Study On Energy Management And Control Strategy Of Hybrid Ship

With the shortage of energy and the increasing pollution problem of the ship industry,replacing traditional fossil energy with clean energy as the main power source of ships has gradually become a research hotspot in the ship industry.Among many clean energy sources,fuel cell hybrid power systems have become one of the most suitable alternative power sources due to their high energy efficiency and environmental friendliness.However,the shortcomings of low power density and slow response speed of fuel cells limit the fuel cell Popularization and application,at the same time,frequent fluctuations in load power will also impact and affect the ship’s power grid and fuel cell systems,thereby reducing the service life of fuel cells and reducing the stability of power systems.Therefore,this paper proposes that a composite energy storage system composed of a lithium battery and a super capacitor has the characteristics of high energy density and high power,which can make up for the shortcomings of the operating characteristics of the fuel cell,and can also serve as an energy storage unit to stabilize the fuel.The output power of the battery fluctuates,stabilizes the DC bus voltage,and improves the stability of the ship’s power system.The specific research content is as follows:First,the German "Alsterwasser" fuel cell hybrid ferry was used as the research target,and a hybrid energy storage system was used instead of the original ship’s battery and fuel cell system to form a modified hybrid power system.By analyzing and comparing the topologies of several common types of composite energy storage systems,the topology of the composite energy storage system is determined.According to the composition of the hybrid power system,the characteristics of lithium iron phosphate batteries,supercapacitors,bidirectional DC / DC converters and fuel cells were analyzed,and corresponding mathematical models were built in MATLAB /Simulink.Simulation results verified the accuracy of the models Sex.Then,based on the relationship between bus voltage and load power in the DC grid of hybrid ships,a DC grid voltage stabilization control method based on DC Bus Voltage Signal(DBS)was proposed,and an improved droop control based on improved And filter algorithm’s power allocation method,the power distribution of lithium batteries and supercapacitors.Based on this,a protection method based on the state of charge(SOC)and the maximum charge / discharge current of the energy storage unit is proposed to protect the energy storage unit while achieving coordinated control between the energy storage units.The principle of the predictive model is to design a fuel cell control strategy.The output power of the fuel cell is changed for different sailing conditions.A simulation model is built in MATLAB/Simulink to verify the effectiveness of the proposed energy management control strategy.Finally,based on the existing conditions in the laboratory,a small-scale simulation experimental platform for hybrid power systems with d SPACE as the core is established.The effectiveness of the energy management control strategy designed in this paper is verified by designing relevant simulation experiments.The experimental results prove that This control strategy is used to stabilize the bus voltage and fuel power fluctuations,optimize the charge and discharge curve of lithium batteries,and protect the energy storage unit.