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Research On Energy Management Strategy Of DC Microgrid With PV Generation And Hybrid Energy Storage

Posted on:2018-02-07Degree:MasterType:Thesis
Country:ChinaCandidate:H M NiuFull Text:PDF
GTID:2322330536965871Subject:Electrical engineering
Abstract/Summary:PDF Full Text Request
With the energy crisis and the deterioration of the environment,as a representative of distributed generation,photovoltaic power generation has been widely concerned.Because of its simple structure and convenient control,DC microgrid has became a hotspot of current research.However,the distributed generation is unstable and has a serious impact on the reliability of power generation system.In order to make the system continuous and stable power supply,the PV system should be equipped with the corresponding energy storage device.Battery and supercapacitor can constitute the hybrid energy storage system,and it can complement each other,make full use of the advantages of the two.The corresponding energy management strategy and control strategy can effectively prolong the service life of the system.In this paper,the problems related to the control operation of DC microgrid which contain hybrid energy storage system are studied.Aiming at the disadvantages of the supercapacitor in the hybrid energy storage system,a hybrid energy storage management scheme is proposed;In order to make full use of the resources in the microgrid,a coordinated control strategy of photovoltaic DC microgrid with hybrid energy storage system is studied.Firstly,the overall structure of photovoltaic DC microgrid with hybrid energy storage system is introduced.The mathematical model of photovoltaic cell,battery and supercapacitor are established,and their output characteristics are analyzed and studied.According to the requirements of the Photovoltaic system,constant voltage control(CVC)and the maximum power point tracking control(MPPT)are established.Among them,MPPT control using conductance increment method.The structure and working principle of bidirectional DC/DC converter and bidirectional DC/AC converter are studied.Secondly,the energy management scheme of a battery/ultracapacitor hybrid energy storage system is studied.According to the working characteristics of the battery and supercapacitor,the charging and discharging process is optimized,The working current of the battery can be changed smoothly,and the supercapacitor can bear the power fluctuation,which can effectively prolong the service life of the energy storage system.According to the supercapacitor energy density is small,this paper studies a kind of limited value management based on supercapacitor SOC(Stage of Charge).According to the division of the SOC in different working areas,battery and supercapacitor each bear the power are reasonable adjustment.The strategy can effectively improve the shortcoming of supercapacitor overcharge or overdischarge cause the system not working,to maintain the normal operation of the system.The effectiveness of energy management strategy for hybrid energy storage system is verified by using Matlab/Simulink.Then,based on SOC and system power balance,the coordination control strategy of DC microgrid with photovoltaic and hybrid energy storage is studied.According to the different working conditions of the DC microgrid,the working mode of the system is divided reasonably,and the working state of each converter is determined.The simulation is carried out in Matlab/Simulink,and the simulation results are given to verify the effectiveness of the proposed method.Finally,the hardware and software of photovoltaic DC microgrid system with hybrid energy storage was designed.Taking DSP2812 as the control core,a hybrid energy storage system experimental platform is built in the laboratory.The experiment of hybrid energy storage power allocation is completed.The correctness of energy management strategy for hybrid energy storage system is preliminary validated.
Keywords/Search Tags:photovoltaic power generation, hybrid energy storage, DC microgrid, energy management, coordinated control
PDF Full Text Request
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