Optimum Design And Experimental Study Of Helical Explosively-driven Magnetic Flux Compression Generator

The explosive magnetic flux compression is widely used in many fields. Two kinds of Helical Explosively-driven Magnetic Flux Compression Generator (HEMCG) have been developed in our laboratory. Their reliability and stability are successful, and they have been commendably used in correlative items. Along with the higher request of outputting power, it is necessary to investigate how to enhance the efficiency of HEMCG and design a device that has higher amplification ratios of energy and current, as well as higher current and energy output.This paper firstly analysed the difference of the device efficiencies between direct feeding and indirect feeding modes under the same original conditions, and then educed the criterion of mode choice, meanwhile this paper simulated the equivalent circuits of the two feeding modes using PSpice program. Then the criterion of mode choice was verified by theory and experiment.The inductance of the first stage is the primary object for the optimization design. This thesis summed up the design principles of the inductance of the HEMCG based on studing the related literatures have been published in detail. Consulting the experience of the domestic and abroad researchers, inductance change rate (dL/dt) must be increased to enhance the efficiency of HEMCG. Thereby increasing the inductance of coil and optimizing the structure at the same time were considered in the coil design. Firstly, the coil is divided into several sections, and the radius of the coil of the different sections is increased gradually. Secondly, the number of parallel wire and the wire interval are increased gradually as well.Timing control system is the important element for HEMCG's operation, this paper introduced the operating principle of classical timing control system using flat switch and the coaxial timing control system which is used in our laboratory at present, and analysed their merits and drawbacks. Based on these, a kind of solidified coaxial switch was developed by means of theoretic and experimental study using ANSYS and LS-DYNA. The experiment results indicated that the delay error of the timing control system which used solidified coaxial switch is ~10%, and the precision of the system meets the request of the experiments of the HEMCG.Based on the theoretic analyses and experimental studies, a kind of modified HEMCG was designed and manufactured. The modified device adopted indirect feeding mode to obtain the initial magnetic flux. The feeding coils consist of two parallel wires and the initial inductance is 56.2μH. Meanwhile, the initial inductance of the first stage is increased to 269.8μH, and the coil of HEMCG1 is composed of six sections with different wire diameters. The primary experiment results proved that the modified HEMCG could obtain more than 1 Wb initial magnetic flux under the condition that the capacitor of 220μF is charged to 5.5 kV, and the modified HEMCG can output about 140 kA pulsed current and more than 39 kJ energy on 4μH inductive load with a current risetime of 12μs. The amplification ratio of current is 14.2 and the amplification ratio of energy is 14.4.