Research On Design And Control Strategy Of Microgrid In The Sea Area

With the increasing shortage of global energy,people are now more aware of the importance of developing and utilizing marine energy.Building a microgrid system that can use renewable energy to generate electricity at sea is an effective way to realize the utilization of marine resources and meet the demand for offshore electricity.Many scholars are committed to research on marine energy development,island microgrid construction,and renewable energy power generation systems that use ocean resources to generate electricity.As a distribution network that uses multiple distributed generations to supply power to islands and offshore areas,the sea microgrid should have the advantages of environmental protection,high efficiency,economy,flexibility and reliability.Due to the intermittent and volatility of distributed energy output,a reasonable control strategy is an important factor to ensure the reliable and flexible operation of the microgrid system.At the same time,distributed power generation units are often connected to the main network through a variety of power electronic conversion devices.Therefore,the power distribution and coordinated operation modes of multiple distributed power sources in the micro network are also very important.Therefore,it is of great practical value to study the control strategy that enables the microgrid to operate stably under different operating modes.This topic firstly combines specific project examples,and is first required to make a preliminary design plan for the construction of microgrid in a sea area.Then we need to analyze and evaluate the power supply requirements of the microgrid and the natural resources of the sea area.Then,by comparing the advantages and disadvantages of the micro-grid in the form of AC and DC,the power supply form of the micro-grid is determined.Combined with the actual geographical location,natural resource conditions and load demand of the region,select the topology of the microgrid transmission line,determine the voltage level and wiring method.Finally,with the minimum net present cost as the goal,the capacity allocation and cost estimation of the equipment in the microgrid are analyzed.By analyzing the expected operating state of the microgrid,many factors that need to be considered in the actual engineering design are pointed out.Secondly,for the distributed power supply inverter control strategy: constant powercontrol,V/f control and droop control,combined with the control block diagram to analyze the control principle,and give their respective decoupling control and disturbance compensation method.For the study of the overall control strategy,the two local control methods are studied: master-slave control and peer-to-peer control,and their advantages and disadvantages are analyzed.All control strategies are verified in the Matlab/Simulink simulation environment,and the actual effects of the control strategy are analyzed based on the simulation results by simulating different operating conditions during the actual microgrid operation.Then,combined with the high flexibility and high flexibility of the control strategy in the future sea microgrid,the increase of the brittle source caused by the integration of new energy sources and the reduction of the system inertia cause the system to be unstable and the anti-interference ability is poor.The virtual synchronous generator(VSG)control strategy is also analyzed,and the relationship between the VSG and the parameters of the designed energy storage unit is analyzed.Furthermore,the VSG control strategy based on flexible configuration parameter mode is analyzed by simulation,and the parameter optimization process is elaborated.The advantages of VSG parameter adaptive mode are reflected by comparison.Finally,the typical distributed units in the sea area microgrid are modeled and controlled.This paper mainly analyses the effect of applying VSG control strategy to the inverters connected to AC micro-grid by DC micro-grid,and through simulation,the two operating conditions of load side power consumption change and photovoltaic output change considering the change of illumination amplitude on generation side are analyzed respectively.Finally,the DC microgrid system with photovoltaic,energy storage and load is studied,and the feasibility and validity of VSG technology in marine microgrid are verified by simulation.