High Frequency AC Power System

The Navy's Next Generation Integrated Power System (NGIPS) master plan calls for the evolution of the IPS system from its current medium voltage, 60 Hz state to a high‐frequency, medium‐voltage AC (HFAC) system in the next 10 years. Beyond that, and pending development of key protection components, a medium‐voltage DC system will be considered for implementation. The master plan calls for power generation modules at three power levels across these systems:



•A low power level (2–5 MW) driven by a fuel‐efficient diesel prime mover,

•A medium power level (10–15 MW) driven by a gas turbine, and

•A main propulsion power level (20–40 MW) driven by a gas turbine.



EMD is currently developing a high‐speed, high‐frequency, liquid‐cooled generator under contract with NAVSEA that will effectively demonstrate the mid‐level generator for the HFAC system. It will be coupled directly to the output of a GE LM1600 Gas Turbine to provide a TG set with power density four times more favorable than conventional ATG sets. The generator development is proceeding favorably, with testing at the Navy's land‐based test site (LBTS) expected to begin in July 2008. The technology embodied in the high‐speed generator can be easily extrapolated to main turbine generator power levels. Given the availability of prime movers at appropriate speeds, the power generation modules for the HFAC system, at all three power levels, could be provided in a much shorter time frame than noted in the NGIPS master plan. This paper will explore the combinations of prime movers and advanced generators that would suit the three power generation modules of the HFAC system. A description of the prime mover and the generator used for each module will be provided to demonstrate the modest level of development needed. The performance parameters for each generation module will be provided, along with key characteristics and dimensions for the set. In the end, the paper will make the case that demonstration of a HFAC power generation system can be made in the short term, allowing the shipbuilding community to take advantage of the benefits of state‐of‐the‐art power dense electrical generation.