| Conventional mechanical drive propulsion and existing onboard AC electrical distribution system results in greater intensity of greenhouse gases（GHG）emission,high specific fuel oil consumption（SFOC）,and poor overall efficiency of the ship power system.In that respect,onboard DC distribution is a state of art technology,which surpasses the abovementioned drawbacks.In addition,due to high power and reliability requirements of the onboard power system,normal three-phase machine structure as generator and propeller motor may be vulnerable in terms of ampacity per phase.To address this issue is to go for the multiphase machine structure.Hence,the main objective of this thesis work is to design and simulate MVDC distribution system based on six-phase propulsion system for a typical all-electric cruise ship in Matlab/Simulink environment.At first,onboard diesel engine generators,battery energy storage system（BESS）,and PV array are sized based on the proposed notional load profile that demonstrates possible operating scenarios during the entire voyage.Secondly,the dynamic model of variable speed diesel engine,proposed onboard six-phase permanent magnet synchronous machine（PMSM）based propulsion system,and their associated control structure is developed.In addition,the PV array and BESS unit with their associated power electronic converters and control structure are designed.Furthermore,for ship-to-shore connection onshore grid and its control structure is developed.All these developed models are first simulated in standalone mode to check their performance under different operating scenarios such that each standalone model could be integrated together to form an onboard MVDC distribution system.Finally,each components are integrated together to form an onboard MVDC distribution system operating under the proposed two-layered hierarchical control structure.For effective power-sharing and co-ordination between the onboard generators,rule-based deterministic power management system（PMS）is proposed and implemented.The simulation results of the overall system under different operating scenario shows the developed model and control structure works effectively such that the system is stable on all operating scenarios. |
