Optimum Design Of Energy Storage Capacity Allocation And Energy Management Strategy For Electric Propulsion Ship

The energy consumption and pollution emissions of the ship transportation industry have received global attention.Green ships and smart ships are the development trend of the ship industry.Electric propulsion ships are highly automated,flexible and clean,and are widely used.Therefore,the research on electric propulsion ships is of great significance to the theoretical development and practical application of ships.Natural gas is a clean and environmentally friendly high-quality energy source.At present,there are diesel-natural gas dual-fuel generator sets used in electric propulsion ships.However,the dual fuel generator set has a long load loading period in gas mode,and the power follows poorly when the load changes greatly,which will reduce the stability and efficiency of the ship's generator set operation.In response to the above problems,this paper uses a lithium battery energy storage device to suppress the power fluctuation of the generator set caused by the load change,and uses an electric propulsion ship using diesel-natural gas dual fuel generator set as a prototype ship,the type selection of the energy storage unit and the type of power converter for connecting the energy storage device to the ship's power system,Focused on multi-objective optimization of energy storage device capacity configuration and energy management strategy optimization design and simulation.The simulation results show that the scheme can well suppress load fluctuations and stabilize the power of the generator set,thereby improving the operation stability and efficiency of the ship generator set,and providing a theoretical basis and method for the application of the energy storage system on the electric propulsion ship.The main work content is as follows:(1)Analyze the operating characteristics of the prototype ship's power system,select lithium iron phosphate battery as the energy storage unit of the energy storage system,and analyze its charge and discharge characteristics through the equivalent model;select according to the characteristics of the prototype ship's power system and energy storage system The type of power converter that connects the energy storage system to the ship's power system.(2)The objective function and constraints of multi-objective optimization of energy storage device capacity allocation are established.Based on the collected prototype ship load data,a multi-objective differential evolution algorithm based on decomposition and technique for order preference by similarity to an ideal solution method were used to optimize the solution in MATLAB software.Then,the results of energy storage capacity allocation optimization are obtained..(3)Aiming at the problem of energy distribution after the prototype ship is equipped with an energy storage system,an energy management strategy combining prototype ship threshold rules and instantaneous optimization of energy distribution is proposed;simulation experiments are conducted,and the results of simulation experiments prove that the energy management strategy can ensure energy storage Under the premise that the system works within the constraints,it improves the operation stability and efficiency of the ship's generator set.