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DC Microgrid Control Based On Battery Energy Storage Optimization And State Of Charge Balance

Posted on:2020-11-11Degree:MasterType:Thesis
Country:ChinaCandidate:Y X WangFull Text:PDF
GTID:2392330596486193Subject:Electrical engineering
Abstract/Summary:PDF Full Text Request
With the increasing demand for energy,distributed power generation technology based on renewable energy has been developed rapidly.Because of its simple control structure and high energy efficiency,DC microgrid has become one of the platforms for new energy distributed generation.New energy generation is dominated by intermittent and volatile wind power generation,and the control of its stability has become the focus of research on DC microgrid control.As an important energy storage unit in DC microgrid,battery can connect to DC microgrid as relax terminal.Its control strategy and service life have great influence on the stability of DC microgrid.Wind and solar power generation are studied.The principle and control method of wind and solar power generation are studied based on photovoltaic and permanent magnet direct drive fan.In order to maximize the use of wind and solar energy,according to the DC interface of photovoltaic and permanent magnet direct drive fan,the control method of maximum power tracking is analyzed.According to the principle and development of energy storage,the principle of energy storage and the working mode to realize the bi-directional flow interface of energy are analyzed by taking the lithium battery which has a wide range of application as an example.In order to improve the power interface of DC microgrid to restrain the shock fluctuation and improve the stability of DC bus,the external characteristics of DC rotating motor are introduced into the interface control of energy storage,and a control method to simulate the characteristics of DC motor is studied.The influence of inertia parameters and damping parameters in the control is analyzed by exploring the control method and modeling the small signal.According to the control method,the wind and wind storage DC microgrid is built on the simulation platform,and the micropower fluctuation and load switching are simulated and analyzed.The stability of DC bus under the traditional double closed loop PI control is compared with that of the traditional double closed loop DC control.It is proved that the proposed control method can optimize the energy storage performance of the battery,enhance the anti-interference ability of the system,and improve the flexibility of the bus bar.In view of the strong dispersion of energy storage equipment in DC microgrid and the inconsistent control parameters,it is easy to cause the unbalanced charge state of battery in operation.The droop control is added to the inner loop of the current and the current correction amount is set.In order to achieve the consistency between the charging state and the output power,the parallel battery can feedback its own state of charge and adjust its power in real time.The characteristic control of analog motor is added to the control of parallel battery according to the drawback of drooping control which can easily cause bus voltage sag.The DC microgrid model including parallel battery is established,and the charge-discharge equalization and DC bus stability of parallel battery are simulated.The results show that the control strategy can balance the load state of parallel battery well.And can improve the bus anti-drop ability.
Keywords/Search Tags:new energy generation, DC microgrid, battery, energy storage optimization, state of charge balance
PDF Full Text Request
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