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Research On Control Strategy Of Independent DC Microgrid With Electric Vehicles Energy Storage

Posted on:2020-03-02Degree:MasterType:Thesis
Country:ChinaCandidate:L Y ZhuFull Text:PDF
GTID:2392330596477954Subject:Electrical engineering
Abstract/Summary:PDF Full Text Request
Microgrid technology provides an effective way for renewable energy applications.Compared with the AC microgrid,due to the DC microgrid does not need to consider reactive power and frequency problems,it can integrate wind,light and other distributed power sources more effectively and reliably,and connect energy storage units,electric vehicles and various loads.The key to the stable operation of the independent DC microgrid is to coordinate the distributed power and energy storage units of the control system to achieve system power balance.In addition,large-scale EV access is not only a load but also a considerable energy storage resource for micro-grid.The dissertation focuses on the problem of stable operation of an independent DC microgrid system based on distributed storage of electric vehicles.1)The structure of an independent DC microgrid system with electric vehicle energy storage and the sub-system mathematical model of the microgrid are established.Based on the distributed energy storage characteristics of EVs,an independent DC micro-grid system structure including charging and discharging cluster,wind-solar complementary generator set,hybrid energy storage unit and load of EV is established.According to the characteristics of each subsystem,the corresponding mathematical model and simulation model are established.2)Research on control strategy of distributed generation and hybrid energy storage unit.According to the different output characteristics of each micro-source in the system,a reasonable control strategy is studied to achieve the maximum output.The wind turbine is controlled by variable step climbing search method;the photovoltaic power generation control strategy adopts improved disturbance observation method;In view of the randomness and volatility of wind and light output,the system uses hybrid energy storage to stabilize power fluctuations and adopts a control strategy based on power secondary distribution.3)Research on charging and discharging strategy of electric vehicle cluster.Aiming at the uncertainty and fluctuation of electric vehicle charging and discharging,an orderly charging and discharging strategy for electric vehicle cluster is proposed.Based on the power difference of the system,the strategy optimizes the dispatch of the electric vehicle cluster according to the operation status,load demand and peak-valley period of the current DC micro-grid to make it charge and discharge orderly.The simulation results show that the proposed charging and discharging strategy can realize reasonable charging and discharging of electric vehicle cluster,ensure the operation stability of independent DC micro-grid system,and realize peak-shaving and valley filling.4)Research on coordination control strategy of independent DC microgrid system with electric vehicles energy storage.In order to solve the problems of poor stability and large fluctuation in the independent DC microgrid system,an independent DC microgrid system with electric vehicles energy storage is adopted,and a hierarchical coordinated control strategy based on power difference is proposed to realize the stable operation of the independent DC microgrid system.The simulation results show that the proposed coordinated control strategy achieves good results in maintaining power balance and voltage stability,and further improves the new energy permeability.
Keywords/Search Tags:Independent DC microgrid, Electric vehicles, Distributed energy storage, Coordinated control, Power balance
PDF Full Text Request
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