Development of a rep-rated capacitor bank utilizing electrochemical energy storage

The U.S. Naval Research Laboratory (NRL) is developing a battery-powered, rep-rate charger for a 60-kJ capacitor bank. The objective is to charge a 4800-μF capacitor to 5-kV in four seconds for a fifty shot burst. A bank of lithiumion batteries is used with a full H-bridge converter, a transformer, and a rectifier to transform the 600V battery voltage to 5-kV secondary voltage. The battery modules are nominally 50-V each until the output relays are energized and all twelve modules are connected in series, at which point the voltage will droop significantly due to circuit loading. The batteries are directly connected to an IGBT-based full-bridge converter that is used in conjunction with a capacitor and the transformer to charge the bank in approximately six seconds. Additional work was also performed in the investigation of the use of Oscillating Heat Pipes (OHPs) to replace the passive heat sink on the IGBT switches. This paper will present results from experiments to date.