Direct comparison of properties for compression generators of pulsed current with iron-core and air-core rotor done by mathematic simulation

Abstract

Summary form only given. Two models of rotating machines for pulsed power generation based on the magnetic flux compression have been considered in the frame of FEM computation system containing up to 2800 knots, that was enough to get a numerical solution for one half of cross section of machine applying the symmetry condition and equality of stator bore diameters of both models. The laminated steel core for both rotor and stator has been assumed for traditional model of generator. The alternative model has contained the laminated steel outer core of stator and laminated non-magnetic steel (or titanium) core of rotor (air-core rotor). The level of initial (exciting) magnetic field can be essentially different for both generators in view of difference in the magnetic circuit design. The calculation model has enabled a combination of field analysis and circuit calculation as parallel processes. The highest parameters obtained for the pulses generated by each generator were taken into consideration for a comparison. Numerical experiments have been performed for the models with total output energy since 100 kJ up to 1 MJ. At the work on saturated part of the magnetization curve the generator with iron-core rotor displays the increase of pulse duration in ratio to the period of rotation, since the generator with non-magnetic rotor's core saves the initial pulse shape. Leaving the problem of mechanical strength, the results of electromagnetic simulation have allowed to consider that the compression generator with air-core rotor is able in the limit to develop both the same and much more magnitude of volume density of output energy, using more light non-magnetic materials for the rotor design. That gives the foundation to believe that this machine can be used as the perspective source of repetitive pulses with improved mass and volume density for energy production in the final stage of pulsed systems.