle velocity and energy of the projectile vs. power supply parameters indicate, that accelerators could be used for fatigue testing of materials.

The influence of the capacitor configuration in the pulse supply system for rail accelerators on its efficiency was investigated in the paper. Two different configurations were compared: the first with a parallel connection of capacitors and the second with a parallel-series connection. In both cases, the same number of capacitors was assumed. All other parameters of the device were kept constant, i.e. mass and dimensions of the armature, rail length and stator geometry. A field-circuit model was used to analyse numerically the transients for different capacitor configurations and voltage values. The model was verified experimentally.

Multivariate calculations of the electrodynamic accelerator with a permanent magnet support and a ferromagnetic core are presented in the paper. The calculations were made with using the Magnetostatic module of Maxwell/ANSYS software. The purpose of these calculations was to determine the size...

Dynamic characteristics for three types of railgun constructions were simulated and measured in this work. The simplest construction is the iron-less (IL) railgun, while the two other ones (IC and ICPM) have an iron-core. The iron-core permanent magnet (ICPM) railgun additionally has permanent magnets. To compare their characteristics, similar dimensions of the rails and iron cores were adopted, and the same power supply system was used. Numerical magnetic field analyses and our analytical models have been used to determine the electromagnetic parameters. They were verified experimentally. The transient states of the railguns were studied with our field-circuit mathematical model, and their results were also verified by experiments.