Study on Metallized Film Capacitor and its Voltage Maintaining Performance

High energy density capacitor is a key device in power supply source in electromagnetic gun (EMG) system. The increase of energy density of capacitor is beneficial from emerge of metallized technology in electrode and advancement in manufacturing. The paper studies a kind of high energy density capacitor made of polypropylene with metallized electrode. The self-healing ability is improved by optimization of the structural parameter of the metal electrode. First, aimed to be used in EMG, experiments such as lifetime test and voltage withstand test are carried out to study the performance of the capacitor. The metallized film capacitor has an energy density of 1.6 J/cm³ under 10 kV. And the lifetime test finds its lifespan of 2000 shots. Then, the influences of different impregnating materials on the voltage drop are compared in the paper for manufacture improvement purpose. Last, voltage maintaining test are carried out to observe the voltage drop of the capacitor. The output precision of the launch system will be consequently influenced. In order to obtain a stable voltage, a constant current and micropower charge control technique is applied to realize fast and high accuracy charge of capacitor to avoid fluctuation of output energy. Using micropower charge control, the voltage deviation in maintaining stage is less than plusmn1⁰/₀₀. And the charge system has a repeat accuracy of 0.520⁰/₀₀ with high reliability.