A Naval Integrated Power System with a Battery Energy Storage System: Fuel efficiency, reliability, and quality of power.

Mechanical machinery has dominated the field of ship propulsion systems in the last century. Since fuel accounts for a large portion of the ship life-cycle cost, the current trend of moving toward fuel economy and environmental regulations in marine engineering has led to the efficient use of onboard energy. Incorporating power electronics into ship propulsion systems has been a very common method of improving fuel efficiency since approximately 1980. One high-profile example is the 1968-built Queen Elizabeth 2, whose steam turbines were replaced with a diesel-electric propulsion plant in 1986. Some commercial ships are now being built with electric drives, such as passenger ships, car ferries, shuttle tankers, cable-laying ships, icebreakers, and floating offshore platforms. Navies around the world have been actively exploring integrated power systems (IPSs) for use on future surface combatant ships since the late 20th ?century. Although the ship IPS has many distinct advantages, such as increased survivability and maneuverability, reliability inhibits further fuel economy improvement. The onboard battery energy storage system (BESS) was recently suggested to increase fuel economy and ensure reliability at the same time. Furthermore, an active front-end (AFE) converter can provide improved grid quality at transient states such as fault and future mission load in addition to steady state as with normal sea sailing.