High-Voltage, High-Power-Density DC-DC Converter for Capacitor Charging Applications

This paper presents a DC/DC converter topology for charging high voltage bulk capacitors for pulsed load applications. The topology is a compact variant of the flyback converter with completely soft switching, variable frequency control, and optimal magnetics design. This converter is capable of efficiently transferring power from 30 V input to a capacitor charging from 0 V to 6 kV. The specific application for this converter is a pulsed sparker for a sonobouy application, but this can apply to a large number of applications, such as defibrillators, communications, pulsed weapons systems, and industrial applications. The proposed converter was experimentally tested, and found to have peak efficiency greater than 92%, with an average efficiency greater than 89% for the entire charging cycle. The power density of the prototype is greater than 1 kW/L, with the potential to achieve 2.5 kW/L.