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The design of an electric ship can be based on several different technologies and architectures, each affecting the design drivers in ways difficult to be foreseen a priori. Moreover, the integration of innovative solutions requires to perform their proof-of-concept, not only related to their proper functioning, but also to their use onboard (assessment of the new system's impact on the main design...
The naval vessels electrification is one of the most important issues to be tackled, because not only it allows a more efficient operation, but also is considered a technological game changer. Indeed, electrification offers improved operational benefits and enables mission systems continuous upgrade. Several technologies can be used, each presenting different impact on ship performance. Thus, instruments...
Nowadays, it is of paramount importance reducing the pollutant emission also of small crafts operating near the coast. This action is an essential issue to preserve the marine and coastal environment. In this paper, the design of a coastal-navigation multipurpose craft to be used in North Adriatic Sea area is presented. The particular service areas are characterized both by inland waterways with shallow...
Sustainable mobility is an essential issue to take for the town planning of a great city. When a high tourist flow is present, the city should be provided of low pollutant emission vehicles for the public transport in order to preserve the environment. Venice is an UNESCO World Heritage Site, where the urban public transport is almost exclusively carried out by boats. This paper deals with the design...
Nowadays, the Medium Voltage Direct Current (MVDC) technology represents a new possibility to renew the shipboard power system of large All Electric Ships (e.g. cruise liners or military vessels.). This new concept is capable of achieving valued advantages, such as simplified system integration, modularity and system efficiency, together with an expected reduction of the space devoted to technical...
The training tall ship Amerigo Vespucci is the masterpiece of the Italian Navy fleet. Counting about 80 years of service, its refitting was mandatory, due to severe critical issues in efficiency, sustainability, logistic management and operation safety. Taking advantage of the full renewal, an innovative propulsion system has been designed. In this paper the new power system configuration, the requirements,...
MVDC distribution systems are proving to be a very promising research topic, given the large number of studies proposed in the academia and in the navies worldwide. In this paper authors present some multi-machine MVDC distribution system architectures, exploiting and comparing a range of choices on the topic of voltage control. Three network topologies are presented and analyzed, applying a series...
The new simulator of the FREMM (European Multi Mission Frigates) electric Integrated Power System (IPS) is treated in this paper. The simulator, recently delivered by the University of Trieste to the Italian Navy, is utilized to study relevant electromechanical transients of the on board IPS. In particular, this simulator is employed in verifying some automated sequences and restore maneuvers, which...
Voltage stability in Medium Voltage DC (MVDC) power systems can be impaired due to the presence of tightly regulated power converters in the points of load. Such converters behave as instantaneous Constant Power Loads (CPLs) and can induce negative incremental resistance instabilities. Linearization via State Feedback (LSF) is a control technique which has proven to be effective to prevent CPL instability...
Power quality is a key issue in islanded electric power systems. Considering the intrinsic weakness of islanded grids, this paramount aspect is not of easy accomplishment. To fulfill power quality requirements in these weak electric systems, high performance voltage and frequency controls are needed, although the interactions between these controls can lead to stability issues. In particular, frequency...
Electromechanical transients in isolated power systems having large and complex structure are challenging phenomena to study due to the intrinsic nonlinearities and to the mutual interactions between the electrical components involved. The problem is faced in this paper of studying the electromechanical transient resulting from a sudden line connection of a thruster motor in a shipboard integrated...
In this paper it will be presented a software simulator designed to study electromechanical transients for new European Multi Mission Frigates (FREMM) electric Integrated Power System (IPS). The simulator was committed by Italian Navy in 2009 and recently delivered by the University of Trieste. After a brief description of the origin and consistence of this Research Program, some of the expected benefits...
Italian Navy is being equipping its fleet with the new FREMM class of frigates, developed under a joint program by Italian and French Navies. They are conceptually new war ships endowed with a hybrid propulsion system, composed by a gas turbine and two electric drives, which can be operated also as shaft-generators. University of Trieste has been charged with developing a software simulator of the...
DC distribution is an attractive solution for onboard integrated power systems of new-generation all-electric ships, especially thanks to the benefits it offers in terms of reducing generation system size, weight and power consumption. Technologies have already been implemented in full-scale prototypes based on synchronous generators feeding the DC grid through rectifiers. In these proven solutions,...
High Voltage Shore Connection (HVSC) is a technical solution to supply ships at berth in an economic way while reducing air pollution in city ports. When multi-MW HVSC installations are to be exercised, electric power has to be delivered to the port from a HV line at voltages higher than 100 kV. In this case, large earth fault currents can arise on the HV side, flowing through the port earthing system...
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