As a natural result of the electrified integration and electrical energy revolution, the electromagnetic launch (EML) technology will be inevitably used for future launch missions. This paper has summarized research focuses in this field according to the published papers on EML in China during the past decade and mainly introduced the current research and progress in several key technologies, including launcher, integrated launch package, high-power high-density supply, and overall control/maintenance. Some common pressing problems are pointed out to provide direction for the application of EML technology in engineering and many other fields, such as launcher life, miniaturization of power supply, and improvement of energy availability.

In order to study the unique dynamic behavior of the lithium-ion battery system in the periodic high-rate pulse discharge, a frequency-domain impedance model and a dynamic extraction method of impedance parameters are proposed. Moreover, a 24 kWh lithium battery system is built to carry out the pulse-discharged cycle experiment. The harmonic characteristics in high and low frequency pulse discharge are studied by harmonic analysis method. Besides, the impedance characteristics of the 24 kWh lithium battery system under different SOC and different cycle are analyzed quantitatively. The results show some new characteristics and verify that the proposed frequency-domain impedance model and impedance extraction method are well qualified to analyze the frequency-domain characteristics and dynamic behavior of the periodic pulse-discharged lithium battery system.

This paper has introduced two important indexes, turn-off surge voltage (TSV) on power switch and peak positive pole potential (PPPP) of storage batteries, which can be used to evaluate switching transient process of high-voltage energy storage system. Research on them is of great significance to power switch choice and high-voltage isolation design in engineering applications. Power switch response process at the turning off moment and transient process in freewheel stage have been analyzed by the established small-signal model of single power switch; then, a power switch test platform for hybrid energy storage system was built to verify it. Taking pulsed-power supply charging device with a novel inductor of low resistance and high inductance as a research object, this paper has analyzed dynamic process of the TSV and the PPPP at the turning off moment through establishing state space model of the whole system. Comparison shows that the numerical curves match the simulated curves well. Finally, the exactness of the employed model has been further verified in two pulse capacitor charging experiments.