Hybrid Electric Drive for Small Craft

摘要

The introduction of unmanned surface vessels (USVs) in the U.S. Navy is progressing rapidly. Recent awards for the Littoral Combat Ship program will accelerate the introduction of these USVs with an initial emphasis on mine warfare, anti-submarine, anti-surface, and electronic warfare missions. There is a strong desire to use mission modules that fit within a common envelope that can be accommodated in one or more offboard vehicle designs. There is also a need for substantial amounts of electric power on USVs for some of these missions. The need for electric power includes legacy needs such as power for minesweeping influence sweep system, active jamming, and dipping sonar to emerging technologies like missile ejection, directed energy, and false signature generation. The weight of a mission-ready USV is constrained by the need to launch and recover these vehicles from surface ships that are operating in a seaway. As a result, any electric power systems should be lightweight and appropriately sized. Electric generation systems should be driven by the relatively efficient USV prime mover whenever possible in order to suppress the added weight of any additional engines. Once the weight penalty of introducing electric power has been accommodated for mission reasons, the availability of electric power can have a strong influence on the options available to the vessel designer. Options include: operation of multiple propulsion shafts from a single engine, quiet operation, improved failure mode response, possible replacement of hydraulic systems with electric systems for weight and maintenance savings, and the operation of ancillary systems at higher voltages for lighter weight. As with other marine subsystems, the durability of the system under harsh environmental conditions is of primary concern. Water-tight integrity, corrosion, ground faults, and maintenance personnel safety are all of concern.