| In order to solve the problem of energy crisis and environmental pollution,the world’s major shipping countries continuously explore the application of new energy technology in the ship platform,among them,photovoltaic（PV）power generation is regarded as one of the most potential green ship technologies due to its unique energy advantages and environmental advantages.In various application modes,grid-connected system is the development trend of PV power generation technology in the marine industry because of its high efficiency of electric energy utilization.With the gradual increase of PV permeability,starting from the requirements for the stability and reliability of the ship power system,introducing energy storage device to smooth the power fluctuation of PV grid-connected system and enhancing the low voltage ride-through ability of PV grid-connected system are the technical approaches to its application in ship platform.Based on the project "2200PCTC grid-connected PV power generation system development".This article uses super-capacitor as energy storage,through theoretical analysis,system modeling,strategy formulation and simulation experiment,to complete the marine PV grid-connected system based on super-capacitor energy storage equipment development and joint debugging verification.The main work of this article is as follows:1.Analyze the difference between the ship power system and the land power system and the impact of the PV power generation system on the dynamic and static characteristics of the power grid after it is integrated into the ship power system.Comparing the characteristics of the two energy storage media of super-capacitor and lithium battery,on this basis,super-capacitor is used as the energy storage power regulating device for PV grid-connected systems,and completed the structural design of 2200 PCTC PV grid-connected power systems;2.For PV grid-connected power system,the model of PV array is established and the maximum power point is tracked by the method of variable step disturbance observation,the super-capacitor and bidirectional DC/DC converter constitute the power regulating device and conduct voltage balanced control for the super-capacitor,the power output of inverter is controlled by PQ control strategy,the super-capacitor power adjustment device adopts the dual-loop control method of the outer power loop and the inner current loop,and proposes a control strategy to enhance the low voltage ride-through capability of PV grid-connected systems by using super-capacitor;3.The model of prime mover and governor,the model of synchronous generator and excitation system are established,the simulation model parameters of marine PV grid-connected system based on super-capacitor are designed,the irradiance change and the grid-voltage drop were set respectively to carry out power stabilization and low voltage ride-through simulation experiments,comparing the power of each equipment and the power quality of the ship power system.The results show: the access of super-capacitor can effectively suppress PV grid-connected power fluctuations and improve low-voltage ride-through capabilities,all power quality indicators are in line with the requirements of the China Classification Society’s marine PV grid-connected guidelines;4.On the basis of theoretical analysis and simulation results,the marine PV grid-connected system based on super-capacitor is developed,including super-capacitor power adjustment device,grid-connected inverter and energy management system.According to the designed system structure,a joint debugging test platform was set up to carry out the test,the results show that: the super-capacitor can effectively compensate for the sudden change in power when the PV power is abrupt,so that the grid-connected power is smoothly output,at the same time,the effectiveness of coordinated control strategy of inverter based on super-capacitor SOC was verified,laying a foundation for the actual installation and use of PV grid-connected systems. |
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