Impact of marine power system architectures on IFEP vessel availability and survivability

In recent years integrated full electric propulsion (IFEP) has become a popular power system concept within the marine community, both for the naval and the commercial community. In this paper the authors discuss the need for a detailed investigation into the impact of different IFEP power system architectures on the availability of power and hence on the survivability of the vessel. The power system architectures considered here could relate to either a commercial or a naval vessel and include radial, ring and hybrid AC/DC arrangements. Comparative fault studies of the architectures were carried out in an attempt to make valuable observations on the survivability of a vessel. Simulation results demonstrate that the ring and hybrid AC/DC architectural contribute to a higher survivability than the radial architecture. However, there are still challenges that need to be addressed and therefore potential solutions such as fault current limiters will be considered

Integrated electrical and mechanical modelling of integrated-full-electric-propulsion systems

Integrated Full Electric Propulsion (IFEP) systems are the subject of much interest at present. Current research is focused on analysing and improving aspects of subsystem and system performance. However, there is a great need to look more widely at the `multi-physics' problem of characterising the dynamic interactions between the electrical and mechanical systems. This paper will discuss the changing nature of modelling and simulation to aid research into IFEP systems, outlining the alternative angle taken by the Advanced Marine Electrical Propulsion Systems (AMEPS) project to characterise and investigate electrical-mechanical system interactions. The paper will describe this approach and highlight the unique challenges associated with the problem, discussing the suitable methods that will be adopted to address these challenges. Finally, an overview of the present and future research opportunities facilitated via the AMEPS project will be presented

A solution for improved simulation efficiency of a multi-domain marine power system model

Integrated Full Electric Propulsion (IFEP) marine power systems offer increased design flexibility and operational economy by supplying ship propulsion and service loads from a common electrical system. Predicting the behaviour of IFEP systems through simulation is important in reducing the design risk. However, the prevalence of power electronics and the potential for interaction between large electrical and mechanical systems introduce significant simulation challenges. This paper presents an integrated simulation tool, which brings together electrical, mechanical, thermal and hydrodynamic models, facilitating a holistic simulation capability. Approaches adopted for model validation and computational efficiency together with two case studies are discussed

Power system protection of all electric marine systems

Several recent and anticipated future developments in marine electrical system engineering will impact upon power system protection. Large-scale IFEP (integrated full electric propulsion) systems are being increasingly introduced. A consequence of this is that the role, reliability, availability and survivability of the power system have and will become more critical than before. This therefore impacts on the performance required of both main and backup protection systems. The relatively low inertia within the power system, the introduction of hybrid AC/ DC power systems and the proliferation of power-converter interfaces all influence the behaviour of the power system and the design of the protection system must cater for all of these developments. This paper will consider many of these issues and, through the use of examples and simulation exercises, discuss and propose a number of protection-oriented solutions addressing said issues

Emerging research issues regarding integrated full-electric propulsion

Integrated Full Electric Propulsion (IFEP) currently provides advantages for both the commercial and naval shipping industries. However, in order to realise the full potential of this concept research into all aspects of IFEP system design and operation is necessary, particularly for naval applications where the operational requirements are more stringent and the need to mitigate the risk associated with the new technology is greater. This paper reviews current IFEP research programmes worldwide and identifies the core research issues under consideration. IFEP programmes such as the Norwegian commercial vessel-orientated EEAES programme and the UK-based ESTD, which is targeted at military applications, are discussed in more detail. This paper maintains that this existing IFEP research is creating further opportunities for research into the system-level dynamic behaviour and argues that such research is necessary to de-risk IFEP design. A simulation case study demonstrating the adverse effects on a marine electrical power system as a result of dynamic loading on the ship's propulsion system is also is included in the paper to support this argument

Power system protection for more and full electric marine systems

Several recent and anticipated future developments in marine electrical system engineering will impact upon power system protection. Large-scale IFEP (integrated full electric propulsion) systems are being increasingly introduced. A consequence of this is that the role, reliability, availability and survivability of the power system have and will become more critical than before. This therefore impacts on the performance required of both main and backup protection systems. The relatively low inertia within the power system, the introduction of hybrid AC/ DC power systems and the proliferation of power-converter interfaces all influence the behaviour of the power system and the design of the protection system must cater for all of these developments. This paper will consider many of these issues and, through the use of examples and simulation exercises, discuss and propose a number of protection-oriented solutions addressing said issues

Evaluation of reverse power flow in electric propulsion drives

An evaluation of reverse power flow in electric propulsion drives

A solution for an improved modelling efficiency of a multi-disciplinary marine power system

Integrated Full Electric Propulsion (IFEP) systems offer increased design flexibility and operational economy by supplying propulsion and service loads from a common electrical system. Predicting the behaviour of IFEP systems through simulation is important in reducing the design risk in a proposed vessel. However the prevalence of power electronics and the potential for interaction between large electrical and mechanical machines introduce significant simulation challenges. This paper presents an integrated IFEP simulation tool, which brings together models from the electrical, mechanical, thermal and hydrodynamic domains, facilitating end-to-end simulation of the behaviour of the propulsion system. This capability enhances the characterisation of modelling interfaces compared to existing tools. The paper discusses the approaches adopted in increasing computational efficiency without unduly compromising the accuracy of simulation results. The model validation process is described, and finally, the paper presents two case studies as an illustration of the phenomena which the model has been used to investigate