| Explosively driven magnetic flux compression generators (FCG) are a type of compact pulsed power sources. In recent years, attention has been given to FCG's application in generating high-power microwaves (HPM). In the dissertation, comprehensive investigation of the helical FCG and of the power conditioning circuit is carried out theoretically, numerically and experimentally.Firstly, an equivalent circuit for a common FCG is discussed and influences of FCG's design parameters on its current and energy amplification are obtained. Mechanism of various Ohmic and non-Ohmic flux losses is reviewed. An equivalent circuit code is realized, where the 3-D effect of helical coil and the distribution of armature's mirror current is considered. Resistance of the stator is obtained by solving a 1-D magnetic field diffusion problem. Based on the code, curves of FCG's inductance, resistance, temperature and its output current, voltage are calculated.Secondly, the expanding process for an armature of a helical FCG is studied in depth by a nonlinear, explicit finite-element (FE) code. To include the effect of strain rate and shock heating, Johnson-Cook strength model with Grilneisen equation of state (EOS) is used for the armature. Arbitrary Lagrangian-Eulerian (ALE) algorithm is adopted. Detonation and EOS parameters for 8701 explosive at various densities are computed based on the theory of mixed explosives. Simulation results give intuitive pictures of the armature expansion process, along with its temperature rise. A tapered armature design is proposed to increase the inductance's changing rate.Then to provide insight into the development of instabilities on the surface of the armature, a viscoplastic constitutive model is formulated in a user defined material subroutine to model the microvoid's growth. In the model, Johnson-Cook strength is combined with Gurson-Tvergaard-Needleman yield criteria, and random distribution of microvoids is used. Results show that quasi-periodic axialfracture will appear, which obstructs the mirror current of the armature.In order to drive a high impedance load such as HPM sources, it is necessary to commutate FCG's long pulse width, high-current and low voltage pulse to a short pulse with high voltage. As FCG's performance depends on the load greatly, the power conditioning circuit should take both FCG and the load into account. PSpice models for FCG, pulse transformer, electric exploding wire opening switch (EEOS), Blumlein pulse forming line, and virtual cathode osillator (Vircator) are created. With these models, various possible power conditioning circuits can be simulated. EEOS' usage is studied by using the above model. New power conditioning scheme utilizing a Blumlein line is compared with the traditional EEOS approach. Better waveforms with faster rise and flatter top are obtained with the new scheme.Except for the instability, experimental studies are conducted to validate the used theoretical and numerical models. Experiments with FCG show that voltage breakdown and fabrication tolerance causes most of the flux losses. The detonation speed of 8701 explosive is measured and accords well with that obtained by empirical formulas used in the text. Optical photographing is used to verify the expansion process of the armature, and shows fair agreement with the FE calculation results. Experiment is carried out on the built power conditioning system, which consists of a pulse transformer and a water Blumlein line. HPM is successfully generated.At last, an orthogonal test designing method is proposed to study the influences of various FCG and power conditioning circuit parameters on the system performance, to find out those most influential factors and to make them optimized.
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