Matthew B. Scudiere

A bi-directional DC-DC converter with minimum energy storage elements

A proof-of-concept military advanced mobile generator set has been developed. The military generator set uses an internal combustion diesel engine to drive a radial-gap permanent magnet alternator at variable speed. The speed of the engine is determined from a user selectable interface that for a given load and ambient thermal conditions controls the engine to run at its most efficient operating point. The variable frequency, variable voltage produced by the permanent magnet alternator is diode-rectified to a high voltage (/spl sim/400 V) DC link, and an inverter is used to produce selectable frequency, controllable AC voltage. As part of the power electronics for this unit, a 7 kW bi-directional DC-DC converter has also been developed. The converter can charge 24 V batteries that are used to start the internal combustion engine and to power auxiliary low voltage DC loads. Additionally, the bi-directional converter can also draw power from the batteries to help maintain the high voltage DC link during severe load transients. Because of stringent weight and volume requirements for this application, the minimum in energy storage elements (high frequency transformers, capacitors, and inductors) was used. This paper presents a description and experimental analysis of this novel DC-DC converter design.

Electronic power conversion system for an advanced mobile generator set

The electronic power conversion system and control for an advanced mobile generator set is described. The military generator set uses an internal combustion diesel engine to drive a radial-gap permanent magnet alternator at variable speed. The speed of the engine is determined from a user selectable interface that for a given load and ambient thermal conditions controls the engine to run at its most efficient operating point. It is also possible to control the engine to run where it is most audibly quiet, at its least-polluting operating point, or at its most reliable, stiffest point such that it is less sensitive to load transients. The variable frequency, variable voltage produced by the permanent magnet alternator is diode-rectified to DC voltage, and an inverter is used to produce selectable frequency, controllable AC voltage. The power conversion system also incorporates a bi-directional DC-DC converter that can charge 24 V batteries that are used to start the IC engine and to power auxiliary loads. The bi-directional converter can also draw power from the batteries to help maintain the DC link during severe load transients. The design of this new generator set offers additional flexibility by being lighter, smaller, and more fuel efficient than a conventional fixed-speed gen-set.