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Research On The Control Strategy Of Microgrid With Energy Storagy

Posted on:2015-02-10Degree:MasterType:Thesis
Country:ChinaCandidate:F LiuFull Text:PDF
GTID:2272330422480429Subject:Power electronics and electric drive
Abstract/Summary:PDF Full Text Request
With the energy cirsis and environmental problem getting worse, the distributed powergeneration(DG) is undergoing a significant development all around the world. Although thedistributed power generation is flexible, friendly to the environment and has the advantage of highefficiency. But large-scale distributed power permeate may produce some negative effects on thestable operation of the grid. Microgrids can not only solve the problem of large-scale DG coupling,but also play full advantages of distributed power, improve reliability of power supply and bringbenefits to users. As a microgrid inverter is the basic power electronic interface unit in microgrid, thecontrol strategies of microgrid inverter play a very important role in microgrid, it is very necessery tostudy how to realize the feasible and effective control.In this thesis, the control strategy of energy-storagy inverter based on the master-slaveconfiguration of microgrid system is studied, andthe method of control loop switching of the energystorage inverter in microgrid is depicted. The mathematical modeling of energy-storagy inverter hasbeen studied, and the inner and outer control loop are designed. Due to the unbalanced load may causethe asymmetric output voltage in the island mode, the root causes of the unbalance and the severalunbanlanced control methods are introduced in this thesis, a method of proportional integral plusresonant (PI+R) is proposed to achieve unbalance control of the output voltage under the condition ofisland operation mode. When the microgird is working under the grid-connected mode, the gridimpedance, the controller parameters and the number of grid-connected inverters have a greatinfluence on the microgrid stability, so the eigenvalue analysis method is adopted to study the stabilityof the micro-grid system. The methods of inproving the stability of the microgrid is also discussed inthis thesis. Furthermore, the simulation model of microgrid is built by the Matlab/Simulink softwareto verify the feasibility of unbanlanced control and the correctness of the stability analysis ofmicrogrid. Finally, a digital control based100kVA experimental phototype of microgridenergy-storagy inverter is designed and built according to the system requirements, the hardware andsoftware design of the microgrid energy-storagy inverter are introduced. The experment results ofsteady operation under different modes and transient transfer are depicted to verify the feasibility ofthe microgrid microgrid energy-storagy inverter.
Keywords/Search Tags:Microgrid, Master-slave Control, Unbalanced Control, Stability Analysis
PDF Full Text Request
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