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Research On Coordination Control Strategy Of Distributed Microgrid

Posted on:2020-07-06Degree:MasterType:Thesis
Country:ChinaCandidate:J T LiFull Text:PDF
GTID:2392330575965581Subject:Control theory and control engineering
Abstract/Summary:PDF Full Text Request
Traditional electric power equipment consumes fossil energy excessively,which causes environmental pollution and affects the sustainable development of human beings.As an effective solution to the large-scale grid-connected problem of distributed generation,microgrid has brought the environmental protection and economic value of renewable energy into full play.The coordinated control strategy of distributed microgrid is an effective way to realize the safe,economical,reliable and environmentally friendly operation of microgrid.Based on the analysis of the structure,control mode,distributed generation and its interface converter of distributed microgrid,the local coordinated control strategy and the upper coordinated control strategy of distributed microgrid are formulated.Firstly,the overall structure of AC/DC hybrid microgrid is analyzed in this article.According to the design principle of microgrid,the overall structure of microgrid is established.Based on the analysis of master-slave,peer-to-peer and hierarchical control modes,a two-layer control structure with weak communication links is obtained,which realizes the coordinated control of the distributed generators and converters in the microgrid.Secondly,the working principles and characteristics of photovoltaic cells,permanent magnet synchronous wind generator,storage battery,diesel generator and interface converters of each module are discussed.The simulation models of each module in the distributed microgrid are established.Then the local coordinated control strategy of distributed microgrid is studied in detail,including the switching of working mode of distributed generation and the control strategy of bi-direction AC/DC converter.The maximum power point tracking control,power limit control,battery charging and discharging control,standby protection control and load automatic switching control are designed.The mathematical model and operation mode of the bi-direction AC/DC converter are analyzed.By comparing the three control strategies of the inverters,the control strategies of the AC/DC converter in grid-connected and island mode are given.Finally,after analyzing the power flow direction of distributed micro-grid,the grid-connected operation of distributed micro-grid equivalent to the grid-connected operation of DC micro-grid,and the island operation of distributed micro-grid equivalent to a small power distribution system.In the two equivalent grids,the power information in the distributed microgrid and the charging state of the batteries are taken as the criteria to divide the system into different working modes.The working states of each module in the system are different under each working mode.By setting the working threshold of each module,the modules in the system can be smoothly switched between different working modes,thus realizing the parallel operation of the distributed microgrid coordination and control in network and island mode.A simulation model of distributed microgrid is established in MATLAB/Simulink,and the above coordinated control strategy is simulated and validated.
Keywords/Search Tags:distributed generation, distributed microgrid, coordinated control, bi-direction AC/DC converter, power information
PDF Full Text Request
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