Research And Design Of Ship Borne Alternative Maritime Power Automatic Control System

Under the theme of "peace and development",the global economy is flourishing and shipping industry is developing steadily.The number of ships in the world has increased dramatically,and the resulting emissions from ships have caused serious pollution to the atmosphere,particularly near the port area.The scheme of the Alternative Maritime Power technology to solve the problem of ship’s emission during berthing has been recognized unanimously around world.However,there are some problems in the current Alternative Maritime Power Supply system,such as low degree of automation,poor compatibility with shore power management system,large impact of live switching on shore power supply,long time and large fluctuation of shore load transfer.As the ship side part of Alternative Maritime Power Supply,Alternative Maritime Power Shipborne System will become an indispensable part of marine power management system.Based on the analysis of marine power management system’s functions,the control ranges of AMPS and PMS are divided,in order to ensure compatibility.Therefore,the overall control scheme of AMP linked by Alternative Maritime Power Shipborne System,which is based on ship-shore information interaction,is proposed.The degree of automation and ship-shore compatibility are improved.The communication technology,protocol,content and format of both parties are introduced in detail.The platform of ship-to-shore power connection system is built,and the process of power switching between ship and shore power is designed according to the actual situation of berthing and leaving the port.The continuity and stability of power supply in the process of power switching are the characteristics of modern AMPS.Based on the detailed analysis of the influence of voltage amplitude,phase,and frequency in the process of power uninterrupted switching,from the point of view of signals acquisition and processing,the instantaneous impulse circulate current is limited to the system’s tolerable range.So that both of marine and shore power system can connected uninterrupted.Three synchronization methods are proposed and applied to the platform of ship-to-shore power connection system for the mode of the uninterrupted switching.As for load transfer between ship and shore power grids which have different power-frequency characteristics,on the premise that the operator of load transfer is the side of the ship,the principle of ship generator speed adjustment is expounded.Combined with shore power system,the overall scheme of load transfer is put forward.In order to improve the rate of load transfer,the stability of the transfer process and the accuracy of load control,the control strategy,which adjust the pulse width of speed adjustment according to the operating conditions by using PID algorithm,is proposed.The Alternative Maritime Power Shipborne System in this paper has verified on Ship Automation Physics Simulation Platform in the ship’s power station laboratory.Using an oscilloscope to collect the changes of impact circulation,voltage and current at the load in the process of power uninterrupted switching,the influence of these changes on the system is analyzed.The contribution of variable pulse width to speed,stability and accuracy of load transfer is verified.The experimental results show that the system can meet the expected design requirements.