Investigations Into the Design of a Compact Battery-Powered Rep-Rate Capacitor Charger

The U.S. Naval Research Laboratory is developing a battery-powered rep-rate charger for a 60-kJ capacitor bank. The goal is to charge a 4800-
$\mu{\rm F}$
capacitor to 5 kV in
${<}{\rm 5}~{\rm s}$
for a 50-shot burst at 10 shots/min. A bank of LiFePO4 batteries is used with a full H-bridge converter, a transformer, and a rectifier to transform the 600 V battery voltage to 5-kV secondary voltage. There are two major aspects to the charger design: battery energy store and the dc–dc converter. A stable battery pack requires active cooling, management, and feedback for proper and safe operation. A design study has been performed to identify an appropriate dc–dc converter that can minimize the weight and volume of the system while maintaining high electrical efficiency. An LLC is being evaluated, as it has the possibility of eliminating a discrete inductor using the magnetizing inductance of the transformer in the resonant circuit. Work has also been performed in the design and evaluation of a battery pack, specifically on characterizing the operational parameters of the pack as applied to the desired load. This paper will present simulation data and results from the experiments.